4 grove crank pully for SBC

[SirRobyn0]

So this started as a side discussion in another thread. Someone wasn't happy that we'd derailed from hub caps to crankshaft pully so I said I'd start a separate thread. Now I'm going to tag everyone that was in on it, but anyone is welcome to join. @AuroraGirl @AyWoSch Motors @bucket

So IIRC the 4 grove crank pully was used on medium duty SBC trucks where they ran 2 belts over the A/C & P/S as well as 2 belts for the Alt. The broken one I have sitting at the shop has a steel inner pully and a cast iron outer pully.

I'm running out of time today to get a picture of it but will try to make it happen before I call it a day.

I do not know why they did two different materials like this.

Ayden, if you have one in your pile I'd be interested and there is no hurry at all. But I'd be interested in discussing buying one from you.

Taylor, you were saying?

Thanks for coming to the new thread!

 

[bucket]

I'm in to see how this rascal is constructed. I'm also curious about the diameter of it.

 

[SirRobyn0]

Ok like I said as far as I know these were only used factory on SBC in medium duty trucks. Maybe other applications I'm not aware of. They seem to be made of unobtainium in the aftermarket world. Bolts to the harmonic balancer just like any normal 2 or 3 grove pully.

Below the two pullies separate, the one on the right is the inner pully the one on the left the outer

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.

Below close up of the inner pully

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Below close up of the outer pully

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Below Close up on the back side of the inner pully, note that it looks like the back of any normal pully for a SBC crank.

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Below close up of the back side of the outer pully

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More in the next post.

 

[SirRobyn0]

Below, pictures and measurements of the two sets of pullies as they would be assembled on the truck.

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[SirRobyn0]

Well that's what I've got. They are just hanging out here at the shop so if ya'll want some other measurement or info of it let me know. I'll be on the road and then on the farm for a few hours so it'll be later tonight before I'm back on. Thanks.

 

[bucket]

So this is a truck with a short water pump? I know they were still in use in the late 70's, along with ram's horns and an air cleaner that would look more at home on a '64 283.

The steel base pulley looks like it may be the same as a Corvette? Then they just added the cast pulley for truck use.

 

[SirRobyn0]

So this is a truck with a short water pump? I know they were still in use in the late 70's, along with ram's horns and an air cleaner that would look more at home on a '64 283.

The steel base pulley looks like it may be the same as a Corvette? Then they just added the cast pulley for truck use.

It's not real easy to tell in the pictures but the steel pully has upraised rounds, kind of like engagement dogs, that fit unto holes on the cast pully. However there are #'s on the steel pully and it comes back as part # for all the flavors of SBC from 1968 - 1986, corvette is listed as well as other cars and a plethora of trucks.

I do not see a part # on the cast pully, but it's pretty caked, so I will have to give that a clean up tomorrow and see if I can find any #'s on it.

IDK on the short water pump as I don't have a complete engine with this setup on it to compare it to but you may well be right about that.

I really am off the site for a few hours now.

 

[AuroraGirl]

So this started as a side discussion in another thread. Someone wasn't happy that we'd derailed from hub caps to crankshaft pully so I said I'd start a separate thread. Now I'm going to tag everyone that was in on it, but anyone is welcome to join. @AuroraGirl @AyWoSch Motors @bucket

So IIRC the 4 grove crank pully was used on medium duty SBC trucks where they ran 2 belts over the A/C & P/S as well as 2 belts for the Alt. The broken one I have sitting at the shop has a steel inner pully and a cast iron outer pully.

I'm running out of time today to get a picture of it but will try to make it happen before I call it a day.

I do not know why they did two different materials like this.

Ayden, if you have one in your pile I'd be interested and there is no hurry at all. But I'd be interested in discussing buying one from you.

Taylor, you were saying?

Thanks for coming to the new thread!

I read something about gm 6.2 and 6.5 with AC could have 4 equal slots on a pulley, i did a private search and found machined pulley with 2 sets of matching grooves one just slightly smaller diameter, so if on the crank the water pump can be captured for 2 ps belts and then 2 belts could dedicate to a alternator, giving good wrap and also ensuring a potentially heavy load alt could be turned faithfully . id think. no ac plans right?

 

[AuroraGirl]

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this is one of those 3 groove pulleys, but i should check the diameter of the odd one out, there may just be a add-a-pulley that would slot right on and would be the same size, giving a match to be 2 sets of grooves not tooooooo different but more than wed maybe want

 

[AyWoSch Motors]

So this started as a side discussion in another thread. Someone wasn't happy that we'd derailed from hub caps to crankshaft pully so I said I'd start a separate thread. Now I'm going to tag everyone that was in on it, but anyone is welcome to join. @AuroraGirl @AyWoSch Motors @bucket

So IIRC the 4 grove crank pully was used on medium duty SBC trucks where they ran 2 belts over the A/C & P/S as well as 2 belts for the Alt. The broken one I have sitting at the shop has a steel inner pully and a cast iron outer pully.

I'm running out of time today to get a picture of it but will try to make it happen before I call it a day.

I do not know why they did two different materials like this.

Ayden, if you have one in your pile I'd be interested and there is no hurry at all. But I'd be interested in discussing buying one from you.

Taylor, you were saying?

Thanks for coming to the new thread!

I'm pretty sure I have the one you need in the pile. Havent been home to go check, but as soon as I get back, I'll let you know. I also know lots of squarebody people, I can ask around if I dont have it.

 

[SirRobyn0]

I read something about gm 6.2 and 6.5 with AC could have 4 equal slots on a pulley, i did a private search and found machined pulley with 2 sets of matching grooves one just slightly smaller diameter, so if on the crank the water pump can be captured for 2 ps belts and then 2 belts could dedicate to a alternator, giving good wrap and also ensuring a potentially heavy load alt could be turned faithfully . id think. no ac plans right?

Currently have A/C not giving it up. 4 groves needed then.

I'm pretty sure I have the one you need in the pile. Havent been home to go check, but as soon as I get back, I'll let you know. I also know lots of squarebody people, I can ask around if I dont have it.

No rush. I have no immediate time frame on the project and did not think about short vs long water pump which might considerably complicate the project. I'd like to add a belt for the alt, not completely rearrange the pully setups. Again no rush, whenever your at home and think of it.

 

[AuroraGirl]

Currently have A/C not giving it up. 4 groves needed then.

No rush. I have no immediate time frame on the project and did not think about short vs long water pump which might considerably complicate the project. I'd like to add a belt for the alt, not completely rearrange the pully setups. Again no rush, whenever your at home and think of it.

AC and alternator would still be possible and in my opinion it enhances that if its on that side, if its off the side of the PS pump, then even tho it requires more it may be worth your thinking of moving the other accessory to the other side and make the ac have its own, but this requires the AC to be the tensioned piece, and sometimes the alt/ps pump may be used to take up that or provide some of the adjustment. pic?

 

[AuroraGirl]

Currently have A/C not giving it up. 4 groves needed then.

No rush. I have no immediate time frame on the project and did not think about short vs long water pump which might considerably complicate the project. I'd like to add a belt for the alt, not completely rearrange the pully setups. Again no rush, whenever your at home and think of it.

I have some assortment of the short(older is short right, usually) because my 400 from early 70s has what looks like a alternator, water pump, crank belt and then the AC it had used a simple bolt on additional pulley, i dont think it came with a ps pump but i wouldnt see you be able to line up a swp add on pulley over lwp regulars

 

[AuroraGirl]

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A little hard to see but the balancer "flares" outward and I believe that is a slightly larger diameter belt track than the one the crank has (the 283 to the left only has 1 groove on 3 parts, so not much there lol)

 

[SirRobyn0]

@AuroraGirl you might find this thought process interesting. So my thought is this. I don't want to go serp belt. For one thing it's new pulleys and brackets all the way around and costly. For another thing to me it looks out of place on an old rig, but.

I'd like to use a 4 grove crank pully in order to go to dual V-belts on the alternator, as well as dual belts on the P/S & A/C which it currently has from the factory. I had not thought about short water pump vs long. If the 4 grove pully requires a short water pump, then that's going to require a lot of reworking on the P/S & A/T side of things, and I'd like to leave that alone.

So if running the 4 grove crank pully requires a short water pump, I'd rather keep the existing 2 belts on the A/C & P/S and convert the alternator side only to a manually tensioned serp belt. Which would require changing the W/P pully and crank pully. I can't remember exactly the years setup like that from the factory, but I think it was the early GMT-400's, someone else might remember better than I.