1996bluexj

hello all,


so about two weeks ago I started to hear a knocking sound from the engine, so I narrowed it down to be either lifters being stuck or piston slap. I took off the valve cover and started to feel the rocker arms to see if they were loose and they were not. my next thing to was to crack open the oil pan and guess what I found #2 piston broken, I found large pieces of piston at the bottom of the oil pan. ( one side of the piston) so I was thinking about doing a rebuild but again thinking about a shop to install a used motor. the shop will charge me 950 for install and used motor. I was looking on rockauto and a engine kits will costs about 300 and I called napa to rebuild the head for 240, what should I do rebuild or have a shop install a used motor???

tech

I've heard of people just replacing the broken piston and re-ringing the others then rebuild the head and having a good running engine . but a rebuilt engine would be nice it up to you on how much you want to spend .

Cherojakee

What does the rebuild kit include? I did a partial rebuild and cost me about $1000 for new cylinder head, pistons and rings, lifters, and new gaskets. Plus tools like flex hone and ring expander, and cleaners plus oil for 3 changes during break in. Before you make a decision on the rebuild kit, I would check that cylinder bore to make sure it’s not damaged. Just some things to consider. It may be cheaper to put a used engine in.

1996bluexj

Hey tech I was thinking that too but if I take everything a part I would like to get everything new, money is a concern but than again I would need to rent all the tools needed except for the hand tools.

Cherojakee, the kit includeds new piston, piston rings all the bearings all gaskets and lifters and timing Chain and sprockets. When I had the oil pan off I was feeling inside the cylinder of the broken piston at TDC, and i didn't feel any scratches but I won't be able to know for sure till I take of the cylinder head.

tech

Once you get the cylinder head off you will be able to tell if the cylinders need to be bored out to the next size , until then you can't even order your parts . If you only need one piston you can buy one piston witch would be cheaper then buying all 6 . You can get the rings , bearings and gaskets as one kit , the other thing I would put in is a new oil pump

1996bluexj

So it's not necessary to get all new pistons??

Cherojakee

You can replace one piston. But like tech said you should measure the bore first. You need a 3-4 inch micrometer and a bore gauge or t-guage. If the cylinder bore is too worn or out of round or taper, you probably want to get it bored to .010” over.

dzywicki

Been there, done that. I did this job and replaced all the pistons, rings and connecting rod bearings (http://www.jeepforum.com/forum/f11/r...skirt-2972761/). That's about all you can rebuild without pulling the engine and getting it to a machine shop. I did not redo the head. After this "****** bath" rebuild, I get 150 psi in all cylinders and 60 psi oil pressure at startup and ~40 at warm idle so I'm pretty happy with the partial rebuild.
If the motor was in good running condition before the broken piston skirt, you should be good with n in place rebuild. I'm not sure I would replace just one piston/rings. You can check bearing clearance with plastigauge and cylinder wear with a gauge also. I skipped that and replaced pistons and rings with standard size.

67 GMC

If you're in love with the Jeep, and you have the money, skills and time, then it makes sense to put work into it. If not, you may want to consider looking for another Cherokee. If you don't have a lot into it, it would make a good parts Jeep for another Cherokee with a good engine and drivetrain. Often it's good to take a step back and see what options are out there before you get in too deep. Paying out $1000 to fix up one Jeep could go a long ways to getting another one and then you'd still have your original Jeep to part-out or sell.

Bugout4x4

Is there any scoring or damage to the cylinder walls? This would be your go/no go factor with this block.