dk98classic

I own a 98 4L, can I go find any 4.0L head? I have seen other posts on weaknesses of different head castings and such. I am looking to pick up a later model equal length intake, just what head is a good head to build.

Thanks

JeepCoMJ

the '95 head (i forget casting number) is arguably the best year to use.

why are you considering replacing your head?

dk98classic

I haven't confirmed it yet, but, I have done a compression test and #1 is low, 80psi. I will be diving into it later this week to take the head off and so how far I am going with it. Will be doing a wet comp test to see if it is the rings or the just the top end.
Crossing my fingers.

JeepCoMJ

any time a 4.0 has low compression, it's typically rings.

dk98classic

How can that be confirmed? Looking at the Hayes manual, I saw a compression test result that said something about a cracked head or bad cam lobe? I will say I am hoping for the cheaper of the option. Just got the Jeep 2 months ago. The mechanic close to where I bought it from said the rough idle is a possible exhaust leak. OOPS! Should have dug deeper...

JeepCoMJ

pull the valve cover off, and pull the relay for the fuel pump.

have someone crank it over, and observe the rockers, lifters, and valves move.


if that cylinder moves funny, a bad cam lobe or bent push rod/rocker is your likely issue.


otherwise, remove the head, inspect the valve seat, and inspect the cylinder wall. if there is scoring, it's probably the rings.


the head that is prone to cracking is prone to craking between cylinder 3 and 4, or 4 and 5.

JeepCoMJ

and it's kind of a long haul, but I'm located a half hour south of milwaukee, and have a ready to go 4.0 for sale...fully resealed and inspected by me.


all it needs is your manifolds, sensors, water pump, thermostat and housing, flywheel and distributor. maybe paint if you don't like yellow lol. but $450 is less money than you'd spend on a head, head job, and gasket set for your motor.

dk98classic

Sent e-mail, let's talk.

dk91ls@yahoo.com