Friday, May 16, 2008
The chemicals shown on the left are all you needed to assemble an early Volkswagen engine (ie, 1100 & 1200). The valves were so small that relatively weak springs were enough to close them. Since the springs put only a modest load on the cam & followers, a special break-in lubricant was not needed.
Except for its color -- German 'permatex' was black -- the standard American stuff worked fine for sealing. If the crankcase parting-line was badly corroded we'd spin a few strands out of a hank of silk embroidery thread and embed the strands in the thin layer of Permatex we had painted onto the parting-line of the left-hand half of the crankcase.
Permatex was also applied under every washer on any stud or stay that had oil on the the other side. Or on this side, which is the case for the four lower head-stay nuts in each of the heads. Oddly enough, although this has been a standard VW assembly procedure since about 1937 a surprising number of today's experts ignore this vital step. And wonder why their engines leak :-)
Ditto for the Loctite, which the German mechanics I learned from adopted as soon as it became available. Prior to then they used gasket shellac, but only after carefully cleaning the threads of all debris & oil, another of those 'unimportant' steps usually ignored by the modern-day expert.
Shortly after the introduction of the 1300 a wide range of thread-lockers and thread restorers became available, and not a minute to soon. The explosive increase in VW sales in the early '60's caused many engines to be damaged by unqualified mechanics. Having no experience with air-cooled engines it was common for American mechanics to assume the VW's torque values were incorrect and apply the Model T Torque Rule, which was as tight as they could get it... plus one turn. I'm sorry to say that's still the case with many VW 'mechanics.'
When the 77mm barrels of the stone-reliable 1300 engine were bored out to create the 1500 engine we began to see an increased frequency of case-shuffling and accelerated cam wear. Volkswagen was aware of the problem and began work on an aluminum-cased 1700 engine but it would not appear on the scene until 1968. In the meantime VW issued a number of SB's and SN's (ie, Service Notes and Service Bulletins) telling us to dope the cam & lifters of newly assembled engines with molybdenum disulfide grease, and to '...locally treat' various gaskets to prevent them from leaking.
To be honest, none of it did much good when they over-bored the 83mm jugs to create the leaky, trouble-prone 1600 engine. Then came the untimely death of Heinz Nordhoff and the engineers -- real car people -- lost control of the company, to be replaced by accountants more interested in short-term gains than long-term quality.
Nowadays it takes a bit more than a can of Permatex to assemble a reliable, durable leak free engine from VW components, especially so if you're building a big-bore stroker suitable for powering a light airplane.
Not according to the experts, of course... those wunnerful folks will look you right in the eye and swear all Volkswagens leak. Or at least, all the ones they've ever built :-)
At the time Volkswagen of Germany stopped making air-cooled engines there were a lot of Service Notes and Bulletins that hadn't been incorporated into the Factory Workshop Manual and in so far as I know, they never were.
Do you like barbecue? Most folks do. Of course, there's half a dozen different styles of 'barbecue' and a different sauce or rub for each, with variations based on the type of meat. The picture above shows the ingredients for one style of barbequed pork. To have it come out right you not only need to know which ingredients to use but how much of each, and -- believe it or not -- the sequence in which they are mixed and the method the sauce is applied.
All of which are considered unimportant details by someone who doesn't know how to cook.
A VW engine converted for flight is an airplane engine. It's not a dune buggy engine nor a hot-rod engine nor something to take to the drag-strip. The sad thing is, a lot of people don't know that.