PChar

Indy I read a bit more about the JB Racing set up and appears $$$reasonable and comparable to light weight RS I have. But the instruction still mention that the hydraulic TOB assy is mounted into the stock clutch arm of the transmission. Which means I am still having the same trouble of repairing the clutch fork mounting boss.

Any thoughts

KaiB

Stephane - you won't want my assembly.

It's a straight out Tilton assembly; the 5.5" dual disk racing unit. Incl flywheel, the entire assembly weighs just at 13.7 pounds and is absolutely unstreetable.

Indycam

That does not sound like the way other hydraulic TOB are mounted .
All of the ones I have seen / read about are mounted to the bell housing .

Makmov

If you can figure out how to mount it, the bearings themselves are not too bad.

A mount basically just needs a strong enough mount on the bellhousing side and the bearing has to fit the guide tube.

http://www.jegs.com/i/Tilton/454/61-612/10002/-1

maybe something like this would work.

http://www.jegs.com/i/Quarter+Master...21100/10002/-1

There is nothing that trick about a HTOB.

Yeah, I cant imagine that you'd use the stock fork with a Hydrolic TOB.

The next question I got is why did it brake. I know it's a weak link, but was it a stronger pressure plate, something bind up, old and just wear?

PChar

No all my set up was the Sachs kit sold by Pelican Parts. Which is stock PP and upgraded disc and LWFW nothing fancy or out of the ordinary. I am beginning to wonder If I reinstall the clutch operating shaft into the fork properly. If I recall it was a bit sloppy, not very tight ???
The motor will be dropped this evening and will seperate the trans, then I'll be able to assess the damages properly.

I am starting to like the HTOB idea.
1) How is it mounted to the transmission bellhousing?
2) Does it operate with the same master cylinder or aftermarket is needed?
3) How are the lines routed into the trans bellhousing without mingling with PP?
4) any pictures available for this set up on a Porsche?

I have made several inquiries about welding into the bellhousing and most don't even want to touch it, and for those willing to do it do not want to put a seal of approval on it,...

Thanks All for the Help

Makmov

I can't blame them I wouldn't want to approve welding either. The problem with welding it is it failed once already. Welding does change the properties of aluminum when you weld it. Furthermore aluminum is somewhat pourous and oil absorbes into the part making it difficult to weld and not that strong or reliable. On top of all those issues, not only do you have to weld it, you probably have to machine some parts of it. Never a good idea to machine a weld because you usually cut of the strongest part of the weld.

They are usually just on a flange that bolts on the end of the front cover. It just had to be strong enough so it doesn't cave in or put undo stress on the front of the transmission.

It has been my experience we did have to use a different master cylinder allbeit on a complete different application. my suspicion is the 964 might have enough fluid volume to get the job done without having to mess with it.

The hoses either are bulkhead fittings through the bell or just routed through the old fork opening.

I could not find anything on it for a Porsche however, it seems to be a common set up on guys using a SBC with a G50 in custom applications.

Indycam

http://store.trgparts.com/sachs-hydr...cup-p8907.aspx

Ken D

Don't know who you've talked to, but make a call to Patrick Motorsports. They perform this fix.

PChar

Thanks Indy, I like that 997 GT3 Cup system from your posted link. Is this mounted/bolted directly inside the bellhousing? If so, isn't it prone to leaking trans fluid into the bellhousing?

Ken, thnaks for the tip, I will call Patrick Motorsport. My issue with dealing with California, is that it will eat up $500 right off the bat in shipping both ways.

I'll see if a known local Porsche Performance shop is willing to install this HTOB into my car.

Indycam

I like it also but it probably will not fit and work , I bet there is some dimension that will not match up with a stock 964 . And then there is that price .

Re leaks , yes a leak could happen , but it can be sealed also .
The oil inside the transaxle is not high pressure so sealing a bolt hole is not a big deal .
If the bolt hole does weep oil , the oil is not going to jump out and attack the clutch .
It will run down the bell housing and drip from the bottom .

PChar

Yes great info. You make a good point, beside who is not willing to deal with a leaking Porsche ,... right!!

I called Patrick motorsport, so far is the cheapest option. I can have the trans diss/reassemble by a locol shop for $1200-$1400 and have the bellhousing shiped to Patrick M. for a $475 welding job. The whole thing at around 2 Grand. I can live with that,... I suppose.

Laker

Have you asked around locally?
Kevin McC comes to mind.

PChar

Thanks Mike, I have inquiries with "THE" specialist Mark Berkit in Allentown.

Thanks for the tip though,..

PChar

Ok, yesterday and this morning working hard to remove the engine and the transmission. Here is the final Verdict:

The clutch mounting boss is broken, the fork and the shaft still looking good, but will replace just because. The needle bearings were completely destroyed.

Laker

Ouch, any idea as to the root cause?