3G Alternator Seized Up???

[93tealstang]

So last summer, I finally got my car to hold a full charge while running underdrive pullies by putting on an ASP overdrive alternator pulley. No problems until a day ago when I was pulling out of my driveway when I heard loud screeching and felt alot of vibrating. I open the hood and see my belt has somewhat melted around the alternator pulley so upon releasing the belt tension, I try to spin the pulley and it's locked up. Has running an ASP pulley caused premature damage to the alternator or is this a common problem? I've has this OEM 3G for about 5 years but just recently switched out pulley's. The shaft is locked and when I do get it to turn, it makes a grinding inside the alternator. Any help would be appreciated.

 

[HISSIN50]

The critical speed for most 3G's is about 15000 alternator RPM. Compare the overdrive pulley to your crank pulley to figure out if the alt could have been overspun. When they hit near their critical speed, they do crap out.

Good luck.

 

[Black1987Stang]

The critical speed for most 3G's is about 15000 alternator RPM. Compare the overdrive pulley to your crank pulley to figure out if the alt could have been overspun. When they hit near their critical speed, they do crap out.

Good luck.

Not to steal the thread but what do you mean by critical speed?

 

[93GTosu]

Not to steal the thread but what do you mean by critical speed?

You can only spin things so fast before they break. 15,000 rpms is the number of revolutions per minute the alternator can spin before stuff starts to break. I think that's what he was saying in a nutshell.

The reading in your dash is RPMs for the "crank" pulley.

The alternator pulley is smaller than the crank pulley. Both are on the same belt. Therefore the alternator is going to spin faster than the crank pulley. How much faster would depend on the ratio of the pulleys.

 

[HISSIN50]

GTOSU has it covered.


The actual number crunch is [(crank diameter/alt diameter) * engine RPM]