Noise In The Front Of The Engine

HI Guys,

I have had a very bad day. After 700 hours over the last year I was ready to test start my 1950 cj3a. I had ran it earlier in the restore/rebuild and it ran great, I even drove it for several miles and the engine ran great. After I rebuilded the entire jeep (except Still working on the hood and windshield) I was ready to test it this morning. It started and ran great, for about 10 minutes. When the temperature reached about 140 there was a horrible screeching sound from the front of the engine. (L134 Go Devil). Hoping it was the water pump or the alternator I removed the fan belt and it restarted it, the noise came again at about 140.

I am looking for ideas, Could this sound be caused by oil not getting to the camshaft gear, oil pressure is good but I guess that the little oil squirter could be clogged. Or is that the sound of the main bearing going out or could it be something else.

I am really regretting ever starting this project. Any advise will be greatly appreciated.

 

Try a stethoscope against the different parts of the engine, locate the exact source point.

A wooden dowel or a long screwdriver pressed against your ear will work. Be careful of moving parts.

Are you sure it's at the front, not the starter or clutch/throwout areas? Did you pre-lube all the bearing surfaces and prime the oil pump when you did the rebuild?

 

Hi,

I tried a wooden dowel against the timer cover, starter, throw out bearing and the sound sounds like is louder in on the timer cover. But I must admit I am not good at that and will get my brother over for a second opinion.
I did not prime the oil pump, I will look into that also. Oil pressure is reading 35 at idle.

I will post again after I get my brother to listen to it.

 

video of the noise ?
Can't see a connection to 140* and oiling problem.

 

HI Guys,

Just posted a video of the engine starting and running, It doesn't have an alternator or a fan belt on it. At about 2:25 in is when the noise starts.



Any ideas would be greatly appreciated.

Thanks Ken

 

Is all that runout in the crank pulley or is the crank snout bent? And is it rubbing on the cover? I don't think any of the rod or main bearings are the source of this.

 

The Crank Pulley was bend when I removed it, I was getting ready to order a new one but was trying to go ahead and test it since everything else is ready. The crank snout seems to be fine. The pulley is not rubbing on the cover as there is a visible gap all the way around.

I may pull the pulley and try to run it that way just to make sure. The thing that is really puzzling is that it never does it when the motor is cold...

Thanks for ideas...

 

in the video just before the 2:20 mark is a hiccup noise....and then again at the same time the grinding starts, does it make those noises every time?
that's a weird sound...

 

Yes, Everytime it does 3 or 4 very short grinding (hiccups) and then a few seconds later it is constant from that point on.

 

I'd pull the timing cover off and see what going on. It sounds like a rubbing/grinding noise.

 

We rebuild everything but the internals of the engine. We did pull the timing cover and clean it up and replace the gaskets put in new bolts etc.

Thanks for all the feedback, I will pull the oil pan and cover again and see what I can find.

 

Had a noise like that on a Hurricane motor, turned to be a cracked belt pulley at the crankshaft end.

 

That really sounds like dry bearing or bushing chatter to me.

Dry distributor shaft?

Just for kicks, next time it does it, push the clutch in and see if it changes.

 

What is your idle rpm?

 

Maybe there’s enough slop in the bushings to spin freely until friction causes it to heat up, then it expands and starts to bind.

My bench grinder does the exact same thing.