S Specific Intermediate Shaft?

[Insomnic]

I've been hearing that I need a specific IMS for the 2.0S motor I'm building. Is this simply a matter of the early IMS' running directly on the case ('Version I' shown in the PET) versus those on the mag cases using insert bearings?

If so, is there a benefit (aside from a less expensive IMS) to having an early case modified to accept the later style shaft and associated bearings?

Thanks in advance.

[edmayo]

Where are you 'hearing' that?

[304065]

You need an IMS that matches the size of your case, which is either a 0 or a 1. And of course you should measure the backlash with everything assembled, before you close the case.

I suppose you could modify the case to take the bearing shells from the later case-- but Porsche only did this because the IMS running in the magnesium without bearings wore the case prematurely. If you look in Bruce Anderson's book you can see the various types including the wear.

SO. . . if you can't find an early intermediate shaft then you have to modify the case. If you can, use that, but make sure it's the right size and that you measure the backlash and it's in spec. Of course you would measure the backlash anyway.

If I were doing it I would box the whole thing up and send it to Ollies and let THEM take care of it.

[geneulm]

I'm sure some experts will chime in but your engine is. An early sand cast alum case. A later mag style ims w bearings will not fit in your case that runs without bearings. You need to find the appropriate early version UNLESS you have Ollies or similar modify your case to fit the newer and more available ims.

[Insomnic]

I appreciate all of the info and the nudge to the Anderson book (who knew pcar book shelves could be good looking AND functional ).

I ended up finding one at a local swap meet for $45; am I correct in believing that this is a proper lay shaft for the early aluminum cases?

[gled49]

Those are inside the engine, so I never leave the ALU gear or the chain wheels to chance. Available ALU gears require machining. G.Led

[crummasel]

The aluminum gear seems to be the later one and its mounting somewhat altered.
I still have one NOS early aluminum gear.
PM if needed.

[Jon B]

The aluminum gear seems to be the later one and its mounting somewhat altered.

That appears to be the correct gear for an early intermediate shaft- why do you think it's a later gear?

Early gears were fastened with 3 bolts and located with 3 dowels, while later gears were fastened with 6 bolts.
Here's a comparison between the two versions, which also had different mounting offsets. Notice that the offset is deeper on the early gear, from this side...



There was never an S-specific gear or shaft for any standard production engine.

Jon B.
Vista, CA