Sportomatic torque converter seal

[Kane k]

This one goes out to the Sporto world.

I am on the third torque converter seal, in 3 years, in a 905. They always leak and finally pop out, the last seal has recently been done and is already showning signs of popping again after 3 drives. The tell tail sign is oil being flicked around everywhere, which leads to smokey heat exchanges, and just general oil everywhere, which drips.
The first seal was a non geniune, which popped. The final two have been geniune Porsche, and have failed.

I'm not sure if Porsche are providing, not to spec seals.

Or is there some kind of mod the can be carried out,to help retain this seal, maybe by using some kind of high temp sealant to hold in position.

Has anyone dealt with this - it's a long shot I know because of the rarity of these boxes.

[Merv]

Kane wasn't there an earlier post on this from one of our members, making these?

[Kane k]

I think you are referring to Bill with these, sportomatic diaphragms.

[Merv]

True Kane, not the seal but Bill may have a source?

[Kane k]

Thanks any way Merv

[Cairns888]

High gearbox pressure? Drill a hole in the top of the box and put in a small breather?

Popping out seals is not good and looks like a pain in the arse to change out.

[Fishcop]

High gearbox pressure? Drill a hole in the top of the box and put in a small breather?

Popping out seals is not good and looks like a pain in the arse to change out.

This was going to be my suggestion... Check the case breather and ensure it's not blocked.

EDIT: I just realised which seal you mean... Not sure about that one. I never had one go at all and I was running mine behind the RS spec engine Have you measured oil pressure in those lines and is there a relief valve in the system between the sporto pump and the tank?

[Kane k]

Case breather.......... Ok, thanks Jim/John.

[72_sporto]

Hi Kane, I only have 925 boxes and, other than slight leaks due to age, have not had this problem. Is this seal meant to be glued in?

[Kane k]

The last seal installed being a month ago was apparently sealed in Bill, and is showing all the signs of failing, if not popped already.

From my very basic knowledge of the system, the oil comes in from one of those tubes, travels around then exists from the other, I don't know why this gearbox can't handle the pressure when others seem to experience no leaks.

Maybe yes John a relief valve needs to be installed to the system.

[Cairns888]

The return line might be partially blocked somewhere?

[Kane k]

The return line might be partially blocked somewhere?

Possibly Jim, for some reason it's building excess pressure.

[Fishcop]

The sporto pump is very efficient. So much so that a lot of the early race cars used the sporto pump arrangement to run extra coolers. It can be adapted to run a second and separate oil circuits (I believe there were a few gearbox cooling set ups that used the sporto pump).

I'm pretty sure there is a pressure bleed or regulator somewhere in the system to prevent over-pressure situations... My gut says you need to pull the sporto pump and open it to check the relief spring and bypass piston for blockages. It'll be just like the engine oil bypass system in in the case and again in the external oil cooler thermostat.

[Kane k]

Appreciate all that info John, that sounds very knowledgeable. Like I said my knowledge is not that great on the system, I'm more of a driver. But that pump from what you are saying, could be the issue.

[Kane k]

John, the only thing in the pump that looks like your talking about would item 15 and 16. Is this what you are referring too.