The Stovebolt Site Forums The Shop Area Engine Shop Problem with alternator fan belt alignment on 292

Is there more than one style lower alternator bracket for a 1970 292. The alternator needs to go forward about a 1/4 inch to line up with the fan & balancer pulley, however theres no adjustment on the bracket??? or is the problem with the alternator? Someone prior to me buying the truck, drilled an additional hole in the bracket & notched out the back hole to move the bracket forward...I would like to restore it the correct way... Any help would be greatly appreciated...Thanks

The 292's that I worked on the alternator had a pulley that the groove was about 1/4 inch forward.

Without it, the belt would not run in line.

The bracket is the same as for a 250, but the alternator pulley is different.

At least that is what I found when working on them.

Roy..This is exactly my problem the belt is off set...I've been going nuts chasing after alternator brackets...then finally it occured to me the problem must be the alternator not the bracket....The auto part stores carry the basic Chevy alternator...my next stop will be an alternator shop....Thanks for you reply....:)

They should have the correct pulley for the alternator. A lot of folks over the years when they bought a new alternator didn't check the pulleys and would have problems.

That was a common problem years back. A guy would take his old alt to the parts store & exchange it for a reman. The reman had the narrow pulley on it & didn't line up right. It seems they just ran it like that anyhow.

I have seen the most common solution is a double groove alt. pulley, but is this correct ? or did the 292 have a unique single groove pulley all of its own?

They had a single groove.

At least the ones I worked with did.

Went to an alternator shop & it was hard to convience the owner that this was a unique situation...anyhow, his solution was to put a shim behind the pulley....got it real close, so unless someone knows a better solution, this will have to be the fix....

I didn't think there was enough room to put a shim behind the pulley. All gm alternators I have seen had just enough thread on the shaft to go through the nut, but didn't stick out much if any.

Well - there was enough room for the shim and still needs another 1/8 of an inch of shim.......The lower bracket is cast iron & there is no way to elongate the holes to inch it forward.... I just don't understand how something that is so simple, turned out to be such a problem....Just wish I could find a picture of how it looked when it was new....I now have the correct water pump pulley..I think...the space between the water pump pulley & harmonic balancer is about 1/4 inch - Should it be so close?

Your best bet would be to find a double groove pulley and use the outer groove for your belt. Your local alternator shop should have one.

Roy..That would be plan "B". Its just so stupid that something so simple has to be a cob job...The truck only has the water pump & alternator to run off the belt. No P/S... Was this how they were when they were new, with a double groove alt. pulley?

No, they came with a single groove pulley that was offset.

If you know someone with a lathe, have them cut the rear groove off a double groove pulley. Not 100%, but would look pretty good.

Joe

The offset pulley sounds like the fix, but another long shot...The alternator shop I went to, does a lot of industrial along with automotive & I didn't see much with a V belt...most everything was serpentine....as with Salvage yards these guys really don't want to be bothered....at least this is what I experienced....

If you cut the rear groove off the pulley, won't you wind up with a single groove pulley like he already has?

Yes, but the groove would be in front of the one you just cut off.

Joe

The alternator shop will go through the archives to see if he can come up with an offset pulley...Meantime I have a friend of mine who bought a C-60? back in the day with a 292...& he will look at his truck & see what it has....its as close to original as can be....Will get more info on the C-60.....more to follow....

Oh...back to cutting off the rear groove...does the double groove pulley alternator, have a longer shaft? or is the shaft the same & the two pulleys are attached together?

I would think the shaft is the same and the double groove pulley has a place for the nut to set in a recessed area. The outer groove would be inline with the nut, and the rear groove would be inline with a singe groove pulley or real close to it.

joe

Find another Alternator Shop! I just went through this with power steering to boot on a 250. For the 250, there at least 4 different dampeners and I don't know how many water pump/fan pullys, but only 4 alternator pullys, 3L, 4L, dual groove and grooved flat belt. There is ONLY ONE alternator mounting bracket! It took me two months of haunting salvage yards and ebay to come up with a complete set of pullys, brackets and hardware! My set came off of a 1970 Buick engine that had been pulled to install a V-8. The owner was in a giving mood and I got all the stuff I needed for a six pack! I used a 2 foot piece of 1/4 round and layed it in the grooves to check line up. Keep at it, you'll get it!

best wishes,

Les

Well just wrapped it up this weekend...Correct only one lower alternator style bracket. Came across an NOS single groove water pump pulley at a car show...The alternator is the key to lining up the fan belt...The alternator shop installed a offset pulley which extends the pulley/groove 3/8 of an inch forward of the fan on the alternator. The pulley is recessed so that the nut will bottom out exposing a thread or two.The fan belt lines up perfectly.. If anyone is interested,.. explain how to upload the pics & you can see....

Haha this is perfect timing.

I have a 1970 Chevy 292, motor came with an alternator that was a 2 shive pulley and a 3 shive harmonic balancer.

I bought a reman alternator from Advance thinking it would fit fine - it doesn't The pulley groove isn't far enough forward. The 2 groove pulley on the stock alternator I have fits.

Glad you got yours figured out.