Hi all,

I have a 1970 small block. I have noticed for a while that I get a loud "chirping" sound when I hit higher RPMs...like around 3000 - 3500. I have always wondered what it was...now I think I know. I noticed that my alternator belt is rubbing on the power steering pump. Part of the belt is warn away from this, so I know it's happening. I'm guessing at certain RPMs, this creates a vibration or something and that is making the noise?

Anyway...it would seem that if I could rotate the alternator up the adjustment bracket (such that the alternator is moving up vertically), this would lift the belt off of the power steering pump. However, I would assume that this would release the tension on the belt? So then I think, simple, buy a new/shorter belt. But, it doesn't seem like the alternator needs to move a lot...so then it would seem like the belt doesn't need to be that much shorter. But it needs to move enough that it would lose tension. So - what do I do? Do they make LOTS of different belts that might vary by only 1" or something? Would I just move the alternator and do a trial and error to find the right belt length?

I don't know if it matters...but I do not have the factory alternator support bracket because the car has headers. Just FYI in case this matters??? The factory bracket would bolt to the exhaust manifold, but the factory exhaust manifold is not there...so previous owner put this bracket on which has a couple mounting bolts right into the engine.

Any advice would be greatly appreciated!

 

My car 70 small block with headers, my alternator was hung on a really crappy home made looking bracket which was bolted above the front header pipe so I changed to the GM bracket which bolts to the front of the cylinder head, I then shortened the adjustable arm with the slot in it and mounted it to the top water pump bolt, looks a lot tidier and no belt rubbing. If I remember I needed a longer belt, I just cut the old one, put it round the pulleys and measured the gap then ordered a couple of belts either side of my measurement. Getting to the power steering pump to top it up is still tricky but no worse than it was!
Graham

 

I had the same problem with my '79, the alternator belt bounced no matter what the tension was. I replaced the accessory drive with a later model serpentine setup.

 

V-belts come in all different sizes, usually by 1/4 inch increments. Any established auto parts house will have a belt gauge. It will tell you how long your belt is, from there you can decide how short or long of a belt you would need or cut to length and also using Graham's method and you could get it right the first time. T

 

You could try to shim the ps bracket forward with a washer between the bracket and block to move it out a tad. The washer thickness shouldn't affect belt pulley alignment to create other problems and it might be just the distance you need to prevent the interference.

 

Thanks for your suggestions guys. I think I will first cut the belt that is on it...then try sliding the alternator up the bracket and getting a new, slightly shorter belt and see if it fits and provides enough clearance so that it isn't rubbing on the power steering pump.

Do I have to take the fan and power steering belt and everything off to put the new belt on?

 

I replaced my alternator bracket with a kit from Allen Grove. No more belt problems here. They also make a PS bracket that replaces the factory bracket. These are some nice pieces and are heavy duty as well.


http://www.alangrovecomponents.com/index.htm

 

I had the same issue on my 69 with factory 350 engine and mounts. One inch length in the belt makes all the difference. It is a very closely run thing.
My belt size is Gates XL7535 (54 1/8" long). It was a bitch to get on but the 55 1/2" belt interfered with the power steering pump. Works perfectly once you get the right belt.
You have to remove the power steering belt to put on the alternator belt.
VERYSOON

 

Thank you for this. Did you have to adjust the placement of the alternator I assume?

 

Thank you for this. Can you send me any pictures of what you used? Or the part numbers?

 

Do you have a picture of this setup?

 

I got a bracket from a 80 vette. The bracket they use bolts directly to the head. My heads are aluminum and have all the holes, can't remember if 70 iron heads have the holes or not. T

 

Saved me a job, yes that's the exact set up I have.
Graham

 

I had the same problem on my 75 (all factory brackets) I put a 1/2 inch longer belt on the power steering pump. That moved the pump down away from the alt. belt and made it easier to get to the power steering dip stick. You might try that.

 

Thank you so much for this! The bracket from the 80 Vette you mention...is it the top alternator bracket or the bottom alternator bracket you are talking about? My car has the same bottom bracket (at least it looks like yours) as you have (which I know is not correct for 1970), and my top bracket looks like yours, but I can tell it's different. For my top bracket, I can't rotate the alternator any more towards the center of the engine as it runs out of slot space, and even if there was more slot space, the alternator would quickly hit the valve covers.

 

Now this might be the answer! I was wanting to do that anyway because of the power steering dipstick issue (I can't even get my PS cap off!). Will this rotate in such a way that it will move that down and away from this belt a bit? This could be the answer!!!

 

It looks to me like a 234L alternator bracket. BUT I would call them and let them know your situation, year Corvette, engine, etc. to get the correct piece. These brackets work with tall valve covers too. You can see the brackets in the link that I posted below...

 

Mpls
I just did this. Changed to a 37 1/8" power steering belt from a 36 5/8". Adjustment is now on the last inch of adjustment and I now have 1/2" clearance between the alternator belt and the power steering pump.
The alternator is on the first inch of adjustment. (Thats why it was such a bitch to put on but I needed that for clearance. Might could run a half inch longer alternator belt now.
Most awesome!!!

Thank you Pa'svette.
Sometimes I do feel stoopid!
VERYSOON

 

Awesome - you just did this today?! That's so cool. I can't wait to get home and try it tonight. Any tips on getting that alternator belt on? You mentioned it was a b#tch...

 

I have LT1 valve covers on my 350. They are taller than stock which makes the alternator hit when trying to get the belt on. Think this costs me about an inch of movement. I took the alternator off, put the belt on the alternator pulley then REALLY tugged on the alternator to get it on the bracket. If this does not work let me know. One other trick but you have to remove bracket on water pump! No biggie but it really makes it easier to get that short belt on.
You really want the alternator positioned at the first inch or two of adjustment to give the most clearance for the power steering pump. That coupled with Pa'svette 's idea and you have lots of clearance.
Good Luck
VERYSOON