My 1928 AA Truck is backing firing at half throttle and higher. I have replaced the condensor,adj the points to .020, timing the distributor using the front end pin. Am using org plugs. Starts fine with spark
Advance at half. What wrong. Need ADVICE.
Backfiring at high rpm
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Chris Haynes
- Posts: 2203
- Joined: September 7th, 2003, 5:18 pm
- Body Type: 82A
- Model Year: 1930
- Location: Camarillo, CA
Re: Backfiring at high rpm
Sounds like a leak in the exhaust.
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Bob C
- Posts: 1442
- Joined: April 24th, 2003, 11:50 am
- Body Type: Mail truck, Stake tr
- Model Year: 1931
- Location: SO CAL
Re: Backfiring at high rpm
It should be started with the spark fully retarded. May be running to lean, how far
open do you run the GAV? Also could be a vacuum leak.
Bob
open do you run the GAV? Also could be a vacuum leak.
Bob
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1crosscut
- Posts: 877
- Joined: December 25th, 2010, 7:22 pm
- Body Type: 82-A
- Model Year: 1929
- Location: Lincoln, NE
Re: Backfiring at high rpm
Need a little bit more information.
Has your engine been running well in the past and this is a new problem?
I know you said you timed the engine using the pin method. Here is a link to timing the engine. http://www.abarnyard.com/workshop/timing.htm
Just want to make sure it is timed correctly to start with. Do you have full travel of the arm where it comes out of the distributor.
Is your distributor stock... or are you using the "modern" set up?
Is it back firing while driving or at rest just running up the throttle?
Is your gasket between the carb and manifold good and not leaking?
Same goes for the gasket between the intake manifold and the engine.
Is your gav set too lean? Most run it aroung 3/4 turn out.
Is there excessive wear around the throttle shaft allowing air to flow past the shaft into the carb?
If you are using the original 1928 spark plugs you problably should hang them on the wall and put in some fresh ones.
Has your engine been running well in the past and this is a new problem?
I know you said you timed the engine using the pin method. Here is a link to timing the engine. http://www.abarnyard.com/workshop/timing.htm
Just want to make sure it is timed correctly to start with. Do you have full travel of the arm where it comes out of the distributor.
Is your distributor stock... or are you using the "modern" set up?
Is it back firing while driving or at rest just running up the throttle?
Is your gasket between the carb and manifold good and not leaking?
Same goes for the gasket between the intake manifold and the engine.
Is your gav set too lean? Most run it aroung 3/4 turn out.
Is there excessive wear around the throttle shaft allowing air to flow past the shaft into the carb?
If you are using the original 1928 spark plugs you problably should hang them on the wall and put in some fresh ones.
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Dave
Dave