Been chasing this noise for a while. Basically it sounds like a diesel engine the way it rattles after warming up.

Described the noise to a long-time Jeep guy that grew up around these at his grandfather's and father's dealership.

The Jeep 4.0 had 220,000 miles on it and still runs OK. I did replace the lifters at 185K due to several losing their prime. The engine cylinder walls were clean with very little ring groove.

I guess I need advice on whether just do the cam, bearings, and lifters or just go ahead and rebuild the whole engine.

BTW, this one is normally my daughter's daily driver.

Opinions?

 

if it was for you I would do cam,bearing and lifters ....
but because it was for your daughter I would redo the whole motor... I am not a dad but that just makes sense to me... Don.t want her to break down for any reason...
or the 3rd thing you can do grab another motor from the jy and rebuild it while still using the current motor.. so you do not lose use of the jeep...
hope that helps...

 

You going to pull it and put it on a stand? May as well do the rings and bottom end too. Toss in a new oil pump and you're good for the next quarter-million.

 

Just tossen out a thought. One poster lately said changing his ROCKERS was his cure. I did see once on an international, the shaft had worn at a angle so when the push-rod "pushed" , it would slam the rocker to the side. Messy job, but I found it pressing with my thumb! (cover off).
I would think a worn cam would leave you with low oil pressure.

I'm with Radi on that "slope". Gonna go all the way to the cam, you are "all in" is my thinking. I don't know where you are.....I run Castrol 30wt here since freezing is rare. 270K, can't be all bad!

 

Oil pressure is 55 PSI at startup, 17 PSI at hot idle, but only 20 PSI at 55MPH cruise.

It might get to 23 PSI by 70 MPH.

It looks like it is using a quart of Mobil 1 about every 3500 miles or so. It used to not use any by 6000 miles.

If I just did the cam, I would leave it in the Jeep and pull everything in front of the engine.

But with 215K, it might end up being more cost effective in the long run just to pull the whole thing and build it.

Besides, it has R12 in the A/C. Evac and recharge would end up costing me about $250 what with the price of R12 nowadays. If I pulled the engine, I don't have to evac the system like I would if I did the cam in the Jeep.

 

I like this idea! may cost a couple extra hundreded to get a donor motor but while your rebuilding the JY one the Jeep is still driving.

 

Well right now she's got my '02 Honda Accord. Which she likes because it gets better gas mileage.

She actually prefers the Jeep, gas mileage aside.