I have had my stock 455 built for my 442 clone convertible. My uncle built the engine. He probely hasn't built an olds in 25 years because he is a die hard chevy man. He is a very experience builder so the isssue is not lack of skill I don't beleive but anyway it is a basically stock rebuilt .30 over new piston and internal new for a basic rebuild when he put it together and got the car running we started hear a rattling noise right over the #3 cyclinder sounds like a ping pong ball rattling right under the valver cover the problem is hard to determine because it comes and goes by the way new valve springs and liffters so I 'm guessing it not that

any additional info needed let me know please let me know

 

I have had my stock 455 built for my 442 clone convertible. My uncle built the engine. He probely hasn't built an olds in 25 years because he is a die hard chevy man. He is a very experience builder so the isssue is not lack of skill I don't beleive but anyway it is a basically stock rebuilt .30 over new piston and internal new for a basic rebuild when he put it together and got the car running we started hear a rattling noise right over the #3 cyclinder sounds like a ping pong ball rattling right under the valver cover the problem is hard to determine because it comes and goes by the way new valve springs and liffters so I 'm guessing it not that

any additional info needed let me know please let me know

 

Ummmm......... so you think some dudes reading this post can diagnose an engine rattle better than a "very experienced" engine builder standing next to this noisy 455? really?

 

I'd be checking valve lash to start with.

 

X2, it does sound like something in the valve train so I'd be checking the rockers. If everything looks OK, leave the valve cover off and start the motor. If you run it long it will spill some oil onto the exhaust, but you should be able to pinpoint where the sound is coming from better. John

 

I used an old valve cover cut the top off it and put it on to watch the valve train run not much oil splash and you can watch for longer

 

Rocker hitting the baffle in valve cover? Something in the baffle? I took a shot.

 

Was in a hurry maybe and forgot to tighten down a rocker, even pros forget saw on Muscle car TV when they forgot also and when they put it on the dyno they heard a knocking noise ... just an idea .....

 

Did you replace any of the rockers when you did the rebuild or are you still using the stock type "bolt in" rockers w/ connecting saddle? If so you may have over tightened a rocker bolt and cracked the worn out saddle causing it to "knock" as the valve train is exercised.

I'm taking a shot...your best bet is to remove the valve cover and see if anything is missing or damaged. It could be anything from incorrect pushrod length to improper valve train geometry. Your best bet is to pull it apart and have a look.

 

Take the valve cover off and run the engine and watch the overhead move. It won't hurt anything to run an engine with the valve cover off but it will make a mess. Cover the surrounding area with rags to catch the splatter. With the valve cover off you will be able to see if one of the rocker levers is not moving as much as the others. Good luck!

 

I merged your two thread together so people will not be replying twice to the same issue. It belongs in the big block section anyway.
Hope you get it fixed!

 

I'm with TripDeuces:


The tin sound suggests something hitting the valve cover and or baffles.

 

I would think your uncle would be able to isolate the problem pretty quick!!!!

 

Do u think after he asks these questions he comes back and reads everyones responses?

Wasn't there a thread on antweave awhile back about him doing this. lol

 

Love people who ask what seems to be a serious question, and just disappear - leaving us to wonder WTF the problem really was!!

Ghost Writer???

 

Sorry if I confused anyone about the issue with my engine maybe my discription is a little unclear. Early this mouth before my engine build the reason I decided to rebuild it was to pistons rattling in the cyclinder and since the build and install the engine has a little tapping right under the valve cover again I am not the builder and I new to the muscle car game and I do ready all of my help from u guess this site has really helped me alot thanks

 

Have you pulled the valve cover yet to see if something may be loose? You don't have to be a genius to notice a gross abnormality. "One of these things is not like the other..." See if you have a rocker arm that's loose or something. Only 10 small bolts and you'll know

 

So there's a midget in your engine with a sledge hammer beating the hell out of #3 cylinder????

 

lmaoooooooooooooooo!