LSR Karmann Ghia Blog, August 17, 2009

The following was sent to the Karmann Ghia Club of North America's email list on August 17th, 2009:

To: Karmann Ghia Club Mailing List <karmannghiaclub@karmannghia.org>
Subject: Aug 17 update on '59 KG on the salt - and run-in plans

On Mon, 17 Aug 2009, scott photo wrote:
>
> Richard,
> with that new motor, or mostly new, and being run in high desert
> heat flat out repeatedly at sustained speeds, will it not need a
> breakin period?
> to avoid seizing.
> keep up the good work, Scott
>

Excellent question, Scott.

I prefer to use the expression "run-in" as I don't want to break _anything!_ -smile-

An engine like this that is not run-in properly first will not - should not - seize up. There's no additional risk of that. What there is, however, is a chance to inadvertently shorten the life of the engine and to not develop full horsepower.

Racers face this kind of problem all the time. With engines that enjoyed good sales volume are used, there are plenty of spares and the engines and their parts are considered commodities and are, more or less, expendable. So, shortening their life is of no concern to racers.

The performance issue is the "seating" of the piston rings. They must have time to wear themselves some to fit their new home perfectly. Racers have various tricks to handle this. There are powders sold that one puts into the intake air stream and they artificially wear the rings (and cylinder walls!) and the old timers would use the cleaners Bon Ami or Commet - Bon Ami is preferred because it is not as reactive with aluminum and magnesium as Commet...

With an engine like the Denzel, none of it is expendable and I don't really want to shorten its life any, either. So, I have a plan...

Recall that last fall I got my dynamomenter online? Well, it actually took until spring to get it going; I plan to use it to put a load on the engine. I'll actually run it for hours if I can! I'll varry the load and such, just as if it were driving! ...I _might_ even get some time to drive it in the actual car! AND, I'll get to do a preliminary tuning. Most of the altitude tuning that needs to be done is related to the carburetor jets and there are known relationships, so one can get pretty close just by looking it up in a table - IF the engine was well tuned in the first place!

...So, that's my plan.

UPDATES:

I ended up having to _make_ valve keepers because I lost mine - there here _somewhere!_ I got some help from a master machinist and he taught me how to do it and we made a set. ...Great experience and it's helping me become a much better machinist.

With the keepers in hand, I now have everything available to completely assemble the engine. And, I nearly did it on Saturday. Here it is Monday and it's still not done yet. The reason: I'm this close, now is not the time to rush! Get it done _right._

To that end, rather than just settle with what shims were available, I assembled, measured, disassembled, lapped, reassembled, measured, etc, repeatedly as necessary to get the cylinder shims _exactly_ right. I hand-lapped the shims to achieve perfection. Three of the cylinders are _exactly_ the same, and the fourth is off by a mere 0.002mm - yes, two thouandths of a millimeter! Factory spec for a Porsche or VW is 0.1mm! (What amazes me is that this small difference is actually measurable with the tools I have and that I could even do something about it if I really wanted!) Having the cylinder shimming done means that the exact (static) compression ratio is now known: it's 10.57 : 1 Yes, the target was 10.5 : 1, but it isn't worth the extra effort to shave off that 0.07 difference. Happily, it's ONE custom-made shim under each cylinder.

Yesterday I milled out and threaded various places on the crankcase to be able to run the stock Denzel full-flow oil pump and filter system. I also drilled out the oil pump housing for a plug (instead of the case) so the oil will flow through the system correctly. It went well.

I double checked the balance of the pistons and cylinders - which I had originally done nearly 20 years ago! Yes, they were sitting in a box all this time, waiting their chance! They were within 0.7 grams, but I got them within 0.05 grams - a drop of oil weighs more!

The paint job didn't go as well as planned so I've started fixing the oopses and will re-shoot, probably Wednesday. The biggest oops was not enough paint in some places. It was a lighting problem - couldn't see that it wasn't great coverage! So, I'm making some lights that mount onto saw horses for good lighting along the lower sides. Other problems were some low spots that I just hadn't seen but should have been addressed before the painting last week. The color is _great!_

I've tried to find the right spark plug, but it's VERY hard! Much harder than you'd think. So, I ended up contacting Bosch's technical department. They are GREAT! Not only did they fix me up with a good estimate - a starting point - that will probably work very well, they also hooked me up with both their Motorsports division, their Research and Development team AND their Racing team! The reasons were varried, but all toward getting the perfect spark plug! There is a special testing aparatus that can be fitted to discover the actual temperature of the spark plug. It costs something like $15,000 - which I can't afford, so they're hooking me up with one of their departments to see if we can borrow theirs for a brief time. And, they're interested in being my sponsor! Yeah! ...Heck, helping me with the spark plug would be help enough - I didn't ask about _money_ but maybe I should!

Note that if the plug is too hot, the engine may experience predetonation and if it's too cold, the plug will be prone to fouling. Other issues are electrode type, resistive or not, and whether the grounds are multiple or singular and how they're placed... It's not just "throw something in and go!"

In assembling the cylinder heads, I may wish to make custom valve spring seats which incorporate the appropriate shimming to set the appropriate "install height" and tension "on the seat." BTW, I'll be running about 90 pounds on the seat. Stock 36hp VW is about 50. Porsches run 90 to 120 or more, depending on camshaft and RPM expectations. The lower the seat pressure, the greater the risk of "floating the valves", the higher, the more horsepower the engine consumes of its own power it's generating and the greater the wear and tear. So, you want to find the sweet spot.

I'm pretty sure I told you about the camshaft last week. I have reviewed the engineering data that came with the cam - VERY interesting. From it, you could have another cam like it made. I will be running different valve lash, intake versus exhaust.

I got a box of "molly" pushrods from a friend to use in making some for this engine - custom length - but I was _shocked_ at how heavy they are! I may end up making my own as originally planned. I'll use old 36hp cam follower / pushrods as cores. The molly ones are over 60 grams apiece while the VW ones - minus the lifter, are barely 30 grams. The lighter the better from a performance standpoint - higher RPM will be possible.

This week I anticipate getting the transaxle completed. Lots of work to do on that.

I also got a lot of the rules clarified - gotta get the rules right!

The headliner arrived - a _required_ part, or, rather, it was; when I clarified the rules the guy added that they have relaxed that requirement. Odd...

More when there's something to report,
Richard

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