engine noise under acceleration

[btolenti]

Gentlemen,

I am having one heck of a problem. I have a rebuilt 302 in my 54 F-100. It has about 5000 miles on it. It is stock other than the edelbrock intake/carb, and the Davis Unified Ignition HEI distributor. The truck seems to run fine at idle. Revving the engine in neutral also is not a problem. The problem is when the engine is under load. During acceleration, I can hear a noise coming from the engine compartment....but only under acceleration. It is not a really distinct "ticking" that might accompany a loose valve or low oil, but more of a muffled knock. At cruising, there is no noise. Any ideas???

Thanks in advance for the help...

[DannyP]

Thanks in advance for the help...

Funny you should mention advance, as I am sure too much of it is your problem. Unplug your vacuum advance, plug the vacuum source, and check your initial timing. It should be anywhere from 5 BTC to 15 BTC. Adjust it toward the lower end of this scale. Try it out to see if this helps. If it is less than 5 BTC or even ATC then your mechanical advance and/or your vacuum advance may be adding too much advance or adding it at the wrong time. Tell us what you find after doing this and we can go from there.


DannyP
89 F-150 4x4 former EFI I-6 now carbed 351W, Edelbrock heads,cam,intake,carb.
MSD 6A, ZF, Sterling 10.25 with 3.55L's.

[lanero]

Could be spark knock?
What is your initial timing set to?
Maybe you could back it off a couple of degrees and see if that helps.

Roger Lane
Test Analyst
Sr. Automated Test Engineer

[btolenti]

Thanks again, guys. I am going to try that tomorrow and I'll get back to you...

[btolenti]

Thanks for the suggestions, gentlemen. It actually turned out to be a faulty exhaust gasket. It must have been leaking between the manifold and head. Your timing suggestions worked well too. After fixing the exhaust leak, I retimed the engine and it runs much smoother now. Again, thanks for all your help.

--Brandon

[wisnowman]