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Unread 10-17-2013, 06:43 PM   #1
PilotPat24
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1995 YJ Wrangler 
 
Join Date: Apr 2011
Location: West Babylon, New York
Posts: 40
1999 Jeep Cherokee Xj 4.0 Rebuild Nightmare Help!!!!

Hey Guys,

Need your help on how to proceed!!!!

Recently rebuilt a 4.0 in my 1999 Cherokee XJ...

After 30 minutes of running time after the initial start-up, the oil pressure went to zero. It was later determined that a faulty brand new oil pump was the cause of the problem. We had to tear the engine apart, replace all bearings, oil pump, distributor, and another new camshaft.

Begin reassembling the engine again and notice that a 30 minute old timing chain has about .40" of play in it. How can this happen????

How should I proceed with this? I have to double check tomorrow but I think oil pump and timing chain/sprockets were from the same manufacture.

A lot of time and money was put into this engine I feel the company that built the parts should be liable.

Any advise would be greatly appreciated.

enginetech.jpg   mopar.jpg  
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Unread 10-17-2013, 10:00 PM   #2
wgirvine
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1992 XJ Cherokee 
 
Join Date: Oct 2007
Location: Rosamond, CA
Posts: 603
I'm curious... exactly how did the new oil pump fail? I've been turning wrenches on cars & trucks for a very long time, and I've never heard of a new pump failing. As for the timing chain, if in fact the oil pump failed and was not pumping oil... oh yeah, it'll burn that chain up right quick. You replaced the lifters with the camshaft, right?

And as for the oil pump manufacturer being liable... nope. Doesn't work that way. See, you could have paid a shop to rebuild your engine, and then they would be liable. But you wanted to do it yourself, (I understand why) so you are the one responsible for determining if parts are of good quality, clearances are correct, torques are correct... all that important detail stuff. Ain't it fun?

As for advice... use good quality parts, and try it again. Double-check everything. Measure everything. Clean everything like it was surgery. (Shop Tip: cover the top of your workbench with butcher paper; lay the clean parts on that.) Good luck.
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Unread 10-18-2013, 05:22 AM   #3
PilotPat24
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1995 YJ Wrangler 
 
Join Date: Apr 2011
Location: West Babylon, New York
Posts: 40
I use to rebuild diesel engines for a living.

The oil pump was pumping oil but at a minimum. Who would of thought that a brand new oil pump would of been faulty? You can see in the pictures that the new oil pump sits cocked on the engine block. Even when you had the gasket in place and the bolts torqued, the pump would of layed cocked on the engine block. That's why the cam/distributor gears were wiped after 30min of run time.

This was also the second pump. The first pump, the oil suction tube fitted very loose. The manufacture gave me a replacement pump. The oil suction tube originally fitted tight when installed. After disassembling the engine again, the oil suction tube was not loose. It now appeared that the oil pump suction hole was filled with some type of graphite/filler. I then checked the oil suction tube fitting with the OEM oil pump and it fitted proper.

I replaced the camshaft since the bearing journals were wiped. The lobes had no wear on them. I did not replace the lifters. I measured the lifters which were all within spec. and they looked like brand new.

The timing chain/sprockets did not show any type of heat or wear. They looked like brand new.
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Unread 10-18-2013, 08:23 AM   #4
wgirvine
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Quote:
Originally Posted by PilotPat24 View Post
I use to rebuild diesel engines for a living.
Then you should have known better than to just build up an engine and not check the parts for proper fit. C'mon, you're no rookie...

And why didn't you have someone in the driver's seat, watching the oil pressure gauge like a hawk those first 30 minutes? Sorry pal, but this one is all on you. It sucks, I know. But that's just the way it is.

Curious, what brand of oil pump was this?
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Unread 10-18-2013, 11:23 AM   #5
PilotPat24
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1995 YJ Wrangler 
 
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Location: West Babylon, New York
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We had a mechanical guage on it. When we saw the guage drop to zero, we shut the engine down. The guage went to zero like someone turened off a light switch. That's why we only lost 2 cam bearings and everything else was saved.

You would of honestly checked the fitting of the oil pump to the block without the gasket in place?

In any evenrt, I couldn't prevent that the oil suction tube went in tight orginally and then came out loose after tearing apart the engine again. Like I said, there was some type of filler in that suction hole. I orginally caught that problem with the first oil pump with the suction hole being oversized. That's why I didn't use it.

Quote:
Originally Posted by wgirvine View Post
Then you should have known better than to just build up an engine and not check the parts for proper fit. C'mon, you're no rookie...

And why didn't you have someone in the driver's seat, watching the oil pressure gauge like a hawk those first 30 minutes? Sorry pal, but this one is all on you. It sucks, I know. But that's just the way it is.

Curious, what brand of oil pump was this?
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