#3 cylinder dead,...HELP!
Laughing Gas
Joined: Jul 1999
Posts: 1,047
Likes: 22
From: Lacey, WA
#3 cylinder dead,...HELP!
It's a 390 in my 70 F-250 4x4. Did a compression check all average 135psi except #3. It is 15psi. Pulled the valve cover and had my son turn it over. Valves appear to be operating normaly. Only odd thing I found is that the exhaust push rod does not spin freely like the rest. I put my finger over the spark plug hole and get weak air flow during cranking. Head is a C8AE-H.
Also found some ground up material laying on the head. It is either hard plastic or brittle metal. I can break the pieces with my fingers. Wonder what it could be from?
Any ideas on what I should do next? On a side note I have owned the truck ~2 years and only put 2K miles on it. It runs OK oddly enough just has never had the power I thought it should have. Now I know why.
Thanks,
Lee
Also found some ground up material laying on the head. It is either hard plastic or brittle metal. I can break the pieces with my fingers. Wonder what it could be from?
Any ideas on what I should do next? On a side note I have owned the truck ~2 years and only put 2K miles on it. It runs OK oddly enough just has never had the power I thought it should have. Now I know why.
Thanks,
Lee
Post Fiend
Joined: Feb 2000
Posts: 5,130
Likes: 8
From: Brea CA
#3 cylinder dead,...HELP!
Maybe exhaust seat recession? Check the exhaust valve stem height, is it the same as the others? The ground-up material could be what’s left of those umbrella type valve stem seals.
