Friday, May 16, 2008

Chemicals


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.

-R.S.Hoover

5 comments:

Anonymous said...

Like so many things, they got it right the first time. Once the accountants (and their pals in marketing) took over, engineering quality took a back seat to engineering quantity. More products, not necessarily better products.

I just sold a complete, original 36 I've been keeping greased and plastic wrapped for 20 years. Went to a friend who cleaned 'er all up and bolted it up in his freshly restored '57. (which, itself was amazingly clean and original. 30+ years in a barn in Virginia. 23,000 original miles, documented!)

It's impossible to look at the simplicity and lines of that engine and not be impressed. Form follows function. Everything it needs, and nothing more. Brought tears to my eyes seeing it start up and idle for the first time in two decades. Runs like a top, too.

By comparison, the fuel injected 1600 of the late 70s is an investment-cast embarrassment.


Bob, have you seriously considered writing a book about the RIGHT way to build a VW? Or, at the least, assembling all your various writings into book form? The world has much to learn from you, sir.

--Jack

Craig Steffen said...

Hello Mr. Hoover,

I'm a computer programmer by trade, but I've always vaguely like working with mechanical things. I purchased a 1972 VW Superbeetle as an incentive and as a laboratory to learn to work on cars and engines (I plan to own and maintain an airplane someday). The experience of working on that car for the past two years has been a great initial education.

You've said in this blog and in your other writings that if the reader doesn't know X, then they shouldn't be working on a VW. But that's my dilemna. I'm trying to use working on a VW as my lever to teach myself these skills. I bought a download copy of your sermons when you had them for sale recently, and reading that was an education in itself. A couple of things you've said here have left me with specific questions, which I'll ask here, lacking a better forum.

In reference to your post about your gasket basket: You said that the non-gasket-material paper oil sump gaskets that you can buy from VW stores leak. My experience is that you're right. :-) Now your advice to make my own oil sump gaskets out of the correct material makes sense. However, the paper gaskets come packaged with a full set of crush washers and it's very convenient. So--if I want to go that route, and use the nicely pre-cut paper gaskets, can I make that work to make the sump not leak? Will gasket sealant applied to the paper oil sump gaskets make them seal? Barring any other information, I'll try this when I change the oil in my VW the next time.

With regards to this most recent post: you give hints here about the proper techniques of case sealing for an overhaul. If I end up overhauling my (1600) engine in a few years, that process will be my apprenticeship in that process. In your estimation, is there any written form of documentation that would tell me the right ways to do these things? I have lots of books on VWs in general, and a couple even on engine overhauling, but when I go to do it, I'm worried that there's something I'd miss.

The "Bug Me" videos talk about "Permatex 3H". Is that what you're talking about when you talk about Permatex?

Thanks for any and all information. Most sincerely,

Craig Steffen

Craig Steffen said...

Mr. Hoover,

A follow-up to both parts of my earlier comments:

I tried to read the photos on your post, but they're not quite high enough resolution. I assume that
this is the permatex you use on the case parting seam on a VW?

Is that appropriate for the cylinder-to-block joints and the cylinder-to-head joints as well?

Since it says "for machined surfaces", I assume it's NOT appropriate to use it to seal the strainer plate? Perhaps
Permatex number 2 is would be better for that?

Anonymous said...

Bob, sure miss the engine posts, hope you are doing ok
V/R
Darrell

big fan said...

Turns out I live right next to a Kipling street here in Toronto & never had a clue what it was about 'til now.

http://en.wikipedia.org/wiki/Rudyard_Kipling

Places named after Kipling
http://en.wikipedia.org/wiki/Rudyard_Kipling#Places_named_after_Kipling
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ps - love to read your stuff & have learned alot. In my books, no one has contributed, as only you can, to the vdub engine & aviation...to say the least :-)

An engine indeed, can't lie.