Rattle from under valve cover. I'm concerned

[WisconsinCutlass]

I took the cutlass for it's last cruise for the year before getting parked for the winter. I was at a friends house and had the hood open with the car running. I reved the throttle and there is a nasty rattle sound coming from what sounds to be the passanger side valve cover. Sounds almost like theres rocks bouncing around in there. I did some research and found a couple thing to check. Make sure the rockers are tight and valve lash adjusted correctly. Other than those things is there anything else I need to look for. I have never done any motor work before so this is another learning experience for me. I hope its nothing major. And motor is a 72 Olds 350. Eldebrock intake, cam, and holley 4150 750cfm. Was told it had a 5 angle valve job done also. I probably wont get to work on it for a bit but would like to get opinions and suggestions so I can research anything I need to before starting. Thanks for the help.

 

[pontiacgp]

get a factory service manual for the 72 olds and read through the engine section so you'll have a good understanding on what may be wrong and how to fix it.

 

[MrSony]

Most likely a very loose rocker, or worst case bent pushrod. My thunderbird sounded very clacky before I took the intake off and saw a banana shaped pushrod. Just take off the cover and peek. What is it, 8-10 bolts? Have someone start the car while you watch for any weirdness. Be prepared to get oil spurts in places. Although first things first get the cover off and look for loose things. I've seen broken rockers, ones with loose nuts and some with no nuts at all so be on the lookout.

 

[Texas82GP]

Does the Rocket 350 have the same 'pot metal' rocker pedestals that the 307 has? If so, that's where I would start looking.

 

[pontiacgp]

One other thing you can check is the EFE valve that is on the pasanger side, if that is broken that could cause a rattle

 

[foxtrot]

Does the Rocket 350 have the same 'pot metal' rocker pedestals that the 307 has? If so, that's where I would start looking.

I think that the Classic SBO (not to be confused with the later VIN9 & VINY 307) stamped rocker is just bolted to the head casting itself.

As others mentioned, it could just be a loose rocker... That's where my .02 would be at.

 

[Gozer442]

The aluminium rocker bridges that both the BBO and SBO share can fatigue and crack...but usually wear out. Check if all the bolts holding down the rockers are torqued down to spec. If they are, and the rockers are still very loose throughout the valves movement, remove the bolts and visually inspect the bridge. Check for a deep ridge that forms between the bridge and the rocker. The higher the ridge, the more wear on the bridge...replace the bridge. If the rocker is still loose with the bridge torqued down to spec, and the bridge is not worn... then its either a bent push rod or a collapsed lifter. Good luck!

 

[WisconsinCutlass]

Thanks everyone for the replies. Nobodys mentioned anything that sounds catastrophic so I'm very happy about that. Im hoping that I can find some time and take a look this weekend.

 

[WisconsinCutlass]

So I didn't have much time but I pulled the valve cover off. Didn't see anything visually that concerned me so I started toucking the rockers. From left to right number 2, 3, 5, 7, 8, rocker seem to be loose. They didn't have any play as far as up and down but I could wiggle them left to right a little. I didn't know if this was normal so I decided to come on here and ask if these should have zero movement before I tried doing anything.

 

[Gozer442]

Well now... that is not a stock valvetrain. Looks like it was upgraded to so Harland Sharp adjustable roller rockers...a great upgrade. Looking at the position those loose rockers are in(valve is closed), they will have some play in them. I'm not sure what the proper valve lash setting is for your setup, but the chances are that they are not out of adjustment. Just to be sure, I'd check the valve lash.

If the noise is still there, try this next. I'd run your motor until it warms up and starts to rattle. Then take off that cover, run the motor while the cover is off, and listen with a mechanics probe to see which one is making the noise.