The Stovebolt Site Forums The Shop Area Driveline 261 and AC

Seems I'm never without a project that needs to be finished. And then more pop up. It's happening again. We stumbled into a very small cash nugget and my half (Mrs. Kathy gets the other) may well go into freshening up a 1959 casting of a 1954 (no captain bars) 261 currently taking up shop space. The primary reason for getting the 261 up to speed isn't due to dissatisfaction with the 57k mile 216. No, it does everything we need it to do. Runs 60 mph just fine.

Air conditioning, that's where I suspect the 216 would fall short. So this thread will either have a mixed theme or will soon diverge with one path being a 261 thread, and a second for low budget AC.

Comments are welcome while the plan comes together.

Ron R

The first thing to consider will be installing some type of 2-sheave crankshaft damper to be able to run an extra belt. Drop me a PM for some suggestions on how to do that without finding one of the 235/261 2-groove dampers that are as scarce as honest politicians! If you're doing a complete rebuild on the 261, think about making a road trip to middle Tennessee to get the block machined for a full circle rear oil seal. If the 216 will be looking for a new home eventually, I'm interested.
Jerry

Jerry, thanks for the heads up on what I hadn't considered. The 261 does have a single belt damper, but it sure looks like it could be machined into a two-sheave.

RonR

I run A/C on my 250 inline, it uses a Sanden 508 compressor from Vintage Air. The amount of drag on the engine is so small I can hardly tell it's running, rpm drops maybe 100 at idle. Every summer I just adjust the rpm up slightly. These new compressor are not like the old 6 cylinder GMs. If you run the belts right, a single groove pull would work if you could get enough belt to pulley contact on each accessory you want to spin.

Joe, your single belt point is echoing a coilover post sometime back about air on his straight 8 Buick. As I recall, he mentioned a single belt driving the generator, ac and power steering. The ac I'm currently considering here claims a requirement of 4 hp. Sorta makes me consider installing with the 216 just to see how it works out.

And then there's 12V electric to consider. This kit would require an alternator upgrade. But that's gotta happen anyway since the '51 is still 6 volt with an alternator. The stated requirement is 75 amps, so using the 25 amp per HP rule of thumb, 3 hp to drive the electric compressor sure seems doable. HUMMMMM

RonR

A 2 sheave damper for a 250 inline six can be modified very easily to fit the 216/235/261. The high mount 216 style water pump can be machined to accept a 2 sheave pulley for a small block Ford V8. Having those extra pulley grooves really simplifies accesory mounting like A/C, P/S pumps., etc.
Jerry

I bought a 2-sheave pulley from an outfit in California several years ago. The damping rubber let go after a while and the sheave stopped turning. I'd seen them slip on the Ford pulleys which produced overheating problems that took a long time to figure out. Anyhow the Damper Doctor people replaced it at no charge in just a couple of days. No trouble since. Been ten years.

You really do need 2 sheaves. I had the single sheave setup I bought from Patrick's while he was living. It ran the alternator off the extra sheave on the compressor. It worked fine in the short term but the combination of loads from fan & WP, alternator and Sandon compressor wore out the belt too quickly. I'm still using the Patrick's brackets but there are a several problems with that. 1) the alternator is mounted too close to the exhaust manifold. Melts the grease out of the rear alt. bearing. So I had to make a heat shield.

2) The combination of belts requires that the AC compressor be swung so far out that it starts coming back in again if you rotate it any further. So I had to build a 1/2 inch shim to go under the compressor. It mounts on the old generator location.
3) The shimmed compressor location puts it and the lo side hose fittings too close to the exhaust manifold necessitating another heat shield.
4) The Patrick's alternator bracket only allows one of the alternator pulley sheaves to be used - The front one. Since I haul a camper with two golf-cart batteries for the house batteries, he alternator is called on to charge the house batteries if they are low and it really should be driven by two belts. Without the load of the house batteries things would probably be OK as is - Except, except that when the AC/heat system is in defrost/de-humidify mode it runs the compressor and the blower fan and it's usually raining so the lights are on, including the running lights for the camper, oh and the wipers, which now are electric, and after a while if you're in traffic, whenever you pull off from a traffic light the belts set up a howl like a hound with a coon up a tree. It eventually stops but it's annoying.

Since you won't be buying Patrick's brackets you won't have my specific problems but other bracket kits may cause similar problems. So mine is a list of things to watch out for. There are many pitfalls. I ran into a similar set of problems shoehorning a 350 Cummins into a 59 KW long nose and then mounting AC on it. The compressor mounting was just the beginning.

Whatever AC kit you buy, if it comes with the service-port fittings mounted on the compressor fittings, throw those in your junk box and buy some without service fittings. Buy fittings to put the service fittings on the receiver/dryer and on the low-side fitting where it comes out of the firewall. I had to do this after it was all built and I had burnt my wrist a couple of times. Also the service port on the compressor fitting is too close to the fender well to connect the gauge set without moving the compressor connecting and then moving it back. Repeat to disconnect. Not only that but the service port hits the exhaust manifold before you can get enough slack in the belt to change it. This requires removing the fan and WP pulley to slip the belts on and off. This isn't the end of the world but adds a half hour to the job.

Try to avoid buying an evaporator kit that combines the evaporator and heater core in one unit. These don't drain the water off the evaporator well AND you can't get a high enough temperature out of the ducts to be comfortable without the windows fogging up almost instantly. The unit I bought was from HotRod Air or maybe it was Old Air in Texas and they are now out of business. I think the ones you see from Vintage Air use the same combined evaporator/heater combination. I think they do that to save space. You might call and ask them.

If I had it to do over again I would try to adapt a factory air system from one of the Big Three, hopefully one that uses an expansion valve rather than a capillary tube. I'm not sure about the disadvantages of cap tubes but it's always seemed like a cheap way out to me. The more expensive cars all used expansion valves in my experience.

The only single belt setup I'd consider would be a serpentine. Those belts have enough traction on the pulleys that they can operate all the accessories in a single plane, and with idlers and a spring tensioner, the accessories can be bracketed to both sides of the engine. Since stovebolts went out of production long before serpentine belts came into use, the brackets will all be custom fabrication items.
Jerry

Engine Shop?

I’ve got a two sheave pulley for a 235 that had an air brake compressor. I think you’d have to use the long shaft pump for it to work. PM me if you’re interested.

Today's plan (yes as the knowledge base expands, plans change). Go with a double sheave pulley on a Sanden 508 compressor. The harmonic balancer directly drives the compressor, the compressor drives the alternator (see image below). This exact setup is being used by others on the 'Bolt. It's simple, clean and proven.

To mount the compressor and alternator a Davis 10032 bracket kit for $120 here.

Found this condenser kit for $305. While you could likely assemble something for less, I do like that it's designed specifically for our trucks, utilizing existing holes and openings (a grain or grains of salt may be appropriate).

The only hole in the grand plan now is the underdash evaporator. With the new coil in the heater box the factory heater does a fine job keeping things warm. The defroster,,,,,,not that great. Most vintage looking underdash units are in the 15 to 16" range wide. This is too wide to keep the original heater And keep the actuation handle for the cowl vent. I really don't want to do away with the cowl vent since for the shoulder months of summer, it does a great job of keeping the cab comfortable. Well that and it just looks right to see the vent open.

In a perfect world I'd locate a 12" or 13" wide evaporator. Since dense, .75" foam rubber along with peel-n-stick from Lowes is used throughout the cab (including the roof and doors) I'm thinking a smaller unit will work. I found a reference to someone using a rear ac from an older Suburban but haven't been able to nail down any specifics. I'm visualizing a ceiling mounted, drop down unit that would work under dash. Don't really know if one exists.

Thanks for all suggestions.

RonR

Your setup has become the preferred method for the single groove pulley for stovebolt engines. No machine work and plenty of belt wrap on all pulleys. Picture is of a 57 3100:

[img]https://i.postimg.cc/yWFb3zp6/IMG-4166.jpg[/img]

Evan, your image is the one I shamelessly copied. I do have concern just how substantial the mounting bracket setup I've linked would be. The brackets in your image look better. Is it shop built or off the shelf? If off the shelf, care to share vendor details? I've got a drill press, grinder, welder, torch and a few other metal working tools and am not afraid to use em, now the skill level is another conversation. However of late I've become a fan of speeding up the process if I can purchase good solutions for a reasonable amount.

Thanks, your input is Always Welcome!

RonR

For A/C to work the way you expect it to, the cold must blow in your face or close to it. Roof mount may not do what you want. Smaller units take less space but tend to freeze up easier. I am using the mini version from Vintage Air, in dash unit. If I don't keep on top of the temp knob, it will freeze up fairly quick. Around town, it blows super cold air, out on the road it will freeze up so I need to warm it up, then cool it back down. It works well this way, but I have been told the bigger units keep steady temps better.

Only thing questionable about the way this mounting system works is the pivot point for the alternator. It should be at 9 o'clock instead of 6 o'clock. Reason? Because swinging the alternator at 6 o'clock makes very little distance change from the A/C pulley to the alternator. May not be enough difference to get the belt tight and to get it off without removing the alternator. Or maybe there is and I just worry too much.

By the way, the similar setup on my 228 GMC swings from 9 o'clock. Works great.

Old Air Products solved this with an adjustment on the non-visible (but reachable) side of the evap box. I've used at various times all sorts of add-on units. The small units (if well-designed) will work fine. Some that claim to be well-designed, but I wonder. I had the same problem you've described many years ago when I was using a hang-down unit out of an MG and the York compressor that came with it. I was in a rush and didn't take time to check the size of the York compressor. It was too large by 2 steps. I could adjust but the thermal expansion valve just wasn't a correct match, so it would freeze up constantly. Since then I've seen some of the add-on units tend to all use the same size compressor and I've wondered about freeze-up as a result.