Hi Guys, Have any of you big motor guys ever checked your cranking compression?  Just wondering what the norm is without a decomp on the ex. cam. Checked mine last night and it showed 265 psi.  

Edited by james509, 11 June 2012 - 10:25 AM.

right in line with what i see depending on how i set them up. some times less sometimes more depending on cam timing and final compression setting.

I normally do leak downs, not compression.. so only have mine to gauge off of.

Notes say that's about what I see on mine

Thanks Guys, I'm not having any trouble with it, just curious what the cranking compression was on other strokers.

Hey James...Have you got a manual decomp fitted??
I recieved my head back from Eddie recently,got him to fit one on the SM head,along with new valves etc....
I am going to install  it this week and finally get the beast back on the road,
It's been a non goer since I busted my ribs on it last November when the head gasket let go...
I figure the man decomp is going to make start ups much easier on the starter motor...
I haven't actually measured the cranking compression, but I figure it's way up there...A 410cca lithium will barely look at starting it....

Adding the manual decomp mechanism certainly helped mine on the starting front, now I know it will fire right up.

No, I havn't tried the manual decomp yet/ My first head was setup for it but the new head isn't. Maybe this winter I'll get it machined to fit it. Craig, I hope your ribs are feeling better. I know how painful it can be.

james509, on 12 June 2012 - 05:07 PM, said:

Thanks for the thought....Prob still around the the 80% better mark...
I am back into cycling, but body repairs take way longer the bike repair,especially as we get older.....