Dodge 4 Cylinder Backfiring Problems- Assistance needed-Please

[Andrew_Lockwood]

Hi Dodge Owners, (Dodge Delux 4 cylinder tourer)

I joined the club a few months ago and am in need of assistance regarding the above car. Please can you offer any advise.

I have finally obtained UK registration for this car, and gained an MOT but cannot drive the car "unless its cold" .

The problem appears to be fuel vapourisation I think!.

The engine is fitted with new glass bowl fuel filter going staight back to the fuel tank. The carb is a stewart, with a stewart Vac pump mounted on the rear last two right hand side engine cylinder head bolts with original brakets.

The symptons are: When cold, the engine ticks over fine and revs ok. When hot if you rev past 50% throttle she slows up and back fires! (ie when carb is opened to more than half way. The Mixture has been adjusted without sucess. When engine back fires you can see the carb fuel control needle jump and then if you not careful as happened last week while stationary I rev'ed the engine and it back fired and caught fire!!!

Carbruetter cleaned and reset needle valve to float chamber precision machined to remove small ridge on needle value, it now seals much better. The carb float was leaking on centre tube so I drill this out and re-machined with new tube and resoldered this in. Weight of float checked still as per original of 35grams.- this does not now leak checked in hot water.

Spark plugs are black ish not too bad.

Any ideas appreciated as I am banging my head against the wall.

Some people say vac pump should not be mounted on engine but this car had been driven in Australia with no problems, and the DB book shows it on the engine? I would like to keep it original if possible.

Many thanks for your assistance

Andrew Lockwood- Stowmarket Suffolk. England

My Email address is alockwood1@toucasurf.com

[jan arnett (2)]

Andrew: You did not mention what year you have but a 1923 has the vac. tank mounted on the engine. You should move this to the Dodge Forum for more exposure but maybe I can help you. There are several things can cause a engine to stall or sputter when hot. There is a tube between the carb and exhaust manifold that must be in place. A second potential problem is a weak condensor that breaks down when it is hot. Make sure you do not have a crack in the distributor cap or a carbon trail. If you valves are set to tight when then get hot they will not seat and cause backfireing and a lack of power.

Hope this helps.

Jan

[Andrew_Lockwood]

Jan, Hi thanks for responding. The car is Jan 1927 wooden spoke artillery wheels with Simms C4 magneto. The car has never stalled or stopped it just lacks power once hot and back fires only when reved above 50% approx. The suction tube is clear and working as vac pump certainly draws in the petrol. I even tried a separte SU fuel pump to see if this would solve the problem no joy.

I will check the valve clearances asap.

Does this additional info help?

regards Andrew

[Mark Shaw]

I suggest yuou check your timing too. It sounds like it may not be advanced enough at higher throttle settings.

[R W Burgess]

Bump to the top. Poster needs more info!

Wayne

[imported_Big Mark]

+

[Guest John1918]

Check compressions. My '25 would slow down and do a mighty backfire and I would take this as my cue to slow down and be more considerate to the old girl. In time the problem revealed itself as a burnt out exhaust valve. Also check that the air intake doesn't pass through the block for summer running. There is a 'twist valve' on the air intake that bypasses the air from passing via the gap in the block. I don't know about yours but some cars use a thick gasket to partially insulate the carb from som of the engine heat.

John

[72caddy]

Don't mean to hijack this thread, but would the timing also be my issue?

I finally got my 1919 on the road this past weekend. Other than 1st and 2nd being rather noisy it ran OK. When I hit 3rd (extrememly quiet) the car would maintain speed but not really accellerate no matter what I did with the throtte.

Any advice on the gear noise and lack of power in third?

[dwollam]

Sorry but gear noise sounds like it is truly a Dodge! When it quits making noise the teeth are all gone! Run very heavy gear oil. The high speed slider is the culprit. It runs in every gear except high.

[72caddy]

I was wondering if the gear noise was just the nature of the car. In second something it really vibrating on the cowl or exhaust- so it may sound wqrse that it really is. I am running 600W oil I bought from the Model T suppliers and even added some STP engine treatment to make it really sticky (as this was recommended by an old newsletter).

Thanks for taking to the time to respond.

[Guest chrysler28]

Check to be sure u are not having an exhaust leak wher it

hooks to manafold. My Model A was sucking air and wow what a back fire. After sealing exhaust I no longer have the

problem.