The Grief Continues
02-06-2009, 10:40 PM
#1
2nd Gear Member
Thread Starter
Join Date: May 2005
Location: Oregon
Posts: 206
The Grief Continues
Well, my ongoing saga of mystery and woe continues.
A month ago I developed a leaking head gasket. I removed the heads (AFR 165) and took them to a reliable shop I've used before. They did a routine resurface on them, and supposedly completely checked them out. They even removed the valves to clean everything.
I decided that while I had the top-end of the engine off, I would take the opportunity to replace my totally stock upper intake with an Explorer intake. I got the new upper and lower intake, all new gaskets, Felpro MLS head gaskets, new ARP head bolts, thoroughly and carefully cleaned everything up and put it all back together. Ever since the head gasket job, I've been very noticeably down on power. I've eliminated all possibilities of vacuum leak, replaced my ten year old fuel pump with a new Walbro, new plugs, cap, rotor all to no avail.
This engine only has 18000 miles on it, and I've never taken it over 4000 rpm! It's my daily driver, and I'm careful with it. I use only Royal Purple oil, and I change it religiously every 3000 miles. Well, for some reason, I had a nagging feeling that I ought to do a compression test. I did one about six months ago, and all readings were within one or two psi of each other. Well, I just got done with the test, and my readings were all between 171 and 175 psi . . . except for number five; it was 140!!! My first suspicion was that the head shop had messed up a valve or stem seal (innocently enough). One site I read on said that one low cylinder was usually indicative of a problem with the exhaust valve.
But here's what made my heart sink. I squirted oil into number five and reran the compression test, and it came up to the same value as the others. This would seem to indicate a problem with the cylinder or rings, would it not? When I had the heads off, I carefully inspected each cylinder and they all looked perfect.
Ideas please!
A month ago I developed a leaking head gasket. I removed the heads (AFR 165) and took them to a reliable shop I've used before. They did a routine resurface on them, and supposedly completely checked them out. They even removed the valves to clean everything.
I decided that while I had the top-end of the engine off, I would take the opportunity to replace my totally stock upper intake with an Explorer intake. I got the new upper and lower intake, all new gaskets, Felpro MLS head gaskets, new ARP head bolts, thoroughly and carefully cleaned everything up and put it all back together. Ever since the head gasket job, I've been very noticeably down on power. I've eliminated all possibilities of vacuum leak, replaced my ten year old fuel pump with a new Walbro, new plugs, cap, rotor all to no avail.
This engine only has 18000 miles on it, and I've never taken it over 4000 rpm! It's my daily driver, and I'm careful with it. I use only Royal Purple oil, and I change it religiously every 3000 miles. Well, for some reason, I had a nagging feeling that I ought to do a compression test. I did one about six months ago, and all readings were within one or two psi of each other. Well, I just got done with the test, and my readings were all between 171 and 175 psi . . . except for number five; it was 140!!! My first suspicion was that the head shop had messed up a valve or stem seal (innocently enough). One site I read on said that one low cylinder was usually indicative of a problem with the exhaust valve.
But here's what made my heart sink. I squirted oil into number five and reran the compression test, and it came up to the same value as the others. This would seem to indicate a problem with the cylinder or rings, would it not? When I had the heads off, I carefully inspected each cylinder and they all looked perfect.
Ideas please!
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