Question about 356c pistons and cylinders oh and valves too.

ziodesign · 01-23-2006, 08:52 PM

I'm rebuilding a 356c engine.

At the moment I see lots of pistons and cylinders for sale on ebay. Are any of these good? Any suggestions for a big bore kit to go with? There are the QSC on the cheap end and AA in the middle and then the NPR or other old stock pistons. I've also been told to replace the valves. I have the stock valves now so can't I just have them ground and hardened? Anything I should look for in new valves? It seems like the prices are all over for these as well. What are the best machine shops to send things like the heads in? I don't want to go cheap but with twins on the way I don't want to go crazy either.

My first time rebuilding any engine... Just to keep me busy and the bank account low until I find the perfect 356 to buy ;-)

Thanks in advance for your help.

Jump2xs · 01-26-2006, 08:39 AM

The short answer is Beg, Borrow, or steal a hard copy of Harry Pellow's (the Maestro) "Secrets of the inner circle" It's out of print and you'll likely pay a hundred bucks, but it will save you lots of money and heartache. It will answer all your questions and take you by the hand to acheive your goals--financial and mechanical.

Choice of pistons should be determined by the intended use of the engine, with some consideration to your wallet. Valves need to be checked for wear tolerances--so don't buy new till they are checked. Shops on west coast include Rimco, Comp. engineering, Ollies.

Buy "Secrets" now, the book not the CD, which I understand has some problems, but can't say for sure. try http://www.hcpresearch.com

ziodesign · 01-30-2006, 10:02 AM

Thanks for the info. The list of machine shops will be super helpful. I'll be looking into a Pellow book or DVD's. Do you know if a compression ratio of 8.5 to 1 is good with a big bore kit? This is what the AA P&C's are.

~dennis

Jump2xs · 01-30-2006, 10:12 AM

Dennis, your question about CR is one of the eternal ones. 8.5:1 is a modest CR, and the P&C's are just part of the equation. Many other factors are in play--head volume, stroke, #of cylinder shims, quality of gas. Seriously, get Harry's book ASAP.

marktodo · 10-30-2012, 02:16 PM

My oldschool mechanic rebuilt my 912 with QSC pistons. He spent a lot of time making the balance correct. He feels that is the biggest issue with cheaper pistons. After about 5000 miles we have broken rings in #1 cylinder. We had compression at about 10.5 , Our thought is to lower the compression to about 8.5 and replace all of the rings. Is this a fools erand ? should we give up on the QSC's. I am very interested in input.
Thanks Mark

Jump2xs · 10-31-2012, 02:58 PM

Wow! I posted the reply to this thread many years ago. I've since sold all my 356's and moved on to other European machinery, but I thought I'd respond anyway.

10.5 : 1 CR is somewhat high for a street engine. The best engine I ever built was one that I used Shasta pistons at about 9.5:1, yes they are more money but pistons aren't where you should scrimp. I don't know what causes broken rings, so I can't advise on your exact problem.

Good luck and read "Secrets"