3.3-3.5?
 

Hi everyone.

A simple cam seal oil leak repair has turned into a full overhaul. It turns out No1 piston top ring cracked and floated around doubling up and each other thus widening the gap, and scratching the cylinder wall very lightly. And No1 cylinder also has a piece missing for the Nikasil coating right at the edge of the combustion chamber. Some of the other pistons show signs of detonation. And the clearance for the bottom oil ring is really tight. Should I be concerned?
I am on shoestring budget so just want to spend as little as possible.
Do I need all pistons and cylinders or can I just change to some JE pistons?
My mechanic showed me a set of 100mm 3.5 Andial pistons and cylinders. He said they came out of a 3.3l 964 turbo but they wont slide into my 81-911 turbo. If I decide to use them will I need to machine them or my case or should they be able to slide in with some cleave use of heat and cold?
Thanks for all your advice.SmileWavy

I don't want shoot you down, but if you are on a shoe-string budget your best bet is simply to replace the warn parts and rebuild as stock. Anything else increases your costs dramatically.

Those 964 turbo cyls are not going to work on your case without some serious case work. I believe the stud spacing is all wrong as well for those. Even if they were slip in you would have to change your intake setup as your old CIS is not ment to power that kind of stuff so there is another serious investment. Its probably easier to just buy a 3.6 turbo engine and throw it in there ;) though that suggestion is testing the limits of my knowledge ;)

You might consider ditching the turbo and putting in a 3.6NA engine. With a few tweaks it might match your stock 930 power output but have NO lag ;)

There may be some kind of kits you can get that will increase your 3.3 and still allow you to maintain the old induction setup. Even so... finding this stuff will be very tough in Japan so expect to ship it west from the states.

-Michael

Rob,

You need new cylinders if yours are damaged as well as new pistons. I would also check the rod bearings since they really take a beating from detonation.

100mm P/C's require case machining to fit; one must be sure they have the right CR for a Turbo motor. I'm not a fan of those in your applications due to thin cylinder walls; they do not stay round and that causes excess blowby.

Your first order of business should be to find out WHY the engine detonated to ensure it doesn't recur.

thanks for the input. I managed to find a set of 3.3s on Ebay and a set of 3.4s here in Japan. The price is double for the 3.4. I will check them out this weekend.

here are some pics:
https://picasaweb.google.com/T3Japan/EngineWork?authkey=Gv1sRgCPept4Tg88agXw#

a set of JE pistons is about 850.00 you could get those in 98mm which would make it a 3.4 then once you get the pistons send them and the cylinders to us auto chrome and they will re-bore and plate your cylinders to match the pistons. a lot of these 3.4 sets you see for sale are exactly that only they used a set of 3.2 cores.