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.

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.

The 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.

The 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.

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.

There 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.

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!

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.

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.

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…..

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…

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.

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!