View Full Version : rebuilding a 4.0
09-09-2007, 07:05 PM
Were would you get a rebuild kit from? I plan on using the comps 410 cam, maybe ported and polished heads and intake, what esle would you guys recomend for the 4.0 rebuild it is in a 1994. It will be used for fourwheeling and thats about it.
Any auto parts store will sell you a large number of rebuild kits, but it really has to be based on an inspection. If you really need to replace all the internals, just get another used engine. Few of them are in THAT bad shape. In particular, the crank, cam, and timing set should be pretty good. You may or may not need to replace pistons and rods, depending if you bore the engine or not.
If you're four wheeling, you do not need power mods. Most of them hurt low end performance.
09-11-2007, 04:03 PM
I agree with MAKG. If you had the time a cyl head pocket port might make a little more power but probably only at higher engine speeds. You could try getting custom pistons or milled the heads to increase compression but then you'd have to run premium gas. I think the Comp Cams cam is pretty tame at 204* at 0.050" lift but a stock cam most likely has better off-idle power.
For reliability and torque production I would stick to external mods like headers and a full exhaust. You could also ditch the fan clutch and run an electric fan. From there just take weight out of the rig where possible.
09-11-2007, 09:11 PM
I mostly agree with these guys......I bet back cut valves might help low rpm power a tiny bit but I have no 4.0 experience to back that up.
09-11-2007, 09:44 PM
Im sure mike will chirp back in on this one too, i agree just do a basic rebuild and you will be happy, don't use a e-fan.
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