Jumps and jerks in 1st and 2nd gear

[Dollar Bill]

OP States: "I almost get whip lash from the way the car moves in 1st and 2nd gears. In first it is smooth up to 5 mph, and in second it is smooth up to about 10 mph. In 3rd gear it is smooth unless I hit a speed bump or railroad track"

Based on the description - Sounds kinda electrical to me - Intermittent short in your distributor maybe?

Check for loose plate or faulty connections inside the distributor.

[Tom Wesenberg]

I agree with Bill, and would pull the coil wire and hold it 1/4" from a head nut to check for a hot blue spark.

[Jacksonlll]

If it was a short, I would think it would be backfiring also????

[larrys40]

Originally Posted by 29FordRoadster

Good Morning Everyone, My 29 roadster jumps and jerks when I start off in 1st and 2nd gear. In first it is smooth up to 5 mph, and in second it is smooth up to about 10 mph. In 3rd gear it is smooth unless I hit a speed bump or railroad track then it jerks till I am on smooth pavement. I can ride the clutch lightly in 2nd gear and the car will move fine. I am thinking my transmission bearings are worn out causing the problem. Does anyone out there have a different suggestion as to what my problem is? It will be two months before I can get the car in a shop to take it apart to see what is wrong. I will let the board know what is wrong when we find out.

After the post and your descriptions if the engine is running smoothly as you say then there has to be a driveline issue or as you say when you hit a "railroad track it jerks till I am on smooth pavement" indicates to me you have front axle and steering gear issues. I would said you probably need some comprehensive chassis work and that those symptoms are not just one thing but a culmination of issues that is causing the death wobble and shimmy. Now if you have a transmission issue as you elude to that would be separate... Sounds like you need a schooled Model A guy to take a look at it. You're south of Indy and there are some "A" guys in and around Indy not sure if they do outside work. If you need outside help PM me as I do "A" work all the time.

I think it needs to be carefully diagnosed and determined and then the required fixes to be applied.

Larry Shepard

[WHN]

I have to ask you a very frank question.

What general condition would you consider your car to be in?

There are some many things that could lead to a problem, knowing the general condition of car would at least help me get started.

I do agree that you might need a knowledgeable Model A guy to take a look. Enjoy.

[Licensed to kill]

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I'm in the camp that it is possibly your foot moving on the throttle only because i had a truck like that. Once it started it perpetuated itself and the only way to stop it was to let off or floor it. Just started out of the blue and didn't happen all the time. I would try, next time it starts, use the hand throttle and see if it goes away. Of course if it a bad rear motor mount allowing the motor to "roll" somewhat, the had throttle could be worse as it would rev as the motor rolled to the left. I can't see this kind of motor mount having much movement though. They are pretty solid.

[29FordRoadster]

Thank you Tom Wesenberg, Larrys40,Jackson, and Dollar Bill and others for your suggestions. I have good spark from the coil. The car is in good touring condition. This spring I had the main and rod bearing adjusted and the valves ground and adjusted. I do not feel the motor is the culprit. I do not have a shimmy in the front end, the steering wheel and wheels stay steady. I will attempt to describe my problem again. It is like you pull the spark lever down half way, pull the throatle lever down to a fast idle and start driving as you go along you quickly hit your brake and release repeatedly as you drive. I think the problem is somewhere behind the motor.The motor is not missing or back firing. I will take it to a knowledgeable mechanic to check it out but it will be a while before he can get to it. Thanks to all who have responded to my problem.

[Jacksonlll]

I keep coming back to that rear spring. Get under there and make sure everything is tight.

[Licensed to kill]

Originally Posted by 29FordRoadster

Thank you Tom Wesenberg, Larrys40,Jackson, and Dollar Bill and others for your suggestions. I have good spark from the coil. The car is in good touring condition. This spring I had the main and rod bearing adjusted and the valves ground and adjusted. I do not feel the motor is the culprit. I do not have a shimmy in the front end, the steering wheel and wheels stay steady. I will attempt to describe my problem again. It is like you pull the spark lever down half way, pull the throatle lever down to a fast idle and start driving as you go along you quickly hit your brake and release repeatedly as you drive. I think the problem is somewhere behind the motor.The motor is not missing or back firing. I will take it to a knowledgeable mechanic to check it out but it will be a while before he can get to it. Thanks to all who have responded to my problem.

Could you have a hub turning on the axle?. Perhaps it's chewed up and what's left of the key grabs for a bit then lets go, goes around and grabs, then lets go. HIGHLY unlikely but easy to check.

[WHN]

Originally Posted by Jacksonlll

I keep coming back to that rear spring. Get under there and make sure everything is tight.

You might want to also check the nuts on your rear axels. If loose with key problem, could cause issues before failure.

Did this problem just come out of nowhere, or is it something that is just getting worse over time.

If it just started one day, I would think something broke, didn't ware out.

[Tom Wesenberg]

Check your parking brake linings. They can be very grabby, and when I bought y 29 Tudor, the left side had no parking brake lining nor band. The right side parking brake lining was held on by only one rivet, and the brake drum was bent and had a 1/2" deep worn flat spot.

[Jacksonlll]

I agree. Something funny may be going on with the rear brakes.

[midgetracer]

The problem description sounds like teaching my daughter to drive a manual transmission. NO help, I know.

[jfreddie]

I also have this problem with my light flywheel, V-8 clutch but only if I'm trying to drive slow in either 1st or second. It will jerk back and forth with the car idling along on level pavement.
I have to push the clutch and reengage it to accelerate out of it.
I attribute it to the light flywheel not having enough inertia to carry the crankshaft through to the next pulse smoothly with a load on it.
My two cents

[Jerry Kzoo]

I am wondering if there could be a couple of teeth missing on the cluster gear or something like that. When they skip and then catch it could lurch. Then when shifting to third it would be direct drive and take the cluster gear out of the path of power.

good luck on finding your issue.

Jerry

[Jacksonlll]

that cluster gear could be the problem. Big repair.

[40 Deluxe]

Can you post a video? That would really help!

[Rich in Tucson]

Check your timing and total advance at the speed you are at when it is chugging. Fiddle until fixed.

[Jim Mason]

Knocked a tooth or two off the ring gear? under load it would jerk, cruising could carry on through momentum. swag