How the cookies crumble

If you have got as far as reading this then you have just been made to dismiss a “rinky dinky” little pop up layer by clicking a button marked “That’s fine”.  This is because as from today, it is now law that all websites owned by businesses must choose between devices such as the aforementioned pop – up, or a £500,000 fine.

Since the subject has arisen I thought that it might be interesting to dredge up a little “cookie theory” from my computer programming days:  Cookies are tiny text files which are stored on a web user’s computer.  Contrary to popular terminology they are not stored “in your browser” because browsers are pieces of software and things only get stored on hardware… ie: in this case, your hard drive.  Cookies are extremely small and simple, comprising of a name and an attribute; if you have ever returned to a website and found that it remembers you by name then almost certainly this was done with a cookie which contained information akin to this:  cookieName=”username”; attribute=”Ettore Bugatti”.  If a website needs to do something more complex than this then it will need to find something more sophisticated than cookies in order to do it.

Cookies come in two flavours:  Persistent or Session.  Session cookies get deleted when you close your browser but Persistant ones remain in storage for your next browsing session.

One of the most important features of cookies which was deliberately engineered by the good folk who designed the whole thing is this:  Only the website which dispensed the cookie in the first place can read it later.  This means that my website can not possibly obtain any data from cookies stored by anyone else’s website.  But what about the so called “third party cookies” we keep hearing about?   In order to understand these we need to know a little about how web pages are made up:  A typical web page contains text from a file with an extension ending in .html (or .htm) but in that file may also be instructions to load other content.  In this blog for example I have added pictures which load amongst the text and which are stored in separate files.  On this site all the content of the blog apart from today’s post, is stored on the computer which hosts the site. But it doesn’t have to be this way – I could use the code of my site to link to pictures stored on other websites and the end user wouldn’t see anything different.

EU Flag

Take the EU banner on the Left for example.  This isn’t hosted by me at all – it is hosted by the official EU website and in order to display it, your computer retrieved it from there. You can test this for yourself by right clicking on it (control clicking if you use a Mac) and choosing to “View Image” All of a sudden the address bar at the top of your browser will no longer contain the address of my website but instead it will display that of the EU website. (You can click your back button to return here afterwards). This means that if the banner had come from an appropriate page of the EU website (which it doesn’t incidentally) that website could have stored “third party” cookies on your computer while you were unknowingly visiting it.  The manner in which I have displayed the image is known as “hot linking”. It’s the first time I have ever implemented it because when used in this way it is considered by purists to be an antisocial pracise. This is because it uses someone else’s bandwidth without consent.  When it is done with consent it is more often than not used to collect or share information without the user’s knowledge. The owner of a website can configure their web server so that hotlinking is not possible but it would appear that the EU either wish to support hot linking or that they are not “tech savvy” enough to bother stopping it.  It is probably true to say that a law requiring sites to declare that they are hot linking content would do more to protect privacy: Cookies are like lead: A simple material which can be incredibly useful, adorns countless church roofs and when combined with a shotgun can also be used to rob banks. Hot linking can be the shotgun.

I do think that it is an excellent thing that users should be openly offered information about cookies but I am also quite confident that they are too simple to pose any serious threat.  Websites wishing to operate in more sinister fashions would need to eschew cookies in favour of “HTTP session objects” which are far more powerful, never talked about in newspapers, and completely unregulated by the European Union…

Happy motoring!

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Drive It Day

The MK2 Jaguar is all ready for “Drive It Day” tomorrow having recently been serviced – an occasion which brings us to a total mileage of nearly 10,000 since we acquired the car at the beginning of February 2011.  To be honest, every day is “drive it day” for the Jaguar which has proved to be an excellent car for modern road conditions, but we will still of course be making sure that it will be contributing to the number of classics out on the roads tomorrow. Regular readers may also notice that the Jag is still called “it” in the absence of any other name – although we did briefly consider “Tabitha” since the longer it is in our tenure the more it becomes “full of good works” (Acts 9:36)

Servicing cars brings me neatly to a subject which seems to have been cropping up often of late: Choice of oil.  I have been meaning to write about this for a while and my inspiration has come from (of all things) my lawnmower.  The mower in question is of American make and although it is now twenty years old it continues to perform faultlessly and never troubles me with the need for repairs.  That’s worth a lot as far as I’m concerned so I consider it worth looking after: The manufacturer specifies SAE 30 so I put in a sump full of one of the more expensive brands available

I’m often asked which brand of oil to buy for a vehicle and without fail I always suggest something which meets the following criteria:  It has the name of a lubricating oil manufacturer on the container, not the name of a shop or a motor factor.  It is one of the more expensive available products. It comes either from one of the “big names” in petro chemicals or from a highly specialised smaller firm catering specifically for a niche market.  There are exceptions to these criteria, but off the top of my head I can think of only one that I would be happy to put in anything that I work on.

People often decide that it will be fine to use something cheaper because the car “isn’t worth very much” or “it’s old and doesn’t need anything too sophisticated” but I’m inclined to disagree:  I use a “top brand” semi synthetic in my 14 year old Peugeot diesel – it’s the most sophisticated oil I could fill it with without risk of glazing the cylinder bores and since the car is worth hanging on to, then I’m going to keep it in serviceable condition for as long as I can. A sump full of semi – synth is an awful lot cheaper than buying another car.  Besides, I’ve had some very disappointing experiences with supposedly reputable but cheaper products:  I once ran in a 40 year old Austin engine using half a sump of good quality classic 20/50 and half of the same grade branded by a well known motoring shop.  After  500 miles I changed the oil and put in a sump full of the high quality oil. The result: 6 psi higher oil pressure at 1500 rpm.  Other more dramatic indications I have seen of incorrect or poor lubricant over the years include damaged big end bearings, excessive oil consumption and, in modern engines, hydraulic valve lifters which “pump up” and cause the compression to fail.

I’d rate the oils which cause these sort of problems as very expensive choices indeed and on that basis we’ll be driving out tomorrow knowing that the “big name” branded oil in the Jag is probably the cheapest thing we could have filled it with.

 

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Engine Conversion

More work today on the Land Rover Series 1 engine conversion which was still in the ‘planning stage’ last time I wrote about it.  This particular Land Rover has already benefitted with a rebuild by its last owner who did a very nice job of fitting a new galvanised chassis. Last year we fitted an uprated gearbox and disc front brakes in readiness for this year’s project which is the fitment of a 200 tdi engine taken from an early Discovery.

The 200 tdi conversion is a popular one – so much so that it has been suggested that there are now more ‘Series’ Land Rovers running with them than there are Discoveries. It is also in essence a very easy conversion because the later engine was based on the original Diesel cylinder block, meaning that it bolts up to the gearbox with little modification and that the engine mountings line up with the chassis if the original mounting rubbers are to be used.

The aim is to produce a vehicle with a “factory look” under the bonnet and which will be suitable for daily use, so some of the smaller details of the conversion have made for very interesting work.

Discovery Water PumpThe engine was removed from the Discovery and after a thorough clean and re-paint it was treated to a timing belt kit and a new water pump. The new installation won’t be using the viscous fan from the Discovery and rather than just cut the thread off the front of the new pump we decided to machine it flush for cosmetic reasons. Similarly there will be no need for a power steering pump or air conditioning compressor so the belt tensioner spigot was machined off the front cover plate and an aluminium plug tig welded into the casting before machining flush and burnishing to a matching finish.

The flywheel housing needed to come off the new engine for some minor machining work and the opportunity was taken to replace the crankshaft rear seal at the same time.  With the new engine ready and subsequently fitted into the engine bay, the next job was to attend to the mountings.  Although the original mountings will bolt straight on using the brackets from the ‘Series’ vehicle it was decided to use the more sophisticated Discovery items in order to gain extra smoothness.  Usual practise when doing this conversion seems to be the welding of new brackets to the chassis in order to adapt the later mounts.  It seems a shame to destroy some of the galvanising on a nice new chassis so a bolt – on conversion has been designed instead.

Land Rover MountingThe trickiest part of the job was the left hand mounting so this was tackled first. It uses a new bracket which attaches to the chassis using the three holes provided for the left hand drive steering box.  These holes have tubes already welded into them so that the stress will be shared by both sides of the chassis box section.  Unfortunately these holes were only designed for 5/16″ bolts and in order to equate to the cross section of the 1/2″ bolts deemed neccesary for the cylinder block side of the mounting, more bolts are needed.  Using five M8 bolts equates exactly to the correct cross sectional area, so two extra holes have been drilled lower down the chassis leg. The whole bracket is then tied in with distance tubes to another non standard bracket which replaces the redundant left hand drive steering bracket and ties into the passenger footwell at the correct point. This latter bracket is shaped to allow clearance for the outlet elbow from the turbocharger compressor to the intercooler – the turbo and manifold assembly having been changed for a reconditioned Defender item which gives better exhaust routing.  The Right hand bracket has now also been completed and the next job is to manufacture a sandwich plate for the new mounting which will provide attachment points for brake pipe clips and for the battery tray.  The battery is to remain in its original location under the bonnet but the tray will now need to be detachable in order to allow engine removal in future.

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Leaving The Premises

A Brace of TR6

At the risk of using up my annual quota for cheesy lines in one go, it has been suggested that Triumph is historically the oldest marque, the earliest reference on record being the book of Exodus (Moses came down from Mount Sinai in his Triumph).

The TR6 was completed early this year and is pictured here about to leave in company of my brother’s 150BHP model on the right.  It’s quite noticeable how different these two cars look with only three years between them: The red fuel injected car lives up to James May’s tag of “the blokiest blokes car ever built” whilst the early carburettor car looks quite delicate in comparison, not least because of  its wire wheels and higher mounted front bumper.

The blue TR had originally come in for engine overhaul as recounted earlier in the blog and the project soon grew to include an overdrive conversion, attention to the rear suspension and a brake cylinder overhaul.  An overdrive really does make the world of difference to these cars and it is well worth uprating the non – overdrive models.  The owner decided that a Laycock J Type unit as fitted to the later cars was to be a sensible and cost effective choice compared to the A Type which would have been original fitment for such an early car.

Triumph Gearbox MountingThere have been conversion kits listed for some while for the fitment of J Type units to chassis which were designed for the A Type but they now seem to be unavailable. Pictured on the right is a new one – off mounting which does the job using a pair of Jaguar mountings which are not only very suitable for the job but are also very readily and economically available.

The carburettor version of the TR6 has a somewhat unfair reputation for poor performance. They certainly have rather a different feel to them compared with their fuel injected brethren but nevertheless make for a very pleasant drive and – particularly with an overdrive – are more than capable of keeping up with modern traffic.

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A Return To The Blog

Shockingly it seems that my last blog dates from October last year: There have been major works in progress at home and since my evenings have largely been taken up with building work, I have to confess that enthusiasm for blogging has waned.  Things are still no less busy but I have at last found the resolve to return to the keyboard – hearty thanks to all of you who have spoken to me about it over the last five months and more thanks too if you are still reading this!

Many projects have passed through the door since the last post, but the one which is interesting me most at present is the cylinder head from a 3.5 litre “Derby” Bentley on which I have finished working today.  The head is a second hand one of unknown origin and although not without faults it was very “saveable”.  Four of the exhaust valve seats had cracked and pressure testing revealed a further crack in the top of the head next to a valve seat guide as well as an area of porous casting.  The exhaust seats were x-ray tested and the cracks were found to be relatively shallow, thereby enabling them to be removed by machining so that hardened seat inserts could be fitted.  The crack in the top of the cylinder head was repaired by cold stitching and the porosity sealed by ceramic treatment.

The final operation neccesary to render the head serviceable has been the cutting of the valve seats which is for me one of the most interesting discussion points.  There seems to be a new phrase in the vocabulary of the car enthusiast these days: “Three angle valve seats”, and I suspect that the popularity of this phrase is largely due to the internet.

Pictured on the left is a nice clear drawing (for which, sadly I can take no credit) of the 3 angles on a valve seat.  The actual seating area on which the valve seals is the area cut at 45 degrees and the remaining two angles are sometimes known as the “topping and tailing” cuts. It is the width of these angles which can be adjusted to regulate the width of the seating area.

 

The picture on the right shows a section of the valve sitting on the seat with the seating surface illustrated in the shaded area of the valve itself.  If the valve were to be tested in the seat with marking blue this is the witness which would show up.

 

 

Perhaps the reason that this all interests me so much is that when I first started to learn the trade, I hadn’t heard of the modern term and I thought that this was just the minimum requirement for “a valve seat”.  The truth is that this design of valve seat goes back earlier than the 1920’s, although it probably wasn’t until at least the 1950’s before people began to realise all the reasons why it works so well.  In the Edwardian era it was understood that the best valve-to-seat seal could be acheived by a very narrow seating area but that this would not provide adequate heat transfer to prevent the valve head from running too hot.  Similarly it was also understood that the best heat transfer could be gained by a really wide seating area but that this would not give such a good (or durable) seal.  Clearly a compromise was in order: Manufacture the valve seats at a width sufficiently wide to transfer heat and sufficiently narrow to provide an adequate seal. Ever since those days the better engine specialists have been cutting what are now known as “three angle valve seats” in order to acheive the correct seating width.  (Note that the valve seat is the whole item with its three angles and that “seating” is used to describe the area shaded in black on the second picture).

In the early 1920’s it became fashionable for race engine builders to use “knife edge” valve seats. This involved “topping and tailing” the seat to three angles in order to produce a very narrow seat which appeared to produce good power but which had short life.  At the time the fact that this produced observably more power was almost certainly put down to the superior valve seal. However it has since been realised that having three angles actually improves gas flow around the seat area because the change of direction from the valve throat area is more gradual.

There is another benefit to this design of valve seat, particularly in respect to exhaust valves which run much hotter than the inlets:  The weakest part of the seat area on the valve itself is right at the lower edge (at the top of the upside down valve in the picture) because here the valve is at its thinnest.  The 30 degree cut on the combustion chamber side of the valve seat relieves this area of the valve from any contact with the seat as the valve spring snaps the incandescent valve shut (25 times per second at only 3000 rpm).

Three angled valve seats therefore have the benefits of better sealing, better heat transfer, better durablility and better gas flow.

I’m just glad that there’s a nice new name for them now!

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Work In Progress

Not only is work progressing well on the TR6 project, but it looks as though work is progressing well now that everything is looking freshly painted and shiny.  I have been in charge of the spray painting in two pack black and Cherine has been ably picking around all the machined surfaces and the plated bits on the engine with a brush.  As usual everything is primed with Red Lead Oxide which gives for a nice long life, all the cast bits are finished in satin and all the pressed steel bits in gloss. Fitting and final assembly is to follow shortly.

Work is also well underway with the 3.8 MK2 Jaguar.  The owner and I had been aware for some while that the engine was a little tired, but an extremely loud knocking had brought the car’s story to an abrupt conclusion.  This is not an entirely unknown phenomenon on the 3.8 Jaguar:  The engine had been originally developed by increasing the cylinder bore size of the 3.4 litre unit and by fitting liners to the cylinder block. Jaguar had initially given suitable clearance for the larger pistons by machining a chamfer on the edge of the combustion chambers in the cylinder head.  It wasn’t long however before someone decided that producing two different heads for the three available capacities of engine made no sense. Therefore the chamfer was deleted from the cylinder head and machined instead on the 3.8 litre pistons.  What this means of course is that it is absolutely essential to make sure that the cylinder head and the pistons in a particular engine are compatible.  In the words of Michael Caine, “not a lot of people know that”.  This car is a 1961 model and has a c1965 cylinder head. All was fine until the big end bearings developed a little extra clearance and allowed the pistons to start contacting the head in a somewhat noisy fashion.

Also on the subject of cylinder heads, I have been attending to one such item from a 1935 Derby Bentley which is suffering from cracks on three of the exhaust valve seats.  Despite this the head is still very “saveable” and well worth doing since few good original items seem to have survived. The sensible solution will be preheated gas fusion welding which will make a nice permanent job and will also allow plenty of scope for any future repairs which might crop up.

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Keeping Busy

Things have been characteristically busy in the workshop since my last post (which is also, as usual, the reason why it has been so long since the last post!).  Work is progressing well on the Jaguar 3.8 and the Triumph TR6 as well as to various “day visitors”: Yesterday saw the return of a 1936 Riley Kestrel 12 which left the workshop some years ago after a long restoration.  I had re-coloured some new wheels for the car in two pack paint after the wheel supplier had been unable to match the correct colour in powder coat, and the first job was to fit the tyres without damaging the new paint.  I’m a great believer in the use of rubber mallets instead of levers or tyre machines when it comes to pre-war rims and the tyres went on nicely with no marking to the wheel finish.  The rear tyres on this car only seem to last for about seven thousand miles, so a good fitting technique is proving to be essential!  The starter motor had been giving intermittent trouble on the car so I had checked over a spare unit which seemed to be working fine, and when fitted it turned the engine over nicely and briskly… sadly for only a couple of times before it expired.  Having removed the exhaust and the engine breather one more time we stripped the original starter and attended to its maladies before re-fitting.

Strangely enough, this experience has been preceded by a similar occurence with the Porsche 944 to which I had fitted a wiper motor obtained through ebay and which had worked a few times before failing.  The owner and I decided to bite the bullet and dismantle the motor which has proved a lot more reliable having polished the commutator and re-seated the brushes.  944 wiper motors, although easily visible with the bonnet raised, are not removed very quickly; furthermore new items from the manufacturer are formidably expensive, so we are both hoping that the repair proves to be long lasting!

Future projects which have been under discussion since the last blog include the imminent conversion of a late Series 1 Land Rover to a 200TDi engine, the possible conversion of an early Series 1 to a Nissan LD28 engine and the conversion of an Alvis TD21 to a Ford Type 9 gearbox.  The 200 TDi engine will be the next major project and to which end there is a very tired looking old Discovery sat in the yard awaiting dismantling.

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Vintage Decades

Does anyone remember that there was once fairly widespread call to class the 1980s as the “Second Vintage Decade”? As far as I am aware that never happened, and rightly so:  The 80s were an interesting time for production car development and they gave us such classics as the Golf GTi, the Peugeot 205 and the new Ferarri Testarossa – which was in essence a re-styled 1970s Berlinetta Boxer….

The word ‘Vintage’ is a winemaker’s term which literally refers to wine ‘of a good year’, and as far as I can ascertain the first official use of the term in referring to anything other than wine was with the formation of the Vintage Sports Car Club in 1934.  The young men who formed the club were of the opinion that the modern cars of the time were fairly ghastly, being the product of the depression years, and that cars built prior to 1930 were generally better built, more exciting and therefore of a good year… Vintage.

The last few days in the workshop have involved work on a few ‘modern’ cars built in the 1990s and 2000s, and for me the 90s is the time period which most nearly fits the bill for the ‘Second Vintage Decade’: Although arguably cars have become rather less interesting over the years it’s probably fair to say that they have become steadily more evolved and more ‘user friendly’, and cars built during the 90s are very user friendly indeed.  Cars have been extremely reliable for the last 90 years or so, but more recent cars are also long lived and low maintainance. Aside from a dreadful ‘blip’ in the 1970s, car manufacturers had been steadily working to make their products better for the consumer in terms of durability and maintainance costs, and the peak of this development was probably the late 1990s.

A good case in point is the ‘works hack’ – a 1998 Peugeot 106 diesel.  I purchased it 3 years ago with 78,000 miles on the clock and, at the cost of a driveshaft, a battery and an exhaust system, it has covered a further 60,000 miles with nothing more than regular service items.  The car is now due for MOT and I have had to fit rear hub bearings and brake hoses; this is cheap motoring – especially since it never fails to return at least 60mpg.  Also due for MOT this week is a customer’s 1997 Volvo S70 diesel which I have known since new.  The only new part this car has ever required other than service items is a replacement alternator.

The problem that I have with cars built since the 1990s is that the manufacturer’s priorities seem to have changed:  The cars have become a little more complex.  Now I’ve no problem at all with complexity – a few months ago I completed quite a lot of work on an early Maserati 3200 which involved setting the timing on 4 camshafts with dial test indicators, and stripping down the front of the engine bay in order to fit a new cambelt (to be repeated every 10,000 miles or three years).  Not a problem really because although it’s a lot of work and expense, Maserati built it that way since it was the best way that they could come up with which would offer the customer the driving experience which they had in mind.

The sort of complexity which I don’t enjoy is the type which has no benifit for the consumer whatsoever, like the E Class Mercedes with no transmission oil filler, and which has to have fresh oil pumped into the drain plug hole. Perhaps this sort of design does have some benefit for the original manufacturer but the trouble is that it needlessly pushes up the cost of maintainance and repair for the owner. The perfect case in point being the 2002 model Vauxhaull I saw this year, on which the screenwash wouldn’t work because of a faulty body control module. After fitting an expensive new module, it has to be coded with a manufacturer specific device in order for the engine ECU to recognise it. If someone can tell me what’s wrong with a switch to control the washers I would be very grateful…..

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Welding and Painting

Hornet Oil Filler

Variety has certainly been the spice of life in the workshop today with work on no less than four different vehicles. The morning has been largely taken up with painting various TR6 bits ready for re-assembly and, while the paint has been drying, work on a 3.8 litre MK2 Jaguar which is an ongoing project due to be finished this winter.  The TR sump, timing cover and various bits of bracketry have been chemically stripped and were originally intended to have been powder coated but I can’t say that I’m too disappointed that this last operation has never happened:  Powder coating looks absolutely lovely but it is quite brittle which can soon leave a car which is in regular use covered in ‘scars’.  Instead of the powder coat I have painted everything in a coat of Red Oxide followed by 2 pack primer and black colour coat.  2 pack paint is good stuff – strictly speaking it’s not actually a paint but an epoxy coating and consequently it is incredibly durable and very shiny which makes it very suitable for sundry items underneath the car as well as for the coach finish outside the car.  This particular job has turned out to be the swansong for my old De-Vilbiss JGA suction feed spray gun: It was the first that I owned and was pensioned off long ago to work only with primers.  I’ve lost count of the number of vehicles which it has repaired or re-finished before I replaced it with a more modern gravity fed De-Vilbiss GTi but since then it has given great service as a primer gun until today, when I have to admit that it’s in a dreadful state and needs to be replaced.  I have to confess that I have developed considerable brand – loyalty for these items: my GTi still looks as shiny as it did when it came out of the box several years ago and as nice as the products are from manufacturers such as Iwata, it will take a lot of convincing me to change.

The morning was finished off with some repairs to the oil filler cap from a 1930’s Wolseley Hornet.  Some previous owner must have been disturbed by all the crank case blow-by and had evidently decided that a more affordable option to an engine overhaul was to drill the beautiful engraved and polished brass filler cap in order to soft – solder a piece of domestic plumbing in place, so that the crank case could gain extra ventilation. After carefully removing all the soft – solder and planishing the cap to remove all the distortion, I used a punch and die to produce a brass disc of the correct diameter to fill the hole.  The disc was then silver – soldered into place and carefully filed flush before sanding and polishing. It has ‘sort of’ effected an invisible repair, in that you can’t see the soldered join but unfortunately the engraving suddenly disappears where the hole used to be.  The owner has taken it to the local jewellers in the hope that they can reproduce the missing lettering.

Final job of the day was to cut a large chunk of rusty metal from the front of a Landrover Series 1 chassis.  The area had previously been plated over and was a good illustration of why it’s a bad idea to cover rotten metal with a patch over the top:  A good part of the job was taken up with grinding away old bits of patch and lumps of weld before a new section of 14SWG steel could be cut and gas – welded in flush. The owner and I carefully treated the repair with Phosphate, painted it and undersealed over the top to match the existing chassis finish… you would never have guessed that both of us are fully aware that the entire chassis is going to be replaced soon anyway…

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Clutches and costly fluids

Re – reading yesterday’s blog suggests that everything has gone according to plan today!  The XK8 has indeed left the workshop, no longer in ‘limp mode’, full of new transmission fluid, and with a centre console which illuminates properly. The unsupercharged V8 Jaguars use a ZF gearbox and the ‘blown’ ones use a Mercedes Benz unit. Both gearboxes were supposed to be sealed for life but experience suggests that it is more than worthwhile to change the oil and filter on either box every 60,000 miles. The fluid for the Mercedes box is available at not too horrendous cost, either from Jaguar or Mercedes Benz dealerships, or at slightly cheaper cost from Shell.  The fluid for the ZF gear box is rather expensive wherever it comes from. The only suitable fluid is Mobil LT71141 (formerly Esso LT71141) which was developed specifically for messrs. ZF. It costs the best part of an arm and a leg but is worth every penny compared to the cost of a new gearbox….

The cardboard boxes which come with the Triumph TR6 indeed seem to contain the right number of parts with which to assemble a complete car, and a few further engine jobs have brought the whole job closer to the assembly stage.

I have also been attending to another (slightly younger) TR6 today which is due for a new clutch.  TR6 clutch replacement is no longer the simple issue which the manufacturer intended it to be: This particular car is a U.S. spec. model for which a cover assembly is available with a nice light diaphragm spring. However the clutch manufacturers have ‘economised’ their range and as a consequence the overall height of the cover plates are not always to original specification. Although the clutch works, it never quite feels as good as the original did because the geometry of the linkage has been compromised. The clutch is due to go in to the car on Monday morning so I shall be spending some of tomorrow manufacturing a new release bearing carrier which will restore the linkage back to the way the factory intended it to be.

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Cars arriving and leaving

It is a time for change in the workshop this week: The Scimitar has now left for home and chose a sunny day on which to do it. Slight surprise there because I’d rather expected it to be raining after Cherine and I lavished a good helping of combined Autoglym and elbow grease on the car the day before.

By Wednesday evening the Scimitar’s place had been filled by a nice early Triumph TR6 which is to be prepared ready for the fitment of its overhauled engine and gear box.  Typical of the marque, the old engine had sounded surprisingly well right up until the time that it was retired after developing a habit of oiling plugs. ‘Surprisingly well’ means that it sounded like an acceptable but slightly tired old TR and didn’t give away the fact that all six pistons were ‘picking up’ on their cylinder bores or that the camshaft and followers were in shockingly bad condition.  The Triumph arrives in the company of sundry cardboard boxes stuffed full of parts which I’m hoping will turn out to comprise everything I need to fit it all back into one piece.

The Jaguar XK8 finally has panel illumination that works, now that suitable  bulbs have arrived with the main dealer, and the car will be ready to go out tomorrow before I start sorting through the aforementioned cardboard boxes.  One expected job which hasn’t materialised is washing a layer of dust off the Triumph, since the trailer ride to the workshop has proved remarkably and unexpectedly efficient in removing the lot by the time I arrived.  The car has been covered with a fabric dust sheet and although it hasn’t prevented dust from settling on the coachwork it has been very effecive in preventing it from sticking!

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To Replace or Not to Replace….

It has been a while since I wrote a blog on a Sunday so here’s a post to make up for it. Actually the fact that the Sunday roast hasn’t yet quite cooked although I have finished sweeping the workshop floor and servicing the machinery is the major factor inspiring this post, not my wish to redress any perceived imbalances of posting frequency.

I picked up a few spares for the MK2 Jag yesterday, at the same time that I collected some Triumph spares from an adjacent premises. This morning I took a moment to unpack them and inspect.  I have been working recently on a Moss gearbox which will end up in the MK2. It’s a box which I have known since the 1970s when it was fitted to a 3.8 litre car belonging to a family friend; when the overdrive packed up he continued to drive it as a 4 speed Jaguar, but when he forgot about antifreeze in the winter and the core plugs blew out, the car (at that time without much value) was forgotten about. Some considerable time later the remains were purchased by a customer and many spares were used in the rebuild of another 3.8 litre car. Further years down the line I obtained what parts were left and have kept them until now.  It’s amazing how much changes with the passage of time: What was regarded, in my childhood as valueless must have been an ailing but low mileage MK2 Jaguar which has yielded an almost unworn gearbox.

It was once suggested to me that part of the skill in overhauling old machinery is knowing what to replace.  I’d extend that suggestion as far as knowing what not to replace:  The gearbox in question is fitted with nearly new Hoffman “two spot” bearings. This dates from the time when ball bearing races were available in three tolerances and had one, two or three little circles etched on the outer race to indicate which one a particular bearing conformed to: One, two, or three spot.  two spot was normal for a gearbox: closer tolerance than a “bog standard” bearing but not so tight that it risked siezing as the case expanded and contracted and the shafts bent and twisted.  These days, a bearing is a bearing – and the tolerance is roughly equivalent to the old “one spot”.  Modern machinery is designed to work at this looser tolerance (despite all the popular myths about the greater accuracy of modern  production). Old machinery has to put up with this sort of tolerance in the absence of anything else. Not this particular Moss gearbox though; that will be assembled with it’s orginal bearings and will give 100,000 miles or so of further pleasant and quiet service before I have to give in and fit new bearings to it.

The other new parts which won’t be fitted to the gearbox are the end gaskets which I picked up yesterday: The holes for the bearings are the wrong size to clear the retaining circlips and the rear bearing oil feed hole is non existant. This of course could be rectified, but what can’t be rectified is the fact that they are four times thicker than the original gasket. This last fault will ensure that the bearings aren’t retained properly in the case, restulting initially in excessive main shaft endfloat and secondly in the case being worn away by live bearings.

This may be sounding a little like a lament of the current situation, but it is far from that; these times are excellent: I regularly turn up unannounced on the doorstep of my favourite parts supplier and collect parts off the shelf for Jaguar, Triumph, MG, Morris and others. That’s certainly far better than you can expect of parts supply for any modern car!

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Buying tube safely

It seems that it’s becoming a rule of thumb that the busier I am in the workshop, the more sporadic the posts become on the blog!  I have been taken up with a wide variety of jobs since my last post: I have been preparing to receive a Triumph TR6 in order to fit a recently overhauled engine and to which end I have collected an exchange gearbox for conversion to an overdrive at the same time.  The Simitar is due out with its new type 9 gearbox conversion, but had decided to develop exhaust manifold trouble just when I thought that everything was finished.  The new stainless manifolds are slightly different to the old ones so I needed some tube of the correct diameter in order to acheive a correct fit to the front silencers.  Since no one locally has any tube in stock I had hoped to save a bit of time by collecting some from the Midlands on the same journey as the TR gearbox.  Sure enough, the big stockholder near Birmingham has it on the shelf; it’s in 6 meter lengths and I wanted two different diameters but I’m pleased to carry some in stock if only they can cut it for me so that I can  get it in my 4×4.  Thereby lies the snag: They can’t cut it into lengths until later in the week. And on health and safety grounds, they can’t possibly allow me to cut it with a hacksaw as I load it into the vehicle, “in case you cut your arm off”.  I’ve blogged before about my ongoing transformation into a grumpy old man so not too much of that here – suffice to say that I have learned a lesson about just ordering the tube and quietly getting on with the hacksaw stuff without further mention.  Readers will, I hope, be pleased to learn that I have now obtained tube from another source which has not only been subsequently cut by saw, trued by lathe and welded by tig, but also has proved to be injury – free.

The fault on the Jaguar XK8 has indeed proved to be with the gear position rotary switch – confirmed by a test of the signals generated at the multiplug.  It was a fairly easy one to home in on thanks to the excellent fault description from the owner:  Strange parking sensor and reverse light behaviour and erratic illumination of the J Gate during selection.  Good observation and description of symptoms can sometimes save literally hours in the workshop!  The fault code is now cleared and all works well. We decided to take advantage of the need to remove the console by attending to faulty panel illumination at the same time and also to change the transmission oil and filter.  This wasn’t originally intended to be a service item since the ‘box’ was sealed for life – or as one enthusiast once put it, “sealed for death”…..

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MOT time

It has been a late night in the workshop today:  I took some time out this afternoon to take the MK2 for its MOT so I have been catching up with all the other jobs awaiting my attention.

I’m glad to report that the Jag passed and the last week has been a useful time to attend to a few jobs which really needed doing.  I blogged recently about the car needing a steering joint and a panhard rod overhaul before the test, but of course when I got down to things there have been one or two odds and ends to add to the job list:  A rattly exhaust heat shield, some rather faded rear flasher lenses and a left hand indicator warning lamp which had decided to work on a part time basis.  It just goes to show that firstly there are always a few more jobs than expected and secondly: for most petrol heads, faded indicator lenses, although an MOT faliure, are hardly worth considering a ‘fault’…..

Working underneath the vehicle reminds me how much I want to find time to do some thorough rust treatment.  It will be lovely to be able to go out in the rain without worrying constantly about the car deteriorating; I don’t think that I have ever seen an unrestored MK2 with such a sound, original undercarriage and I really want to keep it that way!

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Losing Fluid

I have spent the greater part of the Bank Holiday (albeit very contentedly) in the workshop, so it seemed like a pleasant idea to round it off with a trip to the pub in the Jag.  On the way home after dark, less than a mile from home, the low brake fluid light flickered hesitantly before illuminating permanently.  This was some surprise: The pedal still felt firm so it was unlikely that a pipe had fractured yet the behaviour of the warning light suggested that the fluid loss was quite rapid – more so than one might expect from a leaking cylinder. Furthermore I am in the habit of checking the fluid level once a week and it never goes down.  When we reached home I filled up the reservoir in the hope that only a partial bleed may be neccesary after rectifying the fault. This morning the reservoir was empty and there was a large pool of fluid under the Near Side rear wheel.

Knowing some of the history of the car I expected to find that one of the rear wheel cylinders was rust pitted and that the pads had worn sufficiently to bring the piston seal over the top of the damage.  Removing the cylinders revealed something I’ve not experienced before:  The car had benefitted with new pads and brake lines before we bought it and seems that the outer pad on the near side had not been correctly engaged with the piston. This had caused the piston to become more and more slanted in the cylinder as the pad wore unevenly, until the seal would no longer hold fluid.

The Dunlop design of caliper has a retractor mechanism which pulls the pads clear of the disc when the brakes are released and for this reason the backing plates on the pads have to engage with a button on the outer face of the piston so that they can be both pushed into the disc and pulled away from it.  I’ve never seen the results of driving with a pad which hasn’t been properly engaged; it’s potentially not that nice…..

This is probably a good moment to sing the praises of the Dunlop disc brakes. These days it seems fashionable to get rid of them and fit something more modern, but if they are in good order they work extremely well even by current standards. The ones fitted to the MK2 pull the car up very impressively with little pedal effort.  Interestingly the same brake fitted to the Series 1 E Type feels much less impressive: This is partly due to the rather lacklustre Kelsey Hayes servo fitted to the E Type compared to the Lockheed item on the MK2.  It may also, of course, be partly due to the fact that the E Type might need to be stopped from nearly 150 mph on those same brakes….

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A Case of the DTCs

Or to give them their full name, “Diagnostic Trouble Codes”. I have a Jaguar XK8 in the workshop at the moment which drives everywhere in “limp mode” and displays “Gearbox Fault” on the dashboard.  Plugging in the laptop reveals a DTC of P0706 which translates as,  “Transmission Range Sensor Circuit Range/Performance”

Now having a case of the DTCs is perhaps a bit like having the DTs, only a little more alarming when you discover the uncontrolable tremors in the wallet region upon finding out how much the manufacturer charges for that little widget which has failed. It can also, like the DTs,result in hallucinations which leave people believing (or at least wishing to believe) that if they clear the code it will just go away….

The truth is that although technology is advancing steadily, basic concepts remain ever the same: Fougasse and McCullough, in their motoring handbook of the 1930s described the temperature gauge like this: “A clever little device which indicates how hot your engine is. If it points to hot you need more water or a new fanbelt, a new radiator or a new engine, or else a new little device.”  DTCs are a little arbitrary in the same way as the old fashioned type of warning device.  If it says “P0706” you have faulty cable adjustment, a faulty earth, a faulty J-Gate micro switch, a faulty connector block, a faulty rotary switch, a faulty input speed sensor, or a faulty Transmission Control Module.  New rotary switches are in the region of 250 pounds; no one usually dares to ask the price of a new Transmission control module. Therefore it’s going to make good sense to  test the circuit thoroughly before condemning anything.

The cable adjustment was indeed a little out, but correcting it and clearing the fault code hasn’t helped. I’m suspicious that it will turn out to be the rotary switch – particularly since this one shows evidence of having been disturbed before.  It works by generating a 4 bit binary coded signal over a parallel interface, and Jaguar are thoughtful enough to document the signal sequence.  When I’ve removed sufficient bits of underbonnet trim to excavate as far as the multiplug this will be the next thing to check.

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Stacking Dimes

I have a fair bit of sheet aluminium fabrication to look forward to soon, so with this in mind I have been taking a bit of time to practise some extra skills.  Usually my preferred choice for welding aluminium is by oxy – acetylene which has the side effect of annealing the workpiece as the weld progresses.  Since some of the aluminium found in ancient vehicle bodies was somewhat less than sophisticated in comparison to modern alloys, any annealing which takes place is very desirable indeed.  For working with more recent classics or for manufacturing items from new sheet aluminium there is a huge advantage to using the Tungsten Inert Gas process – more commonly known these days as ‘tig’ and to the previous generation as ‘heliarc’.

Tig welding has changed somewhat over the years:  Helium gas has given way to Argon for shielding the weld, moving core transformers have given way to electronic circuit boards for controlling the ‘droop’ of the circuit and symmetrical sine wave converters have given way to square wave asymmetrical inverters.  Not only this but tig has now become susceptible to the demands of fashion:  There is a certain ‘look’ which is found on everything from racing car components to mountain bikes; it originates in America and is usually known as the ‘Stack of Dimes’:

stack of dimes

If you have ever purchased (in the words of the catalogue) a “beautifully hand crafted oil catch tank” or a quality mountain bike, this weld will probably look familiar and in some quarters it is becoming the expected look.  It isn’t a look which quite fits a vintage or classic car, but somehow that sounds like a rather hollow excuse for not producing it. Instead I think that I’d prefer to respond to such expectations with an explaination of how tig welds used to look before mountain bikes existed…. and then to offer to produce the ‘stack of dimes – if that’s what you want’.

It’s taking a bit of practise to get it just right and the technique is proving well worth learning for other reasons to do with controlling the heat from the torch and the control of the filler rod.  Which is just as well because most of my work requires the weld to be filed or ground flush at the end of the job anyway….

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More Scimitars and Jaguar MOT

It has been far too long since I last blogged, which is rather indicative of how busy things have been in the workshop for the past week or so.  This is not least because I seem to have been dealing with a catalogue of minor setbacks which include deliveries needing to be chased up on the phone and new parts which don’t work when they come out of the box.  There seems to be some sort of strange rule in life which makes these things all come at once – although if any kind readers are already thinking of explaining this to me, perhaps I can express a preference for maths based statistical theory rather than the metaphysical!

Speaking of things which arrive  all at once, I have been dealing with more things Scimitar – this time an SE6 which has been rather heavily modified.  I have been storing this particular vehicle for quite some while after I fetched it on a trailer from Devon, but now its owner has come to the decision that it will have to be passed on to someone with fresh enthusiasm.  Many years ago he had fitted a well – tuned Rover V8 to the car, and at the same time the bodywork was modified with some rather aggressive arches.  The work has all been done rather neatly – hopefully it will end up being passed on to someone who will enjoy it!

Coming up at the end of the month is the first MOT for the Jaguar since it has been in our care, so a few late – or should that be ‘even later’ – nights will be called for.  It is a good case in point why the yearly MOT test is such a good thing: There really isn’t that much wrong with the car.  It will need some new rubber mountings on the Panhard rod and the steering column coupling is becoming a shade on the ‘soggy’ side.  The trouble is that without the test, how tempting would it be to delay such jobs for just a little longer?

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Deeply Scratched and Highly Polished

Speedo Drive BracketToday saw the last of the machining operations for the Scimitar – to – Type 9 gearbox conversion with the manufacture of an aluminium bracket which reproduces the original speedo cable fitting on the later gearbox. I learned my first machining skills during school summer holidays, and it wasn’t until I reached the age of sixteen that my tuition became more formal. At that age all the engineering students – myself included – found the hand finishing of machined components to be an onerous task.  Of course, like all people “of a certain age” I am now eternally grateful that in my youth I was compelled to spend hours using emery cloth to polish the file marks from steel plate, because the task is now merely a matter of course rather than a burden. In the case of this particular item I have had to rein in my enthusiasm: Having got as far as polishing with p1200 abrasive paper, the temptation was to finish off with metal polish, but instead I have to remind myself that it would stick out alongside the rough castings of the gearbox “like a nun in a snowdrift”.

Speedo Drive

The design of the bracket is extremely simple:  It bolts onto two unused holes in the tail housing of the Type 9 gearbox and has a flat section of the correct angle and dimensions to align with the speedo drive. The drive housing on the gearbox has been fitted with a counterbored aluminium distance piece which locates the original Scimitar outer cable fitting, and the new bracket is drilled and tapped 1/4″ UNC for the fitting of the orginal forked clamp.

The conversion is now almost complete and just requires the adaptation of a suitable gearlever boot and knob to finish it off.

The rest of this evening has been spent clearing up the machine area of the workshop and filling old oil drums with all the swarf which has been produced during the conversion – let’s hope that the price of scrap steel remains buoyant…..

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Testing cars and signing for parcels

It will most likely not come as any surprise to regular readers that much of today has been taken up with things Scimitar and the car has now had a successful first road test. A temporary cable connection has made it possible to check the new speedo drive against a GPS application and all is very satisfactory. Good as the orginal design was, the Type 9 gearbox makes for a very pleasant drive indeed and the ratios suit the car well.  This evening I have been machining an adaptor and bracket in order to fit the original speedo cable onto the new gearbox since this compares favourably in terms of cost with the alternative option of having a new cable made – not to mention the advantage of being able to purchase off – the – shelf cables for the vehicle in future.

I have been keeping Parcelforce rather busy recently with deliveries of spare parts for various projects – not least the growing collection of bits purchased on ebay with view to future work to the MK2 Jag.  I already have quite a collection of spares which include a good 3.8 litre engine, a straight port head,  a manual gearbox and a rear axle with limited slip diff. Perhaps it’s time to look slightly embarrassed at this point: The 2.4 litre has won my respect but everyone wants a 3.8 and that includes both Cherine and I….

Ebay has proved to be very seductive when searching for the remaining few bits and pieces which we have yet to collect and these include a pair of 2 inch carburettors on an original manifold, a suitable air intake from a Jaguar 420 and a pedal box assembly for a manual gearbox conversion.  More often than not ebay turns out to be an expensive option compared to autojumbles or classified ads, but it is extremely convenient – and not just for the buyer: Because it is so easy to clear out the garage and “bung a few things on ebay”, it also means that there is now a myriad of old car parts which would not otherwise have been offered for sale.  If only I could ebay for the time to fit all this stuff that I have now purchased, all would be perfect….

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