P/S belt question

[Godless Commie]

More annoying than funny, actually..

My power steering belt jumped off twice since the hotside install.
First time around I just chalked it up to a loose belt.
The second time, I know the belt was nice and tight.

Any ideas why this is happening?

[Tom @ Fast Forward]

The face of the supercharger pulley is not aligned with the face of the crank pulley. Either the SC is too far back or forward or tilted.

See the attached sketches I made for you.

[Godless Commie]

Tom, my supercharger belt, tensioner and pulleys are absolutely perfect.

My problem is with the Power Steering belt.
I never disturbed the p/s bracketry except for replacing the tensioner block..
Let's, for a moment, suppose the p/s bracket was "disturbed". The belt indeed would try to jump. BUT, it would do so at the p/s pump (driven) pulley. ,
However, the belt, in my case, jumps at the crank pulley.
Again, the blower belt is fine..

Could it be that the strain of the blower belt could be torsioning or bending the crank pulley?

[Tom @ Fast Forward]

My bad. Well I did make pretty pictures. :) My mind has been on the other project and I have to have that product on the shelves in Japan by August 1.

No idea but that won't stop me from making dumb tries. ;)

Have you checked the alignment of the PS pump and crank pulley? Did you loosen the PS belt and alternator belt when you installed the new crank pulley?

[BlownMX5]

Maybe the crank pulley assembly really is misaligned but somehow the "misalignment" just happens to put the blower pulley in perfect alignment? How much of a gap is there between the blower pulley and the accessory pulley? Is the crank spacer used on an NB Tom?

Pat.

[Godless Commie]

Yes Tom, those illustrations are a work of art, I must say..

Well, problem solved.
And yes, it was all my fault.

Let me just say that, if this car was someone else's, and I was getting paid to install all that stuff, I would not make the mistakes I did.
The reason is simple:
This is a very, very cool toy I had been wanting so badly for so long..
So, I was a bit impatient during the installlation. Well, more giddy than impatient, actually.

I remember checking the p/s belt while I was installing the crank pulley and deciding it needed tensioning. I was so focused on the blower pulleys and the belt and the tensioner that, once I replaced the tensioning block on the p/s pulley assembly, I torqued the adjuster without even loosening the pivot bolts.
Thus, the pulley ass'y was forced out of alignment and the poor thing moved away from its intended plane.

I went back to the shop tonight and took the blower tensioner off, removed and loosened all the proper bolts, and redid the p/s belt - properly this time. Everything fell in place, and things lined up perfectly!

I even made a couple - OK, more than that - 7000 rpm runs, did long decel runs, nope, it does not even think about jumping anymore.

Sorry for taking everyone's time by starting this thread.
The only thing I would hope for would be that this thread might be of use for someone who makes the same mistake I did..

:)

[Godless Commie]

Maybe the crank pulley assembly really is misaligned but somehow the "misalignment" just happens to put the blower pulley in perfect alignment? How much of a gap is there between the blower pulley and the accessory pulley? Is the crank spacer used on an NB Tom?

Pat.

Wouldn't the crank pulley just wobble if it was misaligned?

[Tom @ Fast Forward]

Glad all is well now. Never apologize for starting any thread on these forums. This is family here and family is here to help and assist for any need. Trust me, you are NOT the FIRST to be a wee bit impatient doing an install. :)



Sorry for taking everyone's time by starting this thread.

:)

[MX-Drew]

I agree 100% with Tom.

By starting this thread you may have helped someone else and that is always a good thing!

As they say "you learn by mistakes"

Now enjoy the toy :driving:

[BlownMX5]

Wouldn't the crank pulley just wobble if it was misaligned?

I guess what I was getting at was the presence or absence of a spacer, and where it was placed. Just shooting in the dark.

Pat.

[Godless Commie]

Reviving an old thread here..

I have been extremely busy with work, the Dinosaur Flu (I am now convinced that's what made them extinct) and a sick dog..

Well, the stupid p/s belt jumped a few more times after all the work I have put into it.
The last two times, the belt just shredded to pieces and kicked the blower belt off.

I must add that the alternator belt is just fine and dandy.

A couple months ago I took off all the parts and bits which are involved/related with this belt issue. Using a steel straightedge, I found out the p/s pump was off the intended plane by about 1/16". So, I used washers at the mounting points and made sure it was perfectly aligned with the crank pulley.

I checked the pulleys for burrs and deformations and could not find anything.
I even cleaned the grooves with a wire brush.
I then thought that would be the end of all those problems. I was wrong.

This thing happens if I just "get on it", as in, for example, creeping at maybe 2500 rpm in 2nd gear and slamming the pedal down to launch the car all the way to redline, and upshifting..

Gradual loading of the engine does not cause the belt to act funny.

(Sometimes the traffic just parts just like the Red Sea. I just launch into the opening to get ahead in traffic. It is an unfair advantage I must admit I like a lot..)

So anyway..

I will take the front of the engine apart one more time to check it all - again.

I am running a 130 - 65 mm combo. Do you think the loads on the crank pulley are too great, to the point of tilting the crank pulley?

I am at a loss here guys. Any help will be greatly helpful and of course appreciated...

[Tom @ Fast Forward]

Now you know why I gave up on the hotside. It is really all about the alignment. When I had my hotside, I was also at 130/65 as was Bill and a host of others. Once you get it aligned, it will work. It is just that 'alignment' includes the x, y and z axis.

[FormerDatsun510Man]

Nah, I don't think the loads on the crank pulley are too high. Not with a proper 6-rib pulley and autotensioner. As Tom points out, it is all about the alignment of the supercharger. The Hotsides are very finicky in this respect. The blower has to have BOTH the fore/aft and tilt alignment just right. Also the autotensioner bracket must align the autotensioner correctly. If those three standoffs for the autotensioner are not completely square and equal to each other the autotensioner will thus tilt and then it will throw the belt off when a load is suddenly applied.

For adjusting the blower fore/aft and tilt, a trick I used was to loosen the four bolts (just enough!) holding the blower to the main bracket and then start the engine and move the blower around watching the belt run. I would adjust it to get the belt running as evenly as possible on the autotensioner pulley, especially when blipping it. In my case, that was all I needed to do. Just be careful with a running engine and the belt. Adjust in small increments and stay clear of the belt! Use a breaker bar to move the blower fore/aft.

Bill

[MX-Drew]

Don't forget it is the power steering belt that is jumping not the blower belt.

Can you remove the blower belt and run na and see if the belt jumps, that would at least rule the blower out.

I don't know the belt routing for a hotside but is it possible that the blower belt is hitting the PS belt causing it to jump?