[trucks_chevrolet]

Hello,

I am thinking about building a serpetine belt drive system for an old GMC big V6 using parts from a chevy small block. The problem is the reverse rotation water pump... Did any of the serpentine drive systems use a regular water pump? If anybody is asking why, basicly to mess with peoples mind. I am already working on installing a TBI fuel injection system and with the Serpentine belt drive a lot of people will be doing some head scratching. I already have a hard time convincing people that a 305 is not a 80's small block but a 60's GMC V6 engine. So I thought why not go ahead and really confuse em. By the way this is in a 65 Suburban

Darrell

[techinspector1]

My first thought is that if a guy has the ability to put EFI and a serpentine system on a V6, then he ought to have the ability to adapt a Chevy water pump.

[curtis73]

All factory GM serpentine belts are reverse rotation at the water pump

[Holder350]

not ALL serp pumps are reverse rotation IIRC

If the car has a slotted (groved) WP pulley its standard rotation.


Check out THIS thread. DoubleVision has some realy good advise, and some great pics in that thread to!

[joe_padavano]

Originally Posted by Holder350

not ALL serp pumps are reverse rotation IIRC..

Actually, all factory serpentine systems do use reverse rotation water pumps. This is done to ensure you have enough engagement of the belt on the pulley to turn the pump. Aftermarket serpentine kits are made for engines for which a reverse rotation pump was never available (such as Pontiacs or FE series Ford motors). To ensure adequate belt engagement on the water pump, these kits use a gazillion (OK, it's really more like three...) idler pulleys to force the belt into engagement.

It makes you wonder if all that extra clap-trap and complexity is a net benefit or not.

[Holder350]

Some ford and Lincoln systems were standard rotation for sure.

However they didn't have the nice auto adjusters that we're all use to.

Far left pulley is the WP pulley.

[woodz428]

[QUOTE=Holder350]

Some ford and Lincoln systems were standard rotation for sure.

However they didn't have the nice auto adjusters that we're all use to.

Far left pulley is the WP pulley.
[QUOTE]
Are those from an engine with a single belt?? The term serpentine usually applies to a single belt on all the accessories. That system looks like the one on an early 80s 302 that had more than one belt. I had an early 80s 302 in a rod for a while and it used at least 2 belts and did have a regular rotation water pump. I think of the single belt systems as serpentine. Some used the grooved belts, like a serpentine system, but had multiple belts. They are just using a grooved belt but don't actually fit into the definition of serpentine as it is generally used.
I see the crank pulley has at least two grooves and I see 2 V belts in the upper picture so I don't believe what you refer to is a serpentine belt, it just uses a grooved belt as one of the belts.

[Holder350]

no it is a multi belt system.

But it is a high tension serpentine type system.

Serpentine by definition is

An accessory drive belt, with small multiple v-ribs, routed around most or all of the engine-powered accessories.

Thats what I think of when someone says serpentine.

However IIRC there are no SINGLE belt standard rotation systems.

May be a matter of opinion on the Definition.

[trucks_chevrolet]

Hello,

The reason for looking for a standard rotation system is simple. Yes I could tear the pump apart build a new impeller and make it work in reverse. Then on a road trip pump goes out in middle of the night, unless I build two and haul one everywhere I go I'm stuck. Big 6 parts are not the easiest to locate anyway and I would prefer not to have a modified version of an already hard to find part on a truck I plan to drive a lot. I will have to modify or make brackets to make this work, and the water pump may turn this into a pipe dream.

Darrell

[joe_padavano]

Originally Posted by Holder350

...it is a multi belt system.

But it is a high tension serpentine type system.

...However IIRC there are no SINGLE belt standard rotation systems.
May be a matter of opinion on the Definition.

There are standard rotation systems that use multiple flat ribbed belts in place of V-belts. These are pretty much identical to V-belt systems except for the cross section of the belt. Some people call these "serpentine" systems, but I disagree. The term "serpentine" comes from serpent, meaning snake, which is what the belt looks like when it makes the S-shaped turn around the reverse rotation water pump.

Note the first two definitions from Websters:

ser·pen·tine /ˈsɜrpənˌtin, -ˌtaɪn/adjective, noun, verb, -tined, -tin·ing.
–adjective
1. of, characteristic of, or resembling a serpent, as in form or movement.
2. having a winding course, as a road; sinuous.

The flat, multi-belt systems neither resemble a serpent nor do they have a winding course.

By the way, one of the advantages of true single belt serpentine systems is that they are NOT "high tension". Belt drive systems transfer power with friction only, and the friction-limited power transmission to the pulley is governed by the contact area of the belt in the pulley, the circumferential engagement distance of the belt in the pulley, and the tension in the belt. One big advantage of a true serpentine system is that the flat multi-rib belt and the long S-turn around the crank and water pump pulleys increase the first two factors. This allows the tension to actually be LOWER for the same power transmission capability, which increases bearing life in the water pump and accessories (as well as decreasing parasitic HP losses).

Originally Posted by trucks_chevrolet

The reason for looking for a standard rotation system is simple.

Yeah, I think we all understand that.

Yes I could tear the pump apart build a new impeller and make it work in reverse.

Actually, no, you probably can't. Not only is the impeller different, but the internal shape of the pump housing would need to be a mirror image for it to work correctly.

Then on a road trip pump goes out in middle of the night, unless I build two and haul one everywhere I go I'm stuck. Big 6 parts are not the easiest to locate anyway and I would prefer not to have a modified version of an already hard to find part on a truck I plan to drive a lot.

I would guess that your chances of finding a STOCK pump for your GMC V6 from a normal auto parts store would be close to zero anyway. I think the suggestion of adapting a newer model reverse rotation pump solves both problems. You get the pump configuration you need for the serpentine drive and you get a much more common water pump.

I will have to modify or make brackets to make this work, and the water pump may turn this into a pipe dream.

Since you want to have a reliable driver (and I applaud that), why screw with hand-made brackets and pulleys anyway?

[Mustangsaly]

GM 4.3s and 5.0 & 5.7s the serpentine belt systems turned the water pump shaft in reverse, but the water pump pumped the water in the standard direction.




heres a serpentine belt system A/C by pass Pulley
http://cgi.ebay.com/ebaymotors/ws/eB...2BSI%26otn%3D4

[curtis73]

You could buy two pumps and modify both. Carry the spare.

Another thought... Were those ever used in marine applications? If so, chances are there are marine water pumps available. Marine water pumps don't have any angle on the fins of the impeller. They work equally in both directions.

Having said that... they suck at flowing water. They're designed to create supplemental circulation in a marine block that already has a separate water pump in the outdrive. But, if your V6 isn't too hi-po, it might be adequate.

[joe_padavano]

Originally Posted by Mustangsaly

GM 4.3s and 5.0 & 5.7s the serpentine belt systems turned the water pump shaft in reverse, but the water pump pumped the water in the standard direction...

Not sure what your point is. Do not confuse "reverse rotation", where the pump is turning in the opposite direction, with "reverse coolant flow", as used on some of the SBC LT1 motors. That's a completely different and unrelated issue.

If you look at the inside of a water pump, not only are the vanes (usually) angled for a specific rotation direction, but also the internal shape of the casting is designed for that rotation direction as well. Reversing the direction of the impeller usually requires the casting to be changed to match.

[fiscus]

This thread seems to be going in a lot of different directions at once. I want to comment on the SBC water pump topic, there does exist a standard rotation water pump setup with a serpentine type belt. I have seen it in person on a canadian '86 cutlass with a 305 engine. It had a serpentine belt going around the crank, water pump and alternator, and a v-belt for power steering. There was no tensioner, and it used the old-style alternator bracket to get the belt tight, and the regular water pump.

Here's some pictures of a pair of pulleys I have lying around that I think are the ones I'm talking about.

[woodz428]

Once again the use of 2 belts pretty much removes it from the common usage of "serpentine" Serpentine belts are single belts that drive ALL accesories. What you have there is much like the early Ford transition belts, but not what is known as a serpentine belt. I looked at some early manuals on the 302 from the 80s and they weren't referred to by Ford as serpentine, it was ribbed and V-belt drives.Virtually every serpentine belt system will drive off both sides of the belt, that one doesn't.