Hot Rods Fitting A Sanden Compressor to Cad 500

I have a 1976 Eldorado 500" engine with a Bulldog manifold and I want to install a Sanden AC compressor. I've found that the AC bracket for a 1980-81 Cad 368 engine using an R-4 compressor might be able to be modified slightly to accept the Sanden. The R-4 is yesterday's technology, is noisy and not the most reliable. Plus, even if I used the R-4 I'll have to rig up some bracketry.
It appears as though I may be able to get the Sanden mounted, solid with no way to tension the belt. I am using a 1/2" belt that matches the engine's pulley. I am not using power steering so there's a chance I may be able to use the PS bracketry and install a belt tensioner.
Do I want the tensioner on top of the flat belt, or under it, or would either way work. Looking for suggestions on what tensioner to use. I realize I'll have to make brackets, do some welding, machining, etc. but thought I'd ask the group for advice. Photos show the R4 bracket plus a Sanden unit with tensioner. I can't use the tensioner pictured as the distributor is in the way. Not sure what compressor is used on AC Bracket 2 photo but it looks like a home made bracket to attach the back of it to a manifold. My compressor may JUST clear the water neck inlet, so I've got problems. But here in Indiana, I sure do want to have AC. The LaSalle AC bracket 3 is the R4 compressor.

 

I don't know if it will work with that intake but this one is for a 500 with the Edelbrock intake like what I have for my OT truck. Vintage Air Search Results - Vintage Air
Back in the mid 70's I worked in a shop in Texas that took a lot of those small GM compressors Like the on in your photo off and replaced them with the larger older style compressor so the would cool right. That isn't what you want but it brought back a memory of doing several of them.

 

Consider pivoting the Sanden compressor to maintain belt tension. This is on an extremely off-topic engine, but a variant of this mounting technique might work (much fabrication required). Shown is and air conditioning compressor mount from a 1990 Oskosh van. I found it on a diesel website, I have never seen another one for sale.


The Sanden pivots on both the front and back ear - the 1/2"-13 threaded rod tensions (pushes) on a front ear, with a clockwise rotation. This was too tall and did not clear the hood.


Plan "B". The Sanden compressor is hung over center, and the 1/2"-13 threaded rod tensions (pulls) on a front ear, with a counter-clockwise rotation. Note the Grade 8 pivot bolt with a portion of the head cut off to clear the clutch ***embly. I have 37 states on this set-up.


I went through a few trial-and-error attempts. In this picture, 1/2"-13 thread-all was not quite up to the task. I ordered B7 threaded from from Granger (I think the shipping cost more than the rod). I also discovered 1 long through pivot bolt gave me better alignment than 2 individual pivot bolts.

Russ

 

I SORT of see what you've done but since I can't see the end of the threaded rod (I think you are saying I need a good grade of rod..not familiar with B7) and not sure how you are connecting the rod to the ears...but at least you've set me to thinking. I believe the Sanded should have its ports at 90 degrees upright when it is in running position. I have considered pivoting the unit and it's good to see yours is working fine.

 

Carl,

B7 is a threaded rod grade, somewhere between a Grade 5 bolt and a Grade 8 bolt.

I found some old pictures on my computer (about 9 years ago).

>> ... should have its ports at 90 degrees upright when it is in running position.

Upright ports have caused me clearance issues in previous installations. I ordered my compressor with end ports.
Easier to plumb up the refrigerant lines on a 4 cylinder engine...


Setting the belt tension is critical. Too little and the belt slips. Too much and you break things...
Looks like I'm running about 40-45 pounds.


This was my first attempt - the aluminum bar is for measuring hood clearance. The eye of the turnbuckle pivots on an ear of the Sanden compressor. The hook of the turnbuckle slips into an ear on the mounting plate.
A TOTAL AND ABSOLUTE FAILURE - The turnbuckle snapped in the first 1,000 feet of driving.


This is actually the 2nd turnbuckle - note weld on eye. On the 1st turnbuckle, the eye opened up before the belt reached proper tension <sigh>


This picture shows the detail at tension side ear. Note that the shank of the bolt goes completely through the ear and the hole in the adjuster. No threads rubbing on the ear or the adjuster. If you look closely, you can see where the shank ends and the threads start. The 2 washers are spacers to keep the nylon lock nut away from the shank. Sometime later, I upgraded to Grade 8 bolts - probably when Tractor Supply came to town...

Russ

 

You're great Russ, sure appreciate your work for me. The turnbuckle looks a bit agricultural and I'll bet it was a Damn! moment when she came loose. I have a new Sanden with the ports on top, and I'm replacing an R4. The R4 bracket just nearly fits the Sanden and with a bit of grinding I think I can make the Sanden secure, but the unit won't be adjustable, so I was thinking of installing a belt tensioner using the PS mounting holes for bracketry..I don't have PS, so am thinking I can put the tensioner on top of the V belt and tension it that way. I really didn't know how much tension to use, so your knowledge is coming in pretty handy. Body is off the frame so it's easy to work on. I'll get the Sanden mounted and then really hope I can get the tensioner to work. If not, I'll have to re-engineer so I can get the ports on top, under tension. Plus I won't be able to test the plot until I fire up the car, which will be several months down the road. Never heard of grade 7, so I've learned something. Tractor supply here doesn't have any fine thread bolts, which I probably don't need, but I've worked with a lot of grade 8 bolts over the years. This is an interesting project, but I don't have access to a Bridgeport, lathe and heli-arc as I've had in the past so I'm in hackit and weld mode. Thanks again for the help. Will let you know how I come out. Should have some progress in about a week, waiting for the special bolts-studs for the R4 bracket.

 

I have modified the 368 R4 front bracket for a Sanden in the past with a fabricated bracket on the intake, and it worked fine. It was a solid mount

 

1962 Volvo. Right idler pulley is smooth, rides on the back of the belt and holds the belt off the steering box. Upper-left idler pulley is grooved and pivots to tension the belt.

Russ

 

My 54 Chevy air conditioning system has given me fits. I replaced my R-4 setup with a Sanden last week. I had been through 4, R-4 compressors in the last 3 years. The one prior to this did not last 15 minuets. The Sanden works so much better. I hope it will last.

Although I was able to use the factory tensioner, I could see that a pivoting adjuster could be fabricated. Although the spring loaded tension does allows for some belt stretch as the belt ages. My R-4 set up had an additional bracket that went diagonally back to the exhaust manifold. I choose not to use that bracket on the Sanden. So far I do not see a problem.

 

Am wondering what the right idler pulley, the smooth one, came from. It appears as though I may be able to buy JUST a pulley with a bearing in it and make a bracket that allows for tension. The challenge of course is mounting the pulley which I think I can do off the original mounting bolts for the PS pump. If not, I will use the type of idler pulley you have. Thanks again.

 

I was able to grind the R4 mounting bracket, off a 1981 Cad 368 to fit the Sanden. I ground a couple of half ovals next to the top mounting holes and they allowed the R4 bracket to be bolted to the Sanden. Thus now all I need to do is make an idler-tensioner
which I believe I can do with just another pulley that I'll mount to a bracket, with a slot for adjustment. Hopefully I can make the bracket fit the original PS holes. Am now awaiting the original bolt-studs that mounted the R4 bracket to the water pump. One end of the stud is 3/8--the other 5/16" and there are three of them. The man who sold me the brackets went back to the engine and found the studs still installed so he's sending them. Will know how I fare next week and will post some photos. Thanks to all for the RAPID help, it sure is appreciated.

 

I have a good friend that closed his auto AC shop and worked out of his carport (semi-retired). He had a box full of unused and take off idler/tensioner ***embles and pulleys. I found a used ***embly and got a new smooth pulley from a good local independent parts store (took a couple of washers to space the pulley out a bit).

The upper left pulley came with a pile of used 1970's Volvo parts - the replacement V-belt pulley came from that box of parts (never used).

This link should give you some ideas.
https://www.4s.com/en/ecatalog?part=Idler / Tensioner Pulley&type=p

A good counter person (not the "Studebaker - Who makes that?" kid) should be able to quickly identify a part that will work.

 

I was just at a NAPA store, the most knowledgeable guys I've ever found, and they showed me one of the pulleys you linked me to. Thus I hope to get a grooved pulley and space it to run true with the belt soon as I design a bracket that will go on my 500 Cad engine. Now just waiting for the two-size mounting studs to bolt up the R4 bracket to my water pump and hopefully it'll all work. This is all going into my '37 LaSalle Opera Coupe, the same car I drove through college in the 60's, got it back and took out the flathead. Doing a total restoration and since I now live in Indiana one needs AC . Thanks again.

 

The one question I would ask is whether you could mount the A/C compressor lower and on the side of the engine. Then you wouldn't have the A/C lines running around on top of the motor and would have a cleaner looking installation. I'm working on a couple of Cad 500s for some projects and thats how I hope to do it. As for the tensioners, many of the later model vehicles have spring loaded tensioners that are pretty inexpensive to buy. One or two bolt mounting. I'd put them toward the smooth side of the belt so yo don't have to get exact alignment with a grooved belt.

 

You make a great point about mounting the compressor lower. For a long time I planned on mounting it in the trunk with a 12 volt DC motor running it, but those plans went haywire. Thus I wound up with a nice Sanden with ports coming out of the top. Since I no longer have access to a Bridgeport, lathe, heli-arc, metal cutting band-saw, I'm a bit limited on how much time I want to spend on the whole plot and am seeking an easier way out. I also considered a Ford 9" rear end that has a pulley already installed and running the compressor from the drive-train. I'd like to have a cleaner looking installation, but at age 77 I have lots of projects to finish so this one won't be quite up to my standard, but at least the hood is closed when I'll drive the car.

 

On my 472 Cad in my 49 Buick, I used the Vintage Air bracket. Fit perfectly, works great.

 

Hi: Since Vintage Air makes dozens of brackets it is impossible to figure out which one you are referring to. Photo? Part Number?

 

I can’t help you on this project, but I am a fan of these engines. I want one.

 

Just look for the mount bracket for a 472/500 Cad for a Sanden compressor in Vintage Air's catalog. There is only one.

 

Vintage Air
#15500
#15501
I not sure they will work with your custom intake manifold.

 

Thought I remembered a low clearance fitting option - did a little Google searching, found these - made by Vintage Air and sold by Summit.


https://www.summitracing.com/parts/vta-366102
Available in #6, #8 and #10 sizes. A little expensive, cheap if you need a couple extra inches of hood clearance.

Russ the younger (got a couple of months until I get to 77 )

 

This is a tensioner from mid 90s 5.7L chevy truck. GM used this style all thru the 90s on all types of engines so theyre easy to grab from a junkyard for mockup and youll find various diameter pulleys.

Moint is a thru bolt and a second hole for the pin, pin orientation sets position, spring set tension
This style can be used in a lot of places. Pretty simple mount compared to other options.
Hope that gives some ideas.

 

At least some of the brackets offered by Vintage Air are from Alan Groves Components. I don’t see anything listed specifically for Caddys at the alangrovescomponents.com site, but you might look at other options there and find something you can modify to work for your application.

John

 

Just searched the Vintage Air catalog for Cad 472-500 and cannot find ANYTHING relating to a Cadillac engine..but I'll keep looking.

 

Here are the Vintage Air part numbers:

 

I don’t see anything for Cadillac either, but if you look at some of the brackets for other engines you might see something you can modify for your use. I did that a while ago and for me it was easier than building a bracket from scratch.

good luck - AC will be a good thing !

John

 

I gave you guys the Vintage Air numbers twice. Search on them, you can find them, I know you can do it.

 

You might try this website and ask some of the guys what they are using. https://www.facebook.com/groups/336332916491805/media

If you need some minor mod for a bracket to do what you need, let me know and I may be able to help.

 

EDIT: Fix link
https://www.vintageair.com/custom/product-pop.php?pn=15500-VCB


Cadillac 472/500 Cu. In. with Edelbrock manifold compressor and alternator mount bracket.

https://www.vintageair.com/custom/product-pop.php?pn=15501-VCB


Cadillac 472/500 Cu. In. with stock manifold compressor and alternator mount bracket.

And from Post #1 above:

Bulldog manifold - I do not see a place for the rear support bolts/sleeves on either Vintage Air adapter.


Stock Cadillac AC mount - If you modify this, I "believe" that the Sanden will still need a rear support of some sort.

Russ

 

Hi: I have just ground a couple of 'ovals' on the R4 bracket, next to the large mounting holes on top to give clearance for the bracket to bolt to the Sanden. It appears as though my mod will work, and then I'll have to figure out how to stabilize the back of the Sanden as you did. I'd like to see a photo of what you've done if at all possible. It looks like I may be able to use my Bulldog manifold but not sure as I don't yet have the 'studs' that mount the R4 (just found them, they're 3/8" on one end, 5/16" on the other. If all else fails I'll have to use the stock manifold which I'd rather not do. I did not use the power steering pump initially, which would have given me the tensioner adjustment I need, but now I am considering using the stock PS mount and pump and just using the pump as an adjuster. I can route the feed-return lines into one another so the pump will turn but not use as an actual pump. Then again, I am considering using half of a rack and pinion, feeding it onto a tie rod to give me power ***ist. I can do that mod later, but for now I'm concerned with getting the Sanden mounted so the belt is adjustable.