On Saturday I was driving on the highway when suddenly I get the batt light on and temperature climbing like crazy. Pull over to find out the alt belt has shredded on one side and flow off, taking the SC belt with it. I figured it was an old belt, so I'd just get a new one and that would be the end of it. Not so lucky. I put a brand new belt on and the exact thing happened within about 100 yards of the house. When I first started the car with the new belt, the tensioner did a lot of clicking and moving, but then settled right down so everything seemed fine. What could possibly cause the alternator belt to shred like this? Coming off the side away from the engine if that makes any difference. I've checked the wheels/pulleys and they all turn quite easily.
[This message has been edited by NetCam (edited 09-03-2014).]
Misalignment of pulleys is the #1 culprit followed by rusty pulleys. Check the alignment of all pulleys with a steel straight edge.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Do you have a picture of your tensioner? My swap had a half assed tensioner with it that constantly threw belts as well.. I have a feeling yours is the same
Did you move the alternator? If so how did you reposition it?
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Powerlog manifold, Northstar TB, LS1 MAF, 3" Flotech Afterburner Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Alternator is low mount, so I used this belt routing -
Edit: The top pulley closest to the SC is a ribbed wheel, not the smooth one that I think was stock on this engine.
If your using a ribbed pulley on the smooth backside of the belt, then that's most Lilly your problem. If that's so then change it out to a smooth one. Groves only goes on the ribbed side of the pulley and vice versa.
------------------ 86 SE Convertible 3800sc 4t65e HD.
First that is not a good wrap around the water pump. if belt is ribbed on top then it is fine. Like Dennis said alinement of the pullies or rust or a gouge in one of the pullies. remove the belt and carefully go over all the pullies. then route the belt better around the WP
I would reroute the SC belt to go straight down to the WP. remove the pulley from the firewall side and the bottom one. Put the ribbed pulley on the tensioner next to it.
you will get more wrap around both SC and crank pullies. (that as well could be a issue, belt sliding around the WP because not enough wrap to hold it to the WP)
[This message has been edited by revin (edited 09-04-2014).]
All the contact areas are smooth to smooth and ribbed to ribbed, the pulley by the alt is smooth. I haven't even started with the SC belt yet and won't bother until I get this fixed. Can't go straight down on that one because there's wiring from the battery and C500 that crosses there so I'd have to disconnect it and loop the belt around it. I've picked up a new tensioner and will tackle it over the weekend.
Looks very similar to the problems I had on my swap. Did you do the swap yourself or did you pay someone to do it? If you had someone do this swap for you, hopefully you have some warranty with it.. My belts rubbed into hoses, frayed on misaligned pulleys, and squaled like crazy..... Not fun when they slip off at the side of the road... I guess you are not coming to the cruise tomorrow I hope you are able to get this resolved and finally be able to enjoy your car after all the headaches.
How will putting a new tenisioner on put more wrap around the water pump and crank?????
Would be easier to do what I said and move the batt cable away from all the pullies.
You asked for advise, I gave it, yet you go someother route. Good luck.
ps. I think I see another screw up by looking at the pic...but....
Right now I just want to get the car back on the road because there's a pretty short driving season here, probably only have a few weeks left. I plan on dropping the engine over the winter for the install of an XP cam and probably a few other go fast goodies. Will tackle all the 'ankle biters' while I have the engine out and have some time to do things right and make it all purdy. I'm seriously thinking of relocating the battery up front and moving the coil packs into the stock battery location.
I am not a fan of the tensioner being on the tension side of the belt vs. the slack side.
Ideally, the tensioner should be between the harmonic balancer and alternator (where you have the smooth idler pulley). Where it is now, as you accelerate or the alternator sees a significant load, the increased tension on the belt will pull the tensioner down and create a loose belt between the harmonic balancer and the alternator. This loose/slack portion can cause the belt to come off.
Also put a straight edge across the harmonic balancer (I like to bolt it to it so it stays in place) and measure the distance to the first belt ridge. Then using the straight edge, check the distance to the first ridge for the alternator pulley and the tensioner pulley. They need to be within 1/32" of each other.
Any idler, that you installed that didn't use a bolt hole in the block, should be checked for it being parallel with the face of the engine. If it is tilted, it will cause the belt to track to the side and cause an alignment issue with the next pulley.
From this picture you can see that the belt wasn't using the grove furthest to the PS of the engine bay (clean pulley - belt making contact, except for the outer grove)...looks like it jumped a groove at some point and chewed up the inside of the belt.
[This message has been edited by fieroguru (edited 09-06-2014).]
Good catch, I didn't notice the uneven wear on the pulley. I did, however find one thing when I started to take everything apart. It appears that the vibration of the bad pulley loosened the bolts holding the bracket to the block, you can actually see the gap between the head of the bolt and the bracket. I was able to take out the bolts without even using a wrench. When I have everything apart over the winter I'm going to be putting locktite on a few bolts for sure.