Belt alignment help

[67MPRFAN]

Then I am thinking something alignment wise has changed.
Are you using your old crank pulley or the one off the new motor?
.

Yes same pulleys off the old motor never had a issue with belt

 

[67MPRFAN]

Sure doesn’t look like your belt it tight enough in that video.

Did you say the last belt was fine but broke, never jumped off? I had a real bad time with repop belts from Quanta. They jumped, turned inside out. Maybe try another belt. I have good luck with Continental.

You could always lower your RPM too

Yes last belt was fine until I took the car out for first test drive with new motor, went to O'Reilly pick up another for 6 bucks try it and broke it then try 1 from advance auto for 16 dollars it twisted, started looking things over found the miss alignment between crank and wp pulley added shims got a napa belt for 20 was able to drive around normal then I said okay let's feel the power of the 470 bang flew off again,

 

[Paul_G]

Lay your straight edge across a pulley, with the thin part of the straight edge against the pulley. The belt should be the same distance from your straight edge from one pulley to the next pulley. If it is not then you have a mis alignment between the pulleys.

 

[67MPRFAN]

Thanks everyone for your suggestions, sometime this weekend I'm going to pull the radiator (even though not necessary but gives a little more room) so I can get a better eyeball of alignment

 

[Paul_G]

Here is a picture of what I am saying to do. A picture truly is worth 1000 words. And, giving the belts a good push with your finger, you should have about 1/2" of deflection on the longest run.

 

[MoparLeo]

If it comes off at high rpm's, get a different sized crank pulley and I noticed you said the belt only had problems with the "new motor". So this was an old belt ?
Get a high quality belt like one from Gates. You might want to change pulley ratios if you are constantly driving with the engine wound up.

 

[Brewzer67]

The best tip I received for checking alignment it to use a wooden dowel laid in the pully grooves to check alignment. It makes it really easy to see.

 

[Lefty71]

The best tip I received for checking alignment it to use a wooden dowel laid in the pully grooves

Nice, but too easy to deflect.... Paul_G's got the best way, IMO..... You can lay that in the grooves too

 

[ckessel]

Getting the alignment done is key but if your pullies wiggle you are in for a battle. On my Challenger when the engine was out so I could paint the engine bay, I took time to get everybody aligned. Some brackets needed holes filed to get enough movement to square them up, added some thin washers in areas. Belt selection is a key deal too. Not all belts are the same. Some of them get tossed off way too easy. When I worked for NAPA in the early 90's, they changed styles of the belts for their top grade line. They were notched as opposed to solid. I found out that the cheap line of belt was better due to it not being notched and had cording in both the narrow and wide sections. Didn't toss them and they didn't leave a belt dust trail under the hood. The belt dust trail item was pointed out to me by a repair shop that was next door to us as something they discovered.

 

[67MPRFAN]

If it comes off at high rpm's, get a different sized crank pulley and I noticed you said the belt only had problems with the "new motor". So this was an old belt ?
Get a high quality belt like one from Gates. You might want to change pulley ratios if you are constantly driving with the engine wound up.

No it's like the 4th or 5th belt I've tried, last 2 were from NAPA. Not constantly driving at high rpms, just a little spirited driving getting ready for a tnt day. I do have a moroso crank pulley I may try

 

[67MPRFAN]

View attachment 1142586
Here is a picture of what I am saying to do. A picture truly is worth 1000 words. And, giving the belts a good push with your finger, you should have about 1/2" of deflection on the longest run.

Thanks Paul G I'll check that way also

 

[451Mopar]

With my ATI dampner, I used the March Pulleys for a Fluid damper so the crank pulley does not stick out too far, but I still needed to *** a 3/8" thick crank damper to pulley spacer. Andy F. sells the spacer. The rest of the pulleys aligned pretty good with the stock power steering location, and I put a thin (I think 1/16") shim between the water pump and pulley. Not sure why it was just slightly off? Stuff happens when the engine has no original parts.

I think a big part of the issue is the original pulleys used an 11/32" belt, and the 3/8" replacement belts run higher on the pulley.

 

[Cranky]

It looks on the loose side to me too......general rule of thumb is 1/2" deflection (pushing down in the middle) for 13" to 16" of run measuring from the center of the pulley. I've even heard of 1/64" for every 1" of run measuring between center to center of the pulley but that seems kinda tight to me. Also seems too loose for 1/2" deflection for a 13" run.

 

[Brewzer67]

Nice, but too easy to deflect.... Paul_G's got the best way, IMO..... You can lay that in the grooves too

We'll have to agree to disagree.
The deflection you potentially see is actually the point. You have to make sure you have a straight dowel to start with, but that's kind of an assumed. If you lay it in the the grove on both pulleys you will visually be able to see if they line up. You can then rotate each pulley one at a time while keeping the dowel in place in the pulleys and you will see if it deviates from straight at all. This will show you if you have any defect in the belt grooves that may be causing the belt to throw. If you're not comfortable with the wooden dowel you can always use suitable tubing as well. The major benefit being you can get an assessment of the path the belt sees while things are spinning. That doesn't work using a straight edge.

 

[67MPRFAN]

Using what Paul G described I'm still off

 

[Ronnman]

Your pulley(s) may be worn. There are gauges one can use to check the wear. Most belt problems occur when the side of the pulley get rounded.
Ron

 

[Paul_G]

Using what Paul G described I'm still off

View attachment 1142662 View attachment 1142663

Thats great, now you can see how much it is off, and that is a lot. Is the water pump pulley to crank pulley in good alignment? If so the alternator needs to move back toward the engine.

 

[67MPRFAN]

Thats great, now you can see how much it is off, and that is a lot. Is the water pump pulley to crank pulley in good alignment? If so the alternator needs to move back toward the engine.

Yes they are using that same method

 

[67MPRFAN]

Thanks everyone for your comments. I believe for now the problem has been corrected, I did change up my bracket but with all the tips ensuring straight pulley alignment looks like I'm good