Freshening up a friend's glide and ran into something I've never seen before. The high clutch drum has 4 small holes-roughly 1/16"- drilled into it's outer front face. What are they for? Is it an advantage or? I have seen drums drilled in the outside of drum, where the band rides, but never seen these small holes drilled into it's face?
Posts: 540 | Location: central Ar | Registered: June 21, 2002
Posts: 1135 | Location: The problem is not the problem. The problem is your attitude about the problem. Savvy?” ~~ Captain Jack Sparrow ~~ | Registered: August 21, 2000
In the "Carl" Powerglide Bible he shows drilling one .030 hole in the outermost rim of the reverse piston. [touted to bleed air from behind the piston as fluid is applied] that hole is installed "up" [12 o'clock] then it is covered with the first reverse clutch steel. It is a modification I do simply because it seems reasonable. Yet, as we would expect, many Powerglides are in service and operating properly without that mod.
For what you are describing I think it would create a large internal leak because there is nothing to seal against that forward drum face. Unless I am misunderstanding the description, I suggest installing a different drum without those holes.
No, this is an FTI transmission-or at least he has receipts from a bunch of FTI parts in it, including the high clutch drum assembly. The only non FTI part inside (according to the receipts from the owner) is the input shaft and 1.80 BTE planetary. I'm just freshening it up and seen the 4 holes drilled in the drum; and never run into it before on a powerglide, hence the question. I found nothing wrong inside but he wanted new frictions, steels, and gaskets anyway.
I'll see if I can figure out the picture thing. I'm going to re-use the drum as I see nothing wrong with it and no reason to question it's integrity. Was just curious as to how it worked.
Years and years ago, we used to build C4's. Those, the direct clutch drum was commonly drilled in the piston cavity area in order to let oil escape when it was disengaged. When the drum was turning at speed, there was enough centrifugal force that oil would be forced outward and partially engage the clutch pack. So it was common to drill a couple 1/32" holes in just the right spot which helped the direct clutches last a little longer. Anything to make a C4 last longer was a plus.
Posts: 540 | Location: central Ar | Registered: June 21, 2002
Stops excessive lube oil from building up in clutch pack. It will not effect the piston area of the drum. [URL=one drive][IMG:top]28755jipThis message has been edited. Last edited by: Troy Anderson,
This actually seems like a good idea to me. Took me a while to picture what was meant. I would also like to learn more about this. I have seen some issues with heat dissipation in the direct clutch pack especially with the thin frictions. I wonder if this might help with this problem. I was actually told I was crazy but I have been running the 6 of the .098 OEM thickness frictions and 2 .060 frictions installed on the outside of the pack in my drum instead of the 10 .060 that most run. Last freshen you could still read the numbers on the frictions. Did a freshen up for a friend with basically the identical set up but he was running 10 .060 frictions and the center 4 clutches of the pack were blackened. To me this points to heat dissipation. I wonder if these holes would help with that.
B.J. Masiello
Posts: 250 | Location: Connecticut | Registered: November 27, 2007
Originally posted by MasRacing: This actually seems like a good idea to me. Took me a while to picture what was meant. I would also like to learn more about this. I have seen some issues with heat dissipation in the direct clutch pack especially with the thin frictions. I wonder if this might help with this problem. I was actually told I was crazy but I have been running the 6 of the .098 OEM thickness frictions and 2 .060 frictions installed on the outside of the pack in my drum instead of the 10 .060 that most run. Last freshen you could still read the writing on the frictions. Did a freshen up for a friend with basically the identical set up but he was running 10 .060 frictions and the center 4 clutches of the pack were blackened. To me this points to heat dissipation. I wonder if these holes would help with that.
B.J. Masiello
Posts: 250 | Location: Connecticut | Registered: November 27, 2007
Originally posted by MasRacing: This actually seems like a good idea to me. Took me a while to picture what was meant. I would also like to learn more about this. I have seen some issues with heat dissipation in the direct clutch pack especially with the thin frictions. I wonder if this might help with this problem. I was actually told I was crazy but I have been running the 6 of the .098 OEM thickness frictions and 2 .060 frictions installed on the outside of the pack in my drum instead of the 10 .060 that most run. Last freshen you could still read the numbers on the frictions. Did a freshen up for a friend with basically the identical set up but he was running 10 .060 frictions and the center 4 clutches of the pack were blackened. To me this points to heat dissipation. I wonder if these holes would help with that.
Just wondering when running 10 clutches what kind of clearance do you run?
Posts: 123 | Location: Indiana | Registered: November 13, 2009
We found having the 10 clutches that running .070" to .080" that it would show heat to the center clutches like MasRacing was talking about we opened the clutch clearance up to .100" to .110" and the problem went away. Just something we found.
Posts: 123 | Location: Indiana | Registered: November 13, 2009
We found having the 10 clutches that running .070" to .080" that it would show heat to the center clutches like MasRacing was talking about we opened the clutch clearance up to .100" to .110" and the problem went away. Just something we found
Makes sense. The general rule I usually go with is .010 for every friction which would be .100 with 10 clutches. I do think we were a little tighter than that on the one one I was referring to closer to .090 so it might be worth opening it up to .110.
B.J. Masiello
Posts: 250 | Location: Connecticut | Registered: November 27, 2007
I have .100 in my 8 thin pack and you can still read Made in USA on all of them after many seasons. Probably approaching a 1000 runs in a 7.60/7.70 dragster. I have personally found no advantage to keeping the high pack tighter than this.
Posts: 29 | Location: Pen Argyl, PA | Registered: March 01, 2011
