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preferred heads
Posted: July 6th, 2013, 10:09 am
by heavy equipment
I've seen a list of preferred heads but now I can't find it.
Also, I'd like to know where to find the casting number on the head.
All suggestions will be appreciated, thanks!
Re: preferred heads
Posted: July 6th, 2013, 12:03 pm
by Cheromaniac
http://www.jeep4.0performance.4mg.com/tech_specs.html
The casting no. is stamped on the top driver's side about halfway along.
Re: preferred heads
Posted: July 6th, 2013, 1:30 pm
by heavy equipment
Thanks, Cheromaniac, for the quick response. That gave me all I needed to know. My grandson's Cherokee (my old '89) has a compression leak into the coolant. I don't know yet where the leak is, but I'm gathering information while he pulls the head.
I invented a simple trick to check for compression leaking into the coolant. This has the old style cooling system with the pressure tank and no overflow tube. I tied a piece of plastic bag over the filler neck and secured it with a rubber band. Had my grandson start it and the bag inflated instantly - didn't even have to do a "stall test."
Re: preferred heads
Posted: July 6th, 2013, 6:58 pm
by SilverXJ
Nice trick. You will want a 0630 or 7120 head.
Re: preferred heads
Posted: July 6th, 2013, 9:36 pm
by heavy equipment
Well, we got the head off and it looks like it's just warped. Much cheaper than cracked! I don't have a good enough straight edge to check, but I saw traces of rust in every cylinder and imprints of the steel liners around each cylinder hole in the gasket doesn't go all the way around. This head is a 2686 and appropriate for this engine. My own cherokee has a new 4.7L stroker (that I built), but the one we're working on is a stock '89. If we don't find cracks we'll go back with it, after checking for valves sealing. Grandson doesn't pull heavy loads with it as I do, he just needs it to run well without overheating.
Thanks for the advice - I'll make use of it next time I build one.