Howdy folks. I have an 85 K20 Suburban as a project vehicle. I pulled it out of a field where it sat for probably 3 years with a blown head gasket and a cracked block. I found an eninge from a local wrecking yard and got it going....runs great too. Shortly after that the tranny went out (700R4) so I converted it to an SM-465. Now it has developed another problem and I am not sure which way to go about fixing it.

The problem is it has a lifter tick on the driver side, kinda sounds like a noisy speedometer cable and sometimes, but not all the time, I can hear it rattling around pretty good when I'm going 60 mph. Other times there is no rattling, but it does get a little louder as the rpm's go up. It is getting progressively worse. It used to be it would only sound like a noisy speedo cable at low rpms and would go away at higher rpms.

Could a bad injector make that noise? The engine has the nylon keepers for the rockers, are those known for wearing out and causing noises like that? I pulled off the valve cover and didn't see anything obvious, and aside from the noise the engine runs great with no excessive smoke. I've thought about pulling the rocker shaft assembly off of the old engine to see if that quiets things down.

Any help will be greatly appreciated.

Welcome to the forum! :welcome:

There are a number of things that could cause that. An exhaust leak, a bad injector, an internal engine problem (piston pin, etc), and a problem with the nylon retainer are all possibilities.

The nylon retainers are know for being rather weak and problematic. I would carefully inspect them.

I am guessing you have probably eliminated the exhaust leak as a possible cause... I figured I'd put it in just in case. Holes in the exhaust on one of these engines can cause all sorts of unusual noises that you wouldn't expect from an exhaust problem...

An injector can cause knocking/rattling/misfiring noises... To check this you will have to have the injector tested.

I would look for something internal after you have eliminated all the other problem spots.

Hope this helps!

What year truck did the motor come out of. My 83 doesn't have the nylon rockers. The early 6.2's were solid mounted on a shaft instead of those nylon clips. Not sure what year they switched but if you have a 82, or 83 for sure you won't have to worry about the nylon clips. Welcome to the forum. Fill out a signature so we always know what were dealing with.

POST NUMBER 400!!!

POST NUMBER 400!!!


Congratulations!

I remember my 400th... ):h


By the way, the nylon keepers were only used on late model ('88-'92) engines.

Thanks guys! I'm not sure what year the engine is. If I remember right it came out of an 84 Suburban, but I think the engine is newer replacement....the valve covers had the goodwrench engine stickers on them and the injectors have a remanufatured sticker on them.

I remember the Haynes manaul said 85 was the year GM started using the nylon keepers. The engine I pulled (the one with the cracked block) has the nylon keepers too. I guess my plan of attack will be to try and replace the rocker shaft assemblies on the left bank and then swap out the injectors. Fortunately, I have a couple engines I can raid for parts. If that doesn't work, I will replace the eninge. My friend has a 6.2 in his garage and (supposedly) the heads were recently rebuilt. Thanks!!!

Not for sure but I believe they stated using nylon around 85? If someone GM crated an engine I think they were all nylon.