87 TBI pulleys

[78 Chevyrado]

I'm needing either someway to have a double V-belt pulley for my alternator or maybe swap over to the later pulley set like i had on my 87 r10, as it has the one wide serpintine belt on the alternator.

the alt. i have it pulling too much for the single Stock V-belt to take. either the belt slips, or i have to overtighten the pulleys. neither is good.

If I get a double groove v-belt pulley for the alt, the problem is finding the corresponding water pump and crank pulley to go with it.

If i get the set from a TBI engine, will my current A6 A/C compressor and 78 P/S pump still line up correctly using the newer pulleys?

If they're cheap, I may just go find a set and try this out.

Any thoughts?

[Jonboy]

Kenny, I think I have some. You can have them for shipping if I do. I will have to check, but it will be a week or so. I am going out of town tomorrow for a couple days.

[78 Chevyrado]

I came across a set before I saw your offer. Thanks jonboy!

Got a little bit done today. and i do mean a little.

Got the pulleys bead blasted and painted them with Clear Hard Hat Paint.


I got the crank and water pump pulley on there. Having trouble with the belts. I had to send back the stock v-belts for a 78 for the AC and PS, and swap them in for a 2" longer AC Belt and a 3" longer PS belt. These lengths got the bolts for the adjustment grooves back to where they were before when the belt is tightened up. The v-belt grooves in the crank pulley are larger than the ones on my stock crank pulley. The serp. belt on the alt, is stock to an 86-87 truck.

Also since I have the old A6 AC compressor, I have to use the '78 Belt routing, and NOT the 86-87 Routing. If I tried to use the later routing I'd have to move my AC compressor forward about 9/16" or so. So it will definately end up using the stock '78 belt routing, but need longer belts. If the truck has the Later small A/C compressor, I think the 86-87 routing would work.

The PS pulley seems to be lined up so far. Ill triple check that when I get the belts on it and play with the straight edge.

For the V-belts, goodyear gatorbacks...

STOCK (1978) A/C Belt (54.5") - Goodyear 15550
LONGER A/C Belt (56.5") - Goodyear 15572

STOCK (1978) PS Belt (41.5") - Goodyear 15420
LONGER PS Belt (44.5")- Goodyear 15450

5-Groove (1987) Alternator belt (43.5") - Goodyear 4050435

[78 Chevyrado]

I got it all setup today. My New alternator will be here Tuesday, but I went on ahead and got it done so when it comes it'll just be a bolt in quick swap.






When I first tried it the crank pulley wobbled a good bit and I found out that the lip sticking out the back of the center hole wasn't as large as the one in my stock pulley so it wouldn't center up right. It was an easy fix as I happened to have an impact socket that JUST fit in the hole in the old pulley and I pressed it through the hole in the new pulley, and it ended up being just right when it was fitted to the balancer. I didn't have to move the PS pump, as it all lined up right. No squeals from the alternator and its actually tightened properly now, not too tight like before with the v-belt to keep it from slipping. New V-belts are daycos, as the gatorbacks were too short and have to be returned.

Recap:
-Must make sure hole in center of new crank pulley is same size as in the old crank pulley so it will center in the harmonic balancer and not wobble

-Use the 1978 belt routing with the big A6 Harrison A/C Compressor.

-A/C belt has to be 2" longer than stock (56.5") - puts the compressor exactly where it was before.

-PS Belt has to be 3" longer than stock (44.5") - puts the pump a little farther outward, but 2.5" seemed too tight for the bottom left adjusting bolt to get a good bite on the pump bracket.

-Use stock alternator belt for an 86 or 87 model c10/r10 with a 350 - no modifications needed