Need some help please !

[c10sob]

Ok , so for the last year on my first gen chevy 350 engine compartment or engine noise that has drove me crazy. Ive tired to turn up radio and ignore it but i am into fixing the problem not masking it . I actually started a list of things i took off and dampered to find the noise , at first i thought it was a brake line/ fuel line rattling . nope. maybe the spring from hood, nope . even gone as far as removed fenders, hood, grill , air cleaner, wipers, wiper gears,cowl . thought it might be valves because it only happens at 2000 rpms under load when crusing around 2000 - 2500 rpms. Ive adjusted them with truck running acouple of times , everything looked good and moved good. i thought if the valves are making noise they would do it all the time not at a certain rpms. what do you guys think ? could it be a vacuum leak or ignition problem ? My truck is a 1966 with a first gen 350 . Any suggestions would be great to look for . I did notice that my valve covers were short and i had locking tall hardware on the rockers . i have no idea , i am guessing at this point.

[c10sob]

I should also say it sounds like its only coming from right side . Here is what i have that ive worked on for a couple of years .

[DLW]

So you have to drive it to hear the problem because it only happens under load? Only happens in high gear at around 2000 RPM? Is it detonation issue (pinging) like from timing to far advanced? Really hard to give any good advice on a situation like this.

[c10sob]

defintley underload while driving , sounds like a rattle like brake lines or hood spring but i have either took them off and drove to hear or cut rubber hose and put it around lines to damper and ive gone threw the line a secured them like crazy.

[cv65]

Originally Posted by DLW

So you have to drive it to hear the problem because it only happens under load? Only happens in high gear at around 2000 RPM? Is it detonation issue (pinging) like from timing to far advanced? Really hard to give any good advice on a situation like this.

I agree with DLW sounds like detonation under load,ping or rattle,check your timing

[blown240]

Sounds like timing to me too. Or maybe an exhaust leak, but I thats more of a ticking sound.

[The Rocknrod]

It's not a rattle? Hood, Brace . . .

[geezer#99]

Easy test on timing!!
Plug off vac line from carb to dizzy vac pot.

[forestb]

For the longest time I thought my headers were vibrating against my torsion bars. After pinging it with a hammer it still happened. It was not until I removed the header and found a bolt and the tip of a spark plug sitting where the 4 pipes come together did the noise go away.

[c10sob]

I am defintely going to check the timing . its funny cause i did take my headers off to check for the bolt, good call on that one and i took my hood and hinges off thats wow much this is driving me crazy. So much time and money but atleast it keeps us busy ! i am also going to check for exhasut leaks just in case . Thanks Everybody !

[DLW]

I think the key here that you mentioned is it only happens under load. This is why the timing would be the easiest to point to as it can almost sound like a can of marbles being shaken if it is having detonation issues. Timing would be an easy fix here if this is the case.

[c10sob]

I am going to check that out first thing after work , Thanks !

[joedoh]

put a magnet on a string and drop it down in your cowl to the fresh air vents. I found a two sockets, three bolts and a wrench in the passenger side, and a weird star shaped piece of metal in the drivers side.

[c10sob]

What the hell ! That is funny . I did not even think to check that out . Haha