NF teaser spring

[Klapatta]

I am preparing to do some clutch service work on my 102. The teaser spring is broken and I've gotten tired of putting up with the jumpy clutch.
While I have it apart it will be getting a new clutch disc, teaser spring, additional machine shim washer, and anti- chatter springs. When putting this one into service about three years ago that machine was built on a tight budget and while the pressure plates had been resurfaced and a new throwout bearing that I happened to have on hand was installed, a used clutch disc that had a large chip at one of the driver holes was put in and I had no anti chatter springs on hand.
Yes, I cob jobbed it

Knowing little about the typical wide frame clutch setup other than diagrams I've seen, I'm to understand that a spacer collar was used on that generation of machines which prevented the teaser spring from being pushed or crushed down all the way into forced coil to coil contact by the main spring which I do consider as one of the causes of teaser spring failure, another being the spring hooking on to the driver slot on the clutch disc. That second matter can be resolved by placing a 5/8" machine shim washer between the clutch disc and teaser spring. In my haste, I forgot about that too Not this time
I do know that the part number for the wide frame spacer collar is 711-3040 and costs about ten bucks.
My question is if it possible to install that collar into a narrow frame application as added insurance against premature teaser spring failure, or are there additional factors involved in preventing me from doing this, for example such as a total stack height or a change in drive shaft spirol pin location?
Has anyone tried this or know of the said required modification if need be?
Thanks!

[mgonitzke]

I suspect that would probably change the location of the spirol pin hole for the spring; you can get around that by using a locking collar instead of the spirol pin there, giving you some adjustability.

[dale campbell]

we've done some over the years and we ground the small part of the sleeve away and it still moved the throw out brg.back about 1/4 inch causing some clutch adjustment issues....i seen on the pulling section that some guys are using 5/8 lock washer in place of the spring

[Klapatta]

The teaser springs crushed compression height is .325.
I am going to make a collar something along these lines up and trial it. That should not take me long to make up and I think it's worth a try.

The .890 diameter bore face side would butt on to the bearings extended front face by about .1 inch which is not a lot, therefore the sleeve would have to be made of a high grade steel properly hardened to stand up against the pressure of the main spring. Also, a marginal amount of material could be faced off the bearing extended side as well to reduce the total stack height.
To avoid the clutch stroke problem Dale mentions it will be necessary to maintain a minimal wall thickness at the pressure plate side, I'm thinking no thicker than .12, however using a machine shim washer would become unnecessary as the collars .625 face side would become the shim eliminating the spring hooking issue.
A minor work in progress, let's see what happens- I've failed before

[vince_o]

I use a machine washer in front of it on my 106. Its been in there about 5 yrs now with out breaking. I use the washer on all of my clutches now. I dont have a clue how thik it is just found one that fit.

[mgonitzke]

i seen on the pulling section that some guys are using 5/8 lock washer in place of the spring

That makes for a very grabby clutch, which isn't something you want on a worker.

[Klapatta]

Waiting for the clutch disc to come in so it's looking more like a job for this weekend.
I made the new thrust collar today, I followed the dimensions that I had recorded.

After sketching that up last night and posting it I realized that it would be a far better thing to install the .627 I. D. diameter end of the collar against the bearing, this will greatly increase the collar's surface contact patch against the bearing. I'm not concerned at all about the 7/64" wall thickness on that side, the collar is made from A2 tool steel, is hardened and tempered and would be able to support 10 times the pressure that 600 pound pressure disc spring will make. Reversing the collar however will require the need for a 5/8" machine shim washer on the clutch driver side to avoid hooking, so the total stack height will increase by 1/8". I think the clutch rod adjustment should be able to handle that change just fine- at least I hope so

I trial fitted things up on a spare drive shaft to get a idea of the amount of teaser spring engagement and I think that it's spot on. The spacer stop height setting is set 1/32" higher than the teaser coil crush dimension. No more smashed little spring if this works.

This is the second time for me that I've had to tear into a perfectly good running machine to replace a four dollar spring and I'm hating every second of it
Let's see if this works, whatta have I got to lose

[Klapatta]

I have mocked up the clutch assembly and teaser spring stop limiter collar that I made up and I'm pretty pleased with it so far.
There is more than enough clearance between the collar and clutch fork however I decided to modify the collar slightly by adding a .10 X 10 degree chamfer to the shoulder side of the collar for some additional clutch fork clearance, although that was not really necessary.

I'm still waiting for the new clutch disc to come in and I can't say that I'm too amused about that otherwise it would be together by now.
I did mock up the assembly using the old disc and drift punches, here's a shot of the assembly in the engaged position. The clutch stroke adjustment is still at the middle of the thread and disc separation looks right.

Here's a shot of it in the closed position and that action seems to be good too. Nice and smooth with no drag.

If that disc does not come in soon I'm gonna drive to Whatley, MA. or Waterburry, VT. and pick one up

[Klapatta]

I installed the new clutch disc, bolted down the engine, and connected everything else together today.
The teaser spring stop limiter collar modification is a stand up success!
From here on, any narrow frame clutch service work I do is going to include that modification.
Here's some snapshots of the complete assembly just prior to trial

Clutch closed

Clutch open

The only thing left is to see if it stands the test of time, I think it will.

[vince_o]

Man you guys that make stuff out of metal really do nice work. I always enjoy following posts like this. Nice work!

[ksanders]

I love it. Next narrow frame clutch I do I'm going to make one of those and see how it goes. Probably the one in my 73. It's my main tractor and the teaser spring has broke 5 times already so I quit replacing it. I noticed all day today thinking of this thread how "grabby" my clutch was in the wet grass. I tore little ruts everywhere
Thanks for the great thread.

[Klapatta]

Here are the final sizes of the collar, a cross sectional view is shown.

It's too late for that machine now but one other thing that I would absolutely do next time around is to face off from the hub of the moving driver the same amount of thickness as the machine shim washer. That shim washer has a direct relationship of how much the driver can move back to release the clutch disc.
I'm going to take the QA42 off the other one now