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Discussion Starter · #1 ·
I thought id put this thread up as info for people.

I had a stock crank pulley and never had any issues with any belts with 8700 rpm limit.
my front pulley failed and broke in two, so I upgraded to a ross metal jacket damper.
ever since fitting the damper I kept throwing pas belts, the alt and aircon belt always fine.
when being observed we could see a ripple in the belt.

I spent a lot of time messing around trying to figure it out.
a tuner advised me to fit an idler pulley above the pas belt, so I did that and it stopped the whipping but I still kept looseing belts !
heres the idler set up





by this point I had had enough, had the rad in and out, pulley off while doing headgasket etc.

so I then proceeding to slacken the pas pump mounting bracket and realised I could move the pump forward and back quite a bit in the twist in the bolt holes !
enough so that it made a big difference to the angle of the pas pulley.
the brackets don't have dowels in and move a lot on the bolts.
so I got a perfect straight edge and checked for squareness






so I cut down an old vernier to measure from my straight edge to the top of rib one




my pas pulley was 1.5mm further forward at the top than the bottom ! the ross damper has no sides on the outside edges of the pas pulley so must be perfectly square or the belt will ride off.

I have since launched the car and hit the 8700 rpm limiter a few times and the belt is still perfect. it is surprising how much difference that tiny bit makes, and even more surprising Nissan didn't make them either a tight fit on the bolts or ideally use a dowel to locate it.
 

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Seen this before. If alignment not really good it will throw the PAS belt and boy the steering gets heavy! Its always worth checking.
 

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I also found on my Ross Damper the front PS attached pulley had not been bolted on flush. This is for a brand new unit that came direct from Ross. Took it off and re-installed it flush.
 

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Discussion Starter · #6 ·
well just got the car out today and the pas belt has rolled forward 1 rib AGAIN !

I may go back to stock damper as im absolutely sick of it.
 

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Yes witnessed this before.... ATI don't see this problem
Rich
This is not correct, I had the exact same issue with the ATI pulley...

...first trackday I needed 3 PAS belts as they kept flying off...

...afterwards I checked alignment of the pulleys and the PAS pump and found out the PAS pump needed some adjustment...

...then played around with the belt tension and next trackday all was fine :thumbsup:

Cheers,

Leo
 

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there's a difference between RB20 RB25 and RB26 pas steering pulley place.

if you look at stock pulleys of crank, they are different.

i fixed the allingment with using another pas bracket, so the alligment was correct.
 

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Got a Ross pulley on my car, been to the track and never had an issue with it biffing belts.....
 

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Discussion Starter · #13 ·
I also found keeping the belt tight helps.
and that's the nail on the head, I did this as a last ditch attempt sunday morning, and it didn't move afterwards at all, the belt tension needs to be a lot tighter than with a stock pulley.

and the reason is the edge of the pulley where the edge of the belt sits is open, it should of been made with a small lip either side it would guide the belt and keep it on then like the stock damper does.
 

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Yep, a much tighter belt really helps. The number of times I had to muck around with my belt, I could in the end do it on a full hot engine and in my sleep. I was seriously tired and had it. I had set the alignment that number of times as well.

Then I noticed that each time I was putting in a new belt and the belts would remain ok for some time and then fail. New belts tend to get loose after some time so need re-tightening. I have now kept the tension up on the belt and it stays where it is suppose to. That was my last try.

Glad it worked for you too.
 
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