Piston Ring Size for 2000 XJ

[imoverit]

I am looking for the correct piston ring size for my 2000 XJ 4.0. I have searched all over the place; in threads on here, Autozone, Advance Auto Parts, NAPA and even a Chrysler dealership and no one seems to know if it is the metric or standard size I should use. In fact, the guy at the dealership told me even I used my VIN# he still may not be able to provide the correct size, WTF! Anyone out there that can provide some help would be greatly appreciated.

 

[Rob Mayercik]

I don't know, but I think you might get more of a response if you posted this up over in OEM tech - larger audience over there.

Good luck.

Rob

 

[imoverit]

Hey Rob,

Thanks, I think I just found out the difference from another thread on here and it seems that the newer one's are metric, 96 - 2000, but not sure. The unbelievable part is finding a single piston that has a single set of matching rings. The decision is that I have purchased the Jeep from hell and nothing from day one has been easy!

Lee

 

[ghettocruiser]

Hey replacing the brake line that was .02mm thick wasnt too hard! Also bolting the wheels on went pretty....oh wait, it fought us on that too. Nevermind

 

[imoverit]

Hey replacing the brake line that was .02mm thick wasnt too hard! Also bolting the wheels on went pretty....oh wait, it fought us on that too. Nevermind

Yeah, what a fun 3 nights of fury that was in sub 20 degree temps. I should've just done a stroker and said damn the wallet.

 

[Joev]

I know this guy that has just about all the parts necessary for a stroker..and I hear he is on vacation..hahaha.

But servously. I looked up the piston part number for a 2000 vs a 93 and they are different part numbers.

From rockauto.com

93 4.0
SEALED POWER Part # 677P
Cast; 2 - 5/64 Groove, 1 - 3/16 Groove, 1.585 CD, Recessed Head .116 deep, 0.931" Pin Dia.

2000 4.0
SEALED POWER Part # WH802CP {Cast Piston - Individual}
Cast Piston - Individual; Hypereutectic; 2 - 1.50mm Groove, 1 - 4.00mm Groove, 1.592 CD, Recessed Head .116 deep; DurOshield® skirt coated piston, 0.931" Pin Dia.OR
SEALED POWER Part # WH825CP {Cast Piston - Individual}
Cast Piston - Individual; Hypereutectic; 2 - 5/64 Groove, 1 - 3/16 Groove, 1.592 CD, Recessed Head .116 deep; DurOshield® skirt coated piston, 0.931" Pin Dia.


So there are some differences in pistons with the 93 vs 2000. Your 2000 may be using MM rings or standard. But I don't know enough about it to say it makes a "big" difference if a piston ring is a MM or standard..Knowing Jeeps, they probably all have to be the same..I would assume every 4.0 block is bored the same so maybe using a piston and rings from a 93 4.0 would be OK..Not sure. but like I said, you have 6 4.0 pistons at your disposal.:roll:

Yeah, what a fun 3 nights of fury that was in sub 20 degree temps. I should've just done a stroker and said damn the wallet.

 

[Joev]

So it's good to see my ADD is going strong. Had I finished reading your initial post, you already established that ther are 2 types..metric and standard. OK I doubly established that for you..yeah me.

So, the question is can you use ONE piston that has standard in a motor that may contain metric rings? I would say it probably does not matter becuase the cyl bore "should" be the same in any 4.0 motor.

Can you get one piston - 1 standard, 1 metric with matching rings, then measure the one you have and keep the one that matches what you have. or turn it into a volvo 5 cyl..Ah..Sweden.

 

[alex22]

As long as the bore size is the same it will work.... But, before you go and pop it together weigh the old setup and the new one, if they are close the balance won't be an issue. Next thing is check the dish volume and make sure you won't have too high of compression with the new setup and lastly check the deck height.

 

[ghettocruiser]

Ok...I hate leaving threads "unfinished"...so I figured Ide update it and clarify a few things. Especially since I couldnt find much info on the rings using the search.

First...here's Lee's piston. Um..its the one on the right in case you werent sure...

Bit of a problem there.

Now...this whole ring size situation. Lee's Jeep has fought us from the very start. I dont know why...I think its cursed. Its the only rational explaination.

The "size" pertains to the ring thickness. Some of the pistons accepted a standard thickness of 5/64" for the top two rings and 3/16" for the bottom oil ring. These are too thick for Lee's pistons. His uses the metric size rings. They are 1.5mm for the top two rings, and 4.00mm for the bottom oil ring. The rings we have dont match the piston we got from mopar. So there was the first road block. Lesson learned. We are now trying to source the correct ring set...which is proving to be a problem.

More Jeep retardedness. Lee's Jeep is an 11/99 build. He got a rear main seal for a 2000...and its the regular old RMS with the "ears" on it. When I pulled his rear main cap off...SURPRISE! No ears. Call autozone...and they want $59.99 for the correct one!!! Which only shows up under 2001 by the way. So I got the part numbers for the Mopar seal and pan gasket and he's going through the dealer for the correct parts and hopefully we can get back to work in a few days and get the thing back together.

On a side/good note. His 150k mile rod bearings, main bearings, and crank journals look fantastic. Even more amazing...the bores look great. You can still see cross hatching, even on the cylinder that was missing half the skirt!! I cant believe more damage didnt occur. Actually...I cant believe it was still running as good as it was. Its just another testiment to how great these 4.0s are I guess haha.

One of us will let ya know how putting it back together goes...If we get the right parts, its all downhill from here.

J.

 

[Andy in Pa.]

Holy crap, tell me that the huge chunk missing from that piston just dropped into the oil pan and didn't do anymore damage..... that is incredibly lucky!! Any reasons that this happened? Bad piston/stress cracks? That looks like the kind of thing that happens a few weeks after a 4.0L ingests water.

Does that motor have a coil pack for each spark plug or does it have a distributor? I would check the head too, if it is the later head it could be cracked and that may explain how this happened.

 

[ghettocruiser]

From what I can tell, the chunks broke off, and fell down onto the stud girdle/oil baffle, and then the crank counter balance knocked it off down into the pan. I saw some marks on the counterbalance that suggested it might have hit it. But otherwise, everything seems fine. He's really lucky the pieces didnt get churned up into the cam or something of that nature. Not sure how that luck happened when everything with that Jeep has been bad luck haha.

As for how it happened...Im still not convinced that the exhaust leak didnt have something to do with it. But it looks like the oil ring failed, and caused the ring land to break and took the skirt with it. The oil ring was a mess. Pieces of it were missing, and the top band was gone all together.

Are you referring to a hydrolock situation? I guess that could be a problem, but it wasnt showing any signs of the head crack problem. Oil pressure was fine. All the bearings didnt show any signs of wear...and the cylinder walls werent scored from being washed down. But I guess I cant rule that out. I havent checked the head out real good since he cleaned it up, but he was taking the new head back today...maybe he should hold onto it. haha. Just in case. Ill have to look up where the crack shows up, and check it out.

Hopefully it was just an isolated problem and the new piston, plus new rings will make her run like new again.

J.

 

[Joev]

The sun never sets on the allmighty Jeep!! That 4.0 is one of the best inventions ever made by the hand of man!!

:guitar:

 

[MrShaft696]

holy crap, fixed yet?

 

[ghettocruiser]

New, hopefully correct, rings are coming in today. Along with the new, and hopefully correct, rear main seal and oil pan gasket. Either thursday or friday we'll get her together. I dont anticipate many problems putting it back together. Lee has new head bolts, gaskets for everything else, even a new water pump. The biggest task now is just cleaning things up really.

Oh..and trying to get the exhaust to seal. Thats about the only thing Im worried about at this point. Something wasnt sealing right when he tweaked his exhaust on a rock. I thought something was busted...but we couldnt find anything. So now Im thinking one of the bell flanges on the header pipe is out of round. Hopefully with some new bolts we can crank that sucker down and get it to seal.

J.

 

[imoverit]

When I was cleaning off my cylinder head I did not notice any cracks, hairline or otherwise, anywhere on it. I will be checking everything out again, about the 3rd time, just to be certain there are no cracks or faults. I, also, want to take a good look at the front exhaust pipe to make sure the bells did not go out of round.
As for now I have some final cleaning to do and then we can put this thing back together.

 

[ghettocruiser]

Yup...should be downhill from here.

The only thing I forgot was the waterpump bypass pipe. That rusty pipe thats screwed into your water pump. Past experience tells me that its going to be a bear to get out. Also...past experience with your Jeep tells me its going to be impossible to get out without breaking it or causing a hole that will leak. Therefore, it might not be a bad idea to see if Courtesy can get one in before the end of the day. They're only about $15, and we wont have to mess with it at all. If they cant get one, then we can get around it very easy with some parts from advance/autozone.

I dont see anything else that would stop us from getting the motor back together once we button up the bottom end.

About the only other thing left to do on that motor is the oil filter adapter o-rings. That can be done later though...its not crucial that we do those right now. Otherwise, there isnt much we havent rebuilt haha.

I was talking to joey...and, not to jinx us, but there isnt one major part on that Jeep that hasnt been modified or repaired besides the trans. Everything else has been touched/messed with haha.

J.

 

[Joev]

That pipe isn't too bad to get out. The only place that has that pipe is the dealer. It doesn't cost too much but has to be ordered. Give Glenn a call and see if he can just order it today and have it for tomorrow. He should be cool with dat. And the oil adapter o rings were in stock. I have the allen head to take off the adapter.

So like most jeeps, nothing except the body and ash tray is original. Everything else is new and or messed with..Got to love it!!:repair:

 

[ghettocruiser]

Haha...those pipes can be a real pain... Ive done a few. Some turn right out, some require LOTS of force. Knowing how things usually go on that jeep, Im betting its seized in there real good.

Its up to Lee whether he wants to order the pipe. Just another special trip to the dealer. I dont want to get into the o-rings right now. He should probably pick em up just to have them though. That can be a can of worms and Ill be happy to just get the motor back together and maybe fire it up. The o-rings can be done later. Was your purple jeep an allen bolt or a torx bolt? Im pretty sure my 94 is torx...but Im thinking the newer ones are the big allen. Either way, we can tackle that another time.

 

[Joev]

Ah..the only ones I have done are on 93 XJ's and they all have been the crazy big allen head socket. Knowing Lee's Jeep, it's a specialty torx head that you can only get the socket from Russia or something. Time to give Moscow a call. Holla..

 

[ghettocruiser]

The older motors were like a 5/8" allen or something of that nature. The newer ones are T-60 or T-70 Torx bits...something like that. The issue with them is clearance to the chassis. You cant just put a ratchet on it. You have to separate the bit from the socket, and then put wrenches on the bit itself. Its just a pain that Im not sure Im prepared to deal with haha. I couldnt get mine out. Tried for hours. Finally gave up and took it to courtesy. $100 later and it was done. They used an air chisel on the side of the bolt head to get it out. Only thing thats EVER beaten me on a car to the point where I had to take it in to the dealer. We'll see tho. Ill bring the tool just incase he gets the o-rings.

J.