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Engine help please

WOW..... you have got me stumped. It almost sound like the crankshaft is BENT. That would give it some bowing and anything (like your pulley) attached to the end would spin out of plane (wobble). Did the previous owner ever hydro-lock this motor before the rebuild? I am getting enough age/miles on my 1993 now that I will be looking at the bottom end soon myself. Please try to post the FINAL DAIGNOSIS when you solve the mystery and get her fixed!! Good Luck, Bill-93XJ
 
The timing chain runs on two sprockets, one on the crankshaft, one on the camshaft. The two sprockets are keyed to their respective shafts, and should be stationary relative to each shaft. The two shafts, of course, run on journal bearings in the engine block.

The "nose" of the crankshaft is where the harmonic balancer is mounted. The nose should be concentric with the long axis of the crank, and should NOT move about radially relative to the crank's axis when it's rotating. If it does, then the nose of the crank is BENT, and that's a "bad thing".

If the dampner is really wobbling as you say, I would take the thing back off, and take off the timing chain cover, and look inside there for starters. Maybe at that point, you can have someone crank the engine over, and watch the nose of the crank to see if it's running true or not.
 
I would remove the pulley and check the nose of the crank with a dial indicator. That will tell you for sure if the crank is the problem. Visually it may be hard to see if it's bent, but when you install the pulley it magnifies the deflection. Good Luck.

Woody
 
I'm working on the issue again. I don't know why I didn't think of it before but I removed the belt and ran the engine with it off. The noise is definately coming from the damper area, and now I can hear it clearly without the fan and everything else running. Guess I'll pull the timing chain cover off and see what I can see. Any pitfalls I should be aware of while doing this?

Kevin
 
Pitfalls would include the water pump not circulating with the belt removed; hopefully you didn't run it like that for long.
 
I have the entire front clip removed including the radiator and all lines going to it. I will be removing the timing cover shortly. Would it be ok to run the engine like this for a brief moment (with the timing cover off and all lines disconnected) to see what is making all the noise?

My instinct tells me yes, but it would sure help in troubleshooting.

Kevin

P.S. I ordered my two year membership to NAXJA a week ago. You guys are great!
 
Before removing the HB and timing cover, check for the noise with a stethescope. Check the timing cover and then the pan area - this may save you some time.

I had a 350 making noise similar to what you describe as "marbles in a jar" ... it turned out to be metal fragments in the timing cover from two broken teeth on the cam sprocket.

As for bent crank, I doubt it, you earlier mentioned that the bolt didn't look out of whack when running. As unlikely as it may seem, I wonder if line bore was off centre from factory?

-Brian
 
PuckNuts said:
Before removing the HB and timing cover, check for the noise with a stethescope. Check the timing cover and then the pan area - this may save you some time.

I had a 350 making noise similar to what you describe as "marbles in a jar" ... it turned out to be metal fragments in the timing cover from two broken teeth on the cam sprocket.

As for bent crank, I doubt it, you earlier mentioned that the bolt didn't look out of whack when running. As unlikely as it may seem, I wonder if line bore was off centre from factory?

-Brian
Click to expand...

Appreciate the info. Too late for all of that though. This thing has pissed me off and I'm tearing it apart as far as I can :) I played around with HB and listened as much as I could. All that's left to do is take the timing cover off now. I have everything out of there.

Can I run my engine like this for 10 seconds? That's what I really need to know.

What else should I do since i have the entire front end tore down? The water pump looks good as do all the pulleys. I figure I'm just going to tear this thing up as much as I need to and get it all done right.

The engine is a rebuild - truck has 200k, no idea on the rebuilt engine.

Good thing about all of this is that I will know how to wrench on it better next time. I realize I didn't have to tear everything apart to get to this problem, but it makes the job easier and I learn more.

I concerned with firing it up with all the hoses and tranny cooler lines off and radiator out, and the timing cover off. Bad idea?

Kevin
 
Sure you can run it for 10 seconds without the cooling system. If the water pump is off, no threat of it running dry - everything else will be fine. It takes a few minutes to getting anything warm but don't push your luck that long.

-Brian
 
Not trying to be captain obvious here, but does this indicate a worn or stretched timing chain? ( I have no experience with this)

get-photo.asp


get-photo.asp


Kevin
 
In doing all of this I notice that I do not have an oil slinger installed on my crankshaft and thrust pin/spring was not on the camshaft sprocket. Either the yahoo who rebuilt my engine is a moron (before I owned it) or this is normal. I'm leaning towards the moron side of things.

:twak:

Kevin
 
The guy who rebuilt your engine is DEFINITELY A MORON.
The marks on the inside of your timing cover were caused by the cam sprocket scraping against it because the spring/thrust pin that should have been in the retaining bolt were missing. Just hope that the cam itself didn't walk so far forwards that the tappets would have been severely worn by scraping against the sides of the cam lobes.
It also looks like the chain must have been stretched because the slots that hold the tensioner have been worn away.
Not having the crank oil slinger was less critical but it would have helped lubricate the timing gear if it was there.
You'll definitely need to replace the whole timing gear, get the spring/thrust pin for the cam bolt, and get an oil slinger. You can get the extreme billet timing set for the AMC Jeep 232/258 engine (it interchanges with '87-'95 4.0's) from http://www.fastengineparts.com for only ~$75 through e-bay.

http://cgi.ebay.com/ebaymotors/ws/e...tem=2481335189&category=33625&sspagename=WDVW

You can get the other bits from a junkyard engine very cheaply, and you might even be lucky enough to get a good used timing set while you're there.
 
Dr. Dyno said:
It also looks like the chain must have been stretched because the slots that hold the tensioner have been worn away..
Click to expand...

I'm glad somebody knows what they're doing. Do I need a timing cover as well? I have no idea what it's SUPPOSED to look like, and have no idea how the tensioner works.

Also, what would be the advantage of the nice one on Ebay as opposed to the vanilla brand from AZ or Checker?

According to the FSM my chain is indeed stretched.

Kevin
 
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