Fan belt numbers

[bobs409]

If you have a Gates fan belt with #15445 and you wanted one a bit less in width, do the numbers tell you what to get? If I recall, the part number tells the size in metric?

I have an annoying belt squeel at high RPM's on one of my 454's since day 1. It didn't have a crank pulley when I got it so I put on one of those chrome aftermarket jobs on and I think it's a deep groove where the water pump and alt pulleys are not. Was thinking of trying either a wider or thinner belt so it fits the crank pulley best. (have to look at it yet, going by memory on this)

 

[Phil Reed]

Would it be "better" to find the right crank pulley????

 

[Don Jacks]

Go with a wider belt to reduce slippage

 

[1961BelAir427]

Would it be "better" to find the right crank pulley????

YES


But to answer your first question. 13 - 15 - 17 are the usual numbers from narrow to wider. Be aware the length needed will vary when changing widths due to the belt fitting higher or lower in the grooves. I would guess you'll need around a 17455, but I may be way off there. That will be wider and longer than what you have now. Your 445 is a 44 1/2" belt.

 

[bobs409]

Problem is I think they were all deep groove pulleys. I'll have to look this over and see where the belt sits in the groove now.

 

[bobs409]

Go with a wider belt to reduce slippage

After checking this closer, your right as usual Don! The belts on their now are only 3/8 inch at top and sit a bit low in the grooves. I set an old belt that is 7/16" wide and it looks much better however....

How do I determine the right part number? I checked and the fan belt is 47215 and the PS is 41013. From what I can tell, that translates to 47 and 41 inches for length. I guess the width is not part of the number.

 

[Don Jacks]

Take one of the noisey belts to a NAPA or other REAL parts house.They should have a belt gauge.It sounds like your length is ok,it's just too narrow.With that gauge,they can find the right size and width.

 

[Jim Sullivan]

At my local NAPA or A&A I can usually pick up several different lengths and just return the ones that didn't fit.

 

[bobs409]

 

[1961BelAir427]

After checking this closer, your right as usual Don! The belts on their now are only 3/8 inch at top and sit a bit low in the grooves. I set an old belt that is 7/16" wide and it looks much better however....

How do I determine the right part number? I checked and the fan belt is 47215 and the PS is 41013. From what I can tell, that translates to 47 and 41 inches for length. I guess the width is not part of the number.

The width is part of the number. It is the 13 and the 15 in the part numbers of the belts you have. The wide one that you need will be a 17 series. Like I said above it will be longer than the one you have now as it will sit higher in the grooves than the narrow 15 series belt. I've often done what Jim said and bought several belts with the understanding that I would return all the ones that didn't fit. I've never heard any parts store have a problem with that. Easiest thing to do is to just drive the truck there on a pretty day and find the right one while in the parking lot. If it is a store you frequent then they should let you take a couple outside at a time. It's not like changing a fan belt takes more than a couple minutes and if they don't have the right one you still have your narrow one to throw back on there plus a better understanding of what size you will need.

 

[bobs409]

If it's the 13 & 15 then why are they both 3/8 inch?

 

[1961BelAir427]

If it's the 13 & 15 then why are they both 3/8 inch?

Most likely the 15 has worn narrower by sinking down into the deep grooves. Have you tightened it a few times to try to stop the squeeling? That would cause it to wear down.

I have heard 2 different explanations of that part of the part numbers, but I'm pretty sure the second one is correct.
1. Said that 13, 15, 17 were the width across the top in millimeters. Sounds close on the first two, but 17mm sounds too wide for the wide belt.
2. Said that 13, 15, 17 stand for 13/32", 15/32", and 17/32". That would be just over 3/8", just under 1/2", and just over 1/2". I haven't measured to check, but that sounds about right.

Regardless of what that part of the part number actually means - if you go to the store and compare new belts you will see that they get wider as that number goes up. The other numbers will be a measurement in inches of the outside diameter of the belt.

Also you may already know that the belt should not sit down in the groove towards the bottom of the V, but should have the top of the belt more even with the top of the V and there should be a gap at the bottom of the groove between it and the inside of the belt.

Hope I've helped some Bob.

 

[bobs409]

Well I couldn't find any with part number 47217 but I did find a Good year 15475 on Summit that is the same length with 7/16 width. Now I'm searching for the PS belt and hope to have the same luck.


Thanks.

 

[bobs409]

Got that one too but it's 40.5 instead of 41 inches but will be ok. Well that ends that problem. On to the next...

 

[1961BelAir427]

Bob, I sure hope I am wrong for your sake but I believe that you'll need a little more length with the wider belts. I know you prefer to have your parts shipped to you, but I think this one is a case where it's best to deal with a local parts store as you are likely to have to try a few different ones before you get it right.

 

[bobs409]

All I wanted was a belt change!!!



Naw, I'm undergoing a cam & intake change on 454 #2. Getting rid of the thumper cam and installing a voodoo. Got a better intake too. It will also get those new belts too.

Engine looks like hell but only has 9K miles on it. Truck lives outside so no hope of keeping the engine looking good.

 

[1961BelAir427]

Inside looks clean as a pin and that's what is important.

 

[skipxt4]

Bob; I have (2) Good Year Gatorback belts on my 409. They are wider, than regular belts, and sit a tinny bit, above the pulleys. Oh, they don't squeal either. For my application, the numbers are 15450 (11AV1130) and 15591 (11AV1485).