Question concerning motor just shutting down?
 

My kid bought his first drag truck. For last month been just running it in the shop waiting on April to drag. It was running and just shut off, just like you turned the key off. We are getting spark, put on new msd plug wires,dist cap etc. When try to start it all most will but backfires really really bad about 5th turnover. Seems plugs are wet to after a while of trying to start. We put in new plugs and drained the gas,it ran we took it for a spin and parked it in shop, wouldnt start again. also when it was runnig had to go into the pedal easy or it would spit and spudder.. Plugs look wet again.Put in new plugs again no help. Any ideas would be apprecated. Any drag racers that would be willing to help in my area would appreciate you looking at it. will pay you. 1969 chevy c10-454 motor- bored ten over - Demon 850 carb-msd ignition- etc :?: Champaign/urbana Illinois-area

try these things
 

It may be a couple of things
it may have jumped time, check the timing
it may have got some debri in the float bowls and the needle /seats are up and flooding the motor.
maybe another problem with the carb, if you have another (known good carb) try swapping it
Try those things
jeff

Yep, ditto on valve timing... had a couple circle track engines do that to me.
Also had a guy bring me a circle track SBC that would only idle fair, but went crazy on throttle. I tried EVERTYHING... litterally, until tearing the engine down to find that he had put the top timing gear drive sprocket on backwards, and the timing was out 180 degrees. Turns out his top gear had a mark on the back side also, and he didn't notice it was flipped around backwards and he was looking at the wrong mark to time it.
YES, it did run without hitting any rotating parts while 180 degrees out... he got real lucky... :shock:
I talked him out of using the gear drive for stock class circle track racing, and we put in a chain drive correctly timed, and it runs like a champ with no other changes.

Also ditto on the carb problem. I fought with a rebuilt carb that was doing the same thing. Put on a brand new carb and it cleared right up.

Yeah i agree jumped timing :!: :!:




''JUST MY TWO CENT'S WORTH''

Jeff & those kind enough to respond to my boy & I.
 

Thanks a million for the carb advive, we spent all afternoon cleaning it. We broke the entire demon 850 down , would spray the hec out of it with brake cleaner,then blow the hec out of it all with the air compressor. Then we would start over and do it again. Put the carb back on the 454 and she fired up so quick it scared us. Set the timing at 36 degrees while holding rpm's at 3,000. Man its running fantastic. Thanks again for the replys. Hope to see you folks at the track some time. Later.

Barry & Travis - Central Illinois

Get rid of the Demon, it will do it again. Get real Holley HP and put onit and then forget about it.

I have had 2 demons, still have one of them. Zero problems. The first we had on our sbc nova. Went to Ron's toilet and picked up zero e.t. both on alcohol.

Curtis

Not being a wise guy but you had something wrong if you didnt pickup from going from a demon to a toilet .. that was a easy tenth gain 8)

I had a gas demon carb it was pretty good carb ..not fast by any means but was consistent.

I don't think you are being a wise guy. We heard the same thing from a lot of people and I expected some myself. The motor was tuned with the carb on the dyno before it went into the car and we put the car on a chassis dyno after changing over to the toilet. Saying it is an easy tenth is a pretty broad statement that I'm not sure covers all cases.


Curtis

When both are right with the correct cam/conv change after toilet installed its almost a guarnteed pickup, think of the way the fuel is brought into each hole. What was your setup on the toilet if you remember ? like BV leak down, Nozzels, Pill, color of BV and most important pump and size of it ?