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post #1 of (permalink) Old 04-12-2003, 11:41 PM Thread Starter
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Need help fine tuning 4.3 in jeep (long)

I just purchased a CJ 7 with a freshly rebuilt 4.3 in it. So far, it has been a dream come true, but I have a couple small issues. I would have gone to the regular jeep bbs but I figured who would know more about the 4.3 than the chevy crowd. Any ways, here are some stats to familiarize you with my setup: rebuilt about 120 miles ago, bored .40 over on a non-vortec block, flat top .40 over pistons, crane roller torque cam with roller lifters, TBI with entire wiring harness, MSD blaster coil, timed at 6 degrees, permacool electric fan only mounted directly on 3 core radiator, vortec heads and edelbrock performer intake. The permacool fan is not on a relay as it is only hooked up to a toggle switch inside the cab (for water crossings).I dont know what my compression is, but I bet it is up there. I beleive the thermostat is 160, but it might be a 180. There is no AC compressor either. I want to set up my fan on a relay, but I want to get all my numbers for my thermostat and temp sending unit right. Stop and go traffic is around 180, but highway right now is around 210, and that is only April in Texas. June, Jul and Aug will overheat it for sure. As of right now, I am sure some of that heat is being generated due to the break in of the new (tight) engine, but as I stated before, I want to get it all set up so it will run just below 200. Am I taking the right path, or should I learn to live with the 210? Thank you for any help!! [img]images/graemlins/AR15firing.gif[/img]
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post #2 of (permalink) Old 04-13-2003, 12:34 AM
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Re: Need help fine tuning 4.3 in jeep (long)

Quite honestly, my '98 4.3 always ran at around 210, or just slightly lower (195/200). It's not necessarily a bad thing, and this is also with the stock fan and fan clutch. This was without AC also.

Perhaps there is a way for you to relay the fan, but have a cutoff switch anyway for water crossings still?

If you want to get it around 195, that might be a good path to follow.

J.R. is offline  
post #3 of (permalink) Old 04-17-2003, 12:50 AM
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Re: Need help fine tuning 4.3 in jeep (long)

Is the engine running V-belts or a Serpentine belt?
You have to be real careful here, because you can cook the engine in a hurry!
See, the V-belt configuration turns the water pump in the standard rotation, while a Serp belt turns the water pump in reverse rotation. Did or does the wter pump look new? The only way to check the water pump itself is to pull it out and pull the cover plate off the back to check the direction of the vanes on the impeller.
If the wrong water pump is installed, the coolant will cavitate inside the block and pump, and cause the condition you're describing. It will also try to force some coolant up through the radiator backwards to the thermostat.

Check it out, and get back to me if you need any more help.
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