225 v6 Backfire

Hello all, i am woundering if anyone can help me with my backfire problem. My 1970 cj5 has a 225 engine that has been sitting for about 10 years. i replaced the carb with a holley and installed a HEI ignition along with a lot of other things. i have it running now and the problem i am having is i am getting a small amount of backfire only out of the drivers side exhaust, it is a lot worse when i first start it up and as the engine warms up the backfire is not as bad. sense it is only coming from one side of the engine the first thing that comes to mind is a valve sticking or needs to be addjusted, but then it was brought to my attention that you don't adjust those valves because they are hydraulic. Has anyone ever had this problem or know what the problem is. i believe the carberation and timing are good.

thanks Dave

 

Mine did the same thing only on the passanger side.The timing was out 180 and carb needed to be adjusted and points re-done then the violent backfire was gone tahnk god it was loud.I would look into your timing.

 

I knew the 3 main things it could be were carb. timing or valve. i think the new holley carb that i put on is dialed in, and with the new HEI distributor which have no points i think that is dialed in as well, maybe i need to tweek with then a little more. the reason i am thinking it might be a valve is because it sat for so long. my big question is can the valves be adjusted.

 

No. The rocker arms pivot on a shaft and have no provision for adjustment. I'd suggest hooking up a vacuum gauge and check what the vacuum is doing while running. That can tell a lot about an engine without a lot of work.

Try this site for deciphering the readings.

http://www.visn2.com/UsingVacumeGauge.html

 

wow, thanks for the vacuum info. that will be very helpful. i do have a vacuun gage on the dash and the time i did look at it i remember it sitting at about 20, this time i will take a better look.

thanks again

 

On mine i have a 2bbl roch and no vacuum leaks.The delco from po had it in 180 out after the rebuild i put things together and found he must have put in 180 out and then moved plug wires around.My 225 was backfiring bad loud till i fixed the timing.How do your plugs look are they fouled? make sure your on tdc.