lovemyp-car

Just wanted to pipe in here and say that Constantine's rebuild torque tubes (especially if you spring for ALL the goodies like a brand new driveshaft etc, like I did) are absolutely amazing, beautiful pieces of very (useful) art. If you have the chance/opportunity/money and can wait for him to build one for you, you will NOT be disappointed...

Ethan

Otto Mechanic

Funny how the stuff you have left over is just about worthless and you end up paying to get rid of it, but the stuff you need can't be had for any price. I call it the Porsche Perversity Principal.

If anyone wants a stock 27mm front sway bar let me know, I'll soon have one, free to a good home...

(technically it's a 26.8mm bar but I quote the thickness with the paint)

Black Sea RD

Sorry for coming a bit late to this discussion, currently rebuilding a 968 and a 944 torque tube before taking off this weekend to finally close out our location in Florida and make the final move to Georgia.

We are locating in the Cartersville, GA area for those interested.

As far as the split tubes, we have a detailed write up with pictures on our website under "944 Drive Line Information" which fully explains the problem with these tubes. They came is all 944S2s and 968s up to somewhere in MY 1993-4. Porsche used the split to help attenuate the extra vibration harmonics from the larger 3.0 liter four cylinder engines used in them. Porsche stopped using the split tubes and went to a dual mass flywheel setup in the later 968s, thereby increasing weight to the rotating assembly.

The condensed version of our write is the split widens with age and the front bearing unit, closest to the engine, will walk, get hung up at an angle to the drive shaft operation and become damaged. The widening is very difficult to correct back to the original ID. A bit too much pinching of the split will cause the front bearing unit to come off center of the drive shaft operation and damage the bearing assembly. Don't pinch it enough and the bearing will walk again.

Our only warranty re-do of a torque tube was a split one for a 944S2 we tried to fix and got wrong. Extremely embarrassing and costly for all involved.

Cheapest solution by far is to get a solid torque tube and be done with it. Our Super Bearings help to absorb the extra engine vibrations for these engines and our customers have always been happy with the end results.

Cheers,

Black Sea RD

Thanks Ethan!

Black Sea RD

No part number changes from what we have found.

All 944S2s and early 968s up to somewhere in late 1993 or early 1994.

Too early and the torque tubes would will not have the rear hooks on them.

HTH,

Otto Mechanic

Good information to have Constantine, thanks for explaining. It does lead to another question though, which would be if fitting the late model 968 crankshaft dampener to an S2 at the same time the TT was replaced with the earlier solid design might be a good idea? I'm assuming a "crankshaft dampener" is what I would call a harmonic balancer, I come from the 928 world most recently. It's the large disk of metal on the front of the crankshaft that has all of the crank angles etched into it? When I look in the 944 PET I don't find it, instead there are "balance shafts"?

On a 928, the "vibration damper" is 928 102 120 23. There's a part on the 944 next to the flywheel, 944 116 065 02 that's just called a "damper", is this the part you're talking about?

Dimi 944

Porsche did use a vibration dampener/harmonic balancer in the 2.5L and 3.0 16V 944 engines. It is part of the front crank shaft pulley and NLA part. They changed that and moved to a dual mass flywheel set up in the 968.

FRporscheman

Yes, it's like a harmonic balancer. It's basically the AC/alternator pulley, with more mass.

I bought one from Porsche a few years ago, but if they're NLA, then you'll either have to look for a used one, have one made, or just live without it.

With respect to Constantine, I think only the S2 had the damper pulley - the 968s had only a dual mass flywheel instead.

Otto Mechanic

I'm still not completely clear on that Dimi, is 944 116 065 02 part of the dual mass flywheel? It shows up in both the 944 drawings and the 968, labeled "damper". I don't find a part on the front of the crankshaft where the harmonic balancer is on the 928.

The main reason I ask is I'd been thinking about having my flywheel lightened while it's being resurfaced for the clutch job I'm doing, and now I'm thinking that might be a bad idea. I'd read that the 944 Turbo Cup cars had run light weight flywheels, about 16lbs, they were custom made by Porsche Motorsports on the 2.5L engines and are almost impossible to find. I've also heard reports that putting a light weight flywheel in a 3.0L S2 or 968 is not a good idea, but I didn't understand the reason until I read Constantine's comment on this thread.

So, if I understand correctly, adding rather than removing rotating weight to the S2 or 968 drive train would improve the vibrational characteristics of the car?

Otto Mechanic

So that would be one of:

944 603 121 06 - Alternator

-- or --

944 102 214 02 - Crankshaft?

The second choice would be a closer match to what they did on the 928.

Otto Mechanic

Maybe I've found it:

944 102 123 06 - Vibration Damper - M44.41

It's in the '91 PET. So this is the NLA part?

Otto Mechanic

In the S2 PET the part I'm asking about is #18, see attached drawing.

Black Sea RD

Apologies for all the confusion, I believed I had read that the later 968s had added a heavier engine dampener along with the dual flywheel setup.

Bottom line is that Porsche did away with the split torque tubes in the later 968s and instead added weight to the engine crankshaft assembly to reduce felt engine harmonics of the large 3.0 liter four cylinder.

Adding weight helps to negate some of the harmful engine harmonics as does rubber mounts connecting the engine to the chassis.

Removing weight and hard mounting these engines will almost cause problems manifesting in broken parts and fasteners.

HTH,

Dimi 944

That is the correct part. You do have one on your S2 engine. I have a couple of them on the shelf in used condition.

Dimi 944

Removing weight from the flywheel would improve performance but decrease comfort and increase vibrations in certain low RPM range. If you plan to build the car for the track then you will more than likely be running ot of that range.