01-16-2007, 12:15 AM | #1 |
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compression
im getting ready to do a compression test and i was wondering what the numbers were originaly on a 72 sb350 4b?? im also getting ready to change the valve guides to stop it from burning oil and fouling plugs, is there any tips or advice anybody has to offer??
thanks in advance -steven
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME Last edited by GREASEMONKEY72; 01-16-2007 at 12:16 AM. |
01-16-2007, 12:27 AM | #2 |
The Hammer Man
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Re: compression
ttt
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Boise69. Bought in Boise ID and its a '69 ___________________________________________ 1969 Chevy C-10 SWB 350/400 - drivable project www.americanhammer.com 2013 MBZ Sprinter customized 2005 MBZ Sprinter Van 2004 Land Rover Discovery 2001 Yamaha Road Star 1997 MBZ E420 1989 Ferrari Mondial T |
01-16-2007, 12:52 AM | #3 |
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Re: compression
thanks Boise69
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
01-16-2007, 01:06 AM | #4 |
The Hammer Man
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Re: compression
hey i have the same questions and situation, so i'll be watching this one
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Boise69. Bought in Boise ID and its a '69 ___________________________________________ 1969 Chevy C-10 SWB 350/400 - drivable project www.americanhammer.com 2013 MBZ Sprinter customized 2005 MBZ Sprinter Van 2004 Land Rover Discovery 2001 Yamaha Road Star 1997 MBZ E420 1989 Ferrari Mondial T |
01-16-2007, 01:11 AM | #5 |
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Re: compression
dont know on compresion, probeblt around 150psi, if you are changing you valve guides you need to pull the heads, if you are changing the valve seals you can hook up an air hose to your spark plug hole from an air compresor to hold up the valve while you remove the spring. I like to bring the piston to the top as well as a fail safe so you dont drop the valve in the cylinder. I also recomend the umbrella seals, insted of the o rings
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01-16-2007, 01:13 AM | #6 |
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Re: compression
120 to 150 psi is my thinking. Add oil thru spark plug and retest if it jumps 10psi you have bad rings. You prolly know this tho.lol Im not sure Id just do the guides.....proballt time for a more complete check 2cents delivered.
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01-16-2007, 01:59 AM | #7 |
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Re: compression
we are going to change the seals but kepp calling them valve guides i dont why and i have the house to hook up to the plug hole air in the cylinder and thanks for the tip on the umbrella seals and thanks also for the comp numbers and ill let you guys know what happens and ill try to take pictures and post them for reference if anybody should need them
-steven
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
01-16-2007, 08:02 AM | #8 |
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Re: compression
i did a rebuild last year and did a compression test , the average was 120psi per cylinder
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hey.....smell my finger 64 nova wagon , 63 nova convertible |
01-16-2007, 08:49 PM | #9 |
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Re: compression
thanks jbon64
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
01-16-2007, 11:07 PM | #10 |
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Re: compression
I have a Haynes manual and it says 150 psi for all V8s. I did a compression test on my old 307 that has 100k miles on it without any rebuild and got a little over 150, about 155-160. But it probably has a lot of carbon build up in it. Although I remember reading somewhere that a good street engine should make about 180, but I think that that was in one of David Vizard's books on how to build max performance sbc, so it might be a little high for a regular old engine.
Just remember to keep the throttle wide open while doing the test or it won't be able to suck as much air. Hope this helps.
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1968 C-10 longbed, 307 V8, 4spd- currently under construction Last edited by chevyc1068; 01-16-2007 at 11:07 PM. |
01-17-2007, 12:11 AM | #11 |
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Re: compression
My GMC service manual from 1969 says 150 lbs for all v-8s also.
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01-17-2007, 04:08 AM | #12 |
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Re: compression
thanks alot guys i really appreciate it
-steven
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
01-27-2007, 10:06 PM | #13 |
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Re: compression
so how low is too low? I tested my 327 today and had from 129-149 average for the cylinders... I guess that it's ok then?
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01-28-2007, 01:17 AM | #14 |
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Re: compression
well when i did mine the highest one was 155 and the lowest was 124 so its not perfect but its not horrible either but im gona do seafoam eventually and then do the test again and see how much of a difference there is
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-steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME |
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