Pontiac Serpentine Conversion - DIY???

[Jeffrotech]

Hey - anyone do their own Pontiac serpentine belt coversion?

I'm sure that there are enough GM factory parts out there to make it work without too much trouble. The alternator and p/s pump being the easiest to get. After that - a crank & water pump pulley and the rest is alignment!

Just though I'd check if someone has done this already before I embark.

It'll beat paying $600+ for a March kit that I would want in black anyway!

Thanks.

[wmhjr]

For what motor? I'd be surprised if you would be able to bolt on factory parts to a traditional pontiac standard block. To the best of my knowledge, there has never been a "factory" serpentine on a standard block. The block and head geometry is totally and completely different than on any other engine. If you're talking about a GM "corporate" motor and not a traditional pontiac, then sure. But not for a 326/389/400/455 based motor IMHO.

[Jeffrotech]

Pontiac engine - meaning 326/389/400/455. I figured that would be assumed since I called it "Pontiac". A SBC is a SBC no matter what it ends up in. To be specific, the 1969-1981 Pontiac V8s.

I'll be putting together a conversion using factory parts. When I say that, I mean I will find (most likely) SBC and Buick 3.8 parts that I can retro fit.

[wmhjr]

Since you didn't specify, and since people use a "pontiac engine" term in so many ways, I did not want to assume anything. First 3 letters of "assume", right? Technically the corporate motors are also "Pontiac" engines and qualify as such even in "Pontiac Only" venues such as POCI. That's why I asked.

It'll be interesting to see how this turns out. I'll be a little surprised if it turns out to be very simple. Block and head geometry of these motors is already a little bit of a PITA when it comes to accessories. I really did NOT want to go to a March setup. However, after playing around with some alternatives along with dealing with the modifed clearances due to aftermarket heads, billet valve covers, high lift, etc, I realized it was a little trickier. I could have machined some spacers and tried to move things around but was concerned about throwing belts after doing so. Also, don't forget - you're going to also need an idler pulley. It will need to be either a spring loaded or an easily adjustable idler tensioner.

At one point there was a lot of discussion over on PY about this. To my knowledge, nobody over there ever completed one.

[Lowend]

Pontiac blocks went away in the late 70's. I don't think GM really did a serpentine setup until ~1986.
Seriously doubt any factory stuff will bolt to Pontiac

[Jeffrotech]

Pontiac blocks went away in the late 70's. I don't think GM really did a serpentine setup until ~1986.
Seriously doubt any factory stuff will bolt to Pontiac

And THAT is exactly the point to this thread!

I assumed that it was painfully obvious that no Pontiac engine came from the factory with a serp belt. Hence my reason for calling this a DIY, and not using an off-the-shelf kit from March (nothing against March - I think they make nice stuff!).

[wmhjr]

I thought it was painfully obvious that the comments were really just providing an opinion that it will not be as easy as you allude to in the OP. IMHO the most recent post was just pointing out that brackets (including the specific ones you mentioned) will not bolt up and that as opposed to the OP, it isn't a matter of just finding some brackets and aligning them. Frankly, it may be easier to fabricate brackets rather than to try and retro-fit brackets from a different motor.

I truly hope you are successful. If you are, I would encourage you to also post your results over on PY, as even though it is the largest Pontiac only site in the world with huge amounts of extremely deep expertise, nobody there has seemed to successfuly done it. There are threads where they talked about it, but no results and that's a site where some really crazy things have been done to Poncho motors. If you do, please also note whether you're building a long nose water pump or short nose pump.

[Jeffrotech]

O.k. - all comments & feedback are welcome. I'll clairify what I meant:

I'm sure that there are enough GM factory parts out there to make it work without too much trouble. The alternator and p/s pump being the easiest to get. After that - a crank & water pump pulley and the rest is alignment!

1. Take any GM serp alternator (easy)
2. Take any GM serp p/s pump (easy)
3. Grab a handful of wp & crank pulleys from various GM cars, and redrill (and/or machine the center bore) the best/closest matching ones. Shim out either to get 'em in line.
4. The rest is bracketry. Yes, a bit of fab work needed here, but with a combo of the v-belt Pontiac stuff, and a few serp pieces, this shouldn't be horrific.

I have a 400 sitting on a stand (yes, a Pontiac 400). Once I get my new water pump and balancer, I can get cracking on the wp and crank pulleys.

I've seen some impressive fab work on this site, so I am kinda surprized that nobody has tackled this one yet. Then again, there are also some project budgets on here that are a tad out of my reach! Maybe most builders have the funds to get an aftermarket kit.

[wmhjr]

OK, to help out here's some thoughts and feedback and some issues to consider when you're doing this....

1) You're going to need to work from 2 directions. Example: Depending on the car you're going to use the motor on, and the radiator in the car, and the mounting system of the radiator, and the valve covers you use, and if it's an AC car or not (assuming no AC since you haven't mentioned it.... here are some of the clearances you'll need to consider:

a) Space between center shaft of alternator and valve cover. If you're using tall and/or "thick" valve covers, there can be clearance issues between the back of the alternator and the valve cover.
b) Nose of water pump pulley and radiator/fan. The pulley - if too far forward - can easily impact an electric fan motor if it's a center mounted fan. If it's not an electric fan, it can move the entire fan too close to the radiator.

Ask me how I know these..

2) You're going to need an idler. You keep forgetting that part, and it is absolutely critical. You CANNOT use a serpentine system reliably without using an idler. It will be a miserable and unreliable situation. At close to 600hp, I've got way too much time, effort and money in my motor to risk it.

3) You're going to find that you'll have to weld extensions on most of the brackets that are not designed for the old Pontiac Standard block. There is insufficient material in appropriate mounting locations for other brackets to be drilled to fit in most cases. Again - ask me how I know....

4) Alignment is absolutely critical. The tricky part here will be to find a good quality crank pulley and water pump pulley that take a serpentine, that can be made to match each other, and that allow an alignment that's close enough to allow you to somehow space out an alternator, PS, and Idler pulley - all while maintaining not only correct depth - but correct alignment - and that can stand up to vibration, etc.

The reason that nobody has tackled this is because of the fundamental question - why would they? Even high dollar serpentine systems can have issues. Rodney Red sold one (and still does) but doesn't even market it because of the PITA it is to get correct. Call them and ask them. There's no way in the world I'd consider trying this just because I can't figure out why it would make sense after thinking through it. If you're a Pontiac guy, I'm assuming you also know about the PY board, right? Check it out and search on this subject.

I honestly would enjoy seeing somebody try this and succeed. If there is a combination of OEM type parts that could be made to work reliably, I'm sure there would be interest. Again - if you do, make sure to note which length water pump nose you have.

[68byrd]

Great idea! I hope you get it to work. We were thinking the same thing for the byrd. Just need the time to sit down and do it. Good luck!

[67 455 Bird ragtop]

The previous posters were correct. There were no factory serpentine setups for Pontiac engines. I found a fairly inexpensive one several years ago that I have on my 455. I got it from Rodney Red. Since I haven't got my motor running yet I can't testify to how well it works. But others have used it and liked it. I'm also not sure if they still sell this kit. You might try posting on a Pontiac site like performanceyears.com or pontiaczone.com and see what others have to say. But definitely keep us informed as to your progress.

[delmech]

Hey Jeff- I just read your inquiry about the pontiac serpentine conversion and although it was a while ago I thought I would respond if you are still looking. I took an Alt., P/S pump and idler out of an 86 astro van a couple of years ago and as you said- made a crank and W/P pulley from some other pulleys for about 50$ each and have been running it on my 68-400 for a couple of years with no issues. The Idler is solid mounted and the P/S pump mounted right in the original aluminum bracket so that is how I tighten it. Looks clean and if you want I could send you a picture.
Curious minds are a good thing.

[Jeffrotech]

Delmech,
This little project got sidelined by some other stuff that is far more important... so I haven't had the time to hit a junkyard.

Thanks for the input. I knew someone out there must have slapped something together. Your setup sounds like what I was thinking. Do you remember what you used for the w/p & crank pulleys?

Pics would be awesome. jeffrotech at optonline.net

Thanks again... much appreciated!
Jeff.

[67 455 Bird ragtop]

Ditto on the pics. Please send to [email protected].

[LONE*STAR]

I have been kicking around getting rid of my dual v belted drive on my 67 firebird 400 when I replace my PS pump (not up to par with the new hydroboost). I would like to ditch the water pump for an electric as to accomplish the limited drive accessory's. I really like the industrial look of the 1 1/2" belt drives used in supercharger setups.... Probably never get around to actually doing the mod but it sure would be sweat.

[Concept One Pulleys]

Jeff--

Did you ever get a chance to get this project back under way? We would love to offer some advice, if necessary.

Regards,

ConceptOne Pulleys
Cumming, GA
American Made, American Owned
Pulley Systems

[Jeffrotech]

Hey C1,
Still no... I have the motor sitting on a stand. Life is busy, and this car is a long term project.

I would certainly appreciate any input you have though! I took a look at your website - nice stuff, but no Pontiac goodies. Are you working on something? Would you like to?

Thanks.

[jimmo]

I know this thread is pretty old but I am new to the board and found this doing a search on the subject. I am currently trying to fabricate my own serpentine system for a 2nd gen trans am with a pontiac 400. If anyone is interested, so far, as previously mentioned, there are a ton of alternator and power steering pulleys to choose from so that part is not a problem. I did find that a 5 litre ford engine, not sure what year, has the closest crankshaft and water pump pulleys and would need minimal machining. I collected a bunch of pulleys years ago and am just now getting to this project. This is why a cant remember the exact cars all my pulleys came from.
This set up does move the belt a little too far forward for the alt and power steering which will need a solution. I am thinking about spacing the alt & psp by machining a solid spacer from aluminum and mounting it to the front of the left cyl head. I just started the project and my ideas probably will change as it evolves. I plan on it being finished for the good weather in a couple months and if anyone is interested in the details and pics just let me know. Oh, I do plan on including the a.c. but that part will probably require changing the compressor. Ill cross that bridge later as I need a new condenser so the a.c. is currently not working anyway.

[MARBIL]

I am all for resurrecting this , going to be putting a “old” 455 motor in my 69 bird and want the same thing more factory look ,not a big fan of all the billet stuff , not that it isn’t awesome just not the look I want.
Im a ways off of doing my motor but this has been on my mind.
would love to see some pics from the guys that have done it

[coreybrenner]

I am all for resurrecting this , going to be putting a “old” 455 motor in my 69 bird and want the same thing more factory look ,not a big fan of all the billet stuff , not that it isn’t awesome just not the look I want. Im a ways off of doing my motor but this has been on my mind. would love to see some pics from the guys that have done it

Definitely! Please resurrect, and please post pics! This is important information for Pontiac gearheads! --Corey