What’s the trick to a smooth transition between low and high gear?

[Reno Speedster]

The 22 is running great and I have been driving it a bit. Most times I can go from low to high with no fuss. Sometimes I get juddering. I am throttling back a bit before the shift. What am I doing wrong? Should I be feathering the shift like you do a normal car clutch? Should I be doing it briskly?

[Rich Eagle]

I throttle back all the way before shifting.
Rich

[JTT3]

A balanced & aligned tranny & engine helps too

[Kerry]

To many clutch packs (especially modern ones), drive plates, key ways, axles and diff pinions etc, are stuffed by bad driving habits. I don't blame the driver but the one who taught him. The throttle needs to be fully backed off when releasing from low to high.

[Moxie26]

Reno..... Instead of cutting back on the throttle, leave it in that position you want to speed in low gear, and instead of cutting back on throttle cut back on your spark halfway the same time you lift your foot off the clutch to get into high gear. ... Try it, you'll like it.!! ..,....... And then advance your spark to the car speed you want, also adjust throttle to speed limit signs and road conditions.......... Keep in mind that the throttle will control the speed of the vehicle, and the spark controls the speed of the engine. So when you shift from low to high , engine RPM will be cut a little more than half RPM due to direct gearing, so that's why I retard the spark halfway of the advance I have in low gear, gives a smooth shift into high gear because of the timing change on a slower running engine at that moment.

[Scott_Conger]

Technique is 1/2 of it. The other half is the type of clutch. My experience is that FORD clutches shift smooth as silk if the throttle is momentarily closed and reopened just at engagement.

My father's depot hack has (I think) a Jackrabbit clutch and I have never made better than 10% of the time having a smooth shift...the other 90% are slam/bang shifts no matter what.

If you know what type it is, you should state it and the advice you receive can be tailored to it (including warnings for non-stock clutches)

[Art M]

I try to shift between 10 and 12 mph which results in engine speed of 400 to 500 rpm. I don't like to lug the engine. Several years ago I used tried a farm store conventional 10 w 30 detergent oil which made the transmission very jumpy. I temporarily calmed it down by adding some synthetic oil, until I could change the oil. Since then I use Shell conventional oil and have no problems. I back off the throttle but not sure by how much, because the maneuver is now so automatic.

Art Mirtes

[Tadpole]

The clutch on the only T I have experience driving shifts very smooth when the engine is cold. But as everything warms up and expands it becomes harder to get a smooth shift. I most often end up with a “SHUNK” clutch spring sound whenever I shift up or drop the pedal into neutral. I have no idea what kind of clutch I have. (Don’t mean to derail this good thread nor the author’s questions, just had similar expirience to add)

[randahl]

Don't over think it and don't fight the machine.

[TXGOAT2]

I would use the throttle to control the engine speed. When shifting from low to high, the engine needs to slow down quite a bit to allow the clutch to take hold when both the drive and driven side of the clutch are revolving at or near the same speed. The quickest way to slow the engine down is to close the throttle. If the car is in fair to good condition and the controls are adjusted properly, a quick, smooth shift from low to high can be made. A quick shift conserves car momentum and if the engine and car speeds are matched just right, little or no engine momentum will be lost. A Model T can provide a quick, firm, smooth shift from low to high that is the equal of what any modern automatic transmission can provide.

[TXGOAT2]

Do not slip the clutch. Match the speed of the engine to the car speed in the gear you are shifting to. You can't get from low to high without going through "neutral". To go smoothly from low to high, the engine must slow down during the brief moment the car is in "neutral".

To go from high to low, you must speed up the engine during the moment the car is in "neutral" between high and low.

[Norman Kling]

The trick is to anticipate what is coming when you shift. As you lift your left foot on the pedal, pause for just a microsecond in neutral as you push the throttle up. Then quickly let the pedal all the way out as you increase the throttle. If you are on level, go 10-12 mph. If you are on a slight incline, you will need to rev the engine a bit more in low before shifting. And when shifting down from high to low, you leave the throttle down and just push the pedal. The trick is to get the engine running at the rpm you would be after the shift. So shifting up the engine must slow down and when shifting down the engine must speed up. Do not feather the clutch but move it quickly, not popping it fast but just lifting the foot quickly so the the amount of slipping is minimum. As you practice, you will get better at it. Especially when driving on familiar roads. Even the load on the car will make a difference. With a touring it shifts one way when I am alone and adding each passenger will make a difference. I have hills I can climb all the way in high, but have to shift to Ruckstell when I have passengers.
Norm

[speedytinc]

A stock clutch was designed for some slip. (controlled) That amount of slip can be friendly, slipping or harsh.
Your clutch , if stock, has the fingers set to tight. Adjust to add more slip. Back off the adjustment 1/2 turn each finger till you have a little slip in transition but no slip upon acceleration in high. (once you confirm a stock clutch pack.) This can be identified looking @ the inner disk tabs in the center drive hub.
See that section of the service manual.

Regarding the th400 type clutches. They will wear out fast with the same kind of slip as stock.
Drive it as you would any modern manual transmission. Ease off the clutch pedal a bit slower. Dont jump off as you would with a stock clutch pack..

[RGould1910]

John pretty much nailed it. All the technicque in the world won't overcome misalignment and especially imbalance. I once had a car that would vibrate badly between shifts. I tried changing clutches and a variety of things to fix the problem. No luck. I finally decided to have a knowledgeable T guy balance the rotating parts in the engine and transmission. The cank flywheel and drums were dynamically balanced. The rods and T gears by weight. What a difference! No vibration. The fellow told me the crank was 22 grams out of balance.

[JohnM]

Unless I'm in traffic or need to get a running start on a hill, I shift sooner rather than later. It is easier to shift smoothly at lower engine rpm and it is easier on the drive train. As was said, close the throttle when shifting, retard the spark some at slower rpms then slowly pull the throttle and spark down until your desired speed.

[Reno Speedster]

Thanks for the tips. I don’t know what clutch I have in this car. I just changed the oil to 10-30. Not sure what was in it before.

[TXGOAT2]

An engine that is in good tune that will allow a low idle speed setting which makes shifting easier. It also helps with engine braking.

[Been Here Before]

Low to high.
Ease up on the throttle, decrease engine speed.
Slowly transition from low range to high.
Increase motor speed.

Putting the hobby back another 60 years (c).

[John Codman]

Practice...

[Moxie26]

Hey Reno ..... When you have a chance to sample our suggestions, let us know how you made out

[Reno Speedster]

Will do. I won’t drive it till the weekend.

[Loftfield]

Robert's advice about using the spark advance has merit. I have never tried it when shifting, but retarding the spark has wonderful good effect when the engine is lugging. I believe that retarding the spark in the slow speed lug may help forestall joining the two-piece crankshaft club. While the Model T seems to not be too concerned about spark advance and is apparently very forgiving, in driving my Model 10 Buicks the spark advance is critical to smooth engine operation. Driving today to lunch with the Model T group I will try retarding the spark during shifting rather than the long-used throttle closure. Wonder if the old dog can learn a new trick?

[TXGOAT2]

You will find that using the throttle to regulate engine speed and power will give good results.

Less spark advance is needed when running at low engine RPM with the engine loaded.

Using the spark advance lever to regulate engine timing to suit the operating conditions of the moment (engine speed and power demand) will give good results and avoid needless engine strain.

[Moxie26]

Pat and you are right ! ... So that is why it's beneficial to retard your spark halfway the moment you shift direct drive. Try it, you'll like it.

[TXGOAT2]

Adjust the spark to suit the engine's requirements as dictated by speed and load.
Low speeds in high gear under any significant loading call for a retarded spark.
There is a reason why Ford put the spark and throttle controls at the driver's fingertips.

[Been Here Before]

Additional advice to operate a Model T:

1. It is operated by ear - much similar to tuning a coil.

2. Once on the road, drive by the seat of your pants.

3. Intuition...you can never make a mistake if you drive your Model T by intuition.


After you succeed learning to drive a Model t, and have not done so already, take up motor cycling. Two pre-war bikes of choice, possibly are Indian or Harley. Controls are opposite, and you have a choice of shifter location and foot operated clutch.

As stated it takes practice, and do not be intimidated. A model T is fairly indestructible.

Putting the hobby back another 60 years (c).

[Moxie26]

Loftfield.... Enjoy your lunch and I'm sure we'll hear from you later on. Thanks.

[MKossor]

1. It is operated by ear - much similar to tuning a coil.

Not all Advice is good advice. For example......

[DanTreace]

Should I be feathering the shift like you do a normal car clutch? Should I be doing it briskly?

Just use the Ford instructions in the owner's manual. After experience you won't use the hand lever, but throw it forward and hold the low pedal 1/2 way for neutral and begin your underway. Travel about 20 feet or so, in low, perhaps up to 6-8 mph, then release low pedal to high the same time you throttle down, and then throttle back up as the shift happens for smoothest transition to high.

Made a YouTube video of my shift to high after a bit of repair for a low speed growl.



LINK to Video




https://youtu.be/AJZ8VLPtslQ




Added good info from the Ford guru Murray Fahnestock:

[Charlie B in N.J.]

I with the spark guys. Always worked fine for me.

[Reno Speedster]

Retarding the timing when I backed off on the throttle did the trick. Thanks for the advice.

[TXGOAT2]

Don't run the engine at full advance at low RPM with a load, whether you're shifting or not.
Use the conveniently located fingertip control to adjust engine timing to suit whatever the engine operating conditions of the moment happen to be.

[JohnM]

Regarding the timing when I backed off on the throttle did the trick. Thanks for the advice.

Great! Get out and drive, you'll get even better. It's not rocket science.

[Moxie26]

Hey Reno .... Did you back off halfway on the spark lever??? or the throttle ?

[TXGOAT2]

You're allowed to use both, and you ought to.

[JohnM]

It was suggested the throttle, but I'm assuming he knew to retard the spark at lower rpms.

[JohnM]

You're allowed to use both, and you ought to.

Pat, your advice is usually spot on, and sometimes redundant.

[Aussie16]

An interesting topic. My preference is to fully engage the low gear pedal,full pressure applied,apply some throttle until moving forward at a reasonable speed then back of throttle to zero,let low gear peddle out and reapply throttle once direct drive,high gear is engaged. Works for me. Never tried to retard ignition?

[Loftfield]

Have now had a chance to drive quite a few miles retarding the spark when shifting as per suggestion from Robert in New Jersey. It definitely works. I cannot say with certainty that retarding the spark instead of the throttle gives a smoother shift (if it does the difference is slight), but there is a definite sense that the car moves ahead faster. My thinking, however muddled, is that since the Model T carburetor lacks an accelerator pump, there is always a bit of lag between pulling down the throttle lever and the intended response from the engine. If the throttle is kept in place for the shift, and engine slowed by retarding the spark, when the spark is re-advanced, the throttle is already open and drawing fuel, hence a somewhat faster acceleration after the shift. Meanwhile, the only serious downside to retarding the spark for shifting is the agony of remembering to unlearn several decades of practice slowing the engine by use of throttle, plus being constantly somewhat startled by the change in engine noise as the spark retards. Since we all tend to drive by ear it, again, takes some practice to not panic at the change in engine sound.

[TXGOAT2]

You will get the best results by using the throttle and spark levers as needed, as they were intended to be used. The same is true for the clutch controls.

Timing and carburetor mixture controls affect engine performance and response. Unlike more modern vehicles, these functions are not automated on the Model T.

Manual controls are provided to allow the operator to manage the engine operating parameters to the best advantage under a wide range of operating conditions of vehicle speed, engine speed and load, altitude, engine temperature, and ambient temperature, should the operator care to do so.

Clutch slipping should be kept to the absolute minimum. It is not necessary to slip the clutch when shifting from low to high.

[Ed Fuller]

Practice...

John gave the best advice.

Drive and enjoy it!

[Moxie26]

Loftfield .... Sorry for your agony associated with habit history, but I guess we're accepting to learn a little something everyday that's a little bit different and gives better results. Thanks for your post, I'm sure you have encouraged others to try.

[GregDeK]

Thanks to all who made comments ! Last weekend, I awakened my 23 touring after a 15 year sleep. Things seemed to be going very well until I took her out for a brief run. Shifting from low to high was accompanied by severe lugging which did not disappear once I got the beast up to speed. Made a list of possible causes/solutions mentioned here. Tried one, no luck. Checked to see if all cylinders were firing by grounding each plug with a screwdriver. Bingo ! Number one not firing. Went through 1/2 dozen coils before I found one that worked. Took the beast out for a spin, shifted beautifully.

Thanks to all who offered your thoughts

[TXGOAT2]

It's a great feeling to fix a problem without spending a lot of money!

[TXGOAT2]

Your car would probably benefit from having the coils adjusted. Well-adjusted coils give the smoothest operation and best power, and also make starting easier and prevent problems with the timer.

[Novice]

Retarding the timing might be the solution for My 26 that has had the mag removed. Engine hast to be revved up to start out in low gear with out killing the engine. engine races if You shift with out reducing the throttle going into high gear and usually snorts and bogs for just a second even if you reduce throttle setting. Car has distributor which may be part of the problem. Dies easy but starts right back up. Stock 23 T starts moving without bogging or loading up the engine. once started You can't hardly kill it. You can shift with out reducing the throttle and the engine speeds up a little but does not race like the 26 without the mag. Extra weight of Mag components seems to make a big difference. Wonder how the torque of a model T engine with and without a mag compare.

[TXGOAT2]

For normal driving, a stock Model T needs a stock flywheel assembly. The rotating mass of the flywheel/magneto assembly is needed for the engine to deliver good torque at low RPM. A distributor that is suited to the application would not necessarily cause problems, but the stock ignition system works best for general use, in my opinion. Any 4-cycle, 4-cylinder engine needs a fairly heavy flywheel to deliver smooth power and good torque at low engine speeds. That's especially true with the Model T, which has a very lightweight, non-counterweighted crankshaft. A hot rod T engine with a counter weighted crankshaft and high lift, long duration camshaft could get by with a lighter flywheel, but it would not be well-suited for use with a stock driveline in a stock Model T car.

Best results, including smooth shifts from Low to High, will be obtained when driving a stock or near-stock Model T by using the throttle lever to control engine speed and using the spark lever to control ignition timing as needed. Other methods, such as cutting the ignition, choking the engine, or retarding the timing when shifting, can be used, but using the throttle is easiest and best. When downshifting from High to Low, using anything other than the throttle will give very poor results.

[Norman Kling]

One other thing I don't think was mentioned above is the length of the parking brake rods. If they are adjusted too tight, the cam on the parking brake lever will keep the clutch from completely releasing which will cause the clutch to slip. So if when you increase the throttle after shifting to high, the clutch seems to slip, that might be the cause.
Norm

[Bryce S.]

I have modern turbo clutch disks in my T. I was having the same thing. It would chatter and shudder like crazy and felt like it was still revved up too high. I ended up taking my carburetor off and adjusted my throttle plate so it was closed even more with my throttle lever all the way down. That ended up doing the trick. It was too high of a rev even lever all the way down. I don't know how it got like that but it was. I drove weeks like that and kick my self in the side for putting all that unnecessary stress on the clutch discs and my engine. It does feel fine. I hope this helps.

[Charlie B in N.J.]

I’m with the spark retarding people. Worked well for me. Left the throttle alone and never delayed in the pedal action. Shove the spark lever partially up shift to high and slowly bring the lever down to where it pulls best.

[Moxie26]

Happy July 4th! Charlie... I agree retarding the spark eliminates the chugging on the shift to high .

[TXGOAT2]

The spark should not be full advanced at low speeds, unless you are in Low with the engine running at a fair speed, such as when pulling a steep hill.
The linkage adjustment and degree of wear on most Model Ts unique to each one, so lever positions are, at best, a guide.
Once my car is started, I switch to Mag and move the spark lever about halfway down and use the throttle to control the engine speed.
This gives velvet smooth shifts with no discernable clutch slippage. Once the car is moving at 15 MPH or so, depending on grade, etc, I move the spark lever farther down as needed. Both levers can be managed without taking my hands off the steering wheel or looking at them.

[Craig Leach]

Hi Morgan,
Super glad you found a answer to your problem in all of that. Now in a year or so someone will ask you and you will have to think for a while
before you give them advice because it has become so second nature that you don't even think about it when driving. Unless you ride with
someone that has bad T driving habits. Such as once it's started you don't have to change anything ( as per timing & mixture) I have found
timers set so that the engine can be started without breaking your arm, locked down & the rod removed. Take off in low, rev the engine till
it reaches it's rpm curve, close & open the throttle so fast that neither me or the engine noticed & side step the pedal with a bang ( what I
refer to as the Poly Grip test) then lugging the engine because the timing is advanced to far. I had a neighbor ask me to look at his 12 touring
because he was having trouble keeping upon tours. We took it for a test drive. When I reached down to adjust the mixture he tapped me on
the shoulder & asked what I was doing? I explained & he said he was told not to touch that! Once I found the sweet spot & was humming down
the road ( 37-38 mph) I got another tap on the shoulder, I turned to see wide eyes & white knuckles on the windshield frame & a panicked
request to slow down. Come to find out he had never driven the car over 30mph, the car had a Ruckstell that he drove in Ruckstell unless he
was on a tour then he would go to Ford ( what he referred to as overdrive) He also never road in a T that I was driving again. And then there's
really that's not how I was taught to do it!
I keep my throttle stop adjusted enough that with a little advance the engine runs smooth @ 700-800 rpm then to slow it down I further retard
the timing. What I do taking off is engage low slow & firm, advance the throttle & timing & accelerate till the speed curve starts to fall off,
close the throttle, let out on low like it's a clutch when shifting from 2nd to 3rd in a manual trans, advance the throttle & adjust the timing
for the speed of the engine ( retarded ) then as the engine speeds up advance the timing till the engine is smooth & responsive.
Hope everyone has a great 4th of July & remembers what it commemorates.
On a side note I once had a Englishman ask me how that taxation with representation was working out for us?
Craig.

[CatGuy]

Very interesting reading. I've struggled with this on my '26 Roadster ever since I got it 2 years ago. I'll have to try backing off the Spark next time I have it out. I'm also planing to go through EVERYTHING on the car to make sure all the components are functioning as Henry planned.

[Steve Jelf]

I'm also planing to go through EVERYTHING on the car to make sure all the components are functioning as Henry planned.

Excellent! When we buy a T we have an unfortunate tendency to think what we find is what's supposed to be there. In 100 years a lot of things can go south, from cooling, to fuel system, to electrics, to suspension, to whatever. Some cures are well-known, and some seem to be widely unknown. We know They're not all the same. When it comes to functioning, They all should be the same. Fortunately we have books, websites, videos, etc.

[TXGOAT2]

The timing needs to be somewhat retarded any time the engine is running in high gear at very low car speeds under load. That's true when shifting into high, or any other time. I find it convenient and effective to start the car moving in Low with the timing retarded about half way, more or less. At 7 to 10 MPH in low, I throttle back briefly as I shift to High. As the car gains speed, I advance the timing and adjust the throttle as needed.