engine pin/ knock/ bang noise??
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Hotshot
Joined: Jul 2005
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engine pin/ knock/ bang noise??
this is a 40 year old small bock with a 2 barrel Roch carb. kids have it at school. they said it had a noise and stumble so i took a couplel tools and went to look. starts and idles o.k., maybe a slight miss. when you push the throttle it sould like a rapit fire cap gun inside a 5 gallon bucket.?? i have heard engine ping due to timing, and a piston or rod knock and this dont sould like that. as soon as you back off on the throttle it stops. push the pedal 1/2 inch and you can hear it start again. i would have thought it was timing ping, but like i said it sounds more like a cap gun inside a bucket. constant small banging noise.--- when it gets home in a couple weeks i will check timing, pull the plugs and check them, then rebuild the carb. just wonder if anyone has every seen any thing like this.
it does lack a little power when this occures. almost thought it might be running short of fuel, but again, it is a rapid, sharp, cap gun type noise.
it does lack a little power when this occures. almost thought it might be running short of fuel, but again, it is a rapid, sharp, cap gun type noise.
Lead Driver
Joined: Apr 2007
Posts: 5,958
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From: Houston
If you have a vacuum gauge hook up a vacuum gage to manifold vacuum and run the engine let it idle. If the gauge is steady then your valves are fine. If you had a valve problem every time the bad valve operated it would cause the vacuum gauge to drop at the same percise time.
the 351w firing order was only used on the high performance 302`s
the 351w firing order was only used on the high performance 302`s
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Joined: Jul 2005
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i think your on the right track. i though about it all day. the "bang" sounds like a gas explosion. im thinking "timing", but possibly the distributor cap or something is cracked and when i give alittle throttle the advance makes one cylinder fire into another plug that is not at the fire point, there fore one cylinder is "out of time"??????
