I just want to throw this out there, because I can't seem to figure out why I have this loud tapping sound in my 2F. At idle you can't hear it, and when letting off the gas at speed it is quiet. Only when you open up the throttle and load up the engine does it make this loud tapping. (anywhere from 1000-3000+ rpm)

I assumed that I just had a rocker adjuster back off, so the other night I burned the fool outta myself re-adjusting the valve lash, and it had absolutely no impact on the sound. It taps on a single cylinder as far as I can tell, as it is a fairly long interval given the rpm.

Any ideas? I'm stumped! :confused:

at idle mine sounds like a diesel. i swear....youd never know it wasnt unless i told you! but it also does this under load... mines a deep threapping too. a deep knock...but regardless it does under a load only. wich is allways! :rasta:

I was thinking timing. Then I read your sig line:

TBI 2F

Interesting.

If you think it is 1 cyl...
Produce the knock and remove/replace one plug wire at a time until you locate the bad cyl. Then figure it out.
Or, use a 2" piece of fuel/vac line on each plug or dist cap connection and connect the plug wire to this...
Now use a grounded test light to touch each "splice" in turn.
This will short each cyl. in turn.

Other causes...
End play in the cam or crank shaft.
Loose flywheel bolts.
Lack of 500000000 amp stereo:flipoff2:

Try retarding the timing in case of detonation...
And/or use higher octane fuel.

Thoughts,

Cory

Yeah, I'm the one of like 2 people (just kidding) who went ahead and injected the old tractor motor. In hindsight, it probably was not the most cost effective measure to gain performance, but it does run and idle like a dream, unlike my carbed version.

This knock is something that has developed over the past few months. I can't remember when it started, but it definately didn't do it in the December timeframe.

I'm thinking I might have to refresh the old motor, as she's got 150k on the odometer now... Cyl 1 is like 10 psi down on the rest of them when I last did the compression check -- Is that very bad?

haha....my total psi is no more than 30 on the first 3 cyl's. thats when you know its bad! but really....10 low on one shouldnt be a problem:rasta:

Originally posted by reorx
Only when you open up the throttle and load up the engine does it make this loud tapping. (anywhere from 1000-3000+ rpm)

I Any ideas? I'm stumped! :confused:

It sounds like pinging or engine knock, aka preignition. Fill it up with premium and it will disappear. If you want a long term fix, retard your timing a couple of degrees.

Originally posted by Pin Head


It sounds like pinging or engine knock, aka preignition. Fill it up with premium and it will disappear. If you want a long term fix, retard your timing a couple of degrees.

Bingo!!!

or try tightening the exhaust/intake manifold. That really helps sometimes..