cyl compr test.
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
cyl compr test.
Hi
You might remember my saga about the broken engine head rockers.
2 ea intake and one exhaust rocker just broke like glass after having them in for less than 500 Miles.
I didn't worry about the intake rockers as this should not harm the engine not getting air to fill the piston, but the exhaust rocker was very noisy as the burned gas had no way out except through the piston rings or back into the carb. :mad
So I did a compression check on all pistons, what do you think ?
I hope that the difference is from the old original L71 heads, no work has been done to them so far.
Oh, it's a 427 11.5 compr engine.
All in all, they push pretty high ( 11 + Bar ), don't they ?
I used a push on tester, not a screw on type, so slight losses might have occured.
Gunther
[Modified by WESCH, 5:43 AM 4/20/2002]
You might remember my saga about the broken engine head rockers.
2 ea intake and one exhaust rocker just broke like glass after having them in for less than 500 Miles.
I didn't worry about the intake rockers as this should not harm the engine not getting air to fill the piston, but the exhaust rocker was very noisy as the burned gas had no way out except through the piston rings or back into the carb. :mad
So I did a compression check on all pistons, what do you think ?
I hope that the difference is from the old original L71 heads, no work has been done to them so far.
Oh, it's a 427 11.5 compr engine.
All in all, they push pretty high ( 11 + Bar ), don't they ?
I used a push on tester, not a screw on type, so slight losses might have occured.
Gunther
[Modified by WESCH, 5:43 AM 4/20/2002]
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 98
From: Ontario
Re: cyl compr test. (WESCH)
A bar is 14.5 pounds per square inch (psi). So you are peaking at about 150-160psi in each cylinder consistent one to the other. I will leave it to the engine experts - I have never seen this type of chart before - to interpret but that looks pretty fine to me.
[Modified by paul79, 3:26 PM 4/20/2002]
[Modified by paul79, 3:26 PM 4/20/2002]
Pro
Joined: Feb 2002
Posts: 543
Likes: 0
From: nyc ny
Re: cyl compr test. (WESCH)
considering the push on type tester u are in the money. What you are lookin for is uniformity form cylinder to cylinder. what should do is a leak down test that is a better barometer for internal engine health and can point out your trouble spots ,,,good luck with it :cool: :seeya
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 3,330
Likes: 13
From: Europe , Luxembourg
Re: cyl compr test. (One GM A Tech)
Thanks.
What I was looking for is damage to the piston rings, valve seat or any major other fault, this caused by the failing exhaust rocker. I was afraight about the hot burned gas not finding a way out through the correct way. ( exhaust valve into exhaust , as the valve stayed closed ).
It looks like if nothing major has happened ?
How much difference between cyl press is considered still healthy ?
Thanks Paul79 to help me on this Bar issue.
Your correct, 1 Bar is 14,50377 pounds/inch2 , so 11 Bar is about 160 PSI.
Over here in Europe, we do use metrical units ( not feed , arms or legs )
:lol:
Anyway, I'm working in the airline business, and our company operates B747-400 , so I'm also used to your units. :D
Thanks a lot. Gunther :seeya
What I was looking for is damage to the piston rings, valve seat or any major other fault, this caused by the failing exhaust rocker. I was afraight about the hot burned gas not finding a way out through the correct way. ( exhaust valve into exhaust , as the valve stayed closed ).
It looks like if nothing major has happened ?
How much difference between cyl press is considered still healthy ?
Thanks Paul79 to help me on this Bar issue.
Your correct, 1 Bar is 14,50377 pounds/inch2 , so 11 Bar is about 160 PSI.
Over here in Europe, we do use metrical units ( not feed , arms or legs )
:lol:
Anyway, I'm working in the airline business, and our company operates B747-400 , so I'm also used to your units. :D
Thanks a lot. Gunther :seeya
