Author Topic: compression  (Read 1192 times)

68Zproject

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compression
« 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.
68Z28

69Z28-RS

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Re: compression
« Reply #1 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%...
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
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68Zproject

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Re: compression
« Reply #2 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.
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tmodel66

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Re: compression
« Reply #3 on: May 22, 2012, 04:59:22 PM »
Did you pin the studs after you found this?
Daniel  
'69 SS 350/4 speed  Fathom Green--POP

68Zproject

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Re: compression
« Reply #4 on: May 23, 2012, 12:02:11 AM »
No, I'm putting in the screw in ones that look like originals.
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srode

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Re: compression
« Reply #5 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. 
Steve - 02D Z11 and a Plain Jane hardtop