Hello everyone. I've got a Jeep 4.0, I'm on my 2nd attempt at a rebuild and it's kicking my a** It's not a stroker but I figure y'all know the ins & outs of these engines pretty well so I'm hoping someone has advice.
Pulled a low mileage engine from a 94 XJ, stripped it down, honed the cylinders and assembled it with new rings & bearings, all stock-sized standard parts. Put it in the Jeep, put about 20 miles on it and could tell something was not right.
Compression test ... (1)150psi (2)0psi (3)150psi (4)150psi (5)150psi (6)75psi
Added a little bit of oil to cylinder #6, compression rose by about 20psi.
Did a leakdown on cylinder #2, all the compression is leaking into the crankcase.
So at this point, I'm thinking I must have broken a ring on #2 when installing the piston. Getting ready to pull the head & pan and remove the #2 piston for inspection. My main question is, what should I do about cylinder #6? Is it likely just not seated yet and I should just let it be, or should I pull #6 as well and re-ring it?
And if I do have to re-ring #2 & #6, should I re-hone the cylinders?
Thanks for reading!
4.0 re-rebuild?
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- Posts: 4
- Joined: June 10th, 2014, 4:26 pm
- Vehicle Year: 1995
- Vehicle Make: Jeep
- Vehicle Model: Cherokee
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- Posts: 312
- Joined: February 22nd, 2014, 7:27 pm
- Stroker Displacement: 4.6
- Vehicle Year: 1981
- Vehicle Make: Jeep
- Vehicle Model: CJ8
- Location: New Prague, MN
Re: 4.0 re-rebuild?
I would take a very close look at the cylinder walls of both cylinders. If there is any vertical scoring then I'm afraid it will need to be re honed. And as long as you have the head off it would be worth checking both. IMO
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