Also, I must be loosing it. Where did I get it into my head that 2618 is the high silicon; it's the other way around, the 4032 is the high-silicon. Don't mind me anymore :-) Also, I spoke to one of my engineers, and they couldn't understand the .003-.0035" clearance + .001-.004" extra for turbo. Seemed way too loose. He said that the most he would spec out on our 102s for the 914 would be .003" including the extra clearance for boost, as long as it's not 25-35#s. Then you need some extra room to grow.

Charles Navarro
LN Engineering
http://www.LNengineering.com
Aircooled Precision Performance

I don't understand why you would only get a few hours of ring life. Even if all the info is correct, and I have no idea if it is, the piston and cylinder should have near zero clearence when warmed up, if everything is speced correctly. The only downside would be a noisy warmup period,

Please explain

Chuck,

I'd tend to believe J&E more than a guy who seized his engine... :D

Thanks for looking into it.

I'd tend to believe J&E more than a guy who seized his engine...

Thanks for looking into it.


__________________
Chris Streit
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Keep asking questions Paul- In the end it is your pile and your dough sitting there in a mess. Time for a sad sad story- I was once given an "O too thin" JE wrist pin that seemd too damn thin for me and after a few calls around and alot of gee I don't knows from folks I trusted as in the know sources-, I went with the assurances of the JE salesperon I rec'd them from. Well 3 events later and one sawed in 1/2 3.6 TBO engine I was F'n pissed to find they were not strong enough , then when I had things Rockwelled, x rayed, and tested to every means in my disposal we established it just failed. It was no solace that the piece of work salesman didn't work at JE anymore and that others then told me that that selection was .020 too thin when I called back to raise hell.
(Did you know that they offer like 5 different types of steel composition for the pins as well-why not onlt the BEST toll steel for all??)The nice folks there at JE did offer to give me another set of free wrist pins that were thicker though. Hmm, 120.00 for 15K worth of parts and labor- NO THANKS.

Back to your issues- It has been my understanding and I heard it from EBS themselves, in the past that they do not advocate recoated cylinders for turbocharged applications. The cylinder pressures and tempertures are just too high. I know of two folks(atleast) that have had the coating come off and -as abrasive as it was, it destroyed the entire engine and they got to buy a totally new one to rebuild. The cylinder to piston clearance issue is like rearranging deck chairs on the Titanic. I would ask John at EBS for several references of folks that have used the recoated/JE combo and do your homework. Then go "forward. John is a straight shooter . In the end, no one does it better than Mahle with Ps&Cs engineered by Mahle with Porsche to work together. Is it really that much more cost?

Good Luck,
Kevin Roush
GAS Motorsport
Performance Porsche
Kroush2001@aol.com

Thanks for the comments Kevin. Yes there is quite a bit of difference in cost between the recoated and new Mahle pistons and cylinders. I'am in Australia and would need to pay duty and GST and any parts I bring in. The JE's were the cheapest and according to Wayne's book, the best alternative. First I've heard of recoated cylinders not being to good on a turbo, so I will check with the local shop that doe it. They have a web site, www.electrosil.com.au. I have spoken with them once and they have come highly recommended by a local Porsche shop that has a reputation for specialising in Porsche turbos. Sorry to hear about your wrist pin problem. My car is just for the street, with an occassional driver ed day, so I'am hoping the stresses won't be as great. The wrist pins that JE sent me are supposed to be OK for the 3 litre turbo.

Comment re cylinder plating coming off. I have had many years experience in specifiyng, buying, and testing plating of various metals for use in extreem applications. Properly applied plating does not fall off.

ONe thing you can do to test the plated cylinders prior to actually using them is to heat cycle them, at a temperature higher and lower than they will ever see in use and see if the plating stays put, does not blister, or peel. An even simpler test is to just heat them, for about 5 hours in an oven set at say 200 degrees C. Any good plating should survive. Rember its going to be temp cycled in the engine and certainly going to get somewhat warm so don't let the plater beg off on some kind of test.

Note: platers usually only plate to someones specs. IN other words someone has to properly prepare the cylinders for plating, clean them, use the correct underplatings (if required), spec the thickness and uniformity. Test and Machine the result for proper finish. This someone is usually NOT the plater, unless its someone in business just doing cylinders,