Flywheel step measurments.... ( FAQ )

[Poser]

These are the step measurements on the F style flywheel and the 2F style flywheel...



F Flywheel uses the three-finger pressure plate. .630" step or 16.002mm


2f Flywheel uses the diaphragm style pressure plate. .020" step or .508mm



2F Flywheel for the diaphragm style clutch:

F Flywheel for the three-finger style clutch:

 

[IDave]

Is there any leeway in those numbers, Steve, or is that it?

 

[Poser]

I have found them to be consistent in three different flywheel-cutting tables at different machine shops around here.


I do not think that going a little tighter will hurt anything, as it will only provide more clamping force/crush on the driven disc.

I am changing my flywheel and clutch assembly on the back of my 2F from the three-speed style, to the four-speed style. I had the machine shop cut the step on the 2F flywheel to .030”. I had previously had the 16mm step in the three-speed flywheel cut to 14mm and it has worked fine since 1999.



The only reason that I am changing it is because when the truck was in this position,

I had gear oil leak out the input shaft of my pre 1953 SM420 (the early style does not have a seal on the input shaft) and it has soaked into my clutch disc/driven plate.

So while I am changing this out, I am going to change out the transmission to one of the NOS military 420’s I picked up back in 1995 while I was in Salt Lake, on my way to Moab. It has the seal in the input housing that will hopefully prevent the oil from leaking onto the driven disc the next time I roll over....

 

[IDave]

No seal at all on the input shaft? It must leak some even in the upright position, then. I can see why the extra clamping force would be good.

I'd think you would want to avoid testing even the sealed tranny in the future, eh?

 

[Poser]

No seal at all on the input shaft? It must leak some even in the upright position, then.

Not unless it is over filled...


There are spiral grooves cut in the input shaft that 'walks' any lube that may be out that way back towards the input bearing...

I'd think you would want to avoid testing even the sealed tranny in the future, eh?

I did not set out to 'clean the truck out' OR replace my windshield that day David...

 

[IDave]

Yes, but look at the opportunity it provided.

 

[davisdrafting]

0.022 @ step

I measured twenty-two thousandths after a resurface, should I take it
back an have two thousandths removed??

Never mind, I see you had yours ground to .03
Thanks for having the info at my disposal

 

[Hobbs]

IThe only reason that I am changing it is because when the truck was in this position,

[

Excuse my ignorance, but aren't the black rubber thingies supposed to face downward......?

 

[matt.mcinnes]

Excuse my ignorance, but aren't the black rubber thingies supposed to face downward......?

Nah they work fine that way, he just forgot you can only go sledging in the snow

 

[toy4fun]

Looks like the pilot studs need to come out before resurfacing? If so what is the best way to get then out?
Thanks!

 

[e rock]

Looks like the pilot studs need to come out before resurfacing? If so what is the best way to get then out?
Thanks!

Your machine shop will have no problem pulling them out and replacing them when they're done with it.

 

[Poser]

Putting this to the top because of private message conversations I have received lately.

 

[Henry Edgard Pandie]

I want to ask, how tall is the middle and side corners? My clutch does not bite

 

[Henry Edgard Pandie]

I want to ask, how tall is the middle and side corners? My clutch does not bite