Valve chatter at high rpm’s (1 Viewer)

[Ian Rogers]

So on the way back from surf n turf I was experiencing valve chatter when on the freeway in 4th gear. It would only happen when I would load up the truck i.e. going 55mph and give it more gas. It only seams to happen under load. What could be causing this? I ran a quick go-no go valve clearance check and they were all right on. Intake .010” and Ext .014”. I am running a E-67 135 F motor with the timing bumped to about 10* with a NON-USA distributor

Thanks for the help

Ian

 

[trekker]

Just last night I noticed a chatter and thought it was valves at high rpm but discovered that my clutch slave needed a little adjusting. Sound went away with a little pressure.

Just trying to eliminate the obvious (or stupid stuff) first.

 

[honk]

So on the way back from surf n turf I was experiencing valve chatter when on the freeway in 4th gear. It would only happen when I would load up the truck i.e. going 55mph and give it more gas. It only seams to happen under load. What could be causing this? I ran a quick go-no go valve clearance check and they were all right on. Intake .010” and Ext .014”. I am running a E-67 135 F motor with the timing bumped to about 10* with a NON-USA distributor

Thanks for the help

Ian

Sounds like spark knock, preignition, whatever. Low octane gas and/or too much advance under load is the usual culprit.

If you were to keep your foot in it while it's doing that you could find yourself with a hole in a piston, but most of the time if you just back off when you hear it you'll be OK. I wouldn't use the sound as a tachometer - waiting for it before downshifting or letting of the gas. That's a dangerous practice.

 

[IDave]

Yep. Ping.

 

[Pin_Head]

Sounds like spark knock, preignition, whatever. Low octane gas and/or too much advance under load is the usual culprit.

.

X3

Sorry I missed it. Sucks having to work.

 

[Ian Rogers]

you guys got it i turned the timing back 1/2 turn and it ran like a champ