Hey Everyone,

My funds for my jeep project haven't increased enough for me to have my engine fully rebuilt by a shop or buy a stroker, so while I slowly save more money I've decided to do a in frame rebuild.
I plan do new pistons, oil pump and timing chain what else would you guys recommend changing while I'm in there? Last year I did lifters, oil seals and valve springs. I would like to not exceed $400 for the parts if possible and I am looking at engintech parts.

Any thoughts and recommendations would be appreciated .
Thanks!

 

I'm not a fan of an in-frame rebuild. I'm much rather have the engine out on a stand where I can comfortably reach everything. That includes the freeze plugs in the rear that are otherwise inaccessible.

 

I am not either but work must be done to my engine to get back to decent running order. If I had the room I'd pull the engine and do a complete rebuild myself.

 

Does your Jeep blow smoke, use oil or have low compression ?

Does it have low oil pressure ?

How many miles does it have ?

I would do an oil analysis to see if you have bearing metal in your oil

I personally would not change any of the parts you mentioned unless I had a problem with them

 

I'm all for a temporary in frame rebuild as long as the cylinder bores are in good condition. Valve job on the head, rings, bearings, hone it and call it a day. Definitely not as good as an actual rebuild but should get you by for quite a while.

 

Yeah. What's wrong with it?

 

Low compression in cylinders 1-5 and 6 is extremely low. I can't remember the exact numbers (someone threw away my paper with results) when I did the compression test but what I do remember is 1-5 were lower that what is allowable by a fair amount and 6 was way out of spec. When a I did a wet compression test all cylinders shot up to an allowable number.
Cylinder 6 seems like it fires when it wants throwing a misfire code on that cylinder. I've test for spark, swapped injectors and spark plugs to see if the miss fire follows (it did not).
I figure based on the compression test the rings are shot???
I have 220k miles on the engine.

 

I did a "*****'s bath" rebuild on my 99 cherokee when the #6 piston skirt cracked. Ended up doing pistons, rings, connecting rod bearings and timing chain/gear. Engine has been great for 7+ years. The hardest part was figuring out how to get the oil pan off. Have to raise the front axle so it moves forward. Oil pressure is still great at 240k miles.

 

Good to hear your 4.0 is still happy.
I think I am going to order the engine rebuild kit from Enginetech

 

Other than all the basic tools what you guys recommend? Ring compressing tool, hone tool anything else? Any specific recommendations?

thanks.

 

In frame rebuilds are the reason why the inline 6 is still the most common configuration for transport vehicles. More engines are rebuilt in-frame in one day, world wide, than they are on stands in a decade. I wouldn't be too worried about the one freeze plug that is covered by the bell housing, especially if the block isn't a rusty mess.

The Jeep/AMC straight 6 is very simple and everything is easily accessible. These engines do not have lubrication issues and the bearings always look brand new on teardowns. A quick hone, new rings, clean the cylinder head and cooling passages, clean the deck surfaces, new head gasket and your good for another 250,000 mi. I wouldn't worry about the oil pump. The pump/distributor gear will fail before the pump gears. Jeep pumps always look brand new unless somebody didn't change their oil for 7 years. Install an oil catch can and you might not have to rebuild it ever again. Oil trashing the rings and poor cooling system maintenance are the only killers of these motors.

 

I have the head off, removed oil pan and girdle. I think I am ready to pull the pistons.
Is there any specific process to this? What I am kinda worried about is should the engine be at TDC, does this matter? My plan was to start at cylinder 1 turning the engine over to get the connecting rod all the way at the bottom for easy acess to the bolts and repeat this process for each cylinder.

thanks

 

Label everything. Note which way the rods go. don't nick the crankshaft.

 

Removing pistons, TDC. Installing pistons BDC. Like Cruiser said, dont nick the crank!

 

To help notnicking the crankshaft.is to put some rubber fuel hose over the rod studs so they can not touch the crank shaft .