SC A/C Belt size

patkeefe · 12:59 PM

Anyone happen to know the size of an A/C belt for a 78 SC?

Long story short. I had to mod the crank pulley for EFI, then had to mod the A/C crank pulley. I had to take the mount carrier loose and make a special 19mm wrench to put it together. So, I have one turn in the tub to get the correct belt on before I put it back together. Once it's together, I cannot get it back apart until I change the engine in a few months. Search will take hours, at least, which is time I can't invest at the moment.

No, I can't find the old one I took off 15 years ago. Catalog says Conti 13 x 1200...I have a Seiko-Seki compressor. I have no idea if that is correct.
Thanks!
Pat

walt · walt's Garage

Just this week installed a 13x1100. It was a tight fit to get over the compressor pulley but was fine once in place. 1200 seems a bit long.

Note: I have a Seiko compressor which might have a slightly different pulley position than the original York.

patkeefe · 08-01-2019, 05:57 PM

Thanks Walt. I’m having to build a special bracket so that’s a really good starting point

HaroldMHedge · HaroldMHedge's Garage

If you are making a custom bracket, why not use a cloth tape measure and check the length around the pulleys?

patkeefe · 08-01-2019, 06:20 PM

I actually used a rope. I will bring it to the parts store tomorrow. I really am having trouble figuring how this setup used to work, unless I am missing a bracket or something.

patkeefe · 08-02-2019, 06:35 PM

I tried some different belts I picked up at the local parts store, Seems a 43" Gates works OK. It is a 4L 430, which I believe is 12.7 mm x 1170 mm. Best I could do.

RDM · RDM's Garage

We anxiously await your vent temps...

This is a Pelican A/C thread after all.

patkeefe · 08-04-2019, 07:04 PM

RDM,
Vent temps seem to be the answer to everything here on Pelican

. I prefer to look at the split between the return air temp and the supply (vent) temp. I have just done extensive work on getting the AC to function; included in this was the evaporator. Smugglers box has an opening to the passenger footwell (trapezoidal opening, I shall refer to this as the return). Smugglers box was also open to the outside, down through the opening where the steering/brake lines go through. Evaporator (Behr) also was open to the smugglers box via a 3" hole. So, my estimation was that the evaporator was mixing two airstreams; return air from the passenger footwell, and the air sucked into the opening from the smugglers box itself.. In this instance, the air temp on the warm side of the evaporator coil was probably around 80F or so on a hot day, maybe higher. I can only expect maybe a 25F split return to supply, so I should see 55F vent temps at best in this current configuration. I was getting like 38F temps with the car stationary prior to removing the system. I was running MP-39 (substitute for R-12) back then; I will be using R-134a going forward. I am not finished making the lines yet, nor have I N2 tested and vacuumed the system.

I have sealed the 3" hole into the evaporator unit, such that the only air coming in to the evaporator is through the return. I also insulated the evap unit with 1" or 1/2" Armaflex, as allowable. I practically had to sit on the evap to get it back into the smugglers box. I may be choking the airflow a bit in this case, but I will see when I get it running. My modifications thus allow me to recirculate the cabin air only-I have isolated the evaporator from any outside airstream. I am going to guess I may see 45F vent temps, with a big reduction in humidity in the cabin.

Attached are some pics of assorted bracketry, evaporator and assorted engine supporting stuff I had to remove just to put a belt on. Thankfully, I did not need to remove the turbo. This is not a sustainable option for me simply to change belts. I do have the compressor in, it fits and clears everything. I had to do some relocation of the fuel rail inlet. Everything is a PITA.

patkeefe · 04-25-2020, 07:10 PM

Back to belt sizing here:
I had to build a new pulley for the NA 2.7 engine. It needed to be modded to take the magnets to trigger the coils and EFI. The ideal pulley (we need AC pulley in addition to alternator, after all) was off a 3.2, which I picked up from a fellow Pelican. Alas, it was too big to fit in the engine carrier, even after I machined it. The Plan B pulley was completed and installed. I had to build some custom bracketry for the AC compressor, which is a Sanden SD7H13 (shorter than the common H15 series, or 507 and 508), because I wanted a bit of extra clearance for the EFI fuel rail on that side.

Back to the belts...the old 9.5x725 alternator belt fits well, but the 10 x 725 not so well. I guess the pulleys are from some old engine I found somewhere. The 9.5 section width was once common, I suppose, but it seems to be non-existant any longer. I believe it cross references to a 3L type belt (probably a 3L285). I have a 3L420 AC belt, which works well in the pulley, but a 4L just doesn't like to ride in the groove. Belt in the picture is a Gates 6842, which is a 4L420.

Anyone have any sources for the actual 9.5 section belts? I really need a shorter belt , like maybe a 9.5 x 720.

The current AC belt-4L420...fits OK in the Sanden pulleys, but not so good in the crank pulley

The 3.2 pulley-it had a large diameter drive for the compressor

The current unknown pulley, which only likes the 9.5 section belts

The whole thing