I've had two napa alternators crap out on me since I put the gates rpm belt on, its the bearings. Ive heard that you shouldn't run too tight on the rpm belts but the 75 inch belt was never excessively tight. Indicator on tensioner is in the middle, so I ordered that size. Could this belt be damaging the bearings in the alt?
New Rpm belt killing alternator bearings?
- Thread starter Rambro
- Start date
I have a RPM belt as well with about 7-800 miles in since May and everything appears good. I have no more belt dust on everything when I open my hood. I did go by what Gates recommends on belt tensions though.
I think it's just coincidence or your belt is too tight.
The gates RPM belt has very little give compared to the Gates HD green belt and way less give then the Gates regular green stripe belt going by what Gates says.
I think it's just coincidence or your belt is too tight.
The gates RPM belt has very little give compared to the Gates HD green belt and way less give then the Gates regular green stripe belt going by what Gates says.
I just read a thread from last year and it looks like your running the RPM belt too tight. You don't want the RPM belt to be sized to where the tensioner is in the center position of the gauge. You need to message @fishpick. He had a good thread a while back on these belts.
These belts don’t stretch like any other belt. They put a lot of stress back into the drive accessories when coming off of throttle from what I’ve read.
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These belts don’t stretch like any other belt. They put a lot of stress back into the drive accessories when coming off of throttle from what I’ve read.
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Minus the alternator issue, have you seen any benefit to running the RPM belt?
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Yeah - these belts seem to be very solid in terms of performance... BUT - they also seem to be royal pains in the @$$ to tension correctly. Gates, Whipple, etc all have "slightly" different opinions about it.
The issue is the armird (spelling sucks) core and the utter lack of stretching...
A regular belt you tension tight... like 75% of the tensioner travel to "fully tensioned" - and when you jam on the accelerator the belt stretched, the tension takes up the slack and if you had a snapshot it might be at only 10-20% of "fully tensioned" at WOT. When you get off the throttle the belt contracts and the tensioner snaps back to 80-90% and then idles at your set 75% of full.
These RPM's are backwards from conventional behavior... You want to tension them about as loose as you can and NOT get slippage. That's the key. Because when you jam on the accelerator to WOT the belt won't stretch so the core won't let it... but when you let off fast (like everyone does) the belt's momentum will make it "sluff" forward and the tensioner if at the typical 75% can hit the "full tensioned" and when it slaps back on the belt - because it's got no give - the cords in the core snap - and the belt snaps a short while later.
Last year the Gates RPM guys gave me very explicit direction which basically amounts to tension the belt about as little as you can to achieve no slippage at WOT.
your mileage may vary - ever car is different
The issue is the armird (spelling sucks) core and the utter lack of stretching...
A regular belt you tension tight... like 75% of the tensioner travel to "fully tensioned" - and when you jam on the accelerator the belt stretched, the tension takes up the slack and if you had a snapshot it might be at only 10-20% of "fully tensioned" at WOT. When you get off the throttle the belt contracts and the tensioner snaps back to 80-90% and then idles at your set 75% of full.
These RPM's are backwards from conventional behavior... You want to tension them about as loose as you can and NOT get slippage. That's the key. Because when you jam on the accelerator to WOT the belt won't stretch so the core won't let it... but when you let off fast (like everyone does) the belt's momentum will make it "sluff" forward and the tensioner if at the typical 75% can hit the "full tensioned" and when it slaps back on the belt - because it's got no give - the cords in the core snap - and the belt snaps a short while later.
Last year the Gates RPM guys gave me very explicit direction which basically amounts to tension the belt about as little as you can to achieve no slippage at WOT.
your mileage may vary - ever car is different
I've been debating on trying one of those rpm belts. I've been running a 74.5" belt and the 75" might be fine if they require less tension.
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Be careful ,I'd hate to see that nations get damaged. It seems those belts don't need to be very tight at all. I'm hoping the belt was my problem. I have a fresh 75 inch rpm belt, if anyone wants to pay shipping I'll send it.
Yeah that's one thing that makes me nervous about trying it. These gatorbacks leave crazy amounts of belt dust with my carbinite coated pulley. More than the gates hd green belt.
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No issues at all with the RPM on my car, had it on since December. And I have a napa alt, too. All good, not one startup chirp or failure to hold boost. I do have it "loose" tho compared to the gator I had on before, I have the whipple tensioner slid over quite a bit from where it was. Maybe 1/2"-3/4" more daylight.
I will take it if you still have it just give me your PayPal and I will send you the shipping
It seems everyone talking about belts, but the belts in question seem to be of top quality. Bearings used on rebuilt parts tend to be on the cheaper side, where people are not able to see or check the quality. It seems everyone talking about belts
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