RB power steering - pump pulley vs crank pulley??

[MELLO*SOS]

Edit: problem "solved" see bottom of this post

Ehh not getting the answers I want on the other RB forum so thought I'd ask here..

I have an early silver top RB20
rb25 crank pulley which is the same # ribs as my stock rb20 pulley
Motorset came without PS pump bracket, but came with a HICAS RB pump
I bought a bracket off some kid. Looks like other RB20 bracket's I've seen.
Put the bracket on, put the pump on the bracket, now there is a mismatch between the # of ribs on the pump pulley and the # of ribs on the crank pulley

Crank is 3 rib
_^_^_

And the RB pump is 4 rib
_^_^_^_

I think I had this same issue when I did my Quest 110a alternator onto the KA, and I just used the smaller # of ribs belt, that's been working fine for 2+ years now.

If you have an RB - how many ribs on the crank pulley & how many on the PS pump? Think there's any problems with running the 3 rib belt on the 4 rib ps pulley? What (RB) motor is my ps pump off?


Edit: Here's the reason things are the way they are...

Ok I learned something that might help someone else down the road...
According to the ever useful RB Parts Exchange thread (http://forums.nicoclub.com/zerothread?id=34102&page=5), All RB26s and all RB34s use 4 rib belts. Not only that, the RB26 uses a much longer belt (means larger diameter pulley or different ps pump bracket).

Here's the belt lengths required. (35" = 876mm)
R32/R33 RB20: 3 rib 855mm
R32/R33 RB25: 3 rib 845mm
R32 RB26: 4 rib 950mm
R33/R34 RB26: 4 RIB 969mm
R34 RB20/RB25: 4 rib 865mm

So this explains why the Gatorback 4030335 aka 3pk0850 belt I tried was too short... It seems like I need a 36" 3 rib belt to work the RB26 or R34 ps pump I have with my RB20/RB25 crank pulley!

Crank pulley 3 rib & PS pulley 4 rib:
http://img.photobucket.com/albums/v180/mello88/M01A0443.jpg

PS pump (HICAS) and bracket:
http://img.photobucket.com/albums/v180/mello88/M01A0442.jpg

Here's the Gatorback 4030335 aka 3PK0850:
http://img.photobucket.com/albums/v180/mello88/M01A0444.jpg

If I find a 36" belt in 3 rib I'll update my post with the details/PN... If not, I'll either source a RB26 crank or R32/R33 RB20/RB25 ps pump.

Edit: Alright guys a 36.5" 3 rib belt works perfect, don't even need to slot the PS tensioner bracket. The PS belt comes off a 90-96 NA 300ZX, or a Q45 or a J30, autozone stocks them bitches.

[coolcatracing]

Looks like any other HICAS pump, they have an extra groove for the extra load. Just use the 3 rib belt and you'll be fine, I've done it numerous times.

[MELLO*SOS]

thanks for the reply, that's what I'm planning on doing.

Why would Nissan add an extra rib for the load, but not give us a crank pulley with an extra rib on it? Makes no sense to me... Do some crank pulleys come with the 4th rib??? Or some pumps come in 3 rib form? I suspect the pump was off another car.

edit: pump was off any rb26 or any r34 engine

[coolcatracing]

Yea, there are different crank pulley's too. If you match the pulleys its not a problem, hell its really not a problem either way.

[MELLO*SOS]

Well the 25 pulley I have on there now is identical to the 20 pulley I replaced... Since the motor came with the pump thrown on the pallet and without the bracket, I think the pump is "wrong" in my case. I'll just run the 3 rib belt like I did on the KA, that hasn't been a problem in 2 years so I'm sure it'll work fine

Thank you for your help +rep for youuu youuuuu LOL

[MELLO*SOS]

Thanks coolcat... Figured out the issue.

All rb26's came with 4 rib ps belts. So did all R34 motors. But the rb26 uses a much longer belt, either the bracket is further away and/or the ps pump pulley diameter is larger. I think the pulley is larger because the 35" belt everyone references (4030335) didn't fit (too short). Also turns out 35" is the longest 3 rib the local parts store carries. I need a 36" 3 rib belt, but that doesn't seem to exist.

Either I find that size belt, or get the RB26 crank pulley or pick up an R32/R33 RB20/RB25 PS pump LOL