I am looking to get a new head for my 1993 Ford Explorer XLT engine after
the intake valve on the middle cylender got damaged. Appearantly it's not
closing properly and dumping the gas/air/oil mixture into the intake
manifold. Me and a mechanic looked at it and after he connected a pressure
tester to it we found that it was only getting 50psi while the other
cylenders were getting 150psi each.
Anyway my question is, were the engines in the Explorers similiar for
several years? Because I am probably going to have to goto a junk yard and
look for heads from any Explorer engines I might find and in case no one has
a 93 engine I'm wondering that if the engine of a 92, 93, 94, etc were
similiar or the same?
First, has your mechanic done a leakdown test on the
cylinder to determine why the compression is low? If not,
you may have a problem other than a bad valve like a flat
cam lobe, a bent pushrod or a failed piston in which cases,
your replacement head and the labor to install will be
If you confirm that the valve is the problem, your best bet
is to have the head reconditioned. That way, you know you
have the right parts and what you have to work with. Next
option is to check your local salvage yard for a used head
thatthey are willing to warranty. They have what is called
a Hollanders Manual which will list all of the
interchangeable heads and which vehicles should have them
along with the correct casting numbers to look for. If the
proble is determined to be other than the head, you may have
to consider other options. For example, a bent pushrod
would be a quick fix for under $30 in parts - unless, of
course, the cause of that failure was a failed lifter. But,
then, you have to depend on your mechanic friend to make the
call. That's why you need a competent tech on occasion for
the simplest of problems.
Thanks for the information. As for the mechanic and his capabilities, he's
a friend of mine that I grew up with, just graduated from a college in
Carlise, PA that specalizes in extremely high performance engines, bodywork,
etc. Plus with my computer business I did his and his families computer
work for free and he is going to be handling the labor for free on this as
well. Basically all I would be paying for is a new head or any other parts
Didn't mean to denigrate your friends mechanical ability.
It is good that you have a longterm relationship with him
such that you can properly take him to the woodshed when he
screws up or buy him a cold one for a job well done. Just
wanted to point out that a complete diagnosis should be made
before the heavy tools are brought out and that you may have
better more cost effective options than complete head
replacement. I have seen used heads cause more trouble than
they were worth or more than the ones they replace. A
cylinder leak test is a very basic test that cam be
accopmlished with nothing more than a plug hole adapter and
an air hose. Once your are sure the cylinder is leaking, it
is easy to listen in the intake, exhaust, and crankcase to
determine where the air is going. If it not escaping in one
or more of those directions, the problem may very well be a
bent pushrod, collapsed lifter or flat cam lobe. All of
We talked between doing those two things, letting him take out the head and
taking it to a machine shop and letting them bore out the valve seat (if
it's for sure the valve) and then press in a new valve seat and then he'd
reinstall it for me.
I'll pass along the info regarding the leak test and have him try that. We
was at his garage the other evening where he had his tools. I was inside
finishing up the computers while he was running tests on the explorer.
Sounds like he just did a compression test. How did he know it was a
valve if that all he did? Did he do a cylinder leak down test with
compressed air and listen for leaks?
If he only did a compression test, i wonder how he thought it was the
valves. Could be stuck rings or even a leaking head gasket.
(or even a cracked head)
If its truly the head, take it off and take it to a machine shop.
chances are they can redo it and then your guaranteed that it will work
since its the head that came off the motor. If you have a valve problem,
they can only change out that bad valve. But i would have the rest of
them checked and new seals put in while the head is off.
If its too far off, you might as well do both heads.
A GOOD machine shop will tell you what they recommend if you ask.
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