Backfiring Saturday, 22-Jul-2000 15:52:27 Message: 4.4.195.150 writes: Any body experience any backfiring problems like this? I continue to run into a problem with repeated backfiring, even at idle! I have reset the timing three times in hopes that of putting it near TDC would be the way to go (started @10 BTDC). It hasn't helped. Back firing is most noticeable @ 2000 RPM's on deceleration and can be quit loud. Sounds as though it is coming through the muffler's as it will even back fire right after the vehicle is shut off (engine almost quits turning, then bang). Rarely if ever pop's through the carb's, after warmed up. To many Hydro carbon's? Car runs great, acceleration is smooth and strong, slight flat spot with the timing set at TDC. Steady cruise, as long as accelerator pedal is depressed no back fire, slightly release it and will back fire repeatedly until accelerator is depressed again. Could it be a 009 problem, sticking? Engine is a 2213cc, 009 dizzy, 42DCNF's, Engle 110 cam, Ported and Polished heads 40 x 37.5mm valves, by Clyde Berg, 1 5/8 exhaust ALL the way out (no heater boxes on this baby). Ideas? Thanks for your help! Chas Chas

Replies:

Re: Backfiring (mike) (22-Jul-2000 16:23:42)

Re: Thanks I will check it out! (n/t) (Chas) (22-Jul-2000 18:08:26)

Sounds like an idle mixture problem. Turn each mixture screw in(one at a time) until that cyl quits firing.( RPM's should drop equally for each cyl tested, if they are in sync.) Then back the screw out slowly until that cyl picks up again. Repeat for all 4 then take it for a drive. (n/t) (Ohio Tom) (22-Jul-2000 17:18:50)

Re: Backfiring, check that the inlet manifolds are seated on the heads, a good way to check this is to spray some carb cleaner at the joins and note any changes in the idle rpm (n/t) (max, Der Bahnstormerz) (22-Jul-2000 18:52:08)

Get 48's! (n/t) (Vers Jr.) (22-Jul-2000 20:00:23)

Re: Backfiring (Craig Merrow) (22-Jul-2000 21:41:11)

Re: I had the same before and it was a cracked manifold. (n/t) (John Rayburn DKP3) (22-Jul-2000 23:11:34)

Re: Backfiring Saturday, 22-Jul-2000 16:23:42 156.42.68.6 writes: you almost certainly have an exhaust leak. most likely close to the heads.check where the headers mount to the heads,theyre probably loose or have a bad gasket.the backfireing is cause by a sudden negative pressure in the header when you deccelerate,this causes fresh air to be sucked in and the still very hot left over fuel(the combustion process isnt 100% efficient so youll allways have a little lift to burn)mixes with the fresh oxygen and explodes and causes a backfire.hope this helps!! mike

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Re: Backfiring Saturday, 22-Jul-2000 21:41:11 208.161.21.74 writes: Had a similar problem with my 1776 and Berg 42's; as it turned out, the idle circuit in the right carb was plugged up, but darned if I could get it cleaned out! Steve Hollingsworth has them at his shop to work on. A couple years ago I had some backfiring problems with the same motor and Kadrons; it turned out to be a couple of bad plug wires (brand new at that!) and check balls in the Kadrons not seating and causing fuel to constantly siphon through the accelerator pump nozzles. I replaced the little plastic balls with 7/32" steel balls. Craig Merrow