I have been in search of a double or twin "V" belt pulley for my 64 MK2 air conditioning project. The idea is to run the alternator and crank on the outside sheave of the pulley and the crank, water pump and compressor on the inside sheave.

I never found a double "V," however, I did purchase a 1990 triple "V" crank pulley. My plan is to machine away the outside sheave leaving me with a pulley height of approximately 2 1/8." The crank bolt hole in the center of the XJS pulley is identical to the original "W" crank pulley and the four holes for mounting to the harmonic balancer are also identical. Vertical alignment for the belts on the pulley sheaves is also just right.

The issue is that the diameter of the original pulley is 5 1/8" while the diameter of the XJS pulley is 5 13/16." I won't be able to use the original jockey pulley as its outside edge comes extremely close to the outside edge of the larger crank pulley.

Assuming that I can figure out some type of belt tensioner for the inside belt (crank, water pump, and compressor), is there any problem using the larger diameter crank pulley? My compressor mount is stationary - not adjustable. The larger diameter crank pulley obviously changes pulley ratios but I don't know if this is an issue/problem or not.

Any thoughts?

Thank you.

Lin

 

the S type came with a double V pulley in the 3.4 and 3.8 liter engines.

 

This was the part number of the double V pulley I installed on my 3.4 engine, it needed a little machining to fit but it does work. Came for Jag XJ6 series 2 or 3 I think


C27754

 

Hi Ray, thanks for your response. Do you know the diameter of the pulley? Is the front sheave a smaller diameter than the rear?
Lin

 

here's the pulleys from a 1964 3.8 'S'

 

Jose,
Hard to tell from those photos, but it that a pulley with two sheaves for two belts, or is it a "w" pulley for one belt? It looks like the latter.

I am looking for a pulley for two "V" belts.

Lin

 

yes, I think those are the W pulleys, for one double-wide belt. One is the tensioner pulley, the other is the water pump/fan twin-belt pulley. What is not shown is the crank double pulley.

sorry, I see now what you are looking for.

 

Lin


Sorry I think I confused everyone including myself on this. I have retained the existing single pulley that will drive my new alternator and added an additional V belt pulley part number as indicated, to drive my new A/C compressor. I have attached pictures of this.


The only negative to this is that if you need/want to turn the engine manually you first need to remove this additional pulley to get access to the large crankshaft bolt to turn.

 

Lin,
I don't think it would be a problem. The accessories will be driven slightly faster, but that's not a problem unless you regularly see red line. I removed my jockey pulley as it couldn't tension the belt sufficiently to drive an alternator and power steering. Instead I use my alternator as the adjustable link to tension the belt. So far seems to work.

 

That's good to know, as I'm going thru the same process, fitting p/s and an alternator to replace the 2 ton factory generator. I was wondering how critical that jockey wheel was.