So I just finished my 17% Alta install including new belt. Everything went semi smoothly BUT after buttoning everything up and taking him for a spin, when I give any kind of moderate to hard acceleration the belt starts squealing horribly, and my boost gauge starts yo-yo'n.

I can definitely hear the belt slipping, so it's not the release valve, and it wasn't happening until after the 17% install. Tensioner seems tight. Can see one hole.

What am I missing? Any suggestions??

 

Is the pulley slipping on the SC? If you do not have it tight enough it will do that. You used a torque wrench and red lock tight right? But we have also seen that the belt selection with Alta has been too big, what size is the belt? you should have a 1379mm long belt on there. Made by Gates, we have seen a lot of problems with other belts.

Chad
Detroit Tuned

 

Thanks Chad! Yeah, that was my first thought as well, that the pulley was slipping on the shaft. I was very careful, maybe too careful, when tightening the pulley body to the shaft. Didn't want to over tighten. An no I didn't use a torque wrench. My fault.

The belt I used was the Napa 06032 I think.

 

Go back...use a tourqe wrench, and some locktite....a slipping pulley will dammage the sc shaft.

 

Going to life the motor back out this afternoon. I assume I am just using Loctite on the 2 screws holding the body on the shaft, correct?

 

Yup...
With us sizing, a 535 length belt is fine with a 17%, some have been ttying one size shorter.

 

Well, just pulled the motor again. Tightening everything, and Loctited screws.......still squealing. Belt is 1385mm.

What am I missing here!!!!???

 

How / what was used to remove the OEM Pulley.

 

Used the Alta puller. Everything came off smoothly. So after reading some posts, I'm thinking the belt is too short...

I have ZERO holes showing on the tensioner, and everything I've read says to go with the Napa 060535 or 060532. I'm using the 060539.

Could this be causing it??

 

So what happened to the one hole you saw before ?

I see one hole and at the edge of second hole with the 532 belt.

 

I was wondering the same thing. Not sure why but now I don't see a hole at all.

 

the bigger the you belt..539 is LONGER than the typical belt...should be OK though...heck A NEW stock JCW belt is OK till it stretches...and the belt you have is still shorter than that...
the longer belt might be needed if you have a oversized crank pulley.....might be an alignment issue..can you see the pulley wobble? Get any grease/oil or coolant on it or the pullies?

 

So are you saying the belt I have is ok? Or that it's too long?

 

Do you have a stock CRANK Pulley or a +2%?

a belt that is a bit too long SHOULD work till it stretches.....
just a hunch...do you see the tensioner doing anything odd...is it very stiff or very soft....see any leakage around the MINI strut? Maybe it went bad....
If the alignment is OK, it is not slipping and the belt is ok.....
the case of the hole disappearing hole on the indicator MIGHT be a tell....

 

Stock crank. Tensioner didn't seem soft.

 

Just my two cents for people who are afraid of the pulley spinning on the shaft. Loctite also produces a green colored type, but there are two different versions, so look closely. One is used for bolts that are already installed, and the other is a cylinder liner install. Get the cylinder liner one and follow the directions to the tee. Our machinist took to long to get a liner in and had to machine the liner out and start all over again. You use that when installing the two halves onto the shaft, you'll never have to think about it slipping again. Don't glob the loctite on, other wise the halves won't clamp together correctly, just a dab will do ya. Same can be said and done with the crank pulley since there is no key way.

 

I also have a alta 17% and i can see the first hole on the belt adjuster, i hade to replace the first belt because the idling pulley broke now the other belt broke also and the idling pulley is not alined with the other things what can be my problem?

 

Just an update guys. Replaced the Napa 060539 with a Dayco 6050535 and no more belt slippage! Might even go to a 532 in the near future. Can see just under one hole on the tensioner, so all seems well! Just over 16psi at WOT, and doesnt take much time to get there..

I do have one more question, when im holding the throttle around 50% (8-10psi), the boost seems to drop off (looking at my guage). Its like it "wobbles" back and forth, and doesnt hold steady. If I'm WoT, then the boost holds fine at 15 and builds from there, no drop off. Is this normal? Possibly need to replace the BPV?

Thanks again for eveyones help!

 

You might need a BPV, try zip tying it shut and see if the problem goes away. If not there is something else going on. If it does then it points at the BPV.

Here is a thread from a long time ago that talks about it and why we made our BVP.

Chad
Detroit Tuned

 

Put a 17% pulley on mine, went to a 532 belt and no issues. WMW sent a 535 and it was too big.