1991 Dakota 318 TBI Belt Tensioner made of Unobtainium

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DionR

DionR

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My winter rig is a 1991 Dakota 4WD with the 318 TBI that I have been making plans to replace with a '98 5.9 Magnum. Right now the biggest issue standing in the way of the swap is the garage I have spent all summer trying to build. Now it is too late to do the swap as I need the truck, so that will have to be a next summer project (provided I'm not still trying to build the garage).

In the mean time, the serpentine belt tensioner froze and the truck ate the belt. Not a problem IF I could find a new tensioner. Seems the '91's are a special one year only item and I can't find a new one any were.

So, I am wondering if anyone has successfully swapped the '92+ tensioner onto a TBI motor? I know the air pump would have to go away (darn :)), and the belt length will have to be figured out ('92+ have the idler in a different location), but sure like to see if anyone else has gone down this road.

Note that I posted this over on Dakota-Durango.com but the traffic there seems pretty small so I thought I would give FABO a shot too.

Thanks
 
DionR said:
My winter rig is a 1991 Dakota 4WD with the 318 TBI that I have been making plans to replace with a '98 5.9 Magnum. Right now the biggest issue standing in the way of the swap is the garage I have spent all summer trying to build. Now it is too late to do the swap as I need the truck, so that will have to be a next summer project (provided I'm not still trying to build the garage).

In the mean time, the serpentine belt tensioner froze and the truck ate the belt. Not a problem IF I could find a new tensioner. Seems the '91's are a special one year only item and I can't find a new one any were.

So, I am wondering if anyone has successfully swapped the '92+ tensioner onto a TBI motor? I know the air pump would have to go away (darn :)), and the belt length will have to be figured out ('92+ have the idler in a different location), but sure like to see if anyone else has gone down this road.

Note that I posted this over on Dakota-Durango.com but the traffic there seems pretty small so I thought I would give FABO a shot too.

Thanks
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this might be a dumb question, maybe you've done it already. But have you called a dealer and given them your vin? They at least should be able to give you a part number, to which you could cross reference it and find out if its used on anything else. For example, my wife's 87 dakota had the cruise control unit go out. Dodge couldnt get them, neither could anyone else under the dakota. However, come to find out that Chevy Astro vans used the exact same unit, swapped it right in in 10 minutes.
 
Hmm...interesting idea.

I have been looking for something that would swap without too much hassle, but the only option I see so far is to buy a tensioner for a '92+ and mod it to bolt on. Depending on the brand, it doesn't look like it would be horrible to drill out the stud so I could bolt it on to the existing bracket, but I think I would have to move the locating pin as well. Or hope the bolt would be enough to keep it from turning and eyeball it.

My original plan was to dump the air pump and bolt the bracket and tensioner from the later motors on. But that was partly based on the erroneous idea that the tensioners worked in opposite directions. It appears to be now they spin the same way, but mount in different orientations.
 
DionR said:
Hmm...interesting idea.

I have been looking for something that would swap without too much hassle, but the only option I see so far is to buy a tensioner for a '92+ and mod it to bolt on. Depending on the brand, it doesn't look like it would be horrible to drill out the stud so I could bolt it on to the existing bracket, but I think I would have to move the locating pin as well. Or hope the bolt would be enough to keep it from turning and eyeball it.

My original plan was to dump the air pump and bolt the bracket and tensioner from the later motors on. But that was partly based on the erroneous idea that the tensioners worked in opposite directions. It appears to be now they spin the same way, but mount in different orientations.
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have any pics of this thing
 
I've got a 360 has been sitting in the corner for several years that came out of a 90-ish Ram. I dont remember the year of it. If ya got a pic, I'll see if it's still on the front of this motor and if it looks the same. If it is, it's yours for shipping cost.
 
ragtopfury said:
I've got a 360 has been sitting in the corner for several years that came out of a 90-ish Ram. I dont remember the year of it. If ya got a pic, I'll see if it's still on the front of this motor and if it looks the same. If it is, it's yours for shipping cost.
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Just as long as it isn't froze up like mine. :lol:

Thanks! Let me know, I am good with paying whatever.
 
dukeboy_318 said:
have any pics of this thing
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I don't, other than what the later ones look like:

4.jpg


https://www.autozone.com/external-engine/belt-tensioner/duralast-idler-pulley-305215/199233_297531_0
 
My pulley is different than the one above; smooth because it runs on the outside. But it just unbolts, so no big deal there, and I can still buy a new pulley. It's the stud in the middle that is the big deal.

And I don't really know if the length is the same, just making guesses so far.
 
I know the alternator is still on it. Haven't seen it in a while. And paid in mind to it when I packed up in the spring to move this summer. It's crammed in the garage but I think I can get to it. Still need to know what your set up looks like if you can get a pic of it. I'll be home from work about 2 hrs.
 
My TBI motor doesn't use a tensioner - all v-belts.

Autozone lists one for the '91 that shows a smooth pulley, but it's unavailable. The specs list the same as the '92 vintage from rock auto, but the rock auto part is a grooved pulley. Sounds like maybe just a pulley swap is in order but use the magnum tensioner?
 
ragtopfury said:
I know the alternator is still on it. Haven't seen it in a while. And paid in mind to it when I packed up in the spring to move this summer. It's crammed in the garage but I think I can get to it. Still need to know what your set up looks like if you can get a pic of it. I'll be home from work about 2 hrs.
Click to expand...

I will keep looking for a picture. I won't be home to get snap one of my own until later tonight.
 
Phreakish said:
My TBI motor doesn't use a tensioner - all v-belts.

Autozone lists one for the '91 that shows a smooth pulley, but it's unavailable. The specs list the same as the '92 vintage from rock auto, but the rock auto part is a grooved pulley. Sounds like maybe just a pulley swap is in order but use the magnum tensioner?
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I was looking and saw the same thing.
I know my 89 tbi 318 does not have a tensioner.

Like he said - 1 year only deal?
 
ragtopfury said:
Like he said - 1 year only deal?
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Probably. I missed that part. I checked some photos to verify - if it had a tensioner, I'm a bit closer to spokane but alas it does not. Mine is a 360, but not sure it matters.
 
Phreakish said:
My TBI motor doesn't use a tensioner - all v-belts.

Autozone lists one for the '91 that shows a smooth pulley, but it's unavailable. The specs list the same as the '92 vintage from rock auto, but the rock auto part is a grooved pulley. Sounds like maybe just a pulley swap is in order but use the magnum tensioner?
Click to expand...

I think the '90 and below TBI motors were v-belts? I really think the '91 is a one year only.

I think the big difference between the '91 and '92+ is how it is mounted and where the locating pin is. The '91 uses a long through bolt while the '92+ uses a stud. That is the biggest hurdle I see right now. Locator pin location could be fixed pretty easily in a couple of ways.

Pulley is a bolt on, so that is easy.
 
Here is a picture that (hopefully) will give a better idea of how a '92+ tensioner mounts:

2009-09-06_184136_8087bd03.gif


Mine bolts to the bracket the supports the smog pump. Coming up completely blank of finding a picture of it.
 
ragtopfury said:
So do you need the whole tensioner, or just the pulley that froze up?
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I put a new pulley on mine a short time ago. It is the tensioner that is froze, doesn't rotate any longer to put any tension on the belt. So, need the whole tensioner.

Wish I just needed a pulley, they can still be bought new.
 
Did you ever consider that the belt gave up first and the tensioner just flipped over into the locked position? I have seen that happen, and just used a bar to flip the tensioner back into working mode.
If you try it, be careful what you chose for a prypoint.......
 
AJ/FormS said:
Did you ever consider that the belt gave up first and the tensioner just flipped over into the locked position? I have seen that happen, and just used a bar to flip the tensioner back into working mode.
If you try it, be careful what you chose for a prypoint.......
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Yeah, I could wish. The thing is stuck in between it's range of motion and only moves if I bolt it back on and pry on it. It's frozen.

Belt wasn't that old either. Unfortunately, I get to replace it anyway.
 
So I don't have the one you need, but if you want to experiment with this one, pm me your address and mail me $10 to get it there.

20191118_163641.jpg
20191118_163650.jpg
20191118_163706.jpg
 
I found a post on here of all places where @66plyValiant showed how he deleted the air pump on his '91 Dakota. 1991 dodge dakota v8 smog pump removal tips

Unfortunately (for me), he used the existing tensioner and only used the Magnum pulley. I am ok with deleting my air pump, but I need to do it so I can run a Magnum tensioner I can still buy and I don't have a functional tensioner that would do what he did.

But maybe it will give some more visuals to what I am looking for.

BTW, it appears that the Dakota was the only TBI motor to get a serpentine belt and need this tensioner. All other models or engines had enough room at the time to run a traditional v-belt style accessory drive.

So, ragtopfury, since you have a 360, I can assume it came out of a full size truck or similar, and probably doesn't have a tensioner, or it is a Magnum. Be great if you could still take a look, but I'm not holding much hope that it will work. Appreciate the offer though.
 
ragtopfury said:
So I don't have the one you need, but if you want to experiment with this one, pm me your address and mail me $10 to get it there.

View attachment 1715425226 View attachment 1715425227 View attachment 1715425228
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That is the one I want to try. Just wish I wasn't forging new ground.

I am going to pick up the one at Autozone and see if there is much chance of it work only because it saves me having to mod the truck right now. Doesn't mean I have to commit to that path, but maybe gives me some insight into an option. I will get back to you if I decide to go down this road, though. Thanks for being willing to help!
 
DionR said:
My winter rig is a 1991 Dakota 4WD with the 318 TBI that I have been making plans to replace with a '98 5.9 Magnum. Right now the biggest issue standing in the way of the swap is the garage I have spent all summer trying to build. Now it is too late to do the swap as I need the truck, so that will have to be a next summer project (provided I'm not still trying to build the garage).

In the mean time, the serpentine belt tensioner froze and the truck ate the belt. Not a problem IF I could find a new tensioner. Seems the '91's are a special one year only item and I can't find a new one any were.

So, I am wondering if anyone has successfully swapped the '92+ tensioner onto a TBI motor? I know the air pump would have to go away (darn :)), and the belt length will have to be figured out ('92+ have the idler in a different location), but sure like to see if anyone else has gone down this road.

Note that I posted this over on Dakota-Durango.com but the traffic there seems pretty small so I thought I would give FABO a shot too.

Thanks
Click to expand...
 
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