Exhaust Manifold "SPARKING"

[Texacola]

Ray, Myers has the correct exhaust pipe and nut should you find an original non-modified manifold. Bill

[R.White]

Ray, Myers has the correct exhaust pipe and nut should you find an original non-modified manifold. Bill

Thanks Bill. I will bear that in mind.

[R.White]

Good news at last. I disconnected the vacuum tank and fitted the new electric fuel pump. I also opened up the air intake a bit more and re adjusted the tappets. There was an great improvement and so I took the car for a spin. No more back firing or loss of power. At last I feel confident that the old girl will not let me down. Neighbours remarked how beautiful the Dodge looked and my old friend Steve said it was about time I had put a smile back on my face!

I still need to work on many other areas; especially getting the starter to operate so I don't have to crank the engine by hand. On the other hand for many people these days to witness a car starting up with a pull on the handle is a novelty!

Thanks to everyone who have helped with this unusual problem.

Ray.

P.S. There is no more sparking from the manifold but it could still do with replacing.

[1936 D2]

Great news! Always good to have the old cars moving comfortably!

But - what is the answer to the strangely described "sparking"? What was making a 2" to 4" spark near the manifolds?

So, is post #45 still the best reasoning for the "sparks"?

Edited June 21, 2013 by 1936 D2 (see edit history)

[R.White]

Sorry, the topic has drifted somewhat. I am pretty sure the sparks were iron filings blown by the fan. The exhaust pipe fitting had been changed from a uniquely Dodge arrangement to a 3 point flange to facilitate a modern exhaust pipe. Unfortunately the welding had encroached on the bolt holes resulting in the use of smaller than the normal size bolts being used. I relieved the surplus weld by filing and fitted the exhaust pipe with the correct size bolts. I believe it was the filings from this work which were getting hot and flying off the manifold with the draught from the fan. That's my theory, anyway.

Ray.

Edited June 21, 2013 by R.White (see edit history)

[Texacola]

Ray, So have you concluded there is a problem with the vac tank? I know you spent a lot of time rebuilding it...are you going to give it another go? I'm curious as my DB came with the tank disconnected and ran well with the electric fuel pump the prior owner installed (he said for reliability) but I would like to go back to the original set up. Would be most interested in you findings. After running your engine (and experiencing backfiring) did you disconnect the fuel line from the vac. tank to see if the tank had fuel..sounds like it was starved (lien condition). Bill

[R.White]

Hello Bill. Yes, the problem lies with the vacuum tank. It is always frustrating when you restore something and it fails to live up to expectations. I was not getting sufficient vacuum to draw quite enough fuel to keep the carb topped up. This became apparent when I tried substituting my spare carb. There was not enough suction to fill the vacuum tank so I had to pressurise the fuel tank to push the fuel forward. I had not experienced this problem previously. It is unlikely that there was a leak as all the connections were tight and I had applied thread seal. I can only conclude that a problem has developed within the tank. The filter is clear and allows a free flow. The float and springs work the valve mechanism fine. My guess is that there is a problem with one of the small valves in the top. Closer inspection has revealed a slight bend in one of the little brass valve stems. Perhaps this is the problem?.

I have two or three options. 1) remove and repair /replace the valves making sure they really do seal under pressure, 2) replace the top with a refurbished one from one of our cherished suppliers, or 3) replace the entire Stewart Warner tank with a rebuilt English 'Auto Vac'.

I don't give up easily so it is unlikely that I will stick with the electric pump (although I have plans to incorporate it as a back up) as, like you, I would prefer to use the original set up if I can.

Hope this experience has been of some value to you.

Ray.

[Guest occrj]

Good to hear things are improving, little by little. You say that you've lost the backfiring now that the fuel supply has been altered? that's interesting. Although I favour originality whenever possible, nowadays even more I value reliability and usability so I'd be sticking with the electric pump if there are no associated issues. At least while getting some mileage in with the car to test the rest of it out.

I was out in mine today too, getting better slowly but surely .. more anon

RJ

[R.White]

Hi Richard. In the past, when I have had a fuel pump on the way out, it has manifested itself in a misfire as a consequence of fuel starvation; never a backfire. My attention was draw to this possibility by our friend, Jack M. who said a backfire suggested a lean mixture. I was thinking more along the lines of the opposite.

Whatever the physics of the thing, I am just glad to have the car running properly.

I shall be taking the starter motor to an Auto electrician on Monday. Hopefully he will be able to get to the bottom of the problem. In the meantime I will be using the handle (crank) but even here there is an issue. Without a plug, oil is sprayed out of the crankcase. Temporarily I have plastic petrol cap which helps. I bought a new plug with a copper crush washer to fit the hole but the threads in the crankcase must be damaged as it will not screw in. I will have to get a closer look so the apron will need to come off. If the threads need cleaning up I will need to borrow a suitable tap - a big one with perhaps 16 t.p.i.. I will seek out a machinist and see if he can find a suitable tool to match the plug.

Cheers,

Ray.

[Guest DodgeKCL]

I'm intrigued by all the problems you guys are having with vacuum 'fuel pump' tanks. I had a friend who drove a '29 Plymouth for many many years,including a trip across Canada sea to sea, and he insisted his Plymouth be original and that includes the vacuum tank. If I remember correctly the tanks were Stewart Warners. I had a '29 as well that still had the vacuum tank. Not to pick on anybody, but I found them dead simple to set up and once set up they never gave any more problems. Yes I did install a petcock on the line from the tank to the carb because try as I may I could not stop the carb bowl from overflowing when in storage between weekends. I would have installed a rubber tipped needle valve in the carb had I known such a thing could be done. I do now and highly recommend it. The originals were just plain brass. The tanks just suck fuel from the gas tank up to themselves and shut off the vacuum via a float like a toilet when the gasoline gets to a certain point. Then it's all downhill from there by gravity. Other than making sure it's air tight for the vacuum to work, the rest is automatic. Until camshaft operated mechanical pumps came out, these were the only fuel pumps available. With all due respect(I know how my words on these sites can be misinterpreted) you guys must not understand how these vacuum tanks work? Can I give any help?

Edited June 23, 2013 by DodgeKCL (see edit history)

[Guest 1930]

Just to throw it out there CKL early Plymouth used the Kingston, also Ray I remember that you modified your tank or changed things around when you rebuilt, I remember this because I commented on it back then, springs or something if I remember correctly. Cant re-engineer things in my opinion and expect it too work every time. Good luck

[JayG]

Don't discount the fact that a fitting may be leaking. I had issues with my tank and took it apart numrous times making sure the gaskets were set etc. drove me nuts. I finally replaced the inlet fitting and no more problems. Jay

[Guest DodgeKCL]

I don't recognize the name 'Kingston'. It may be we Canadians had Stewart Warners and just maybe they were a better vacuum tank.

[Guest 1930]

I have read that all Chrysler products went over to Kingston at some point in 28 as the Stewart patent rights had worn themselves out, I know very little about Canadian cars though.

According to the Canadian model specific GP000P-GP580S Windsor parts book the vacuum tank part assy part number was 43280. I will see what this crosses over into if anything.

Edited June 23, 2013 by 1930 (see edit history)

[R.White]

I felt all along that the reason for the backfire and drop off in power had something to do with the vacuum tank. The ignition system and timing checked out O.K. and the carb is clean and properly adjusted. The problem only occurred while on the road after driving for a while. It even looked like a heat related issue but it proved not to be.

It's easy to forget what I started with. The tank was all rusted out with springs missing or broken, a worn out valve mechanism and a punctured float. The vacuum and vent connectors had been blanked off and the inlet had been fed by an electric pump.

When I restored the tank I had to experiment with different spring tensions to get the 'trip' of the mechanism just right and make up my own C spring and filter. As I mentioned in my previous post (No.87) I have subsequently noticed that one of two little valves in the top (which regulate the vacuum and fuel) has a bent stem. Although I tested the sealing of these valves by sucking/ blowing to make sure they worked before installing on the car, I am wondering if this may be the cause. Fuel being drawn down the vacuum pipe is a known problem when the valves become worn. This could also have caused a backfire with unburned fuel getting into the exhaust; while the same fault can weaken the vacuum and lead to fuel starvation resulting in the inevitable drop off in power. The two things go hand in hand. This may be flawed logic but I do understand how the system should work; I am just trying to make it work.

Ray.

[Guest occrj]

Do you have any photos of the SU pump installation? You talk of a drop-off in power after a while, and the backfiring at times, sounds similar to things I've encountered and I'm wondering about testing a revised fuel supply to compare to the current setup.

RJ

[R.White]

Do you have any photos of the SU pump installation? You talk of a drop-off in power after a while, and the backfiring at times, sounds similar to things I've encountered and I'm wondering about testing a revised fuel supply to compare to the current setup.

RJ

Here it is. Not very pulchritudinous, I'm afraid but it is only a temporary arrangement - at least it works!

I have taken the 6 volt feed from the coil and earthed to the scuttle. The outlet pipe to the carb needs to be a fairly small bore or float chamber flooding may result. It is essential that a low pressure pump AUA26 be used. If it says AUA25 it is a high pressure unit. To be sure the pump is 6volt (not 12 volt) the ground screw is the same size as the 6 holding screws. Unless the pump is new (like this one) what the cap says -6 or 12 v - cannot be relied on. Plastic caps get broken and swapped about.

It's probably worth experimenting with the fuel supply on your car - if only to eliminate that side of things.

Edited June 24, 2013 by R.White (see edit history)

[Guest occrj]

Interesting, thanks for posting. Although some people get a bit sniffy about altering things from original, tests like this can prove very useful in identifying where (original) parts are going wrong. I may well try something similar myself, although I've a few more checks to make before I'll do anything radical :-)

RJ

[Pete K.]

Pulch what?? OK, you woke me up. Your problem on loss of power & backfiring is NOT the vacuum tank in entirety. If you think you are not getting fuel to the bottom section of the tank, you will soon eventually burn up what's left in the float bowl, and "run out of gas". The engine will virtually die quietly and coast to the side of the road, hopefully. Owning Ford Model A's, I am guilty of forgetting to turn the cabin fuel cock "on" a few times and within 100 yards the little Ford, (not so much different than our Dodge engine), quietly dies. I turn on the valve and she starts right up. No coughing, backfiring or long moments of loss of power. I do believe you have other problems, possibly a combination of the big three, "spark-fuel- compression" Installation of another type fuel pump is not necessary and a waste of resources. I think it may be the carb you have Ray.--Just a guess. Please don't take this as sniffy. ---Pete.

[R.White]

Not sniffy at all, Pete. I welcome your contributions. I would not consider the purchase of a fuel pump as being a waste because I have another use for it when this experiment with the Dodge has been concluded.

If the problem is not the vac tank, Pete, how is it that the problem went away as soon as I fitted the electric pump?

Perhaps it will return to haunt me yet again. Time will tell.

JayG wrote how much trouble he had experienced with his vac tank which was eventually tracked down to a faulty fitting. On removing my tank, I noticed that the vacuum elbow had thread damage. This might have led to a leak. I put my hands up and admit that I must have over tightened it. My theory is that the carb float chamber was not getting enough fuel. I'm not saying that it emptied completely but that perhaps it was not keeping pace with the demands of the engine and as a result was running lean.

Jack M said that backfiring led him to think running lean. I guess the mixture could be too weak to ignite by the spark but could build up in the exhaust and backfire. The loss of power would also not be total like running out of gas.

Whatever the cause, the problem has gone away. At least I hope so. I have been able to take the car on a good run with no problems. I tell a lie... the windscreen wiper fell off!!

When I am happy with the vac tank I will refit it to maintain originality. I have every confidence in the original system but it needs to be leak free and working as intended. Then it will look much more pulchritudinous

Ray.

[Pete K.]

There's that word again... Where be my Funk & Wagnall? Yes, I understand the experimentation with the electric pumps. I had one on my '27 Packard for a while until I bit the bullet and "fully" restored the vacuum tank. No need ever again for the electric pump and it was still working fine, years later when I sold the car. I guess I should thank my lucky stars when I restored the vac. tank on my '25 last year, she works the bomb. There's not much to it. It only uses engine vacuum to operate the tank and fill it a quarter way with fuel, plenty enough to keep the tiny float bowl happy. As long as Earth has gravity...

[MrLiken]

On 6/3/2013 at 2:52 PM, R.White said:

The advantage, as I see it, to having a screw in compression tester is that you (or rather I) can dispense with the disgruntled other half. Just screw in the tester and hit the starter. Mine has a large, easy to read dial with a pressure release button on the side. There are different adaptors which screw into each other depending on the size required. A nice piece of kit.

Tomorrow I will get on with checking the timing regularity with the strobe light. I thought perhaps I could use a 12 volt battery charger rather than trying to lift the big heavy duty battery out of the Range Rover?

Ray.

This is exactly my issue.  Can you tell me the name of your adapter kit?

Thanks,

John