MTFCA Forum

Currently Lang's can not provide their Turbo 400 clutch kit because they are out of the special machined clutch hub. If I'm not mistaken, both Chaffin's and Snyder's, only offer the Jack Rabbit clutch discs. I have checked Rock Auto, O'Reilly's, and Auto Zone and they are temporarily all out of these discs. I did find some on EBAY under GM Delco original part number 8623151. Are these the ones that T guys are using by modifying the teeth on them, or is there another replacement (Delco or otherwise) ?

Whats the end game?
Do you have a modified clutch hub & need to replace the worn out disks?
Are you going to use a stock clutch hub & file away most of the teeth on the GM disks?

There is nothing wrong with using a stock clutch hub with accurately punched teeth out of stock disks.
The last motor refresh had 10K miles. I reused the old disks as they had no measurable wear to the disk material & barely noticeable displacement
on the disk drive tabs.
The Set Chaffins sells is top notch, pun intended.
I think Smith & Jones also sells them.

What is the resistance to the Jack Rabbit Clutch set up?

I thought Jackrabbit used Turbo 400 disks. I may be wrong.

Remove 5 skip 2..."The Model T Ford Transmission" repair manual put out by the club covers how to convert stock disks on page 19.

My experience has been that all turbo 400 clutch discs are not created equal and that they are available with various lining material. Some good for use in a T and some not so good. Buy them from someone who knows the difference! Just sayin.

Dan McEachern wrote: ↑

Thu Feb 15, 2024 3:12 pm

My experience has been that all turbo 400 clutch discs are not created equal and that they are available with various lining material. Some good for use in a T and some not so good. Buy them from someone who knows the difference! Just sayin.

Chaffins sells a modified disk set with the heavy duty friction material for truck & racing applications. This is the ideal material.
The disks are accurately punched so that all 6 hub contact tabs contact equally.
Chaffins provides an extra disk, making a 9 pack. No need to add extra large disks to enlarge the pack.
Why except/buy a lesser quality set?

speedytinc wrote: ↑

Thu Feb 15, 2024 12:52 pm

Whats the end game?
Do you have a modified clutch hub & need to replace the worn out disks?
Are you going to use a stock clutch hub & file away most of the teeth on the GM disks?

There is nothing wrong with using a stock clutch hub with accurately punched teeth out of stock disks.
The last motor refresh had 10K miles. I reused the old disks as they had no measurable wear to the disk material & barely noticeable displacement
on the disk drive tabs.
The Set Chaffins sells is top notch, pun intended.

The end game is I want a "free" neutral, and since the 27 transmission I have needs a going through and inspecting, I figured this would be the time to do it. Presently, it is 100% stock. I was willing to buy the Turbo 400 kit from Lang's but as I said, they are out of the specially machined clutch hub. So, PLAN B is buy Turbo 400 disks and modify them for the stock clutch hub. PLAN C is use a Jack Rabbit clutch kit which I was saving for another T. The reason is that Although I could get a hundred opinions on Turbo 400 versus Jack Rabbit clutches, the consensus opinion that I have arrived at from previous Forum posts are that the Turbo 400 are the preferred disc, but everyone has a right to their opinion.

Your goal for a true neutral is a good one.
Jack rabbit clutch was modified th400 heavy duty/racing disks.
These disks are available with a variety of friction materials designed for light automobile to HD truck & racing applications.
Bobs purchased modified TH400 sets & sold them to Snyders. At that point in time they were the best material & fit. @ some point Snyders had their own custom made. Quality & fit ???

Hand cutting/filing can be done, however its a lot of work & the left over contact tabs will not all make equal contact until they wear in.
This was the original reason for removing the extra material on the disks with a punch press & custom die.

Folks who believe their Ts can be improved by altering the original design and retro-fitting "modern" parts and materials are convinced there will be a miraculous improvement in the operation of their car. Anecdotal experience is generously provided on these boards, both pro and con, and that's the value of this forum, so long as it's helpful.

If you are wanting a "free neutral", perhaps a turbo or jackrabbit clutch may not provide that. I bought an older restoration several years ago with the provenance that it had been toured by two previous owners a total of 20,000 miles since its initial turnout. No information whether the turbo clutch was installed initially or at some later point. I drove it for five years without knowing it had a turbo clutch. The car's native tendency to creep when cold was no different from Ts with a stock clutch.

A seized wrist-pin last summer put me in the way of a full overhaul. The clutch facings had mostly de-laminated, depositing fragments of lining material in the engine oil, and the "lugs" (altered from full-spline to fit the stock clutch spool) were reduced to less than 2/3 their intended width. I rebuilt with a stock clutch pack.

I have replaced many of these after market clutches, if you drive them right they will last but if you slip them then your asking for trouble, to me the big issue is if and when they fail they are deep in the engine and it has to come out to replace, I have never seen original ones fail!

If you’re wanting a good free neutral, the first place to address is to replace the low speed notch and cam. While you’re at it, replace the reverse and brake cams to. I use standard model t disks and always rebuild the hogshead and this has made it easy to setup a free neutral.

I have had one turbo 400 clutch pack disintegrate. The linings just shed from the plates. When I bought replacements from the local Auto trans specialist, he said it was most likely due to water contamination in the engine oil. They made good money rebuilding auto trans failures in cars where there was a leak from the radiator into the trans cooler in the bottom tank. Apparently the bonding agent holding the lining material to the plate failed in water contaminated oil. Perhaps long periods of inactivity and condensation in a T motor would be enough. My problem stemmed from a weeping head gasket.

Jack Rabbit clutches use turbo 400 discs. As stated, there are many different linings on these, to suit different applications.

Whatever clutch pack used, it should be close to the thickness of the original Ford steel disc pack. Fewer discs in the pack means wider gaps between each plate, so less drag. With the Watts clutch pack with its even thicker fibre plates, these gaps are even wider.

I believe Henrietta has an original Ford clutch pack, and it works well. She still creeps, even when warm.

Allan from down under.

If your engine and transmission are absolutely stock and you don’t have a good free neutral, then something is broken that needs to be fixed…

When I had my engine rebuilt in 2019 we put in a turbo 400 clutch. It seemed to work fine to me. At 5500 miles I discovered a cracked reverse drum and triple gears that were seizing on their pins. During the tranny rebuild the rebuilders strongly suggested going back to the original metal clutch discs due to some problems they were discovering with Turbo 400 installations. The rebuilders have done a couple of hundred Model T engines so I listened to their advice.

FWIW - I had a good "free neutral" with both the Turbo 400 and the original metal discs. Both can exhibit a little "creep" in neutral when the oil is cold and thick.

And of course everyone knows to store your car with the handbrake forward in order in order to squeeze all the oil out between the clutch discs and relax the high gear spring as much as possible. Just throwing that out there as best practice.

Getting a free neutral could be as simple as oil changes. In my instance, I had to jack up the back wheel to start the car, both on electric and crank, except on a warm summer day. I knew the clutch discs were gummed up with old oil - the transmission has never been apart. So, I drove around with 0W20 oil for a while to clean it all out, and then switched from my usual 20W50 to 10W30. I can now hand crank in winter without jacking up the back wheel.

I got my replacement discs from a local transmission supply shop. We matched them up instead of looking for a given part no.

Thanks to all who responded. Now, I am in a dilemma. There will always be believers, and always be naysayers, and each will have valid reasons for their opinions. I have owned 5 T's in the last 55 years and the only one that had a "free" neutral was because it had a Warford in the driveline. No wonder it had a "free" neutral, huh? All had at least a semblance of a "free" neutral, except the one I'm working on now. The engine, even though well broken in, always was a "bear" to start, when cold, either by the electric starter or hand cranking. Jacking up one rear wheel was the only way to get it to start and it got to the point I drove it less than any of the others. I guess, I'll listen to those who told me to use the original clutch discs, but I hope I don't live to regret it, because this is the last T engine and transmission that I intend to rebuild and re-install in a car. The question in the back of my mind is, why do the "big 3" T parts vendors, sell Turbo 400 or Jack Rabbit clutches, if they are troublesome, AND why does the MTFCA Transmission manual tend to recommend Turbo 400 clutches in a rebuild, if they are troublesome?

ModelTWoods wrote: ↑

Fri Feb 16, 2024 6:04 pm

The question in the back of my mind is, why do the "big 3" T parts vendors, sell Turbo 400 or Jack Rabbit clutches, if they are troublesome

For the same reason the grocery store sells cigarettes… Because some people want them…

Adam wrote: ↑

Fri Feb 16, 2024 8:20 pm

ModelTWoods wrote: ↑

Fri Feb 16, 2024 6:04 pm

The question in the back of my mind is, why do the "big 3" T parts vendors, sell Turbo 400 or Jack Rabbit clutches, if they are troublesome

For the same reason the grocery store sells cigarettes… Because some people want them…

Adam, I thought it was for the same reason that drug dealers sell pills laced with Fentanyl; to make money.

ModelTWoods wrote: ↑

Fri Feb 16, 2024 6:04 pm

Thanks to all who responded. Now, I am in a dilemma. There will always be believers, and always be naysayers, and each will have valid reasons for their opinions. I have owned 5 T's in the last 55 years and the only one that had a "free" neutral was because it had a Warford in the driveline. No wonder it had a "free" neutral, huh? All had at least a semblance of a "free" neutral, except the one I'm working on now. The engine, even though well broken in, always was a "bear" to start, when cold, either by the electric starter or hand cranking. Jacking up one rear wheel was the only way to get it to start and it got to the point I drove it less than any of the others. I guess, I'll listen to those who told me to use the original clutch discs, but I hope I don't live to regret it, because this is the last T engine and transmission that I intend to rebuild and re-install in a car. The question in the back of my mind is, why do the "big 3" T parts vendors, sell Turbo 400 or Jack Rabbit clutches, if they are troublesome, AND why does the MTFCA Transmission manual tend to recommend Turbo 400 clutches in a rebuild, if they are troublesome?

After reading my post and all the advice that I got from responders, I thought, "well, if a Warford gave me a "free neutral on my 1916 touring, why not put one in my 1927 coupe. I have the Warford, already, and I have Rocky Mountain brakes already; all I have to do is get the driveshaft, housing, and rear radius rods shortened, and I'm guaranteed a "free" neutral, AND if I still want to use my Ruxtell rear axle, I can still do that, too. I had both on my 16 touring. !2 forward gears were very interesting !

I have A jackrabbit, Turbo 400 & a Watts. I find they have a easier to achieve disengagement than stock T clutch. My speedster has a Watts and
one person can push it in neutral even cold. I have not had a failure in any of them. We loose sight of the fact that Ford abandoned the all
steel clutch in 1928 for the same clutch almost everyone else was going to use for the next 100 years or more. I have only had one stock T clutch
failure & I blame myself for that. So I think that they all work great & we need to accept that when installed & used correctly they are all
acceptable. Now if you have a Auxiliary trans you can benefit from a good disengagement for shifting. And even when adjusted correctly a stock
T clutch may not be the best. AS for the purists that will not accept anything but what Ford put in a model T, I admire your dedication and
believe your insistence is a a very important part of our hobby because some of us loose sight of it.
Craig.

A few things to consider when we discuss how well a given "improved" part functions.---- Some T's are driven WAY more than others, some Ts are driven WAY harder than others, every driver may use a different technique when driving, using the throttle etc and any time you ask a group of folks about how well something works, you will get a response based on THEIR experience. Then you have the issue of how correct was the installation and adjustment of the part in question.

With regard to this particular subject, probably the correct adjustment of the clutch fingers, slow speed clevis etc is one of the most misunderstood subjects when it comes to Model T maintenance.

The owner that takes his car to the ice cream parlor a few time a year is going to have a totally different experience than a Montana 500 participant or a cross country owner. Some owners can detect a slipping clutch the 1st time it happens and some never will.

We should all keep this in mind as we play with our treasured cars.

Are the Watts, Jackrabbit, and Turbo 400 clutch disks all still for sale?

J1MGOLDEN wrote: ↑

Sat Feb 17, 2024 3:32 pm

Are the Watts, Jackrabbit, and Turbo 400 clutch disks all still for sale?

Jim, Turbo 400 discs, either original or modified for a T, are still available. I'm not sure if Delco still puts their brand on them, or whether all Turbo 400 discs currently available are 'knockoffs'. The Jack Rabbit discs are still available from Chaffin's, Snyder's, and Lang's. The Watts are out of production, if my memory is correct.

If the turbo 400 hubs are not being made anymore. This may be a solution ( I picked this up some time ago) It is a 400 hub machined & welded into a T hub. I have had good luck with cutting the teeth out of stock 400 discs but it is time consuming. I have
had a Jackrabbit in my firetruck for 14+ years with no issues. The Watts clutch is out of production because the friction material is too expensive
to make a marketable unit. There is still some out there, I was able to find one new & two used a few years ago. They are a lot like Kevlar bands
they take some adjustment at first till they seat in. ( I think that's why I got two very lightly used ones ) I'm under the impression they all work as
good as a ford one if not abused. They all seem to be about the same price??
Craig.

Thanks Allan, it's corrected. Every time I get complacent with Tech it bites me

There goes auto correct again Craig. How does it get expiative out of expensive?

Allan from down under.

You might try Summit Racing in Akron OH. they carry many items or have access to them. Also if you do find one of those modern clutch hub kits pay close attention to the thrust washers in front of it. I had to machine 11 thou. off to get any neutral plus smoking the original thrusts. When later I had Joe Bell do my engines, cause I'm a coward, he said I'm better off with good old Ford steel plates. I trust his experience he does a fantastic job. Have a safe service oriented day.

I talked to Lang's, Steve said the turbo 400 hubs are a while out, but they have the clutch discs in stock & that others may also.
Craig.