What is the MAXIMUM 100mm forged piston/cylinder clearance I should run for a turbo application on alcohol, allowing for thermal expansion, but keeping blow-by at a reasonable level?

What does Woods and PAMI recommend?

Is the OEM cylinder nikasil coated? It cannot be bored without re-coating? Re-sleeving may be the cheapest way to go?

 

Can't help you with your question scooby, but i have one for you.

We want to see that bad boy run in Aledo texas. We are reworking our dirt strip, how much room do you need, we currently run 800 feet with 200 shut down, can extend 600 more.
Bomb riders at my place- Hurycne, roostinonyou, buttfungus
Yami riders- 14mins, raptorrrc, raptorcrc, banshee2ky, blasterboy. We can round up plenty more to come see the show! What do you think?

 

don't have all the answers but my stock piston had .003-.004 clearance
originally. Don told me that with a forged piston the clearances can be greater. The stock cylinder is nikasil coated and there is no sleeve in an aluminium cylinder- can be bored and recoated. Don says he has seen several cylinders come to him that were bored w/o renikasil coating and were showing signs of extreme wear.
If you are concerned that there is too much clearance I believe that you could send the cylinder and piston to a shop that nikasils and have them build up the coating to your specifications- I have the
names of a couple of shops in the mid west that do good work if your interested pm me.

 

I would contact your piston manufacturer on the clearance. They know the exact expantion for your piston.

The cylinders that I told you about majorecho were HONED[not bored] and not re-nicacyled. They showed more were than a cylinder with equal time and no hone. If you were to bore and not re treat it, you would not last long.

The cylinder is not curently sleaved, so re-sleaving is not an option.

 

14mins, as long as possible, I don't start hooking up until 800 feet.

My leakdown is 2% so someone did their homework.

Compression seal is fixed with O-ring, but I need to seal the coolant and oil better - not easy with a copper head gasket. It looks like the base gasket might be leaking oil.