Alum. drums

[buzzinhalfdozen]

Thanks Alan, that plan has being been on my mind, having a hard time seeing how these scarf seals can actually seal well as they seem to have little to no tension to the drum bore. Joe

[buzzinhalfdozen]

Tom, very good point, I,ve considered the majority of wear would be caused by drum moving fore to aft.I,ve seen the metal seals eatin away to about half their thickness, but little to no wear to drum, more the seal wearing on the shaft. One more question....I've always heard that hard anodized parts are either Black or dark grey, this drum is Pewter in color. Joe

[Tom Goldman]

Anodizing can be done in any color ,including clear.
there are different processes that can enhance hardness,but bottom line is that it's still aluminum.
Alan's recomendation to install a thinwall sleeve is probably the best route....Ive done this to save a few PG drums over the years.
The reason the rings wear on the lands us usually due to the soft cast iron type ring ,and boosted line pressure.....Years ago when we were running a ClutchTurbo in a B/Altered we had to go to the teflon rings due to wear on the center support caused by the higher pressure we were running. ....Now ,years later ,I've been using nothing but the hard chromed rings in TH 400's ,and have not had a failure in years.
Every builder out there has their favorite combination. ...My preference ,especially on lower pressure S/SS type trans are the chrome rings. ...

[Alan Roehrich]

Hard anodizing doesn't necessarily have a lot of color, it usually darkens the surface slightly.

The scarf cut Teflon seals work fine. They seal better than you'd think.

There's nothing wrong with the chrome sealing rings. I've used them, and still do. I also use the scarf cut Teflon sealing rings.

[buzzinhalfdozen]

I guess most of my confusion on the hard anodized is I've been lead to believe it is VERY hard and durable, not what I'm seeing on this drum. I wouldn't expect the teflon seals to even damage a bare Alum. drum. Maybe I expect too much. Joe

[Tom Goldman]

Joe , Teflon can wear into most everything given enough time.
I just replaced a PG ringless input shaft because the teflon rings in the stator tube wore into the hardened Vasco steel shaft!.
Those rings do not turn, they ride stationary on the spinning shaft.
Tom

[ss3011]

The reason steel rings spin with the drum is because they have a thicker width which creates a higher force radially and overcomes the frictionally force created by oil pressure pushing the seals against the groove sides. The teflon seals are narrower so the force balance keeps the seal stationary in the groove and slips on the id of the drum. The teflon has a fiberglas filler material and that is what wears into the aluminum bore. One thing to keep in mind is aluminum drum expands alot more than cast iron drum and the steel seals typically have a clasp in the gap of the seal. If the bore wears too much or the aluminum drum get too hot , the clasp could prevent the seal from growing to keep the seal in contact with the bore. That creates a huge leak. Recommend a scarf cut teflon seal, and just live with the wear.