V belt size

[Twister]

I am doing a 3g alt swap on my 87 b2. I got the alt bolted up and everything, I am trying to find a longer v belt. I found one that seems like it will work but I think it is too thick. Herr is a pic if it on the alt pulley. What do you guys think? Also, if the alt pulley is a bit offset from the crank and water pump pulley by a tiny bit, will it hurt anything?

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[509lifted]

if its offset it could keep popping the belt off so it depeneds on how much is a tiny bit

 

[riss6270]

I would say its an ax or bx series. I am going to get one of my mechanic books our. It tells you how to figure the belt size. Is the belt going to sheave to sheave or is it going over this under that through this and over that? Also if you have some precision measuring tools I can give you the size in width for belts and just measure the sheave the belt should sit flush with the sheave when installed. If it sinks in you will wear the sheave. If it rides to high you will cut belt like by 36 percent. Stand by for the info. I need to find it.

 

[riss6270]

Ok can't get the pic t upload
A series .5 w x .31 d
B series .66 w x .41 d
C series .88 x.53
D series 1.25 x .75
E series 1.50 x .91

A series belts range in length from 51-128 in b series 35-300 in.

A belts outside Ida of smallest sheave inches min 3.0
B belts 4.6

If your sheave are different sizes you have driver rotational speed / driven rotational speed = driven pitch diameter / driver pitch diameter Or fph = d(pi) x rpm.

So most of what is above might be making your head spin. Only moles sense if you have to use the math everyday. Most is just useless info for you.

To get your belt size if it is sheave to sheave measure your drive to driven sheave to the outer diameter. You can go to Goodyear website and get he specs for belts. That's the only belts I use. If you were to measure 49.83 which is the standard distance for an ax49 belt. You would need an ax49 belt. Depending on the point of contact on the sheave too. This probably sounds very confusing. If you need any clarification let me know.

I have taken a lot of classes on power transmissions motors and drives bearings and pumps and seals so I have a lot of books laying around that I crack open when I see these kinds of posts.

 

[4x4junkie]

I'd look for a different pulley for it (maybe the one from your old alt).

I have a 3G alt on mine and after changing the pulley the stock belt fits perfect.

 

[Twister]

What bracket did you use? I put the pulley from my old alt. I found a write up that said they used a 2.8 alt bracket because they don't have the offset ear. How many bolts are suppose to hold on the lower alt bracket?

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[4x4junkie]

Stock 2.9 alt bracket. I think I modified the bolt on the alt to work with the bracket somehow, though I don't remember for sure, this was maybe a bit over a year ago.

IIRC, my alt is from a '95 E-150 w/300I6 application.

 

[Twister]

Stock 2.9 alt bracket. I think I modified the bolt on the alt to work with the bracket somehow, though I don't remember for sure, this was maybe a bit over a year ago.

IIRC, my alt is from a '95 E-150 w/300I6 application.

OK maybe ill throw the 2.9 bracket back on. I looked up the one from the van and it looks identical to the one I have. Their part number are almost exactly the same.

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[Twister]

Stock 2.9 alt bracket. I think I modified the bolt on the alt to work with the bracket somehow, though I don't remember for sure, this was maybe a bit over a year ago.

IIRC, my alt is from a '95 E-150 w/300I6 application.

Would you mind posting a pic of your setup, i think i fixed the offset of the pulley, but i cant find a longer belt. The stock belt is not long enough and the belt i bought is the one in the pic and looks a bit to big. Do you think the one in the pic would be ok or should i look for another one? If i should look for a different one, what would be another car i can look for one from?

 

[4x4junkie]

My belt is the stock 2.9L application belt... not sure anything changed '87 - '90 or not (the one in your pic is begging to slip off or become twisted).

I'll go get a pic of mine...



This help? (best I can get without dismantling a bunch more stuff):

 

[Twister]

My belt is the stock 2.9L application belt... not sure anything changed '87 - '90 or not (the one in your pic is begging to slip off or become twisted).

I'll go get a pic of mine...



This help? (best I can get without dismantling a bunch more stuff):

Did your new alternator have the offset ear or the straight up and down style? I think I may have found a belt that will work on autozones website. Just got to pick one up.

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[4x4junkie]

It's offset just like the OE one, just a 3G unit (and had a serpentine-belt style pulley I swapped for the standard V-belt one).
The straight-up/down one looks like it would for sure require modifying the bracket.

 

[Twister]

Got a better v belt, it sits down inside the pulley like it should . Now to the wiring. I have read a couple write ups but they are a big vague on the wiring. While i was at the junkyard i snagged the alt harness from a 94 mustang with a 3.8 ltr, which was identical to the wiring in the Taurus but wasn't permanently tied into the whole engine harness.

So far i have a wire going from the charge post, to a 175 amp fuse then to the batter post on the starter solenoidf

There are two plugs on the original B2 harness, one that fits into the alt and the square one, i take it i don't need the square one right?

The other plug that looks like this:

How do i wire this up right?

 

[Twister]

Phone wouldn't let me edit last post. From what I read, there is a single white wire on the square plug I need to cut and put it on the charge post. Plug in the other plug making sure the wires are in the right spots, cut the white wire(middle one), splice in a single plug for the stator wire.

Sound right?

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[4x4junkie]

I need to look at my notes again... I recall it was really stupid-easy though.

I do remember you cut off the larger 3-terminal rectifier plug that has the two thick cables, tie the two cables together and attach them to the output post on the new alt with a heavy-duty eyelet. The 3rd (white) wire from that same plug I think does hook to the single (stator) terminal on the new alt, and the plug you have pictured above then plugs into the voltage regulator same as before.

You may want to verify this for sure first though as I'm just going by memory on it.

Also, that fuse setup is no bueno. You need to either get a proper fuseholder for that thing, or just not use it at all (IIRC there are already alt fuses in the Power Distribution box). Those fuses were never made to have huge wires hanging off them like that.