Help Low compression in one of my Cylinders

sebas54

sebas54

Petty Officer 1st Class
Joined
Jun 17, 2007
Messages
334
Hi, I have just checked the compression on my engine. The compression is 140 90 140. I have a 1987 4.3l merc. Could this be becaus of the head gasket? If not, what else could be the problem? Could the head be cracked? I am very desperate to get this fixed because i love to fish and the stripers are here. Is this worth fixing? Please help.
 
Haut Medoc

Haut Medoc

Supreme Mariner
Joined
Jun 29, 2004
Messages
10,645
Re: Help Low compression in one of my Cylinders


Put a little oil in that cylinder & see what happens to the compression.....
Could be rings, could be valves.....;)​
 
Bondo

Bondo

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Apr 17, 2002
Messages
71,357
Re: Help Low compression in one of my Cylinders

Ayuh,.......

What Haut said,............

Btw,....... That's only 3 holes,...... What's the Other 3,..??....
 
Don S

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Help Low compression in one of my Cylinders

I am very desperate to get this fixed because i love to fish and the stripers are here.
Click to expand...

Time to slow down, find the problem, fix it correctly, then go fishing. Or hurry, take short cuts, spend 2 to 3 times the time to finally get it slightly usable for 10 minutes, then it falls apart again.

I just have to ask, why did you want to do a compression test to begin with. Because it was running rough?
How old are the exhaust manifolds?
Did you see any rust or water on the spark plug that came out of the 90psi cylinder.
Lilke Bondo, what about the other 3 cylinders.
Do you know how to do a leakdown test on the cylinders?
 
sebas54

sebas54

Petty Officer 1st Class
Joined
Jun 17, 2007
Messages
334
Re: Help Low compression in one of my Cylinders

Thanks for the replies and the info. I think that the mans/rise are 2- 3 years old. I dont have a compressor do a leak test. I don't know the compression on the other side. I have started a new thread and have posted pics of my head and gasket. Please help
 
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