Customs Buick Straight 8 Gurus...advice needed

I'm installing a Vintage Air system in my '41 Buick Super and I'm figuring out whether to run the compressor off the crank pulley or the water pump pulley. Engine is a '49 248ci straight eight. Either way I'd have to make a pulley (or find one that was the right size). Are any of you familiar with the bearings in those water pumps, and do you think that running the compressor off the pump would put too much stress on it?

Alternately, is it possible to separate the harmonic balancer from the crank pulley to weld a second pulley for the compressor in between the balancer and the stock pulley? I haven't had the balancer/pulley off so I'm not sure how it's assembled, but it looks like there's enough clearance to add a second pulley in the middle and push the balancer about an inch forward.

Thanks.
Curt

 

I have given some thought to that issue and while I have not gone so far as to finalize a design, I have a suggestion. I think it might be feasible to drive the A/C compressor from the crank pulley directly and solely. Using a common dual sheave compressor clutch pulley, drive the water pump and alternator from the second A/C sheave. Gives maximum belt wrap for the A/C pulley, and can be tightened sufficiently without damage, and it should also be more than adequate to drive the pump and alt.

 

Thanks for the reply Ray. So you're saying one belt between the compressor and the crank, and a second between the compressor, pump and alternator (or generator)? I would think that would require spacing the water pump pulley and repositioning the alternator forward to align with the outer sheave of the AC compressor, correct? Just wondering what the advantage is of doing all of that versus just finding or making a dual sheave pulley for the crank or the water pump. (Making one for the water pump seems easier if bearing wear isn't a concern.)

 

Yes, you got the pulley/belt idea. I would expect the alt/gen to be stacked on the A/C pump mount on the driver side of the block. The water pump pulley would have to aligned accordingly, of course.

It was/is just a musing about an alternative to the very issue you raise......providing an extra sheave on the crank dampener...which may pose some spacing concerns on a stock Buick installation.

Eventually, I will be dealing with this and have to choose a solution.

 

Initially I was planning to run the alternator and compressor on the driver's side like you mentioned. But with a second sheave (either on the water pump or crank) there's actually room to run it on the passenger's side. It would require re-routing the radiator hose, but it would allow me to run all the lines (AC, heat) down that side and keep the alternator in the stock location (I'm running a PowerGen). Regarding crank pulley spacing, it appears there's about an inch below the balancer and about two inches in front of it to work with.

 

However it works out, I feel pretty certain that I will not use the water pump to drive the compressor. I think that is too much of a load on the pump to risk it.

 

I did something like this with mine. Driving the comp and water pump off crank and alt off compl . Several thousand miles and no problems.

Ben

 

Now, how do we drive the p/s pump? Maybe electric P/S.....

 

Ray, there is a firm in the Dallas area that makes a "power gen" type alternator with the P/S poump built onto it ala the mid-late '50s Chevy. Power Gen does not offer this. This firm also has a complete kit, for some apps, to add the P/S. It uses a [supplied ] ram to the drag link.

Ben

 

You ran the alternator off the compressor? Do you have any photos you can post? Interested to see how it's set up.

 

Back up. Interesting project.

 

Curt, I answered you over on Team Buick. Will do so here as well.

Thought I had pictures. I have searched with no joy.

The two groove pulley comp is mounted on the original generator bracket. Used spacers to align the inner groove with water pump and crank pulley. The alternator is mounted a top the compressor on a homemade bracket/mount. It is driven from the outer compressor pulley.

If I do not find the pics soon I will try taking some. My middle name is procasterntor, though.

Ben

 

Thanks Ben. Did you have to change the water pump and crank pulleys in order to run a smaller belt? The only Vintage Air compressor I found that will accept the big belt that's on the car is their single sheave "wide groove" pulley. I would think that running a smaller belt on the stock pulleys wouldn't work because they'd bottom out, but I'm interested to hear what you did/what your experience was.
Curt

 

Yes, on the narrow pulley. I have a '51 engine in mine, so it has a narrow pulley. They are not too difficult to locate. Serpentine would be the way to go!

Ben

 

Just did a quick search and it looks like they were narrow pulley from '51 forward. I actually have a narrow water pump pulley in my garage. If I can find a '51-'54 crank pulley and balancer, can I just swap that onto the '49 engine? (Just making sure the balancer isn't matched to the engine on those...I wouldn't think they would be.) If so, then I like the idea of the dual sheave compressor pulley...one belt for the pump, crank and compressor, one for the compressor and alternator. @Hnstray do you know if the '51 263 balancers interchange with the '49 248s?

 

Backward compatible for sure.

Ben

 

As it happens, I have a ‘49 248 engine and a couple of ‘53 263s, so perhaps I can pull the the pulley/dampener from the ‘49 and check it out. I would be willing to bet, though, that it will fit.

Edit: I see Ben answered that question in the post that followed....

By the way, that lump on the front is not (in this and most cases) a ‘balancer’...it is a ‘dampener’.......it is dynamically balanced as is, but is a specific weight chosen to dampen the natural harmonic frequency of the engine that may occur in the useful rpm range.

 

Awesome, thanks both for the info. I think we have a winner. Now I just need to track down a '51-'53 dampener/pulley. You wouldn't want to sell one of yours would you @Hnstray ? Had to ask!

 

Don’t have any spares.......sorry....

 

No problem, I appreciate all the info and help! Keep you posted on progress.

 

@Hnstray @firstinsteele interesting option...I found a guy who's sending me a dual sheave crank dampener from a '52 263 that had power steering. This way I can run the compressor (mounted low) off one, and the pump and alternator (mounted high) off the other. It will require a fan spacer, but otherwise seems pretty straight forward. From what I understand, there weren't a ton of 263 power steering set ups in those years...pretty neat.

 

That’s a great solution! I sincerely hope that works out.

Your post is very timely. I was looking for this thread when I got the alert. This afternoon I spent a little time examining both a 263 and the ‘49 248 crank dampener....along with a couple of aluminum pulleys I had previously picked up at swap meets, one is a two sheave and the other a rhree sheave.

The construction of the stock Buick dampener/pulley is an assembly consisting of a hub and flange (one piece) and a number of thin round plates and a sheet metal pulley, riveted together. The hub/flange piece and the thin plates are riveted together with four rivets. The sheet metal pulley is also riveted to the hub with an additional four rivets.

One potential solution to adding a sheave to the dampener assembly would be to first disassemble it, remove several of the thin plates from the engine side, thinning it, and adding the dual sheave pulley and riveting the respective assemblies in the manner they were originally. This method adds an additional sheave without increasing the total thickness of the assembly while permitting retention of the original sheave alignment.

Now, the question comes to mind....how does this affect the dampener’s effectiveness for it’s original prurpose? I have no formal engineering training. But I am willing to risk the dampener, as modified, will pose no problem. I believe this, in part, because the dampener was originally designed to cope with harmonics of a specific rotating mass. Even without the dampener mod suggested here, the rotating mass will be different from the original engine/drivetrain because of an adapter kit that permits installation of either a stick or automatic transmission and the corresponding coupling parts.

 

Please post a few good pics of that dampener/pulley when you receive it. I am very interested to see how it is constructed. Thanks for mentioning what you have found.

 

Interesting! I was under the impression the Roadmaster was the only one with the P/S as an option. The dampener/ pulley will probably still work.

Ben

 

Sucker hs a lot more pieces, Ray. Will attempt adding pics.

 

See those "bars" in the openings in 5907-5908? Each "bar" is a pack of several spring steel pieces. I think these are what absorb the damaging pulses the Buick engineers were concerned with . My son and I were trying to replace the Sheave with a double one.

Ben

 

Ben,

WOW! Those photos are really interesting! I knew the 'disc' portion of the dampener was laminated plates, but had no idea that the internal sections looked like that. Thank you for posting.

Obviously that is a more complicated device that I suspected. I thought just having the visible laminated discs had something to do with vibration absorption, but bars pressed into the internal holes is a level of sophistication I didn't anticipate.

In my simple minded homespun 'engineering theory', I thought it possible to just reduce the number of laminated plates, narrowing the hub to make room for a double sheave pulley. I do suspect though, that the long crankshaft may have a more pronounced harmonic than a shorter shaft. The question is, at what rpm range did/does that harmonic vibration occur?

Dodge 241/270 Hemi V8's have no harmonic dampener and there have been reports of crankshaft failure attributed to that. Any of the MOPAR guides to building suggest that one retrofits a dampener from a later LA series (318/340) engine to deal with that.

I guess my under educated notion was that any dampener mass was better than none and the total mass was going to be different than stock anyway as the transmission end was all to be replaced with small block Chevy parts, whether stick or automatic. Looks like Curt Six has come up with a possibly less risky, but hard to find, solution with the factory double sheave dampener.

Any real life engineers on the HAMB that can weigh in on this topic??

 

Not shown is another item that complicates it further. The brads are shouldered, therefore allowing only so much squeeze on the parts.
I am leary of the dampening effect after so many years. Things are/were pretty rusty.

Ben

 

You and me both! That's pretty cool...thanks for the photos Ben. Regarding what cars had power steering, I'm having trouble confirming this 100% because there's conflicting info out there, but I have found a few places that said in '52 it was optional on Roadmasters and Supers, and one source listed production numbers of a few thousand Supers (with the 263) equipped with PS.

I'll post shots of the dual sheave dampener when it arrives...should be Saturday or Monday.

 

Here are some shots of the dampener off of the '52 Super (263cid) with the power steering option @Hnstray @firstinsteele. It is 2" deep (same as the original), and it's 1/2" wider in diameter (8" where the original was 7.5"). Because the second pulley is in front of the dampener I'll need to space the fan slightly so it will clear the belt and the dampener.

It was pretty salty when it arrived (first pic) and I don't have a blast cabinet here, but it cleaned up pretty nicely with a wire brush and an overnight bath in that Metal Rescue stuff. You can see the dampener itself is thinner than the original (fewer plates)—think there's any issue there? If it came off a 263 I wouldn't think so.