Compression problem
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
Posting pics here of found conditions can help us to help you.
At minimum, pull VC on side where zero pressure .... look at retainers-valves on cylinder w/ zero pressure ... see if it's stuck open.
As RD says ... Probably need to pull heads & inspect valvetrain & cylinder bores.
Before you pull heads, Help yourself by bringing #1 cyl to TDC with timing mark at zero and rotor pointing toward #1 cyl.
Make a Crayon-mark at base of dist & adjacent on intake ... that's your reference index. Then pull dist, then intake, then heads.
again, Posting pics here of found conditions can help us to help you.
At minimum, pull VC on side where zero pressure .... look at retainers-valves on cylinder w/ zero pressure ... see if it's stuck open.
As RD says ... Probably need to pull heads & inspect valvetrain & cylinder bores.
Before you pull heads, Help yourself by bringing #1 cyl to TDC with timing mark at zero and rotor pointing toward #1 cyl.
Make a Crayon-mark at base of dist & adjacent on intake ... that's your reference index. Then pull dist, then intake, then heads.
again, Posting pics here of found conditions can help us to help you.
Drifting
Joined: Aug 2013
Posts: 1,263
Likes: 512
From: perth Aus w.a
2020 Corvette of the Year Finalist (stock)
C3 of Year Winner (stock) 2019
I would remove valve covers and try to wiggle each rocker to see if they are loose or to look for any thing that don't look right .Always check the simple or obvious things first 
Drifting
Joined: Aug 2013
Posts: 1,263
Likes: 512
From: perth Aus w.a
2020 Corvette of the Year Finalist (stock)
C3 of Year Winner (stock) 2019
Check your valve springs ,I had two broken on my l68 and they were hard to see because the inside spring held the rocker up so everything looked ok
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
There is always the chance the compression tester itself was not fully seated in the head. This would be nice to know before jumping the gun and ripping things apart.
Diagnostics is everything. Diagnosing saves time, money and embarrassment. Premature disassembly is foolish.
It could be something real simple and cheap. Take your time with it. You can not have good compression if a cylinder can not get air. Why is that cylinder not getting air?
(see post 7, again)
Diagnostics is everything. Diagnosing saves time, money and embarrassment. Premature disassembly is foolish.
It could be something real simple and cheap. Take your time with it. You can not have good compression if a cylinder can not get air. Why is that cylinder not getting air?
(see post 7, again)
Last edited by HeadsU.P.; Sep 21, 2019 at 07:00 PM.
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