Thumpercross85

The BMW turbo F1 1500cc in-line 4cyl engines of the early 1980's used the standard cast iron blocks of the road car engines, eventually producing 850hp in qualifying trim. Apparently they did select the best quality castings from the production line, but then left them outside in the open weather for 6-12 months to settle and achieve full strength.... the newly cast pistons in the Thorny I'd suspect are a little too fresh, and could well have moved around a bit, such that it would be best to strip and measure before trying loading the engine any more. I would imagine wide tolerances might be best for an engine of this era and materials, rather than the extreme materials, lubricants and tolerances used in the miracle that is current F1 engine technology...

PTFE is a fluoropolymer whereas Viton (DuPont's tradename but there are other equivalents from other manufacturers) is a fluoroelastomer, but they are both fluorocarbons. I'd be surprised if the PTFE is swelling in fuel but if it is under compression in the tap what you could be seeing over time is creep instead, with some degree of extrusion into gaps, as PTFE is relatively soft....? Modern fuel compatability is a bit of a minefield as the materials that are good for petrol dont like ethanol and vice versa, so the new bio fuel mixes have caused a lot of new issues - nothing that cant be overcome but it does need careful material selection at times. Happy to try and help if you can give me the specifics.

The issue will be whether the binder that has been used to reconstitute your particular bit of cork will survive the fuel exposure, and modern fuels have all sorts of additives that give traditional rubbers a problem. If you arent sure of the heritage of the cork a soak test is essential as it could literally disintegrate. We have 20mm thick nitrile bonded cork in stock, but having had an issue with modern pump fuel attacking a cork filler cap gasket I made for a friends Metisse recently, it turned out that once again, the right spec of Viton rubber was the answer...

While replacing the tyres on our combat rims pre Xmas, I was surprised to find a layer of gloss royal blue amongst the various drab and bronze green layers of paint. On reflection it occurred to me that I had seen the same colour combinations on the dash of an unrestored British Jeep that appeared at the Chalke Valley History Festival back in the summer, and I would be fascinated to know what campaigns / regions / duties these various colours might have related to, as we have no service history for our vehicle. It was with the British Army till 1957 so there was plenty of opportunity for "recycling" no doubt...any info much appreciated....

Glad you did not use the fabricated item, superglue is not really suitable for hot water, and yes, the hard spot created is sometimes an issue. Much better to use a proper fully moulded seal, though EPDM or Silicone would be better in the water system than Nitrile which is really for oil contact....

Agreed, these coatings are thin and need to be correctly specified for the substrate & fuel, but when used in conjunction with welding etc to repair heavy damage first (eg broken circlips scoring barrels) can result in very impressive rescues of apparent basket case jobs. Having said that it is only one avenue to look at, and as others have suggested, various liner options may also be a very good solution depending on the wall thickness available in the original casting. The best answer will perhaps become apparent after showing the cylinder to a few of the guys who specialise in this kind of work but one thing is for sure, this engine will live again one way or another I have no doubt!

It may be time to look at modern cylinder refinishing processes - and have that particular bore refinished back to size to suit the piston & rings that you want to fit in it. This process is typically used on aluminium one piece barrels and is excellent, but I think it can be applied to cast iron as well. Perhaps worth chatting to these guys with the specifics and see what they say....http://www.poetonaptec.co.uk/aptec-liners.htm

Inspirational, and so refreshing to see traditional skills researched & demonstrated in such a rewarding way. Modern technology & processes are amazing, but too easily these days the grounding for good engineering design & practice is forgotten. This thread should be required reading for all aspiring young designers & technicians.........

Let me know when you get to this stage, I should be able to help with the rubber element; we often get called on to recreate obsolete parts. http://www.martins-rubber.co.uk Lovely to see another major project coming back to life, well done, Adam

It all depends on the shape of the diaphragm (top hat form or flat gasket style for example), the travel required, pressures involved, and especially these days with unleaded fuels, the type of fuel in contact with it. Also, are we talking immersed in fuel, or simply exposed to fuel vapour? Nitrile based materials are usually suitable, but the Viton type polymers are generally better although a lot more expensive. Pretty much anything can be reverse engineered, but as ever, complexity usually equates to cost..... Sheet diaphragm materials with fabric re-inforcement are readily available, formed diaphragms are more difficult unless it is a stocked part, otherwise you are looking at tooling and minimum batches......

These old jacks were very well made, and, so long as the sealing surfaces are in reasonable condition, can simply be resealed. We are based in the UK but if you look for a local Seal-Jet or Economos outlet for example, they can most likely make you a set of seals to fit your Jack. Its best if you strip and clean all the parts so that the seal styles and housings are easy to check & measure. Then it should be a simple re-assemble, re-fill with oil (usually H32 hydraulic oil) and it should be good for years more service.

Very interesting reading on this thread - having run our Jeep just over a year now its really quite nice to have a "British" vehicle and find that they were in everyday military use for so long. Is there a register of survivors anywhere do you know, having been surprised and pleased to see 36 YH 32 & 71 YH 99 at the Beaulieu show back in May, standing out amongst the US jeeps....

I applied for our Key Card via the RLC Museum and fortunately yes, they had it and it did quote the M number assigned prior to the 78 YH 97 on our chassis plate. So it may well be worth a try although it seems there are no guarantees the Card will either exist still or what it may show ..... At least we now have two chances of finding out more about our Jeep's history, and I was also able to get a copy of the civilian log book from DVLA using Historical Research as the justification, which was a bonus.

Have now looked very carefully there too, and no sign of plate or holes, the mystery continues.....thanks, Adam

Huge congratulations to all concerned - I found this thread fairly late on and reading up on the early work and seeing the proper use of real engineering skills both modern & traditional has been inspirational, especially when allied to the great commitment to originality. Wonderful stuff, and very well done in hitting your self imposed deadline in style!