Buttoning up a 727 - final end play

[msbaugh]

 I really enjoyed rebuilding this thing and learned a ton in the process, but it was a lot of work! With the parts I put into it, it should be good to go up to 700 horsepower...

I had .075" total end play on the input shaft before I disassembled my 727. This was with a .082" thrust washer behind the pump and a .062" thrust washer in between the clutch packs.

I've since changed the thrust washer behind the pump to .102" and increased the thrust washer in between the clutch packs to .082".  My total end play is now in the .042" range... Is it ok to up the size of the washer in between the clutch packs or can I only up the washer behind the pump? I can go larger if need be, would just have to take the pump off and order a couple more.

Thanks for your help

[734406pk]

I really enjoyed rebuilding this thing and learned a ton in the process, but it was a lot of work! With the parts I put into it, it should be good to go up to 700 horsepower...

I had .075" total end play on the input shaft before I disassembled my 727. This was with a .082" thrust washer behind the pump and a .062" thrust washer in between the clutch packs.

I've since changed the thrust washer behind the pump to .102" and increased the thrust washer in between the clutch packs to .082".  My total end play is now in the .042" range... Is it ok to up the size of the washer in between the clutch packs or can I only up the washer behind the pump? I can go larger if need be, would just have to take the pump off and order a couple more.

Thanks for your help

I think your in spec at .042". What is the end play you are looking to for?

[msbaugh]

 

I think your in spec at .042". What is the end play you are looking to for?

I'm wanting to get it as tight as I can, .025"-.035." Ya boys at tsr racing were able to hook me up with some larger custom thrust washers to make that happen.

Only issue I'm having now is bench air testing my pieces. The rear clutch is air tight... Good leak free engagement. The front clutch is difficult though. I've got two Teflon rings on the stator support and it's taking almost 60 psi to get any action. Even after greasing the hell out of it takes that much pressure.

With anything under 50psi I can feel air coming out in between the front clutch and the bushing

[734406pk]

.025-.035" is pretty tight. The factory spec is .034-.084" for the input shaft. However using aftermarket steel or billet aluminum replacement internals can reduce the end play requirements due the lower thermal expansion rate. Check with TSR to confirm the end play. You want to be 1000% correct in this area.
 I think you have a leak in the front clutch somewhere. Possibly the Teflon rings or the piston seal(s) themselves. Try to air test the front clutch independently from the stator support if possible. It should have leak free engagement as well. The Teflon rings get damaged easily on assembly. Its better to find out there is an internal leak on the test bench than after installation.

[6packCuda]

.042" end play is fine. I wouldn't go any tighter than that though. However, the thrust washer in between the clutch packs is not selective. You should really put the .062" one back in and use a thicker one on the pump.

Teflon sealing rings never air check as well as steel ones because they need oil psi to push them out against the wall. Try squirting oil in the passage where you're applying air, then apply air. You might have to do it a few times but the oil should help it seal up. It also helps to spin the drum as your applying air.