I am helping a friend with his 1911 Model T, which had been on the receiving end of an absolutely HORRIBLE "restoration" before it came to him. If it was possible to assemble parts upside down, backwards, or left out completely, that's what a former "restorer" did to this poor car. I can trust NOTHING that was previously done. 'Know the drill? Licenses ought to be required to get married, have children and restore antique cars!
With that off my chest, I have a question or two about the aftermarket clutch pack that was inside the transmission when we disassembled the power plant. See the two accompanying photos. Is this a so-called "Jack Rabbit" clutch, a "Speedy" clutch or a newer generation Turbo 400 clutch? I guess it doesn't really make much difference because the layering with the large original clutch disk procedure is about the same for all three styles of aftermarket clutch. I'd just like to know which we have for my own edification.
But you can see at least two problems in the two photos. (1) Most, if not all, the nine large clutch disks appear to have burn or discoloring marks on their faces. From slipping? We never heard the POS engine run (what a mess!!!), so we don't know if the clutch even worked, or if the previous owner installed the disks with these marks still on them. At any rate, these marks are suspicious. (2) Note that in addition to the nine large original disks, there were also two smaller ones with the inside notches. According to the on-line instructions and Model T discussion forum threads I found for these clutches, only the large disks are supposed to be used. I measured the stack (after cleaning off oil and crud) at 1.21". The on-line installation instructions specify this height is supposed to be 1.12". Could those extra two small disks that created the excess height have caused the burn/slip marks on the large disks? Isn't the correct height 1.12"? Should the large disks with so many burn marks be replaced or just sanded down? They are dead flat with no arch. Shouldn't there be a slight bow to each disk?
The engine is a 1915, but I can't be sure of the transmission vintage. So many parts on this car were mismatched from various years. There was no early engine spacer disk at the bottom of the clutch disk stack. How can I tell if this is an early transmission that requires the stack plate? Is there some telltale sign on the clutch hub or inside the reverse drum that indicates a spacer disk is needed?
If we keep these large disks, I'll do a trial assembly without the two smaller clutch disks and hope that the three pins on the clutch ring extend 1/4". Is that the determining factor whether the stack height is correct? Other comments/suggestions?
I only want to do this &^%#%& job ONCE and it should be done correctly the first time. If the transmission gurus in the crowd see other problems in the photos, I'd like to correct them BEFORE everything goes back together. What a nightmare this car has been so far!!! It's making Chevies look good!
Thanks in advance.
Marshall, the pictures in the thread below will help you determine if you need the spacer disc or not. The drum on the left requires a spacer disc. The one on the right does not. I believe the turbo 400 setup is supposed to have 8 turbo plates and 9 large Ford plates. Maybe the extra two plates were put in to make up for a weak clutch spring. I ran into that while working on another club member's transmission. In his case the two extra plates made it impossible to adjust for a good neutral. Your steel plates are still good as long as they're flat and not cracked or badly pitted. The plates are not supposed to have a bow or dish in them. They're supposed to be flat. My advise would be to use good original Ford plates if you want a clutch that engages smoothly, is cheap and cannot burn or wear out. There is not one reason why the Ford clutch needs to be improved.
OOPS! Yes, I should have written "brake drum" instead of "reverse drum". Duh!
Thanks for the pictures, Stephen. I'll use them tomorrow to compare against what's in this transmission.
I thought I read somewhere that the clutch disks were supposed to be slightly bowed to impart a spring action when in use. I guess I need to change my thinking there.
Looking at your pictures again, they appear in a vertical orientation, not a left-right horizontal orientation. Just so I don't misidentify the brake drum in my friend's transmission, can you tell me which drum is which in your photos, as "the drum on the left" and "one on the right" do not apply. 'Sorry if the difference between the two drums is obvious. It's just not obvious to me. Where should I be looking for the differences?
Marshall, the clean drum with the small holes is on the left. The dirty drum with the larger holes is on the right. If your drum has a step in the back where the discs sit you do not need the spacer disc. If the back is flat from the outer edges to the raised center than you do need the spacer.
That Is the Jack Rabbit. The TH400 Clutch uses all 42 teeth in the friction plate. On the Jack Rabbit they remove 30 teeth and place them on the stock hub. The plate teeth are at an angle and the stock hub has straight grooves. Its a bad match. The TH400 hub and plates have matching angles and the plates can float freely. Smoother applying that way. Scott
You have the Turbo 400 converted disk. The stock clutch pack is 1 1/8" tall, when I put mine together thats what I used. I added large outer disk to makeup that height.
Thanks, Stephen and Scott, for your replies so far. Stephen, your explanation of what to look for is just what I needed! I THINK I see the difference now.
And thanks to you, too, Mark! You were already posting while I was typing my thanks to Stephen and Scott. 'Didn't want to overlook your contribution!
As some others have mentioned, they are the Turbo 400 discs. I would NOT use them. They are very unforgiving of a slipping clutch. If you're intent on using them, get an extra strength clutch spring and do NOT slip, or "feather", the high speed clutch.
You mentioned that the larger, non-lined, discs looked discolored from heat. Those discs would be the original Ford ones. I've never seen a used Ford disc yet that doesn't look discolored. Don't worry about that, as long as they're not cracked or badly warped. My personal choice would be to use original steel discs. I pick out good ones, then grit blast them until they look like they're satin-chromed. Clean them very well to remove the grit and you're ready to go.