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1925 Maxwell/Chrysler won't start


Max4Me
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I started and ran my 1925 Maxwell/Chrysler in early to mid November of this year, and it ran perfectly. About 3 weeks later I went to start it to prep for a local Christmas parade and it would crank, but not fire. I have the vacuum fuel pump and there is gas going to the carburetor (clear glass filter just prior to carb is full). I did rebuild the carb about 18 months ago and it's been working fine. I pulled the coil wire and grounded it and got a clean spark. I then pulled the #1 plug wire, grounded it and got a spark. I even did one thing I am usually against- I gave the carb a quick shot of starting fluid and no indication it even wanted to fire up. Today I cleaned the distributor cap contacts and the rotor. I also pulled, cleaned, and reset the gap (.020 according to the manual) on the points. I also pulled a plug and it looks OK (no heavy soot or fouling apparent). When not in use I have a battery tender on the battery so that should not be an issue; besides, it cranks fine. Any thoughts on what I've missed or what I should check next will be greatly appreciated.

Edited by Max4Me (see edit history)
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Regarding my Maxwell that won't start: I've been trying to track down a 6 volt coil and condenser. Got one at a parts house that said they were 6 volt but the insert in the coil box says it's 12 V. I have some electrical knowledge (if you grab one wire and nothing happens, leave the other one alone!) I can use a multimeter and understand ohms and volts OK, but coils are another story. Will a 12V coil/condenser work in a 6V system without causing damage? Parts are Standard coil #UC15T and condenser is Standard DR90T. Info from internet searches are all over the place and no help. Thank you for your help!

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Thanks for the input, gents. No offense, Joe, but unfortunately, there seems to be two opposing schools of though: one group says 12V with internal resister will work, others say no. So the answer is clear as mud for me. I am inclined to agree that a 6V system should use a 6V coil! Back to my 'Easter egg' hunt. 

 

Narve, you're right, an extensive internet search for capacitance was as fruitful as finding the answer to why are we here?

 

Again, thank you for your replies.

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The parameter for a coil that matters is its resistance to current flow to achieve the right magnetic field to generate a spark.  Magnetic field strength is based on the number of turns of wire in the coil in the primary and secondary sides and the current flow, in amps, in the primary side.  When the key is on and the points are closed and the engine is not running you get maximum current flow in the coil.  Many cars specify that current to be about 4 to 5 amperes under this condition. In dc electricity, the current flow can be determined by dividing the applied voltage by the resistance of the coil.  In a 6v system the coil resistance has to be about 1.5 ohms (6 / 1.5 = 4).  So a typical 6v coil will measure about 1.5 ohms from battery input terminal to points side terminal.

In a 12v system, the same 4 amps is desired so to achieve this the resistance of the coil has to be doubled to 3 ohms to get 4 amps (12 / 3 = 4).   So a basic 12v coil will have too much resistance to meet the 4 amp requirement when used on 6 volt systems.  But…some 12v coils will be only 1.5 ohms internally and will use an external 1.5 ohm resistor to get the 3 ohms needed to make 4 amps flow through the coil.  That’s why some 12v labeled coils will work on a 6v system.  You need to know the coils internal resistance to determine if it can be used on 6 volt ignition.  Some coil manufacturers do publish the primary circuit resistance value so you can make the correct choice.


Hope this helps.

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  • 2 weeks later...
On 12/26/2021 at 12:20 PM, donk said:

If you have spark ,  take out the spark plugs & put a little gas in each cylinder & put the plugs back in and try starting again, if it fires you are not getting gas to the cyl. 

Bingo! Possibly. I was able track down 6V coil and condenser at NAPA (from a 49 Chevy of all things). Unfortunately it didn't help. I pulled all the plugs and, though to really bad, gave them a good cleaning and checked the gap. Before installing them I drizzled a little gas in each cylinder. Once the plugs were installed and reconnected I cranked it over, and it fired up for about two seconds. I then disconnected the fuel line to the carb and drizzled gas in it and it seemed to take a fair amount. Unfortunately it still it did not start or even fire. So next chance I get, the carb comes off for further inspection. Thanks for your willingness to communicate, Donk, but I haven't given up yet!

Edited by Max4Me (see edit history)
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Definitely a fuel problem. 

 Before you strip the carb, check to see if there is gas coming out the bottom of the autovac. If not, then you may have,

 Run out of fuel and the autovac is empty, or 

a blocked gas pipe from the tank,

a broken suction line to the autovac ,

or problems with the autovac itself.

 The autovac seldom gives problems, but I have had ,

 A broken or cracked suction pipe, so no fuel is sucked from the tank.

 A autovac top gasket that has shrunk and cracked with age, so no suction to the tank.

 The flapper valve in the bottom of the autovac may be damaged or stuck.

 The flip flop valve seats come loose in the autovac top, these can work intermittently to drive you mad.

 Cracked or damaged autovac top, the diecast is breaking up.

 Have fun

 

 

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18 hours ago, viv w said:

The flip flop valve seats come loose in the autovac top, these can work intermittently to drive you mad.

Any tips to for how to rectify this? My Series 65 with original autovac/vacuum tank has an intermittent fuel delivery, apparently the fuel intake valve gets stuck in closed position and then the tank runs empty (normally in the middle of dense traffic) and requires a lot of rattling to come free again. Is this a sign of worn needles, weak springs, or can anything else be done?

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Narve,

Check the diecast top, to see if the brass valve seat insert has come loose. A friend of mine had one that would pop out of place and jam the valve. I used a drop of Loctite (permanent bearing fit or thread lock) and pushed the seat back into place. It's been 15 years or more since I did that and the guys car is still going with no more problems. Just be careful and make sure the Loctite only goes on the outside of the brass insert where it goes into the diecast, or you will have a permanently stuck valve.

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3 hours ago, viv w said:

Narve,

Check the diecast top, to see if the brass valve seat insert has come loose. A friend of mine had one that would pop out of place and jam the valve.

I once had a S-W tank that did a similar thing with the needle popping out of place, or maybe just not seating properly.  It was due to sloppiness from wear.  I fixed it my making up a spacer of sorts.  Check for wear in the mechanism.

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On 12/22/2021 at 4:28 PM, Max4Me said:

I started and ran my 1925 Maxwell/Chrysler in early to mid November of this year, and it ran perfectly. About 3 weeks later I went to start it to prep for a local Christmas parade and it would crank, but not fire. I have the vacuum fuel pump and there is gas going to the carburetor (clear glass filter just prior to carb is full). I did rebuild the carb about 18 months ago and it's been working fine. I pulled the coil wire and grounded it and got a clean spark. I then pulled the #1 plug wire, grounded it and got a spark. I even did one thing I am usually against- I gave the carb a quick shot of starting fluid and no indication it even wanted to fire up. Today I cleaned the distributor cap contacts and the rotor. I also pulled, cleaned, and reset the gap (.020 according to the manual) on the points. I also pulled a plug and it looks OK (no heavy soot or fouling apparent). When not in use I have a battery tender on the battery so that should not be an issue; besides, it cranks fine. Any thoughts on what I've missed or what I should check next will be greatly appreciated.

Hi: Sorry about your situation. I have a rare 1922 Chalmers Roadster (Maxell-Chrysler) previously owned by Ramon Navarro 1st actor of movie Ben-Hur 1925. (Some one stole it from my barn)  If you or someone you may know to have a magneto I'm desperate looking for one. Please let me know....cubacombia@comcast.net. Wish you a happy new year and hope you got your car running. THANK YOU FOR YOUR EFFORTS IN HELPING ME. J lizarazo. 

1922 CHALMER ROADSTER  (Ramon Navarro-(Benhur-movie actor) at Jesus I Lizarazo Collection.jpg

KGSH7679.JPG

IMG_3638.JPG

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Viv, thank you for your input! Unfortunately the autovac is not the issue nor are the fuel lines/tank. When I first acquired the car, not knowing its previous care, I pulled the tank and cleaned it out and flushed the fuel lines.I have a clear filter right after the tank and it has minimal debris in it. I have a glass filter before the carb and it is clear and has fuel in it. Also, as was suggested, I opened a drain on the bottom of the carb and fuel ran out so the carb is getting gas. So the question is now what is the carb doing with the gas once it's in there? I have pulled the carb off but haven't yet opened it up. BTW, before removing the carb I checked the bolts for tightness thinking if they were loose, it might be sucking too much air and not creating enough internal suction to pull in gas. Nope, they were tight. Next step....

 

Jesus, so sorry for your theft.  Unfortunately I do not have a magneto. Best luck on your search and a happy and safe new year to you!

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Any chance those filters are reducing the gas flow? I know my Dodge using its vacuum tank has a very low PSI draw. Conversely adding a electric pump at too high pressure causes issues as well. Have you tried without filters? Or was this the configuration as you got the car and it ran fine before?

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72 caddy: It did have an electric fuel pump when I got it. You’re right, creates its own set of problems. The filters were part of the system when I got it.  I took the electric pump out of the set up and re-plumbed the vacuum tank. This set up was working fine for more than a year before the current no-start issue. Filters are not the issue because there is always fuel in the float bowl (though I’m not crazy enough to open the bowl drain while it’s running to see if there’s a constant supply, so maybe….).

 

So now I have a bigger problem that probably is not part of the issue. After removing the carb I noticed carbon build up on the top near where it mounts to the intake manifold (which bolts to the exhaust manifold). Yep. Gasket leak. The worst part is while taking the manifolds off I noticed what looked like (and is) a hairline crack in the exhaust manifold. It is so small I doubt it is interfering with combustion. Top pic is outside of manifold, bottom is inside. Interesting block set up, it appears only two ports are intake. They appear wet, but it is gas not oil (not slippery and smells distinctively of gas). Bottom pic is the exhaust manifold. Notice the intake port is glazed. Thoughts? I don’t think any of this caused the sudden no-start problem.

 

Suggestions as to whether or not I can get the manifold welded to prevent more cracking or leave it alone? Sources for new exhaust and intake manifold gaskets?  As always, thanks to all!

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