Trouble w/ Shuddering and No Power in High Gear

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drzomber
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Trouble w/ Shuddering and No Power in High Gear

Post by drzomber » Wed Jul 23, 2025 5:48 pm

This is my first Model T (I've had quite a few A's) so I appreciate your patience in advance.

The car is fine in low gear but shudders when shifted into high for the first bit. It also feels completely gutless in high. The other day I was trying to take it up a small incline and even in low gear it was barely able to make it up the hill.

Background on the car:
•It was in storage for years (decades?) and was pulled out last fall when I got it
•The engine was rebuilt at some point and has a cam & z-head on it
•It is using a VW distributor
•It has a Ruckstell in it but I have been keeping it in low
•When I got the car I rebuilt the NH carb, decked the head, replaced the plugs, and adjusted the points
•It does need new rings soon as it is burning some oil but it isn't terrible


speedytinc
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Re: Trouble w/ Shuddering and No Power in High Gear

Post by speedytinc » Wed Jul 23, 2025 6:44 pm

Are you sure you are in rux & not direct with 3-1 gearing?

Do a compression test first. You should have a consistent 60+ # in each cylinder.

Recent rebuild needs rings. This dosent fit.

Shudder going into hi is indicative of a slipping clutch, but not your major problem.

Sure timing is correct?
Have you tried advancing the distributor while running with the linkage disconnected looking for a pick up in speed as advanced?

I once got a new defective "driver" cam that idled great, but wouldnt climb a 3' driveway.
You may need to degree the motor & evaluate all the valve timing events.


TXGOAT2
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Re: Trouble w/ Shuddering and No Power in High Gear

Post by TXGOAT2 » Thu Jul 24, 2025 6:37 am

Rings may be stuck or not yet seated if engine was newly rebuilt. Old gasoline or residue from old gasoline can cause a LOT of problems in vehicles that have been in storage. Have you cleaned and gapped the spark plugs, or replaced them? Have you cleaned or oiled the timer?What about the fuel filter? Have you made any effort to check the function of the coils? Is the carburetor adjustment working as it should? Is the spark advance control working as it should? Does the engine have compression on all four cylinders when you crank it with the hand crank? Is the exhaust plugged with mouse nests, acorns, mud dauber nests, or other debris? These things can be checked and adjusted without spending money. The Model T service manual is available at low cost and can be very helpful in solving problems.


Norman Kling
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Re: Trouble w/ Shuddering and No Power in High Gear

Post by Norman Kling » Thu Jul 24, 2025 11:33 am

Ruckstell lever should be back toward you in Ruckstell and forward away from you when in Ford direct drive. check to see if the magnets are still on the flywheel, get the magneto working. Remove the distributor. The Model t's work best on the original type magneto and coils. I know it is a bit hard to set it up at first, but works for a long time before it will need attention. When you shift to low push the pedal down quickly, and then when you shift to high, quickly push the throttle up while you quickly let out the pedal and then pull throttle to the speed you want. Likewise when you shift from high to low, leave t he gas where it was while in high and quickly shift to low. A T doesn't do well with slowly shifting like you would do with a more modern stick shift and single disk clutch.
Norm

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Steve Jelf
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Re: Trouble w/ Shuddering and No Power in High Gear

Post by Steve Jelf » Thu Jul 24, 2025 11:51 am

Norm is on the right track, whether a particular Model T runs well or not. If I go shopping for another T, I'll take a pass on the ones with "upgrades" that aren't easily (cheaply) corrected. I don't subscribe to the superstition that a disturbutor is "more reliable". Experience teaches me otherwise.
The inevitable often happens.
1915 Runabout
1923 Touring


TXGOAT2
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Re: Trouble w/ Shuddering and No Power in High Gear

Post by TXGOAT2 » Thu Jul 24, 2025 12:15 pm

I really like the original ignition system. It's very unlikely to quit on the road, and it offers "extras" like free starts and non-reliance on a battery. Correct coil adjustment can be an issue, but it is rarely needed if once done right, and the car will still run with one or more coils out of adjustment, it just won't run as well as it should.


Topic author
drzomber
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Re: Trouble w/ Shuddering and No Power in High Gear

Post by drzomber » Thu Jul 24, 2025 2:16 pm

Great advice here! I pulled the whole intake/ exhaust manifold yesterday and found it absolutely full of carbon and there was unspent gas in the intake ports so it was running obscenely rich.

I will rebuild the carb and adjust the float in hopes that that will help. I followed the directions in a book last time but that obviously did not suffice. Any tips for adjusting the NH carb?


TXGOAT2
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Re: Trouble w/ Shuddering and No Power in High Gear

Post by TXGOAT2 » Thu Jul 24, 2025 4:46 pm

If you gently seat the carburetor adjustment by turning it left until it just stops, then open it 1 full turn, it should be close enough to start and run. Most linkages have some slack, so allow for that. I would make as many checks as possible before taking things apart. Most issues can be corrected without removing parts. If the car sat for years, it may have one or more stuck valves. They can usually be freed up without major disassembly.

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jsaylor
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Re: Trouble w/ Shuddering and No Power in High Gear

Post by jsaylor » Thu Jul 24, 2025 6:38 pm

Distributors are fairly easy to set up. Remove the cap and with #1 piston at TDC mark the distributor body with a permanent marker at the point where the rotor points to #1. You need to make sure the spark event happens just after TDC, with the crankshaft past the TDC so that when the points open and the coil discharges the piston will force the crank to rotate forwards, not kick back.

The best way to check this is with an ohm meter on the points, battery disconnected. Rotate the engine, watching thru the spark plug hole as the valves both close as the #1 piston comes up on its compression stroke. At the same time the distributor rotor should be approaching the #1 position. (the mark you made above) Watch for the points to open exactly at the point where the piston starts downward as indicated by the ohm meter going to "open" or "infinity" resistance. I set my points at .020 and the plugs at .035. (different than with mag-coil system.)

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