aluminum underdrive pulleys are a MAINTAINENCE item
 

so you have a set of those cool aluminum underdrive pulleys and think they are pretty neat. they are.

for a couple of years.

pop the hood. grab the water pump pulley and try to turn it. my guess is the odds are 50/50 you can.

if your belt is adjusted fairly tight and you can turn your water pump pulley guess what happens to your cooling above 5000 rpm?

the problem is the back side of the belt is the only pulley contact. there are a bunch of degree lines machined into the surface of the pulley to promote grip. since they are only a thou deep and the material is aluminum it is bye bye traction in a couple of years.

so what are our options?

it doesn't make sense to drop $200+ on a complete new set of pulleys. and i don't think anyone sells just the water pump pulley... which is the ONLY pulley needed.

i took my pulley into the local machine shop and asked them for a quote. they will do a diamond (that's diagonals going both directions) for $159 which includes setup and programming. they can do a bunch for $59 thereafter...

anybody have any better ideas?

check your tires. check your pulley.

howard coleman

I was just going to say you can buy both the alt and W/P for $40 shipped on Ebay. Then you can sell off the spare alt pulley or just keep it as a back up.

the FD waterpump has a press on pulley? why not cut a key way into the pump and broach the pulley itself

if the pulley already was knurled and it wore down, doing it again probably wont work for very long as for the raised portion of the knurl wont be nearly as tall as the original

I know if you go to a shop with a manual lathe, they can dut a basic knurl on for under 20 bucks...

hes not talking about the pulley slipping on the pump but the belt slipping on the pulley

any1 no the best place to get the pulley and belt and blocking plats to remove the airpump

Or you can buy an airpump idler pulley and have your belt go most of the way around your water pump pulley.

Or go EWP ;) just playin'

[/quote]This is why I dont understand poeple paying a couple hundred bucks for "the real quality brand name item" when you can get the same thing for 40 bucks on ebay, and if it wears out or tears up then big deal, you pick up another set a couple years down the road.

Why not just put the pulley in a vise and use a center punch to make a bunch of dimples in it for grip? IT might not look like it did when it was new, but it should function well and be free.[/quote]




I got mine for the preety...LOL..

http://img.photobucket.com/albums/v2...S/DSC_0115.jpg

+1

I don't know about the price, but a real shop with a [manual] lathe and real machinist can cut a knurl onto the pully. Aluminum is relatively soft and it's very easy to put a deep knurl on it. Setup is the time consuming part of this gig, cutting the knurl will only take a couple of minutes.

This is why you use the pineapple idler pulley kit (or similar idler pulley) instead of that vastly inferior Greddy kit. That Greddy kit scared me with how sketchy it was... I know a lot of people use them with success, but it just didn't seem like the proper solution to me.

Ah, ok i understand

Howard,

Do you feel this is a problem when using the airpump also? Having a good surface area of belt to pulley contact is a key element here also.

http://img.photobucket.com/albums/v4...0813081847.jpg

If you still have the airpump, then you wont have this issue.

REALLY good post, Howard! I never considered that, and it makes perfect sense.

Seems like Pineapple is going to start getting a bunch of orders for their idler pulley!

Dale

You just have to convince them to make it again! I am not sure if they started again or not.

Garfinkle has one in fab...stay tuned.

if you know his oil pan brace or engine torque brace...you know the quality this thing will be.

howard and pineapple are probobly in cahoots with each other. haha

Actually, it's the angle of the contact surface and its coefficient of friction (CF) that are important. It's called the "capstan effect" from sailors using multiple wraps of rope on a post so that a few # of tension can hold an ocean liner from moving. The force to slip is exponential with CF and wrap angle. If the angle times CF is small, not much torque can be transmitted. Page 4 of the linked explanation below shows how this works.

http://pergatory.mit.edu/2.007archiv...Components.pdf

So increasing either the wrap angle or the CF will improve the situation.

So I have had the greddy pully kit on my car for roughly 3000 miles and one day a little after I got on it my car all of a sudden started getting warmer than it ever had before.....went out and checked and yup I can turn my water pump pulley with my hand.

So lets see I spent 140 on greddy pullies to eliminate and air pump and have higher water temps and now have to fork up the 170 for the idler pulley...this is crap!

BTW thanks howard for another informative thread.

thanks Banzai/Chris.... i tripped over to ebay and found a couple of vendors that offer a 2 pulley (alt/water pump) deal for 41 shipped.

i also took one of my spare wiped out water pump pulleys, my set of punches and in short order had a whole lot of "H"s punched into the mating surface. for anyone not wanting to spend the $41 that would be a simple option.

plus it relieves stress if you have any.

hc

Remember, do NOT over tighten the belt to prevent the water pump pulley from slipping. If you tighten the belt too much, you will pull up on the E-shaft and cause premature wear on your bearings!!!!!!

Chadwick do you have an idea on the price of your idler pulley?

what about the guys with LARGE singles? we have no room for an idle pully.....

pineapple used to make one as stated above. perfect even for guys running large single, It is the size of a half dollar in diameter. They really need to make them again.

they really need to, mine spins really easy...... so it sucks, i have unorthodox pully set and am only Running alt and waterpump... so yeah i need to do something, i think i am going to cut ribs into my waterpump pully and see if that helps at all....