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Motor grenaded today

ratman572

NAXJA Forum User
Location
Tigard, OR
Since the day I picked up my XJ over a month and a half ago, it has exhibited some strange noises coming from the lower front end of the motor up near the timing chain. The noise sounded like a bad lifter tick sometimes, -and other times, sounded like a really quiet diesel when listening from underneith. Sometimes once warmed up, the noise would all but go away.

I attributed it to lifter noise, but was I ever wrong. Today my motor tossed the #1 rod through the side of the motor.

Upon initial inspection, I discovered that the #1 rod has in excess of .050" side clearance, -waaay too much. Obviously, this was the noise I've been hearing since day one, -and was very likely the reason the rod fatigued and ultimately failed.


grenade2.jpg


grenade3.jpg



grenade4.jpg


The bad news about what I found is that even if I had discovered the excessive side clearance early on, there would have been little I could have done about it other than a full teardown and a crank kit and rod (at the very minimum).

All I can say is that I'm glad it broke close to home and not up on a trail somewhere.
 
j99xj said:
Sorry to hear and see this.

But if I were you I would take this as a blessing......because you now have a very good excuse to build a kick butt stroker engine.
As tempting as it is to build a stroker, I think I'm just going to pick up another used motor. I know, I know, -ya never know what yur gonna get.

However, I did find a complete running HO motor with 120k on it (90 day warranty from a reputable local wrecker) for 550 bones.

I'm a single dad with a mortgage payment, -so I gotta watch my spending. I just want it back together soon so I can go wheelin with the guys.

Yeah, -considering I've only had the jeep for a month and a half, it is kind of a bummer. Fortunately, I got the jeep for 600 bucks!!

Even putting a motor in it, -I still didn't come out too bad.

What sucks is that I just did lift and tires, -so needless to say, I'm broke!

Figures, -don't it??
 
That does not look good. Sorry about that. Any ideas how many miles? I know I will be thinking about it as I make my long journey home on Sunday!!!

Bob:scared:
 
cherokee4fun said:
That does not look good. Sorry about that. Any ideas how many miles? I know I will be thinking about it as I make my long journey home on Sunday!!!

Bob:scared:
This particular engine showed 191k on the clock when I got it. I have absolutely no history of maintenance, -so it was a roll of the dice.

Granted, I am disappointed, but I still came out not too bad considering I only paid 600 for the thing. I wonder if the people I bought it from knew something I didn't??

It was their daughter's rig, -maybe she ran it low on oil or something. My experience with inline sixes over the years has been great. I've had 250 and 292 chevy's, and a ford 300, -and they were all bulletproof and lived well past the 300k mark.

I think this was definitely an isolated incident with this particular motor. Like I said, without having any knowledge of how well it was cared for, -who knows what it had been through.

For a rod to have that much side clearance, there most definitely had been a time in it's life where it was starved for oil.

When I get the time, I'm going to go into the autopsy a little further and have a good look at the crank and bearings. From what I can tell, the thrust clearance on the crank seems ok.

Unfortunately, that's just how these things go sometimes.........
 
tallbluexj said:
Now I feel better. I just blew my 4.0l the other day, and had many people saying it was unhead of. Mine had 216K, blew out the oil pan.
Were you able to determine if it was #1 that let go?

Looks like most of the damage in your pic is isolated toward the front end of the pan?

Your picture looks eerily familiar!!

Correct me if I'm wrong guys, -but aren't #1 and #6 rod bearings the "last in line" to get oil?

Oh, believe me, -I'm taking quite a bashing from inline engine guys saying they can't believe I grenaded an un-modded inline six!!

Well, it just goes to show, -NO engine is entirely bulletproof, -not even an inline six.

BTW, this is the very first inline six I have ever had catostrophically fail. I have done in a couple of V-8's over the years, -but never an inline six.
 
tallbluexj said:
Now I feel better. I just blew my 4.0l the other day, and had many people saying it was unhead of. Mine had 216K, blew out the oil pan.
Sorry, forgot to ask, -but was your motor a HO?

A few local XJ'ers have lost motors, -and ALL were HO's.

All the RENIX motors are still running........
 
Dude, my buddies kept saying that I must have done something stupid, "you can't blow a 4.0L". When I got my XJ two months ago, #3 push rod was bent. Once replaced with a new one, it ran fine.
 
OUCH!:shocked: The pictures speak for themselves. Let me know what happens when you to tear down the block or if you need any help picking up the motor. And thanks again for helping out with the breaker bar.
 
Glad to help. It took me a while to figure that out also. Basicly the RENIX engine was put in the XJ up to 91 I think. So any inline six in a 80's XJ would be RENIX. Which stands for RENULT-BENDIX. We just shorten it and say RENIX. The HO (High Output) inline six replaced the RENIX in 92 I think. It has a little more horse power but I dont think it has as much low end torque. I could be wrong on that one but hey. Also in my experence the RENIX engines seem to last a LOT longer than the HO's. Im sure I will get flamed for that but hey. Do a search on miles and let others driving RENIX's back me up on that. I think 5-90 said something about more nickle content in the block. I cant remember but anyway. I have about 303,000 miles on mine and it still runs better than my wife's 2000. IMO. I run with a couple of guys around here with more than 350,000 on theirs.
 
My 92 HO is history, at 176k. There's a wave of sudden motor death?
My number 1 piston cracked a month ago, cylinder had 90 psi on compression, had been slapping a long time.

My wife, before we met, had driven it almost 19k without an oil change. She drove at 80 mph, 70 miles per day. Tough engine, but I couldnt save her...tears.

Yes, the Renix engine is tougher, there I said it.
 
Last edited:
mcnamaag said:
The HO (High Output) inline six replaced the RENIX in 92 I think. It has a little more horse power but I dont think it has as much low end torque. I could be wrong on that one but hey.

The RENIX was used from 87 to 90
The HO began with the 91 model year

Later,
Joe
 
blibra said:
OUCH!:shocked: The pictures speak for themselves. Let me know what happens when you to tear down the block or if you need any help picking up the motor. And thanks again for helping out with the breaker bar.
No problem man, -glad I could help you out. I got your message BTW.

Yeah, -most pictures are worth a thousand words, -these pictures are worth two or three! <G>

I think you might know the words I'm referring to!!
 
Holy cow! Going from the responses of "I have never heard of that happening", to all this. A new brotherhood is developing, these of us that has lost our engines. Perhaps a tatoo could uniquely identify us few!
 
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