Weird belt problem - ZR-1 Net Registry Forums

ALLTHECAMS · 06-02-2017

A few times I've noticed that the blades on my alternator have bent out and began to fray the belt. Ive especially noticed it after spirited high rpm driving. Then today I noticed to my shock that the belt was down to four ribs and a alternator fan blade had broken off! I checked the bolts on the alternator and they are tight. what would cause this? Belt tensioner bad?

mgbrv8 · 06-03-2017

Quote:

Originally Posted by ALLTHECAMS

A few times I've noticed that the blades on my alternator have bent out and began to fray the belt. Ive especially noticed it after spirited high rpm driving. Then today I noticed to my shock that the belt was down to four ribs and a alternator fan blade had broken off! I checked the bolts on the alternator and they are tight. what would cause this? Belt tensioner bad?

If it is a tensioner I wrote a article in the Heart Of the Beast publication (Relief for a Tension Headache) to rebuild your tensioner. If you go to the main website and log in and then go to the Members Only section and then Newsletter and select issue 34 and Page 28. Hope that helps

Dave Hetrick

A26B · 06-03-2017

Quote:

Originally Posted by ALLTHECAMS

A few times I've noticed that the blades on my alternator have bent out and began to fray the belt. Ive especially noticed it after spirited high rpm driving. Then today I noticed to my shock that the belt was down to four ribs and a alternator fan blade had broken off! I checked the bolts on the alternator and they are tight. what would cause this? Belt tensioner bad?

Did you replace your alternator & replace the pulley with the one from your original alternator?

GOLDCYLON · 06-03-2017

And did you use the spacer. If you replaced the blades with no spacer this will happen

ALLTHECAMS · 06-03-2017

I have not replaced the alternator. It is the one that was in the car when I got it in December. However I do not see a spacer between the pulley and the fan.

Sent from my XT1080 using ZR-1 Net Registry mobile app

A26B · 06-03-2017

Quote:

Originally Posted by ALLTHECAMS

I have not replaced the alternator. It is the one that was in the car when I got it in December. However I do not see a spacer between the pulley and the fan.

Sent from my XT1080 using ZR-1 Net Registry mobile app

You would need to remove the pulley to see the spacer, if it is there (image below shows the "stack"). As you suspect, if the spacer is missing, the Original pulley will press against the fan when the shaft nut is tightened. As the fan warps from the pressure & heat cycles, the pulley can also slip on the shaft under charging load, compounding the problem.

Roadster · 06-03-2017

When I had a similar problem, my fan blades were hitting the alternator housing in different spots., they were not forcing the blades out. And it was making quite a racket. I tried bending the blades out myself to eliminate the noise. Little success for a very short time. And that was with a factory pulley. That's when I figured out that the replacement alternator did not have the factory spacer, it didn't have any spacer at all. My lack of the spacer did not cause the belt to fray in anyway. Not saying this could not be the cause, just from my experience on my engine.
When you use a replacement alternator, just make sure you use your original pulley and spacer as mentioned, (that's if they are still on the vehicle, which in your case they may not be) and you won't have any problems.
Just thinking out loud, IMO, your alternator fan blades would have to be so out of round and distorted to cause a blade to break and the belt to fray. I would tend to agree with Dave, that it may be the belt tensioner that could be causing this type of problem, to where higher or even normal rpm operation would be causing the belt to be interfering with something that would cause it to fray.
It would be interesting to see what your alternator fan blade looks like, post some pics if you can....
And was or is your alternator charging properly during this time???

XfireZ51 · 06-03-2017

Try to identify the belt and see if it is the correct length.

ALLTHECAMS · 06-09-2017

I got the pulley off today. The spacer is there so I'm at a loss for an explanation now. Belt is also the correct length.

Roadster · 06-09-2017

Can you provide pics of the alternator, pulley, fan and spacer?

Sent from my SM-G935P using ZR-1 Net Registry mobile app

06-02-2017	#1
ALLTHECAMS Join Date: Jul 2016 Location: Bloomington, MN Posts: 127	Weird belt problem A few times I've noticed that the blades on my alternator have bent out and began to fray the belt. Ive especially noticed it after spirited high rpm driving. Then today I noticed to my shock that the belt was down to four ribs and a alternator fan blade had broken off! I checked the bolts on the alternator and they are tight. what would cause this? Belt tensioner bad? __________________ 1991 ZR-1 #520 Arctic White/Gray

06-03-2017	#4
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,155	Re: Weird belt problem And did you use the spacer. If you replaced the blades with no spacer this will happen __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

06-03-2017	#5
ALLTHECAMS Join Date: Jul 2016 Location: Bloomington, MN Posts: 127	Re: Weird belt problem I have not replaced the alternator. It is the one that was in the car when I got it in December. However I do not see a spacer between the pulley and the fan. Sent from my XT1080 using ZR-1 Net Registry mobile app __________________ 1991 ZR-1 #520 Arctic White/Gray

06-03-2017	#7
Roadster Join Date: Mar 2014 Location: Warrington PA Posts: 1,914	Re: Weird belt problem When I had a similar problem, my fan blades were hitting the alternator housing in different spots., they were not forcing the blades out. And it was making quite a racket. I tried bending the blades out myself to eliminate the noise. Little success for a very short time. And that was with a factory pulley. That's when I figured out that the replacement alternator did not have the factory spacer, it didn't have any spacer at all. My lack of the spacer did not cause the belt to fray in anyway. Not saying this could not be the cause, just from my experience on my engine. When you use a replacement alternator, just make sure you use your original pulley and spacer as mentioned, (that's if they are still on the vehicle, which in your case they may not be) and you won't have any problems. Just thinking out loud, IMO, your alternator fan blades would have to be so out of round and distorted to cause a blade to break and the belt to fray. I would tend to agree with Dave, that it may be the belt tensioner that could be causing this type of problem, to where higher or even normal rpm operation would be causing the belt to be interfering with something that would cause it to fray. It would be interesting to see what your alternator fan blade looks like, post some pics if you can.... And was or is your alternator charging properly during this time??? __________________ Tom 1994 ZR-1 #009 "captured test fleet car" 1974 LS4 454 Vert 1974 L-82 355 Vert. 1982 L83 CFI...now a retired "dd"....Sold WAZOO Member Last edited by Roadster; 06-03-2017 at 06:42 PM.

06-03-2017	#8
XfireZ51 Join Date: May 2007 Location: Chicagoland, IL Posts: 9,708	Re: Weird belt problem Try to identify the belt and see if it is the correct length. __________________ [SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX

06-09-2017	#9
ALLTHECAMS Join Date: Jul 2016 Location: Bloomington, MN Posts: 127	Re: Weird belt problem I got the pulley off today. The spacer is there so I'm at a loss for an explanation now. Belt is also the correct length. __________________ 1991 ZR-1 #520 Arctic White/Gray

06-09-2017	#10
Roadster Join Date: Mar 2014 Location: Warrington PA Posts: 1,914	Re: Weird belt problem Can you provide pics of the alternator, pulley, fan and spacer? Sent from my SM-G935P using ZR-1 Net Registry mobile app __________________ Tom 1994 ZR-1 #009 "captured test fleet car" 1974 LS4 454 Vert 1974 L-82 355 Vert. 1982 L83 CFI...now a retired "dd"....Sold WAZOO Member

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