pulley for 308 GT4 a/c sanden conversion

I converted my 77 GTB to a sanden and did not change the crank pulley. I used an off the shelf belt that fit in the sanden and did not have any problem with the crank pulley. It does run a slight bit higher but does not slip. I also eliminated the tightener pully assembly and use the compressor to tighten the belt. You just need to make sure that the belts are aligned correctly and you have the belt tight. Oh I did use a ribbed belt similar to the old Ferrari belt used on the York compressor.

 

I did my sanden conversion back in 02 or 03 so it has been a while but I used a Dayco belt from Pep Boys. I didn't use a tensioner either and the belt tensioned when I tightened the compressor. I ran it for years and it never broke. I would really check both pullies and see what is going on. I can try to find the belt part # for you. I think I have a record of it still somewhere.

 

Did you gents notice a measureable improvement in AC performance, over the stock unit?

Best,
David

 

I did the conversion about 6 months ago and have had no problems at all.Like the others I removed the tensioner pulley and took the tension up when tightening the compressor bolts.If I went for a smaller size belt I probably could have kept the tensioner though.I had to replace because the seal blew on the compressor and it was easier to replace with the sanden than rebuilding the compressor.The sanden is lighter and takes less strain off the motor.I had modified the cooling ducts in my GT4 and it made a huge difference over stock,but yes it aint no modern car.The biggest improvement was going back to R-12 over the retrofitted R134a that came with the car.9 degC vent temps with R-134a versus the 1-2degC vent temp with the R-12.I have since sold the car and the new owner hasnt had a problem with hte A/C yet

 

I noticed a huge difference. I could use my 308 in 90+ temps with the a/c on. I put in a larger drier and replaced all of my a/c lines when I did the conversion. I flushed the system good also. The sanden doesn't rob near as much power as the york style. I charged it with a blend called Freeze 12. I don't remember exactly but I was getting in the 40s at the vents.
Even after 30 mins or more of driving and sitting in traffic it kept the car cool.

 

I found as long as the car sits in the shade during the day the AC works just fine . It is not like new but it is comfortable while driving. The sanden set up is much simpler and when time comes for the belt change it should be a little easier. I am using 134 due to all of the restrictions on r-12. If you are breaking belts my bet is their is an alignment problem between the compressor and crank pulley. Also use the gates ribbed belts. Good luck

 

I did the conversion on my 308 used R 12 and noticed a consideral advantage in cooling.
In that the SD 507 conpressor comes with different diameter clutches and belt widths, the belt length would be a variable and if the alignment is correct the most simple way would be to replace the AC clutch to match the crankshaft groove. I also insulated the engine firewall, the frount trunk area and the headliner. In that the alignment of the the Ac compressor is time consuming with lots of in and out trials to get the shim pack correct, I would look there first. I did the conversion myself therefore I know how muck time it takes to get it just right. good luck, Kdl

 

I bought spacers and washers at ace hardware for my compressor. I only needed 1 spacer and one washer to get the exact alignment. I still have some of the spacers somewhere. I can measure them if anyone needs me to. I made my lines a little longer also so you can swing the compressor out of the way with the lines attached for a belt change.
I also plugged the back of the compressor with block off fittings so it would clear the fuel tank.

 

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Having re read your origional post I can see the problem as the wrong choice of belt.
Just fit the belt to the pully with the larger width as the belt is aparrently bottoming out on the other pully and therefore cannot drive the compressor. The new belt will ride higher in the smaller width pulley but that is much better than it being at the bottom of the groove where it cannot function properly. I did the belt trick on my 911 and it has worked out fine for thousands of miles. Kdl

 

Your crank pulley requires an 11M (60' angle) "V" belt, your Sanden compressor requires a conventional angled "V" belt (around 45 degrees), unless you're running a Ferrari pulley on your compressor.