water pump pulley question

[steves sl]

Is there a double grove water pump pulley available used? What model and year?  My vehicle 1965 230sl...127 engine.

[dirkbalter]

My W108 has a double groove water pump pulley. Only one of the grooves is used though. What do you want to use it for?

[steves sl]

I am adding  a Saden type A/C compressor. I don't have power steering...original belt drives water pump and alternator. Need a second belt from water pump pulley to compressor pulley. Bracket fabricated, looks like everything will work. I will post pic's when finished as a sedan bracket will not work on a 127 engine.

[ja17]

Most of the mult-groove water pump pulleys are four hole pulleys (250 and 280 series).  You need a three hole water pump pulley for a 230SL. Most add a second groove crankshaft pulley to drive the AC.

[Shvegel]

Joe,  This might be a lot of messing around but would a 4 hole water pump fit on a 230?  You would have to use a 4 hole fan clutch as well but it might be a solution.

[steves sl]

I have everything setup for a 2 grove water pump pulley, thinking that won't be a problem to find a 2 grove pulley. If a 4 bolt pulley center locating hole is the same as a 3 bolt (230sl) ....I could easily weld the 4 bolt holes and re dill 3 holes. The center locating hole is 32mm in diameter. Does anyone have a 2 grove pulley for sale if the above is true?

[dirkbalter]

I am following your thread with interest as I am also planning to add AC to my 230 as well. If I understand you correctly, you will drive the compressor with the water pump pulley. Is that what the double groove pulley was used for?

On the W108, the AC as well as the power steering is driven direct of the crank pulleys. I am still wondering what the second groove in the water pump pulley is typically used for?

Do you think or know that the water pump is strong enough to drive the compressor in the long run?

The MB EPC (W108) shows 3 numbers for the pulley. The picture shows only a single groove pulley though.
 A 11 420 500 10   A 11 420 501 10  A 11 420 502 10
Possibly one of them is the double groove, in case you can not get a used one.

[steves sl]

My thought process is that the simplest solution to adding A/C to a 127 engine is to use the water pump to drive the compressor......there by the original fan belt is used for the water pump and alternator (I don't have power steering) adding a second belt for the water pump and compressor with a fan belt tensioner. I will post a pic in the next few days on my progress, I also can make a pattern of the fabricated bracket when finished if there is enough interest.

[dirkbalter]

My thought process is that the simplest solution to adding A/C to a 127 engine is to use the water pump to drive the compressor......there by the original fan belt is used for the water pump and alternator (I don't have power steering) adding a second belt for the water pump and compressor with a fan belt tensioner. I will post a pic in the next few days on my progress, I also can make a pattern of the fabricated bracket when finished if there is enough interest.

Yes, please do.

[steves sl]

See pictures of what I trying to accomplish if I can find a 2 grove water pump pulley. This is the mock up to date...the yellow tape area has to be cut out for the thermostat housing......belts were made up of old mower belts and hog rings. The bolts are not correct just used for the mock up. To me this is the simplest solution to adding a/c to a 127 engine. You thoughts...will this work? or add joke here.........

[steves sl]

additional picture

[dirkbalter]

Steve,
I like it. It definitely simplifies the assembly. As long as the water pump can handle it, it looks like a good way to do it. I was looking at the complete assembly from buds bez with the double pulley from the crank ($$). Tempted to followed your lead.

[steves sl]

I am waiting for the experts to way in.........if my solution will work......before I finish. My thinking is that something must have been driven by the second grove on the water pump pulley....so why not an A/C compressor especially a Sanden type. Still trying to locate a 2 grove water pump pulley with a 32 mm center hole or was that a 23 mm I'll check today.

[dirkbalter]

What are you doing with the blower unit inside? Did you find a used one or are you going with a new one? 

[450sl]

Thought about tensioning the belt?

[steves sl]

The pulley center  hole is 32mm.  I haven't looked at interior evaporator and blower units yet but I am leaning toward the small units that are available for 60 and 70's that fit over the transmission tunnel or the narrow long units from Buds. There is a belt tensioner in the pics (blue & black serpentine bearing) that rides on the outside of the belt. If this doesn't work I can always switch to 2 grove pulley on the crank shaft but I thought that this design might be easier on the 127.... 4 main bearing crank shaft. waiting for the experts to way in before I finish.

[steves sl]

Experts opinion  needed. Please advise will this fabricated bracket work? I will wait for opinions before I proceed or change direction. Previous entries will explain my thinking. Thanks.

[450sl]

this is my setup , hope this helps.

[steves sl]

Thanks....It appears that you are driving the compressor from the water pump pulley......so you must think that said pump is stout enough to handle the load. How long have you used that design and how do you adjust the belt tension? Any problems?

[450sl]

A lot of applications like dynamo, waterpump and steeringpumps get their bearings destroyed by "specialists" who set belts so that you can play gitar on them.

If you design a good tensioningsystem ( with a fixationpoint after tensioning) and make sure you use fresh belts , and do not over tension belt, you should be good.
I used the upper bolts as a pivotpoint.

[steves sl]

An update on installing a A/C compressor on an early 1965 230SL. Fabricating the bracket and spacers was a real pain. I am 90% finished..still have to plug the air idle port on the front of the intake manifold and  drill and tap the rear of the manifold to move the banjo fitting, and correct the bolt/washer sizes. You will notice that the original tube from the thermostat housing to the WRD no longer fits.....not wanting to cut up the original (pic)  I had to order a solder banjo fitting  and reroute the tube to fit a hose to the WRD.....several years ago I fabricated a heat shield from 1/8" aluminum (pic) as luck would have it the original was damaged and has to be shortened to fit around the fabricated A/C bracket... shortening the original with asbestos wasn't an option I would answer any questions about this project. Would I do it again probably NOT....to many issues like putting 20 lbs. of stuff in a 5 lbs. bag. I will be interested in opinions.....it appears that this is the simplest solution given the 127 engine limitations.

[steves sl]

Still waiting for expert opinions.....will this idea work or did I waste considerable time and effort. Any opinions would be helpful good or bad. Money spent less compressor about $30 US not counting scrape steel, welding wire, and bolts.

[Benz Dr.]

Everyone who knows me also knows how much I hate AC in 113's so I'm unable to give an unbiased opinion. I will ask why you would put it in the engine with weakest crankshaft? And, why living in Wisconsin you think you would need it? I'm sure it gets as hot as it does here where I live but that's only for a month or so.

Other than this, I have no opinions.