Alternator pulley/belt alignment.

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J

joeyg1973

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East Hanover, NJ
So I have had to create an alternator mounting bracket for my 2f and I thought I could go with the old calculated eyeball, but I just don't feel comfortable with that right now. I am a bit stumped as to how to do the pulley alignment for it without having to go out and spend an obscene amount of money on a laser tool. Any suggestions on how best to do this?

Joe
 
Got a straight edge that is 18" long? The damper pulley should be a machined item having a machined front surface. Hold the straight edge against the outside front edge of the pulley and measure over to the center of the alternator belt groove on the damper pulley. Now go out to where the alt will mount, keeping the straight edge on the damper pulley, and measure out where the alt will mount, making sure the belt center is the same as the damper center.

This a simplified description and requires about three hands to do but I don't think you will have any problem understanding what I am trying to explain. This is the method I used when I put a CS130 alt on my F engine. I used a 2F alt bracket and modified it to make the bracket fit and line up properly. Worked great.

Don
 
Damper pulley? What the heck is a damper pulley? Do you mean the crank/harmonic balancer pulley? If so that is going to be difficult because it is a 2 belt pulley and the alternator pulley is a single belt that is supposed to connect to the inside belt groove.
 
I read that a couple of times... I think I got what you are saying... use the front of the harmonic balancer, put a straight edge against it, measure to the center of the inner belt groove on the crank pulley then just use that measurement to line up the alt... got it.
 
Many can do this by eye and get it 'close enough for goverment work'.
 
why dont you just get a factory mount, then it all alignes itself.

What is the year and model. and what and where are your accesories?
 
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then you need some creativity!

what I do is hold the item (alt, p/s pump whatever) in my hand with the belt on it move it back and forth until it appears in line. Then visualize/measure for a bracket, built it and mock everything up so the accessory can slide for final positioning. Hold, clamp, remove and drill/weld/whatever to finalize the location. A little play is good for fine tuning later if you need it. Bolt in, adjust and wa-la.

laser tool...that's funny
 
Dude. Wrap a long loop of dental floss around the crank and the water pump. Those will be points 1 and 2 of your triangle. Put the alternator on its bracket, put the pulley in the dental floss loop and put the mount on the block. Get a pencil or whatever and mark the block where the bracket is once the floss line is square to the other two sides.

Do you need to know how to correctly drill the mounting holes for the mount to the block? It also involves common every day materials as well.

Why the fxxx cant anyone figure s*** out on their own any more?
 
joeyg1973 said:
I read that a couple of times... I think I got what you are saying... use the front of the harmonic balancer, put a straight edge against it, measure to the center of the inner belt groove on the crank pulley then just use that measurement to line up the alt... got it.
Click to expand...

Yes, you got it!
 
71-CRUISER said:
why dont you just get a factory mount, then it all alignes itself.

What is the year and model. and what and where are your accesories?
Click to expand...

Well I started with the factory mount, but then I figured I would be clever. :doh: So rather than drill out the GM alternator to match the holes and bolt for the stock mounting bracket I decided to weld one of the holes on the stock bracket shut and drill it out on the drill press using the open hole as a guide of sort. Unfortunately even after annealing the weld as best as I could, it was still way to hard and I have a couple of drill bits now that are as sharp as a bowling ball. :whoops:

So I have piece of half inch flat stock that I bent into a U and drilled so that it fit the alternator appropriately. I went and cut the tabs off the stock alternator bracket where the mounting holes were as they were useless and figured I would just weld up this new mount using the old calculated eyeball. And that is were I ran into this problem of having too few hands and clamps to do hold, align, and weld all at once.
 
Pinion said:
Dude. Wrap a long loop of dental floss around the crank and the water pump. Those will be points 1 and 2 of your triangle. Put the alternator on its bracket, put the pulley in the dental floss loop and put the mount on the block. Get a pencil or whatever and mark the block where the bracket is once the floss line is square to the other two sides.

Do you need to know how to correctly drill the mounting holes for the mount to the block? It also involves common every day materials as well.

Why the **** cant anyone figure **** out on their own any more?
Click to expand...

I am very good at figuring s*** out, but how easy a solution is to implement and how functional it is very much dependent on experience. I don't have a whole lot of experience in belt/pulley alignment or any experience that would be similar enough to apply to this task.

I would like to know what your method for drilling the correct mounting holes to the block is.

Keep in mind this isn't as simple as it first seems. There are 3 alignments that you need to get right for the pulley to work. Vertical angle, horizontal angle, and the horizontal plane alignment. It's very hard to get all three set right at the same time. That's why the very expensive laser alignment tools that make the job easier exist.
 
Grab a piece of construction paper or notebook paper. Put it over the holes and rub your dirty hands across the holes. Find the center of the holes, place the cardboard on the bracket and mark them. Drill the holes.

I've done this several times with power steering and alternators on my 2F without any problems.

If you havent done this before, think before you post a comment like you did. Dental floss works 100% of the time. It will also help you measure the length of the belt you will need once you get your accessory installed.
 
Pinion said:
Grab a piece of construction paper or notebook paper. Put it over the holes and rub your dirty hands across the holes. Find the center of the holes, place the cardboard on the bracket and mark them. Drill the holes.

I've done this several times with power steering and alternators on my 2F without any problems.

If you havent done this before, think before you post a comment like you did. Dental floss works 100% of the time. It will also help you measure the length of the belt you will need once you get your accessory installed.
Click to expand...


Btw, the dental floss method would work great if I started with a completely from scratch bracket. I am not, I am still using the stock bracket and welding a new base mount on where the old one was.

The reason I question the use of dental floss is because if you look carefully at pulley, it has a fairly large flat space at the bottom of the groove that the dental floss won't locate the center of properly as it isn't thick enough to reach the sides of the V.

Joe
 
OK I think that I might have a way to do this now that I have thought about it for a bit. I am going to need to make a simple adjustable jig. I have the plan in my head and will take pictures when I have it complete if it works. It's hard to explain.
 
It's too freaking hot and humid to work on it today.

I went and took a second look at the pulleys again. The bottom isn't flat but is beveled so the dental floss should work when I get around to it.

The more I look at the stock alternator mount position, the more concerned I am with the amount of belt contacting the water pump pulley. It's appears to be less than 1/4. I did this conversion in the past to my last 40 but I always had an issue with overheating on the highway. I know a lot more now and I am wondering if the small contact patch of the belt to the water pump allowed enough of a slip at 3000 or so RPMs at highway speeds that it wasn't circulating effectively to cool the motor. The belt could have been squealing slightly and truthfully, I would have never heard it because of all the other noise from a 40. Normally the alternator belt is assisted by a second belt to the smog pump or PS.

I am thinking of just starting from scratch at this point and not using the stock one as a base and hanging the alternator upside down and lower to get more contact patch between the belt and the water pump pulley.

I am also starting to think I am overthinking this...

What do you all think?
 
I put a CS130 alt on my F engine using a 2F passenger side alt bracket. My F had only two of the three pre-drilled holes in the head that the 2F has, but it has worked great. To get the CS130 to fit the 2F bracket I made an adapter bracket. It is a modified H shape. The two bottom legs of the H go between the 2F bracket ears. The top legs of the H are wider with the extra width being put into the right side leg and these legs straddle the CS130 mount. It looks like this and lines up the belt perfectly with the pulley.

l___l
l l

It did raise the CS130 alt slightly, but not enough to be a problem. Another thing that you have to watch out for is the width of the belt. Schucks and other auto parts stores will gladly sell you a belt that is the "right" size. But, unless you special order the correct width belt all they will have on hand will be too narrow.

I hope my "drawing" doesn't get distorted when I post this. (It did, the bottom right leg should be further to the right)

Don
 
BTW, I have had no overheating problems with this even though I have no more water pump belt contact than you describe. The reason I mentioned the correct width belt previously was because a too narrow belt can cause the slipping problems you describe.
 
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