4.3L engine compression

[Faerbairn]

Here are the compression numbers. Any ideas what is causing the 95? Could the valves be slightly open or carbon build up?

#1 150psi
#2 160
#3 160
#4 95 ??
#5 145
#6 130

Thanks,

Adam

 

[JustJason]

Re: 4.3L engine compression

Could be the valves... could be the rings.... could be a head gasket.... only way your going to find out for sure is to do a leakdown test.

 

[mthieme]

Re: 4.3L engine compression

You could a wet test to narrow it down from lower / top end.

 

[JustJason]

Re: 4.3L engine compression

eagh..... a wet test does nothing more than load the compression gauge full of oil.
IMHO

 

[mthieme]

Re: 4.3L engine compression

Don't use some much oil.

 

[Faerbairn]

Re: 4.3L engine compression

Thank you for your input. How do I do a leak down test?

Thanks..

 

[JUSTINTIME]

Re: 4.3L engine compression

you need a leak down gauge
where is the boat?

 

[iang]

Re: 4.3L engine compression

Ex Riser leaking onto No 4 valve causing it to rust and seat badly???

 

[JustJason]

Re: 4.3L engine compression

google "leak down test"

 

[mthieme]

Re: 4.3L engine compression

Ex Riser leaking onto No 4 valve causing it to rust and seat badly???

Possible.
Have you removed the manifold and inspected?