Belt guidance

-
A

Abodysrule

FABO Gold Member
FABO Gold Member
Joined
Jan 30, 2018
Messages
301
Reaction score
80
Location
California
I'm putting a 360 magnum in my '67 dart, setting it up as an LA would be, OEM LA type alternator and Saginaw power steering brackets. I bought what I thought were the correct v-belts for the alternator (goes on alternator and rear balancer pulleys) and water pump/powersteering/fan (goes on water pump, power steering and front balancer pulleys). Both of these belts are about 4 inches (guesstimate) too short. Neither works for either side, but were advertised as "small block mopar" appropriate belts. Am I running them on the wrong pulleys? The pulleys I recited align properly. Does the alternator belt go to the water pump as well, maybe that's my issue, the altnerator front tab can be inside or outside of the bracket... The part numbers I have are Gates 7480 and 7370. I don't have AC.

Does anyone have part numbers/recommendation for what belts I need? If I measure using a string, can order by length?

Brian
 
Last edited:
From my 67 273 car,federal pump, not sure how old that PS belt is, or how current the part number is. This one had been sitting a while. Hopefully the pics can be of some help.

image.jpg


image.jpg


image.jpg


image.jpg
 
For sure the alternator belt takes a trip around the top of the waterpump, then down and around the LA damper, them back up to the alternator.

If you ordered belts for a 67, the book assumes you have 67 pulleys.
There was no 360 that year, so you should have received belts for a 273, and that engine would have had a cast-iron waterpump with timing tab on the passenger side.
The 273 damper would have been about 7 inches, with a two-row pulley, and the W/P probably a lil smaller than the damper pulley.
The single pulley on the 273 alternator would have also been very small; Ima guessing around 2.5" max od, maybe a wee bit bigger .

Without a pic, it's hard to say what's wrong but I can tell you that there are at least a dozen alternator-belt permutations and at least four P/S permutations. So.............. pics would really help.
 
Last edited:
OK, great...so the belts I have would fit MidnightSwinger's arrangement, but... I took some pics of my set and it looks like my pulleys align as I described (see pics) that is: water pump, power steering pump and front balancer pulley, and then, alternator and rear balancer pulley. So, I'll need to find a set to fit that...

2.jpg


1.jpg
 
No, no, no; that's all messed up!
Firstly the alternator pulley is on backwards,
Secondly your Waterpump is wrong for a 67, that pulley will never work,
Thirdly the alternator appears to be spaced too far forward. and
Fourthly, that Saginaw has an exceptionally long nose on it. I can't recall ever seeing that in an A-body.
Methinks
Yur gonna have to get some different parts, and Ima thinking you may not find a WP pulley to work on that pump.
Furthermore, IIRC Magnum truck pumps that had the serpentine belts, were reverse rotation pumps; so make sure yours is not one of those..
FWIW
I think the damper will be right, for the correct 67 parts or
Maybe you can find one that sticks out far enough to work with the current WP and PS pulleys, and then you still have to deal with the alternator spacing.

Here's the deal, to shift at 5500 or more, your belt alignment has to be spot-on, else the alt-belt will fly off, leading to engine overheat. Take your time, and don't rush this. If the belt flies off once, it may fly off again. So once you get your pulleys bugged out, get a spare belt.

Oh and FYI,
1) the PS belt always goes closest to the rad, and
2) flex fans are a known trouble spot. Engines with those lean towards overheating in traffic, and the blades have been known to occasionally fly off.
With as much room as you have there, I highly recommend a 7-blade all-steel fan, from a 318 car with A/C, and put it on a thermostatically controlled viscous clutch. You will never be sorry.
 
Last edited:
I have been in this situation before, Bring your pump, alternator up about 1/2 from the lowest adjustment, you would want to have your belt to slip over the pulleys. I take the right size belt (width) cut and using the cut belt take your measurements.
 
I appreciate your concern AJ/FormS, but think it's OK. This is a 360 magnum. That is not a reverse flow pump. The alternator pulley is not on backwards, it was a dual pulley that was cut in half at some point. Also, the pulleys as I have them are aligned perfectly. I just measured the pulley arrangement with a cloth tape, it appears that a 44-45" belt for each side will work. Thank you all for your help.

Brian
 
Looks to me like you've got '69 and earlier brackets and pulleys on a '70 and later front cover & water pump. The two generations of water pumps have different depths and use their own different pulleys and brackets which is causing your mismatch.
That power steering bracket is unlike anything I have seen (and I've seen a lot), there should be a front bracket (missing on yours) AND a rear bracket... I would definitely not run it like that, you could tear the reservoir apart.
The belts should be: Alternator, water pump, and crank; and P.S. pump and crank.
(P.S.- Guys, the Magnum water pump has a completely different bolt pattern and will not even fit an LA timing cover.)
 
Last edited:
The alternator brackets are '70 and up, like this: MOPAR 1970 & UP Small Block Alternator Bracket Kit NON-A/C Dodge Plymouth 71 72 | eBay

The ps bracket is Borgeson specifically for mopar small block and Saginaw pump. See: Small Block Mopar Pump Kit That bracket is nearly 1/2" thick steel plate. Are you telling me that Borgeson didn't engineer it to properly, that it still needs a front bracket? Seems pretty solid I have to say.

Are you saying my water pump pulley doesn't match the water pump; that is, is there a specific "70 and later water pump pulley?
 
Last edited:
Abodysrule said:
Are you telling me that Borgeson didn't engineer it to properly, that it still needs a front bracket? Seems pretty solid I have to say.
Click to expand...
No, what I said was
Professor Fate said:
That power steering bracket is unlike anything I have seen
Click to expand...
I should have been clearer and said "unlike any FACTORY bracket".
Since you're mixing and matching factory and aftermarket pieces, the routing could be anything. I couldn't find where Borgeson's site even specified what years (spacing) that bracket is designed for, or what pulleys it is compatible with; nor do I see a means of adjustment for belt tension. With a non-factory setup and non-factory routing, don't expect to use factory belt sizes- you'll have to do the "string thing" to size them up.
 
Ok, the Borgeson unit's tension adjustment is underneath, that's why you can't see it in my pics. So, yes, the Borgeson single bracket doesn't look anything like an OEM set of brackets. It's quite nice actually, very very solid, no chance of it bending out of plane. Sorry for any misunderstanding by reciting my car is a '67. Generally on these forums that question always comes up, even though in this case it is irrelevant what year it is.

I'm good, thanks again everyone. Inertia, I don't think you'll need your popcorn.

brian
 
I have a gen 2 hemi, that I used all the pulley's off a 383 with the Saginaw pump. Everybody called for a 39 1/2" pump belt, but I had to get a 44" to get it right. Local auto stores are phasing out belts, because the serpentine belt is the now in belt. I used a string around the pulley's to get me the right size. Anybody interested in a 39 1/2" belt never used. Just kidding.
 
Yeah, tonysrt, I measured 44-45 inches for both sides in this configuration. I ordered two 44 3/8" belts this morning. Gates has a nice lookup tool for sizing, width and circumference inputs, shows you the part numbers and sizes available.

Note of caution for anyone ordering custom sized belts - make sure you're ordering high-quality and specifically automotive belts.
 
For 40 years I was using the wrong PS belt. It was pretty much not letting me adjust tension properly. It was also a 3/8" wide where now I have the 1/2" wide and adjustment is now in the middle of the bracket slot. I wrote the # down in my book but I doubt I'll ever need another new one. I keep a book dedicated to my Cuda with all the maintenance done, mileage, date and cost. In the back I list all part #'s for replacement parts. I keep a book in all my cars so I know when maintenance is due.
 
factory Non-AC pulley arrangement 1970

Alternator, water pump on the crank groove closest to the engine

2020-05-26 22.59.45.jpg


PS on it's own belt in front crank groove

2020-05-26 22.59.23.jpg


I can provide measurements of pulley depth and height if you want since I have a back-up set of these pulleys...
 
Last edited:
Yeah, I have a note on my iphone that has all the part numbers I used on mine. Always a good idea, as I'm getting older.
 
So the belts you have are 7480 and 7370. The first 7 is the width of the belt, the last three numbers are the length. 48” and 37”. If they are 4” too long go buy a 7440 and 7330. If the number is 7485 it is 48.5” long. There are a number of water pump pulley dia. A/C, non A/C etc.
 
Abodysrule said:
OK, great...so the belts I have would fit MidnightSwinger's arrangement, but... I took some pics of my set and it looks like my pulleys align as I described (see pics) that is: water pump, power steering pump and front balancer pulley, and then, alternator and rear balancer pulley. So, I'll need to find a set to fit that...

View attachment 1716246319

View attachment 1716246320
Click to expand...


wrong pulleys.. thats an a/c waterpump pulley you have there.. can't tell what the crank pulley is.. you have a 70-up water pump it looks. so you'll need 70-up non a/c pulleys..


rear belt will go: crank. water pump and alt.

the front pulley will go crank and power steering pump...


.
 
Last edited:
The Magnum had a Serpentine belt. It sounds like your LA pulleys are lining up but there is no "application" to get the correct ones. You will need some rope to wrap around the pulleys to measure the length then off to the parts store you go. Make sure the alternator and PS pump are in the middle of their adjustment slots so the belts you get will fit and adjust properly.
 
AJ & AbodyJoe nailed it.

You’ll just have to measure it up with a string/rope or cut up belt. That’s what I had to do with my mixed bag of crap. Also custom cut spacers.
 
You must log in or register to reply here.
-

Back
Top