CRG Discussion Forum

Camaro Research Group Discussion => Maintenance => Topic started by: 68Zproject on May 21, 2012, 04:27:47 PM

Title: compression
Post by: 68Zproject on May 21, 2012, 04:27:47 PM
I read some threads about what the compression should be on a 302 ,but I don't have the original 30-30 cam.  I have a ccxs282s.  Anyway I did a compression test because I had a full throttle episode and then it ran a little rough.  I freaked out but was relieved when I took off a valve cover and found I pulled two rocker studs and didn't damage anything. However, My compression was 210-230 on every cylinder and I thought that was a little high.
Title: Re: compression
Post by: 69Z28-RS on May 21, 2012, 05:40:10 PM
Were the studs partially pulled?  or pulled totally out?   Did it damage your valve covers?  When I bought my '69, back in '76, one of the valve covers had been cracked (and welded) as had the head...   due to a stud being pulled out..
 
PS.  I'm unaware of any engine problem that would make all the cylinders exhibit consistent 'high' compressions..  :)
I'd think your engine is OK with those numbers; 210-230 is 5%...
Title: Re: compression
Post by: 68Zproject on May 22, 2012, 04:48:24 PM
No, partially pulled out.  In fact I couldn't tell at first and tried to lash them down with no success.  Then I measured them.  No damage and I sure got lucky.  Apparently my cam doesn't bleed off pressure like the original.
Title: Re: compression
Post by: tmodel66 on May 22, 2012, 04:59:22 PM
Did you pin the studs after you found this?
Title: Re: compression
Post by: 68Zproject on May 23, 2012, 12:02:11 AM
No, I'm putting in the screw in ones that look like originals.
Title: Re: compression
Post by: srode on May 23, 2012, 12:25:29 AM
I used to have 250 on a 350 with 11:1 pistons and 64 cc heads - I don't remember what cc the 302s heads were.  A 350 would have a little more compression with a comparable domed piston due to the stroke though.