Super Jet Can I use 83 mm domes with 85 mm bored cylinder?

[kabaraka]

Hi , I bought the ADA girdled head that came with the 83 mm domes and used with my 84 mm bored cylinder. Then I rebuilt my engine and bored to use with 85 mm pistons with the same domes. So I wondered if it's ok? I'm worried about the o-ring domes that sit closely to the top of the sleeves might get too hot till melting? The engine runs great right now, by the way. But afraid that the o-rings won't last.

 

[Sospikey]

Nope, no good. Use the 760 size domes ( for 84 mm and up).

 

[sjetrider]

not unless you clearance them, then its a crap shoot on compression. They may work if you have like .060 initial squish which I doubt with aftermarket head.

 

[#ZERO]

The ADA O-rings are the same size for the 701 & 760 domes so that won't be an issue but your squish relief is .015" with an 83mm diameter with 10.5degree angle on the 701 domes and it's .015" with an 86mm diameter on the 760 domes. You may want to have someone increase the squish diameter slightly using a lathe or just go with the 760 domes.

 

[kabaraka]

Thanks a lot everyone for good helps