Compression numbers in...bad news

[jeepthing]

Well, I confirmed what I expected.... I did a compression check today, and all cylinders were 155 range, except number 4 at 90.

That plug was fouled when I originally bought it and did the tfi upgrade. When I pulled the plug this time, it had fresh oil on it... the car also idles very rough, and just doesn't seem to have that much power.

In case it's a ring problem, isn't there something I can add to the oil or something to help it seat... I'm screwed any way I look at it, so I'm looking for options to extend the time until I need a rebuild...

[Crazy_Jeepman]

squirt a bit of oil down that cyl through the spark plug hole, then do another compression test on it. If it comes up its rings, if not its a valve. I think by the others and the drop in one Cyl. it sounds like a Valve. Even if it were rings, I do not think you would notice it running bad with the compression drop on only one Cyl.

[Rogue]

if it were the rings it would pretty much have to be broken to leak down that much - sorry no miracle in the bottle here - looks like you are facing teardown, good luck

[FSJeeper]

Originally posted by RogueStar:
if it were the rings it would pretty much have to be broken to leak down that much - sorry no miracle in the bottle here - looks like you are facing teardown, good luckI second this motion. Fix it right the first time and you will be money ahead. The longer you wait, the more you take the chance of screwing up your cylinder bore. You can sleeve that one cylinder if it is scored out of spec though.

[porchpiggy]

I've got to go with Crazy a little on this one, I've got a SBC with similar numbers, one cylinder at 90, but it uses very little oil and runs smooth as silk, lots of power. I don't think a more worn ring on one hole would make it run bad. Unless maybe it is what caused the plug to fowl fast.

[Crazy_Jeepman]

Do a vacuum test as well. That would show up a bad intake valve. Bad intake valve on one Cyl would make a differance in the way it runs. more noticeable than a bad cyl.

[mechanic58]

Engines will fool ya sometimes. Burned or bent or stuck valves cause wierd symptoms. I had a 2.3L ford one time (in a pinto...lol) that spun #1 rod bearing and eventually through that rod. I took the rockers off that cylinder and drove the car for 3 months. It ran fine...even idled smoothly. Just sounded like it was a couple a sandwiches short of a picnic. NOW I KNOW YOU GUYS KNOW I DON'T LIKE FORDS...BUT I WAS JUST A KID THEN. Cut me some slack.

[PAJEEPER]

Originally posted by mechanic58:
Engines will fool ya sometimes. Burned or bent or stuck valves cause wierd symptoms. I had a 2.3L ford one time (in a pinto...lol) that spun #1 rod bearing and eventually through that rod. I took the rockers off that cylinder and drove the car for 3 months. It ran fine...even idled smoothly. Just sounded like it was a couple a sandwiches short of a picnic. NOW I KNOW YOU GUYS KNOW I DON'T LIKE FORDS...BUT I WAS JUST A KID THEN. Cut me some slack.Oh come on man you darn well that Fords rock!! See it still ran didnt it?
tongue.gif

[ February 02, 2003, 04:38 PM: Message edited by: PAJEEPER ]