View Single Post
Old 03-27-2013, 12:09 PM   #5
truckster
Registered User
 
truckster's Avatar
 
Join Date: Jan 2001
Location: Orem, Utah
Posts: 8,021
Re: 1970 C-10 knocking sound

Quote:
Originally Posted by ghill901 View Post
the timing is what i thought was off also, I had the timing adjusted but still the same rapid knocking noise. Also when i decellerate my truck backfires. it sounds like it is coming from the carb itself. What controls the spedometer cause when i hit 60mph the needle goes crazy and drops.
I would look for a lean mixture as well.

The speedometer is run by a cable coming from your transmission. If it works correctly up to 60, it's likely the speedometer head (the part behind the dial you see on your dash) needs to be repaired.
truckster is offline   Reply With Quote