Thread: can a motor backfire if you overwind it???

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Originally Posted by jerry clayton

They usually only do it ONCE!!!!!!!

I think I still hold the altitude record for a 6:71

i remember reading about a somebody who had a brand new pink blower and backfired it thru the O in the champion sparkplug sign on the top end i belive it was riverside?

Thank you Mike, Shoprat, Pro70, Jerry, Pat & Gassersrule, Then I think this is why my motor is backfiring at high RPM's. I've been overwinding it. I looked at the paperwork that came with my motor & redline is 6000 RPM. I've been winding it over 6000. I'm sending away tonight for a 6000 chip for my rev-limiter. I don't think it's running too lean cuz the motor was professionally built & tunned. And the guy who put the motor in set the fuel pressure regulator at what he said was the right pressure {6 pounds?}. It also backfires when I'm turning it over to start it but not once it's running {at lower RPM's}. So maybe the timming is also off? In fact, I think I read where blower motors should start in an instant. Why does mine turn over & over? Thanks again! Bill

Check the intake valve springs. If they are ok, do a comp. test, may have a bent intake valve. Backfire when cranking means something is allowing combustion into the intake. Not good with a blower!

Interesting... but not surprised... I'm not an expert in racing designs by any means... but by the time ones takes a big block and strokes it out another 100 plus CI or so... its getting a bit long in the stroke.... 7k is pushing it... isn't it?

Originally Posted by dem45133

Interesting... but not surprised... I'm not an expert in racing designs by any means... but by the time ones takes a big block and strokes it out another 100 plus CI or so... its getting a bit long in the stroke.... 7k is pushing it... isn't it?

your kidding right ? i have 548.565.589s 632.s running past 7000 .valve train is key