Gordon

mikiec · #1 (**permalink**) 12-06-2001, 01:13 PM

Gordon,

I'll need you to take my car for a drive on Sunday. Backpopping through the exhaust od deceleration. Bad enough that I blew another power valve yesterday on the way home from my visit.

Said the heck with it and bought a new, instead of used, carb. This one has blow out protection. Holley 670CFM.

I'm going to check the exhaust system for leaks tonight.

Mike

Gordon Levy · #2 (**permalink**) 12-06-2001, 02:18 PM

no problem Mike.

BMMILLER · #3 (**permalink**) 12-06-2001, 03:49 PM

Mike: I'm curious what you find regarding the backfiring. I have an Edelbrock 600 on my 302. I have always get lots of backfiring on deceleration. I always thought this was an inherent problem with the style pipes we have. I know I'm running rich, but that's intentional. Let me know what Gordon thinks.

Thanks, Blair

mikiec · #4 (**permalink**) 12-06-2001, 06:49 PM

Blair,

I'll let you know.

The backfire through the pipes on deceleration is a recent happening. Thought it might be the used carb I purchased. Figured it was running very rich. That along with an exhaust leak. Can't find the leak. Had the carb gone through and leaned out was fine for awhile. Started again. SO out went the Holley 650 Dbl/mechanical. On went a brand new Street Avenger 670 CFM.

Car runs better but still have the backfire. Possible a blown exhaust manifold gasket but I can't hear it leaking.

So it was time to call in the big guns....

Mike

BMMILLER · #5 (**permalink**) 12-12-2001, 01:44 PM

Mike: From viewing the posts, its apparent I missed a great gathering last Sunday. Curious if Gordon got a chance to drive you car and if so, what I thought??

Thanks,

Blair

BMMILLER · #6 (**permalink**) 12-12-2001, 01:45 PM

What "he" thought.

If I would just read what I write!!

mikiec · #7 (**permalink**) 12-12-2001, 01:54 PM

Blair,

Yup you missed it. 21 cars 70 people. We had many members bring their kids with them.

As far as my car ... No Gordon did not get a chance to drive it. However, we did talk about it and he suggested that I was running to lean and to increase the jets in the primary. I'm going to see how the new Carb does. I'll Probably take the car by Gordons shop sometime next week.

I'll let you know what I find out.

Mike

coyled · #8 (**permalink**) 12-15-2001, 01:55 PM

Mike, sorry I missed the big bash, I have been out of town a lot lately. My guess on the backfire is an exhaust leak. But, remember, when you let off the throttle, the throttle baldes shut so that the only fuel the motor is getting comes from the idle circuit. I would try richening up the idle circuit(idle screws out) and see if that helps. good luck, scott.

mikiec · #9 (**permalink**) 12-17-2001, 04:28 PM

Thanks, Scott I'll give that a try...

Can't find any leak. But, I'm going to repaint my pipes, at that time I'll replace all gaskets.

Sorry you missed the bash... It was fun. Especially seeing Gordon sporting a pair of Devils horns. Pic's will be posted soon.

Mike

BMMILLER · #10 (**permalink**) 12-18-2001, 11:19 AM

I could use help regarding the backfiring problem too. I have replaced header gaskets and the header to side pipe gaskets. The engine still backfires on deceleration. Could this be due to just running way to rich?? I'm not clear on how increasing the richness of the idle jets would help - wouldn't this make it worse??

Blair

mikiec · #11 (**permalink**) 12-19-2001, 07:12 PM

Blair,

On your backfiring....

Do you get it all the time?

Did you have it before the head and cam change?

Mine is almost gone. Carb change helped the most. I went from a 650CFM Holley Dbl with mech sec to a new Street avenger 670CFM. Richened up the idle circuits..per Scott. However, I have only had it when I let off the gas above 3.5K RPM. Also, when hitting the rev limiter.

Mike

BMMILLER · #12 (**permalink**) 12-20-2001, 10:11 AM

Mike - Yes, mine has backfired from day one. Maybe it is the carb. It actually is worse now with the new heads. I'll try richening the idle jets and see if that helps any. I am confident that I don't have any leaks. Maybe a new carb is the answer?

Thanks,

Blair

Gordon Levy · #13 (**permalink**) 12-20-2001, 02:15 PM

It sounds like you have a very lean condition. when you changed the heads it got worse because with a more efficiant head your lean condition gets worse. Without seeing the car and working on the carb I would go up a little on the primary jet size and fatten the idle curcuits. I would be happy to help tune it if you made your way up here some time.

BMMILLER · #14 (**permalink**) 12-20-2001, 02:44 PM

Gordon: Thanks again for your help on the phone.

Holley 670 Street Avenger it is! Picking it up this afternoon.

Blair

mikiec · #15 (**permalink**) 12-20-2001, 05:29 PM

Blair,

You will still need to do some fine tuning of the new carb.

I'm fiddling with mine. Told Gordon that when I'm finished playing and it is toast then I'll let him work his magic.

Mike