View Single Post
Old 04-18-2011, 09:42 AM   #21
Foosified
Registered User
 
Foosified's Avatar
 
Join Date: Oct 2006
Location: Edmonton, AB, CAN.
Posts: 152
Re: SBC 350 Engine Backfire Through Exhaust and Carb

The heads I wouldn't say are fresh. They were bought used 15000km approx. on them. When I installed new springs I seem to remember some valves moved more freely than others, but I'm not engine builder, so never thought anything about it. I have a feeling they may be the problem or part of it, as that issue may have caused some detrimental wear on the cam and/or lifters/pushrods.
Quote:
Originally Posted by cableguy0 View Post
very doubtful to have valves sticking on a fresh motor. Im thinking more along the lines of a cam starting to wipe out. Its really hard to sit here and guess. But to have a backfire both through the carb and out the exhaust its the most likely suspect. Just for giggles pull the distributor cap and make sure the mechanical advance is actually moving. I know you say your timing is 12 at idle but if you have a timing light capable of showing advance see what timing is at 3k rpm.
__________________
May all your ups and downs be in the back of a Chevy!:
Foosified is offline   Reply With Quote