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Allis B won't start - ChatGPT suggestions
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Dale (Stonelick) View Drop Down
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Joined: 13 Jun 2019
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    Posted: 18 May 2026 at 6:47pm
Attached are some AI (ChatGPT) suggestions on what I should check on my Allis Chalmers B that won't start.  AI says first thing to check is my Point GAP - it should be .020 inches (not .030 to .040 as stated in my manual).  Can someone verify the correct Point GAP?

Secondly, can someone verify that solid copper core spark plugs wires should be used?
1951 CA - 1944 C - 1949 B - Kubota M6800
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SteveM C/IL View Drop Down
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Points: 9256 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SteveM C/IL Quote  Post ReplyReply Direct Link To This Post Posted: 18 May 2026 at 10:23pm
.018-.020   30-40 would never work, Solid wire on a mag

Edited by SteveM C/IL - 18 May 2026 at 10:24pm
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steve(ill) View Drop Down
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Points: 93444 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 18 May 2026 at 10:50pm
pull a spark plug, ground to the motor block, crank engine and see if you have a GOOD SPARK...

--- i read you post above........ see comment below..


Edited by steve(ill) - 18 May 2026 at 11:01pm
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Points: 93444 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 18 May 2026 at 10:56pm
this is what you wrote....

It ran two years ago (by pull starting and by starter motor) after fixing several issues. One was installing a new 6 volt coil. Last year, I stripped it down for a paint job. This year I re-assembled it, but it will not run. It fires - black smoke from exhaust - but will not run (either via starter or by pull start). I used starting fluid. Tried with choke on, then off. It has a 6 volt electrical system. I did install new spark plug wires during my reassembly process. I did adjust the point dwell to .036 inches with a feeler gauge after it wouldn’t start the first time. I am considering trying to use my old spark plug wires and then buying new points and condenser to see if that solves the issue. At last resort, I’ll install a new electronic distributor with appropriate solid core spark plug wires

---------------

sounds like your timing is off..... You should have the #1 plug fire when you are at TDC... with maybe a .020 point gap...... As you increase speed, the advance will go to the FIRE mark at 30 degrees BTDC...... you said a new 6 v coil, so i assume you have a distributor..


Edited by steve(ill) - 18 May 2026 at 11:02pm
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Points: 93444 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 18 May 2026 at 11:04pm
with the #1 plug out, you rotate the engine untill you feel compression thru the plug hole.. continue to rotate about 90 degrees untill the TDC mark is in the timing hole... Now the #1 post on the distributor should be aligned with the rotor to fire...  ???
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Points: 1925 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Les Kerf Quote  Post ReplyReply Direct Link To This Post Posted: 19 May 2026 at 7:52am
Originally posted by Dale (Stonelick) Dale (Stonelick) wrote:

...  AI says first thing to check is my Point GAP - it should be .020 inches (not .030 to .040 as stated in my manual).  Can someone verify the correct Point GAP?...

My AC shop manual shows the spark plug gap should be 0.030"-0.040", not the ignition breaker points.
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steve(ill) View Drop Down
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Points: 93444 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 19 May 2026 at 8:29am
if the distributor was not pulled out during the "painting"... then i would assume that part is OK.... Since it sounds like you are not TIMED RIGHT, i would guess the plug wires are on the wrong cap terminals, or you have the 1-2-4-3  sequence out of order.. or your POINT gap is not opening at the TDC mark for static timing..
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Dale (Stonelick) View Drop Down
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Points: 193 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Dale (Stonelick) Quote  Post ReplyReply Direct Link To This Post Posted: 27 May 2026 at 2:49pm

Thanks for everyone’s input on this.  I haven’t been posting updates because I’ve been locked out of the forum for  some reason. I’ve been working on this over the last several weeks, and these are some of the results.


First Try: corrected the ignition point gap to .020”, firing sequence was already set at 1-2-4-3, set to TDC (using compression feel) then set distributor rotor to plug #1. It would not fire up - used battery & starter, starting fluid and full choke.  It quickly flooded. Later tried without full choke, but still would not start.


Second Try: set to “FIRE” on fly wheel then set rotor to plug #1. It would not fire up - used battery & starter, starting fluid and full choke.  It quickly flooded.


Third Try: kept “FIRE” setting, held plug tester in hand to check for spark and got big jolt with the tester lighting up. Removed plug tester and it quickly started and ran good for 30 seconds, then died.  Used starting fluid & no choke.  I have no clue why it started this time - maybe the fact that I didn’t choke it?


Immediately tried a Fourth attempt, but used full choke - it wouldn’t fire and quickly flooded.


Would appreciate any thoughts on my next attempt.  I’m thinking of moving it back to TDC and don’t use choke.  Then try TDC + 90 degrees as Steve suggested. Undecided if I should use solid copper core plug wires or not.
1951 CA - 1944 C - 1949 B - Kubota M6800
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Points: 9256 		Post Options Post Options   Thanks (0) Thanks(0)   Quote SteveM C/IL Quote  Post ReplyReply Direct Link To This Post Posted: 27 May 2026 at 3:21pm
Solid copper for magneto. Distributor doesn't care. Good wires are needed. Old carbon wires could be failing. I would pull center cap wire and hold 1/4 inch from block and crank. It should have a blue arc to the ground. Yellow is weak. If you don't have good spark from the coil wire that's a problem. With all the flooding you've done your plugs may not "work "anymore. One turn with the choke is plenty. Sounds like your method of timing is all over the place. If it's close it should fire and start. Can perfect it after running. Are you sure you have correct direction of rotation when matching wires to cylinders?

Edited by SteveM C/IL - 27 May 2026 at 3:26pm
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Points: 93444 		Post Options Post Options   Thanks (0) Thanks(0)   Quote steve(ill) Quote  Post ReplyReply Direct Link To This Post Posted: 27 May 2026 at 4:43pm
if you can guarantee you have SPARK, then your timing is still way off... You need to have the point start to open when the PISTON is at TDC...It will NEVER start if its firing at the FIRE MARK at cranking speed..... The distributor ADVANCE will move that to 30 degrees AFTER it starts. ......  also need to GUARANTEE that your 1-2-4-3 is in the Correct rotation..

Edited by steve(ill) - 27 May 2026 at 4:45pm
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HudCo View Drop Down
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Points: 4259 		Post Options Post Options   Thanks (0) Thanks(0)   Quote HudCo Quote  Post ReplyReply Direct Link To This Post Posted: 27 May 2026 at 5:55pm
you must use supression wires if you are going to install are pertronix ingnition system
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Points: 1925 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Les Kerf Quote  Post ReplyReply Direct Link To This Post Posted: 27 May 2026 at 6:41pm
Originally posted by Dale (Stonelick) Dale (Stonelick) wrote:

...

Third Try: kept “FIRE” setting, held plug tester in hand to check for spark and got big jolt with the tester lighting up. Removed plug tester and it quickly started and ran good for 30 seconds...


This indicates that you have the rotation correct (Clockwise). Now, with the plug tester installed in the #1 position, slowly rotate the engine using the hand crank and stop exactly when the #1 plug fires. you must be able to see the TDC mark in the timing hole on the left side of the engine or it will never start correctly.


Keep adjusting and testing until the TDC mark is right smack dab in the middle of the hole, joy will soon follow.

Best wishes Smile
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i can't read between the lines....Is this a mag or distributor? Never been stated that I can see. Makes a difference when trying to set spark at TDC.
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WF owner View Drop Down
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Points: 5325 		Post Options Post Options   Thanks (0) Thanks(0)   Quote WF owner Quote  Post ReplyReply Direct Link To This Post Posted: 28 May 2026 at 5:20am
Originally posted by SteveM C/IL SteveM C/IL wrote:

i can't read between the lines....Is this a mag or distributor? Never been stated that I can see. Makes a difference when trying to set spark at TDC.

I am assuming (we all know the problem with that!) that it is a distributer since he said he had used a 6 volt coil.

"Third Try: kept “FIRE” setting, held plug tester in hand to check for spark and got big jolt with the tester lighting up. Removed plug tester and it quickly started and ran good for 30 seconds, then died.  Used starting fluid & no choke.  I have no clue why it started this time - maybe the fact that I didn’t choke it?"

Personally, from my experience, my first suspect would be a bad condensor. Did you verify that it still had spark after it died?

Is the carburetor float free and level set?

The first thing you have to determine is if you have a spark or fuel problem. 


Edited by WF owner - 28 May 2026 at 5:37am
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Dale (Stonelick) View Drop Down
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https://drive.google.com/file/d/1quhS1clgbp9lHp9XbFf1NXXRG-LAcq9q/view?usp=sharing

Finally got the Allis Chalmers B to start - see video. It is even charging the battery while running.

Some of the things I did: rechecked the ground, carb and firing order (they were fine), installed new ignition points, condenser and rotor (not sure that this was needed), set ignition point gap to .020", cleaned distributor contact points with Dremel small wire brush, set to TDC with rotor pointing to #1 plug (it was off 180 degrees from the last time I set it), added extra gas to the tank, did not use choke but used starting fluid.

Thanks to everyone for your help.
1951 CA - 1944 C - 1949 B - Kubota M6800
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Points: 2391 		Post Options Post Options   Thanks (0) Thanks(0)   Quote Trinity45 Quote  Post ReplyReply Direct Link To This Post Posted: 23 Jun 2026 at 5:26pm
Originally posted by Dale (Stonelick) Dale (Stonelick) wrote:

https://drive.google.com/file/d/1quhS1clgbp9lHp9XbFf1NXXRG-LAcq9q/view?usp=sharing

Finally got the Allis Chalmers B to start - see video. It is even charging the battery while running.

Some of the things I did: rechecked the ground, carb and firing order (they were fine), installed new ignition points, condenser and rotor (not sure that this was needed), set ignition point gap to .020", cleaned distributor contact points with Dremel small wire brush, set to TDC with rotor pointing to #1 plug (it was off 180 degrees from the last time I set it), added extra gas to the tank, did not use choke but used starting fluid.

Thanks to everyone for your help.
Had trouble with my B last fall and it turned out to be the condensor.
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