84.4mm piston compression?

[jacobey54]

Hi, I am new to the board and have a 1974 with a 1756 engine that was rebuilt in 1989. It runs well now other than needing a exhaust manifold to downpipe gasket (anyone know where to find one?). I was just running through some old receipts and couldn't find a part number on the pistons but I was trying to figure out what compression they should be. I just know that they were sold from then Bayless in 1989 and were 84.4mm. I am hoping they are 9.8to1 compression or higher. I could run a compression test but I am not sure going by psi would tell me too much. Any ideas? Also I'll post a pic of my car in the proper forum.

Jake

[vandor]

Hi Jake,

The fact that they are 84.4mm diameter does not really tell much. You may be able to tell a little by doing a compression test.
A freshly rebuilt stock engine will have ~150 psi compression. A well running used engine can have as little as 120 psi. An new engine with ~9.8:1 CR will have ~190 psi.

My company has both the flange gasket available:

http://stores.auto-ricambi.net/-strse-1 ... Detail.bok

I can ship it in a padded envelope by mail, so you don't pay $10 for Fedex.
Thanks,

[jacobey54]

Thanks, I'll do a compression test one of these days. It says that your company is out of stock of the gasket, do you know when you will be getting more?

Jake