March billet aluminum underdrive pulleys... belt numbers?

[tpaul]

Nice work Terry!!! Now that you've figured this out I may have to put the pulleys on the car! What did you figure out for the AC belt? My AC doesn't work right now, but I recently threw an alternator belt. The AC belt saved my a** to keep temps down so I could drive home.
Thus the reason I don't drive the car much. Florida heat + Black Car - AC = Hot as hell!
P.S. Thanks for backing up my thoughts on the pulley speed. Sooner or later you run out of $250 bolt-on upgrades!

 

[tpaul]

Just about to install the March Pulleys. Any ideas on an AC belt #?

 

[tpaul]

AS GN84TURBO figured out, the 15 is the width and the next 3 numbers relate to length. ""."
From the Dayco page:
How to read a part #:

15445
15 15/32" Nominal Top Width
445 44.5" Effective Length

So with that fact in mind; our PS belt is the 15365: 15 width and 36.5" long, the Alt belt, 15450 is 45.0"

I'll have to install the pulleys to get an accurate AC belt number

So a smaller crank pulley slows things down. This system has a much larger water pump pulley (not smaller like a previous writer guessed.) PS will slow down, as will AC and ALT. However, isn't the WP brought back to normal speeds?

Look, I purchased this kit strictly for looks years ago. Are there really any gains to this system? My experience in the past has been that slowing the alternator is a bad thing. I'm currently running a strong battery and the Powermaster 140 amp ALT.
I'm not afraid to put them on, it's just not a read the instructions and bolt on system. Even March has no idea what belts to use!!! This has been a long process. I was okay with my stock pulleys until I realized my AC was resting on the O2. If I have to change that belt I might as well swap pulleys.
Any seat of the pants results from this conversion?

 

[tpaul]

AC belt Dayco #15490... shorter than stock, but fits well, and allows clearance for a heated 02.

 

[youngstr]

if this car is gonna be street driven then be careful with underdrive pulleys, I bought my car and they were on it, now I'm on a searching for a smaller alt pulley, with the stock pulley in drive sitting at a light with the lights on I'm only putting 11.4 into the battery, 11.8 with the lights off. once you're off idle its fine putting 13.2 to 13.8 in, its sitting at a red light that does u in and I have my idle set up at 775 in drive, 850 in park, point is if you do a lot of city driving like that you'll send your battery to an early grave.

The large waterpump pulley should be fine as long as you have a decent sized radiator with dual fans. As long as your cooling is under control, that big pulley will extend the life of your water pump.

 

[ZNix]

Wish they were stock sizes! I would have liked a set. I guess ill have to get a set of TR Custom Parts when I can afford it.

 

[charlief1]

Thanks for bringing this back from the past. Good info.

 

[Boost231]

Wish they were stock sizes! I would have liked a set. I guess ill have to get a set of TR Custom Parts when I can afford it.

didn't know Tr customs made a set for our cars (84-85)

 

[tb3]

they don't, he's thinking this is 86/7, but you already new that. lol! i just ordered the water pump pulley from wysco. $68. i threw away the stock 3 groove pulley a long time ago and have been using a 2 groove pulley from a 79 na 231. it looks better, but is very heavy, not sure by how much, but heavier than the stock 3 groove pulley. i don't want under drive pulleys. the stock crank pulley i'm not going to mess with since its actually quite light already. i may post a pic when i get it installed if anybodys interested

 

[charlief1]

they don't, he's thinking this is 86/7, but you already new that. lol! i just ordered the water pump pulley from wysco. $68. i threw away the stock 3 groove pulley a long time ago and have been using a 2 groove pulley from a 79 na 231. it looks better, but is very heavy, not sure by how much, but heavier than the stock 3 groove pulley. i don't want under drive pulleys. the stock crank pulley i'm not going to mess with since its actually quite light already. i may post a pic when i get it installed if anybodys interested

Part number and pics please.:biggrin:

 

[ZNix]

If I didn't come back and read this thread, I would have made a mistake .. I didn't realise they were difference between the years.

 

[tb3]

Part number and pics please.:biggrin:

for you charlie,.... most definetly bud! the 84/85's are three groove, which i don't want since we don't use the 3rd groove. so i ordered a 2 groove for a buick 350. that should be the same size right?

 

[tpaul]

Thanks "youngstr" for the advice. I never thought of that as an issue, but Tlink confirms your comments. At idle in "drive" with the electric fan running and lights on I am putting out about 11.7v from my Powermaster 140 amp alt with the standard March alt pulley.
However, let me ask you all this... with a cruising output of 14+ volts and a battery rated @ 700 CCA, 675 CA what is the true downside?
Am I wrong to say that even in Chicago stop and go traffic the car would continue to run? I live in the Orlando area, but the car will be in the Chicago area soon. Maybe I'm an idiot, but shouldn't a 12v system be able to function @ near 12 volts? I know my Silverado runs around 14 -16 volts. Voltage on this Grand National has never been an issue before the pulleys. Look, I've been stuck in car show cue lines miles long. The last thing I need is to kill a battery.
I test drove the car the car the other day and it was as bad as ever! I'm just trying to narrow down any future problems!
Thanks in advance for the groups input.

 

[charlief1]

for you charlie,.... most definetly bud! the 84/85's are three groove, which i don't want since we don't use the 3rd groove. so i ordered a 2 groove for a buick 350. that should be the same size right?

So you've got a spare 3 groove pulley now? The 350 may work but check the spacing first.

 

[tb3]

ithrew away the 3 groove long time ago. all the 81-87 na 231s had the three groove and I've thrown away 4 more of those pulleys in the last 4 months. if you are needing one I would have sent u one for nothing.
don't the Buick 350 use the same timingcover as the231?

 

[charlief1]

They use the same timing cover design but there are variations in the water pumps (slight) and pulleys.

 

[tb3]

i called them back and put my order on hold. they're going to take some measurements for me, i'll report back