It's been almost a year since I have updated this thread. I still have my 77 Puma GTE and still have the monster type 4 engine mounted to a Ranch pro comp suby geared transaxle. To update, I installed the engine with the new LE200 HAM super heads last fall and the engine runs like a scalded dog, alas I still have a small amount of compression leak around the surface where the cylinder top seals to the head. The engine runs amazing, the leak cannot be heard or felt even though in my mind there is power being lost. The reason I even know about the leak is the gas and oil mix that gets spit out on the floor during cold starts. I even believe the tiny leak seals when the engine comes up to operating temps., but I can't prove that. Regardless, I am not going to settle for this issue on an engine that has the amount of time and money invested as this engine has, it is around $15k at this point. I spent the winter setting the project aside and gathering more information about the issue. The block mounting surfaces and heads are all flat and square, therefore we have ruled this out as the problem. The engine is set up at this point for a little over 10:0 to 1compression which makes holding the seal even harder. What I have been told and come to believe is the issue of having much larger pistons and cylinders than designed for. The engine has 104mm pistons and cylinders that are being held in place to create an airtight seal with 4 studs. This is much greater distance between each stud than the engine was designed for, and we are trying to hold in more compression than originally designed. Some people that have fought the same issue on these big type 4 engines ad 2 additional studs to each cylinder having to modify the block and heads to do so. Big job big dollars, but it works. Another way this is solved is by having a small groove cut into the top of each cylinder and a pc. of piano wire laid into the groove and attached to the cylinder in some many of which I know not at this point. When finished the hardened wire protrudes above the mating surface of the cylinder top by .015". A .040" copper head gasket is used in conjunction to allow the wire to bite into the copper when the heads are torqued into place creating to perfect dam seal in the process. George at European Motorworks is one of the many people that I spoke with that suggested this approach, in fact he is the one I sent my cylinders, to have the piano wire modification done. He did the work within 2 weeks and charged me a very fair price. I have done business with George in the past and find him to be a great resource for all things air cooled, especially big type 4 engines. I received the cylinders back this afternoon and will be reassembling the engine this week. I will do a leak down test once the heads are torqued in place and report back once the beast is running. Thanks for sticking with me and reading this long post. I love this forum and the people on it. Carlise or bust,, Sorry, I am bringing the Magnum not the Puma. Is there anyone that wants to bring the Puma for me?
One of the pics show what spits out during cold starts now and should be eliminated once the engine is back together. Stay tuned motorheads, more to come soon!