Projects Giant speedster project

Well, I didn't actually "make" the valves. About half the valves were rusted away real bad. I ground them down and a buddy welded up the faces. Then I resurfaced them back down to standard. I wonder if the engine is just running too lean. The original carb was gone when I got the engine. This carb came from ebay. It's the right size, but is it jetted right? Most real old carbs have an adjustable main jet but this one does not. I wonder... An old mechanic once told me "you gotta do something even if

Jerryit's wrong."
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the water down the carb running is great for getting rid of carbon build up. which causes those hot spots. did it to a sbc that was dieseling and it cured it

 

I was Groucho one Halloween! My wife was Harpo!

Favorite line: "I can see you're a girl who's had a lot of bad breaks. Well, we can clean and tighten your brakes but you'll have to stay in the garage all night."

Jerry
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Jerry,
There have been some very sound suggestions.
Is there any way the decompression system is not fully off & is affecting the #5 &#6 exhaust valves? I am not sure how it works but on mine it appears it probably shifts the exhaust side cam lengthways in some manner. I have worked on a 1904 Olds that shifts the exhaust lifter to a different lobe when you activate the decompressor - you need things adjusted correctly or trouble developes. When the firing order is 1, ,1, ,1, ,1, ,1! A miss is very evident.
Jack

 

Those wires were just an old set I had lying around. It wouldn't hurt to make up the "real" set with that solid core vintage wire I bought.

Jerry
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what if you opened up one of the primer holes and using a spray bottle with some gas in it try to richen it up a little?

 

Mrs. Schwartz, I see here you have 19 children. That's a lot of kids!

Yes Groucho, it's because I love my husband sooo much....

Lady, I love my cigar too but I take it out of my mouth every now and then...


Sorry, felt the need to share

 

The exhaust cam moves forward or back--I can't remember--which lifts the exhaust valve off the seat. But I pressurized the exhaust to check the valve seal and it didn't leak. Still...

Jerry


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I'm thinking of getting a spray bottle and shooting the gas right into the carb.

Jerry

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^^ garden sprayer

 

The engine sucks up about a third of a gallon during a ten minute idling session. Is that a lot?

Jerry


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It'd be a lot for my little A banger... but sadly I bet that's on par with the behemoth!

 

is this strictly a gas engine? or was it kerosene? with just gas primer cups?

just thinking about my old duel fuel farmall

 

LOL! Well if that's true, I think you can rule out the possibility of a LEAN misfire!

 

No, just gas. LOT'S of gas!
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ok, was thinking about the tractor because it ran gas till it warmed up then u switched to the kero because it was cheaper.

 

After hearing it I'm still thinking intake leak, put a little oil in the primer cups above the guilty cylinders and see if it gets sucked down with them closed.

 

The priming cups go right into the combustion chamber so the oil would either get sucked in or blow out all over you depending on what stroke that cylinder was on.

Jerry
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Just stick your thumb over the priming cup while it's running...if it's leaking you will know. I'm thinking ignition wires.

 

Maybe on to something with those plugs...perhaps a little leak was there? I wonder if snugging them all down and then maybe squirting soapy water around the threads might give up a possible leak?

 

Cpt. Spaulding: "One time I shot an elephant in my pajamas....how the elephant got into my pajamas I'll never know"

My friends 1909 Brush is the same way...if you have a miss, it is rather noticeable!

So the Seagraves use a mechanical compression release that slides the exhaust cam shaft out of the way? Interesting! The only time I had ever seen that was on my friends 1913 White "30". The compression release on the White 30 hp L-head pushes the cam shaft forward to open all 8 valves. It is really a neat and ingenious design.

It still sounds like valves to me for some reason, but you guys all have allot more experience at this than I do!

Jerry, you mention the distributor. Is this engine a twin ignition motor? I would have expected it to be twin magneto fired or at least both mag and distributor...in case of failure, could be wrong though.

 

Jerry,

I think you said you checked for intake manifold leaks. I have fixed several model T Fords that would miss on the rear cylinders & in each case it was the manifold seals. It always seems to cause trouble at the rear of the engine - even on a cold engine.

I also have richened the mixture on a few engines with mysterious trouble with propane. An unlit plumber's torch stuck in the carb inlet has a valve that you can regulate the ammount & it does not have to vaporise in the venturi. Maybe worth a try.

Jack

 

You can select either mag or distributor but I don't think you can choose both--too hard to synchronize.

Jerry

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I'd forgotten about the propane trick. That's a great idea to eliminate a too lean mixture problem. I'll do it tomorrow.

I didn't have time to investigate the Seagrave engine today. I had to rebuild the carb on an old Toyota dump truck I used to haul trash. Got all done and found out someone stole my gas by taking the drain plug out of the tank. They could have at least left me the plug!

Jerry
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That is true, it would be one or the other. Usually you would start it with the Battery/distributor ignition then switch it over to Mag once it was running. Was kinda curious if you had a mag for it or were even planning to run it mag fired later on.

 

I've got the mag and I had it tested. It's a beautiful thing but it showed a weak spark so I figured I'd run it on the distributor until I could spend more time on the mag. The spark is pretty is pretty hot with the coil plus the problem seems only on be on #5 and #6. which actually have the shortest wires. I wonder if the magnets are weak. Could you piggyback a couple of modern magnets on the old ones and revive the mag?
Jerry

 

Jerry,
If your mag feels "lumpy" when turned by hand, the magnets are likely OK - if not they can be recharged. If the magnets are good often the problem is dirty points or a weak condenser. The condenser is often burried inside the armature so that is not good news. What make & model is your mag?
Adding magnets will not likely help. If you take it apart - mark exactly where the magnets are mounted - they need to go back in the same position.
Jack

 

Insane project! Freakin awesome! Subscribed!

Hope you track down the backfire issue soon!

Alex

 

The mag was a mess so I carefully took it apart, cleaned out the dried up crud and greased it. I didn't fell competent to test it that's why I sent it out. As I remember it's an Eisemann. I'm sure the magnets need recharging. The vehicle sat around for years and years before I got it. It was a miracle the mag was still on it.

Jerry
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Backfire solved??

Jack,
I took your advice about testing the mixture by richening up the mixture. However I didn't think there was enough gas in a plumber's torch. I use a 20lb propane tank and heater to heat my shop so I thought I'd just stick the hose in the carb and turn on the gas. Surprise, those new fangled tank valves won't let you do that. You've got to have some back pressure. So I got out my little pressurized hand sprayer and filled it with gas. As long as I kept the stream in the carb throat the engine ran smooth. If I stopped spraying, within a ten seconds (when the extra gas burned off) the back firing started again. I never did see any black smoke, nor did the engine ever stumble like it was running too rich. I think it's just running too lean. (You'd probably need a garden hose to make it run rich.)
The carb came from ebay, but the bore and the flange size were a perfect fit. It's a simple thing, like a gargantuan lawn mower carb. I could hog out the jets but I'd rather make an adjustable main jet. That would save me a lot of trial and error. You can see the main jet set up in the next to last picture. The last picture is the wrench for taking off the plugs over the valves.

Jerry

Jerry
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