RS pulley

[Bill Verburg]

single sheave



Triple sheave


double sheave

[Don Plumley]

That's on my to do list one of these days...

[kurquhart]

I have my mechanic converting my 90 3.6 to a single pulley setup at this time. My main motivation is improved reliability (avoid possible bearing seize) and ease of replacement. I shredded an alternator belt at my last track event and it was quite tricky to replace.

There is a rumor that this conversion increases engine output, but it seems to me that the same load is present: both the fan and the alternator are still being turned.

[Bill Verburg]

The alternator now runs at the slower fan speed, the result is slower charging rate of the battery

The solution for shredded fan belts is a serpintine or the Smart Racing dual set set up.

[kurquhart]

Originally posted by Bill Verburg
The solution for shredded fan belts is a serpintine or the Smart Racing dual set set up.

Do these setups help prevent breakage, ease replacement, or both?

[Bill Verburg]

Originally posted by kurquhart
Do these setups help prevent breakage, ease replacement, or both?

Which? The RS is better than std, the serpintine was developed to solve the problenm on RSRs I assume it works, the Smart Racing I dunno, they usually make stuff that works.

[kurquhart]

My mechanic took a slightly different route: Patrick Motorsports makes a part that locks the two shafts together so that the fan belt also turns the alternator. This appears to be a minor variation on the RS theme.

I still have the triple on the bottom; swapping to a single requires partially dropping the engine so I will wait until I need to do that for some other reason.

[Bill Verburg]

Originally posted by kurquhart
My mechanic took a slightly different route: Patrick Motorsports makes a part that locks the two shafts together so that the fan belt also turns the alternator. This appears to be a minor variation on the RS theme.

I still have the triple on the bottom; swapping to a single requires partially dropping the engine so I will wait until I need to do that for some other reason.

How is that different from the factory RS?

The lower 964 pulley incorporates the harmonic balancer, your crank will love you for leaving it alone.

[kurquhart]

Originally posted by Bill Verburg
How is that diufferent from the factory RS?

Like I said, this appears to be the same solution as RS, just with an aftermarket part instead of OEM.

That being said, I can't see single pulley parts for either 964 RS or 993 RS in the ROW PET. Am I reading PET wrong?

The lower 964 pulley incorporates the harmonic balancer, your crank will love you for leaving it alone.

This is good to know - thanks for the tip!

[Mahler9th]

One concept on some of the race cars out here with high displacement motors: use an alternator from an earlier car. My 3.8 is set up this way. No need for the hefty 946 or 993-sized alternators on a race car. With an earlier alternator, you use a conventional 911 fan shroud, fan and pulley. You can use the 993 crank pulley or the Patrick unit. Works great.

[johnsjmc]

Anybody have a dimensioned drawing of an RS pulley?

[CBRacerX]

Originally posted by kurquhart
My mechanic took a slightly different route: Patrick Motorsports makes a part that locks the two shafts together so that the fan belt also turns the alternator. This appears to be a minor variation on the RS theme.

I still have the triple on the bottom; swapping to a single requires partially dropping the engine so I will wait until I need to do that for some other reason.

This is really what I want, did you have to pull the fan to install?

[kurquhart]

Originally posted by CBRacerX
This is really what I want, did you have to pull the fan to install?

I don't believe so, but I did not do the install myself. I could check with my mechanic, but you might want to simply call Patrick Motorsports for the details.

[CBRacerX]

Is this the part number for the RS version? Any other parts needed?

993.106.051.80

[Bill Verburg]

The RS parts are
993-106-051-80 impeller hub for the alternator

993-102-050-40 pulley for the crankshaft

[CBRacerX]

Originally posted by Bill Verburg
The RS parts are
993-106-051-80 impeller hub for the alternator

993-102-050-40 pulley for the crankshaft

Thanks Bill. I only want to do the alternator, since I will be using A/C in my street rod - is the factory hub still a viable option?

[Bill Verburg]

is the factory hub still a viable option?

Yep, I am t/ping my 3.8 into my blue car and want AC, so that's the way I'll do it, stock lower and RS upper.

[Don Plumley]

Bill - did you disconnect the fan breakage sensor? I managed to break mine when I pulled the fan to swap to the RS Pulley.

[Bill Verburg]

Originally Posted by Don Plumley

Bill - did you disconnect the fan breakage sensor? I managed to break mine when I pulled the fan to swap to the RS Pulley.

Yes, you don't need it any more as the alternator light will come on if the belt breaks

[Don Plumley]

Mine's finally in.

Tyson helped to pull the fan off the alternator. So a couple of weekends ago I installed the alt/fan back into the car. Then I pulled one of my all time great moves - snapped one of the studs holding the pulley on. Poo.

The local "has everything" hardware store actually had M6 automotive studs, but either way to short or too long. So I took a 50mm M6 bolt and cut off the head. Used a little blue locktite to just make sure. And bolted it all back together (again):



Got to use my new handy-dandy belt tensioner from Napa. All running good so far. Nice to have it in: one less belt to break and much easier to change trackside just in case.

I did think of pulling out the other two studs and re-using the Allen head cap screw, but liked the ability to use a 10MM socket. Anyway, I drove it around a little to make sure all was good - now time to put on the SS brake lines...