4.3l V6 cylinder head work

YJJPWrangler

YJJPWrangler

Well-Known Member
Joined
Jul 19, 2005
Location
Charlotte
so I am at a dilemma. I am debating on whether or not to get the cylinder heads magnafluxed, decked, and new valves installed. The motor in question is a 1991 4.3l V6. From the tag on this motor, it was rebuilt in 1999 by GM. I have pulled the motor completely apart and the head gaskets look very clean. My only concern is that I had a small amount of oil on top of the piston in cylinder 2. No milky oil was present. Is it worth it to spend $3-500 on the heads at this point? Or do I just put the motor back together with new gaskets etc.?

Thanks,

Zack
 
Thats the only issue I see so far. I just don't want to button this thing back up and theres an issue somewhere. But on the other hand, I dont' want to spend unnecessary money on it. Ill get everything good and cleaned up and then give it a thorough inspection.
 
IMHO, let it be until you fire it up and actually have an issue... otherwise, you might be replacing stem seals, etc. that are completely fine for another 8-10 years.
Heads ain't that hard to yank and then your only out another set of upper end gaskets.

Unless you're one of the anal retentives that go thru near new running engines "just because"? :D
 
Well the only reason I tore it apart was nobody had a history of it running. However after tearing it apart, I see no reason not to just run it. Looks like I'll be ordering some gaskets from summit as well as a few other things.
 
Yes, stem seals aren't too bad. Advance rents a nice compressor for heads off the engine. Was there crap in the coolant? I would do a visual check of the combustion chambers for cracks at minimum and also check flatness, or drop it by a machine shop get it checked if you don't have the ability to. My machine guy probably would just run a precision block with paper over it to check flatness roughly. Worth doing it only one time imo. May as well at least leak check the valves with cleaner if you are going to bother with pulling them and stem seals. You can always give them a quick lap if they aren't way out. Or even if they aren't. Better valve seal never hurts anything.

Did you perform a compression and leak down test prior to pulling the heads?
 
I do not know if there was any crud in the coolant. Nobody seems to know the history of this motor(got it from @BigJUGGY). He got it from his neighbor who was planning on an engine swap. Tag on the motor said it was rebuilt in 99 by GM. As far as I know it has not been installed on anything. There was no coolant in the oil and the heads/combustion chambers look very clean.

I rented a valve stem compressor and will hopefully knock that out today. I did not run a compression test on the motor prior to tear down.
 
Back
Top