Checking crank pulley to gen/alt pulley alignment

[javabug]

After putting a factory alternator pulley on this summer, I started flipping the nice Gates belts. Had no trouble at all when running the chrome aftermarket piece.

Alignment is thought to be the cause. But, when running a straight edge from the back of the crank pulley, up along the belt to rest on the side of the alt. pulley (not behind it) and measuring the distance of belt edge to straight edge, it appears aligned to my untrained eye (and depth gauge).

Is there a more accurate way to check this? If I don't need to order a shim kit (CB is out of stock until end of next week), and pull my Berg crank pulley, that would be ideal. But I'm going broke buying belts.

[TexasTom]

Until I got my belt alignment PERFECT, I'd just keep it under 6K "unless it was absolutely necessary, Officer".
One thing that helped was swapping to an 11.3X912 alternator belt as it rides lower in the upper pulley. If i run the gen. belts (9.5X905), they flip over like clockwork as soon as it rolls past about 6400 ... that's just no fun at all.

BTW, Berg usiually stocks the shims for the upper pulley ... they "Have It All."
TxT

[javabug]

Thanks Tom. I'll triple check the alignment and see which way to go. I do have an upper shim, but probably the crank pulley needs to come outward.

Do you have any more info on the 11.3X912 belt? Just to confirm if I am already running it or not. Been using the Gates/NAPA toothed #25-7335.

[glenn]

Tom,

I run a 11A0900 and only use Gates belts since they have additional cords across the top. I've yet to have one flip, but threw one when I missed a shift and the tach bounced off 8000rpm. That's another reason I like the V belt over the serp belt.. it's a rev limiter

[Brandon Sinclair]

I have a section of round tubing that I put in the pulley grooves and look at the engine from the side.  It has made it easier for my eye to tell if the pulley needed to be adjusted in or out.

[TexasTom]

Guys---
I use the 11.3X912 Continental belts simply because that's what we stock at the shop. Original equipment/manufacturer freak that I am I guess ... LOL
The wider belt requires more shims, but I think the pulley has greater control over it riding lower in the groove(?).
I have also (over?) revved mine multiple times ( ) ... now I have yet to have a problem.
It definitely becomes a struggle between the fan and the engine. The engine says Yes, the fan says NO. So, yeah, it's kinda like a rev-limiter. But not very effective! 

I install the belt with light tension & use a 12"rule/straight edge against the lower pulley checking for a constant gap between rule and belt to the top.

[Donny B.]

If I rev the engine quickly and hear the belt squeak just a little then I fell I am good to go.  I also use that gates belt.  Make sure you have a good German pulley on the alternator/generator.  If it is out of true it can throw the belt.  I am now running a billet Aluminum pulley and it is better than any German pulley I have used in the past.  For what it's worth...

[javabug]

If I rev the engine quickly and hear the belt squeak just a little then I fell I am good to go.  I also use that gates belt.  Make sure you have a good German pulley on the alternator/generator.  If it is out of true it can throw the belt.  I am now running a billet Aluminum pulley and it is better than any German pulley I have used in the past.  For what it's worth...

I go for the squeak, also.

Thanks for the info from everybody. I'm going to give it another looking at tonight.

[TexasTom]

A lumpy cam, large tube exhaust, dual dual throat carbs, straight cut gears and hint of belt squeak ...
WATCH OUT people, HERE WE COME! LOLOL
 

[Sarge]

Being a parts guy, I like using what the book says... 11.3X912 (111 903 137 E) for use with an alternator.
Check how the alternator fits in the stand... some casting schlag could be keeping it from sitting in the
stand properly.  No way would I mess with the crank pulley.

[javabug]

Funny thing, parts guy  , is that I ran the same belt for over a year until I changed to the German alt pulley this season. I don't want to go back to the chrome crapper though, so I'll work it out somehow.