Rattle Noise At Idle At Front Cover

This has been driving me nuts. I think I have a timing chain noise at Idle. If I take the engine off idle, the noise seems to be barely noticeable. The noise is the loadest at the Dist cap. I just put HEI in it put it has the noise before. I didn't pay attention to it. I rotated the crankshaft back and forth, and there seems to be a lot of travel. I used a borescope, and the chain does have movement. It s been in the family since new and is in very good condition. The oil is spotless. Also, it has 37000 original miles on it. I am having fun restoring it, and it's the last vehicle I will ever restore. I have 43 years as a GM Master tech and ASE Master Tech working with GMCs and Cadillacs and Buicks. Is this normal for an Odd fire 225 to make a rattle at Idle when the chain is worn? Any advice would be appreciated before I tear apart so that good advice would help. Thanks

 

Hi Speedybon!
Welcome from up the coast!
I think I know the rattle you are describing, because I’ve got it too.
From searching around here, timing chain/tensioner is my culprit as well.

Looking forward to what the knowledgeable folks around here have to say about it.

Tell us mote about your Jeep and add some photos!

Andy

 

Common noise for the mileage stated on the original nylon cam gear.
Sounds like it might be time to remove the timing cover and have a look.

 

I thought old Jeeps were supposed to rattle

All seriousness aside the only thing that puzzles me is the noise being modest at the distributor cap, but noises can travel, otherwise it does sound like it may be a loose timing chain.

 

I found another post talking about it sounding like a diesel at Idle. And that's sound I here, so it's timing chain timing. Is that right that it has from the factory nylon timing gear? I guess they used a car engine when they decided to go with GM Buick V6. What would be the best chain to run double roller or just steel gear. Or go with a high-quality chain and gear set/ tensioners. Thank you guys for the help.

 

Welcome. I did the double roller. Pretty easy to do.