I bought a new set of march underdrive pulleys for my truck, figured what the hell, I had the water pump off to replace and fan clutch so thought I would do it now. When installing them today I noticed that the alt pulley is actually bigger and the water pump pulley is the same freakin size and doesn't even have a belt groove. The only pulley that is actually an underdrive is the crankshaft pulley, it is way smaller. I basically paid $86 plus shipping for one pulley thats actually going to be an improvement. I don't know yet if I should install the alt & pump pulleys since they are bigger. Have you guys noticed this on you're pulley installs?

 

Chill out, you didn't get ripped off at all. Think about how a belt drive actually works. The damper pulley is the driver, making it smaller slows down the belt. The alternator pulley is a driven pulley, making it larger makes it spin slower for a given belt speed. Both of these are "underdrive" it's just the difference between driver and driven pullies. As for the waterpump being ungrooved, it had better be. You've got a serpentine belt, and the water pump is driven off the back (i.e. flat) side of the belt. grooves would only tear up the belt. As for the diameter it is still underdriven because of the lower belt speed from the smaller damper pulley. IIRC the stock water pump pulley on my Mustang was somewhat smaller than the underdrive one, but the difference wasn't all that great, you may want to re-measure. It is entirely conceivable that because this is a set of pullies for a truck, they chose not to underdrive it quite as far due to the likelyhood of higher cooling loads.

 

Well I understand the alt pulley being bigger now that you explained it, duh, it actually makes sense, can you believe I am a manufacturing engineer? The groove I was talking about is not the groove that matches the grooves in belt ( I know this pulley runs on the back of the belt) but a channel or slot that the belt rests in that keeps it from sliding off, like the stock pulley. The water pump pulley is about .25" larger in diameter than the stock one. Thanks for the input, I can start drinkin now

 

You are hereby sentenced to repeating ES201 Kinematics - that is a fate worse than death.

 

My FRPP set uses a smaller crank pulley, larger water pump pulley, and a smaller alt pulley.

That does kind of lead to being deceptive advertising. If the only one that really changes is the main then they should sell it as a single pulley, not a three piece set IMO.



As far as I remember my stock water pump pulley had no groove in it at all. I might have to dig the box out and check now.

 

I got the March Power and Amp pulley set, and my Crank pulley was alot smaller, alt pulley smaller, and water pump bigger. This is a pic of my water pump pulley, and while it does that that no painted part, it is completely smooth all the way across, the black is completely even with the unpainted. Nothing holds the belt from flying off.

Sure the shoe looks horrible, but hey I just got off of work.

 

there was a note on the directions that said march tested the water pump pulley without the groove for a year before they switched and found no problems with it. so far neither have I.

 

If they're gonna go through the trouble of testing the pulley one year without the groove to make sure it works, why not just put the groove in and be done with it? Sounds kind of silly if you ask me, but what do I know, I'm not an engineering major...(I'm just a math major).

 

Odd how some of you had larger stock alt pulleys and the march alt pulley was smaller, my stock alt pulley is so small I can't imagine it being made any smaller. I wonder if Ford made different sizes for a reason, of course with 300k on my truck the alt has been replaced by a rebuild, more than once.

 

Not sure about this since I have the ASP pullies on the Mustang, not the March ones. What if difference in the alternator pulley is due to which set of pullies you buy. If you get the "standard" underdrive set you get the large diameter alternator pulley; if you buy the "power and amp" or whatever they call it you get a somewhat smaller pulley to restore some of the alternator output. The alternator is not a huge HP drain anyway, something less than 2HP at full charge, so there's not a lot to gain by marginalizing it. The big gains in pullies come from reducing the water pump and fan speed.

 

OK guys, put on the thinking cap here......if you have proper alignment of the pulleys and the tensioner is doing it's job, there is no need for a groove or lip on the flat side water pump pulley because there is no way for it to move from side to side and slip off, make sense now?........for shame, I am a Sparky (Elec Engineer) and figured that one out.

Hey, don't feel ripped if you got the aluminum pullies especially, less weight, less rototing mass and no rusty steel anymore.

You now must also go back and retake EML3500 Machine Design and Analysis...LOL!!!!

 

BLAH, BLAH, BLAH

 

LOL!!! Right on!

 

OK I have a 97 F150 w/5.4 tow package and all them do dads so I was thinking about getting a set of underdrive pulleys since I will be installing an Electric Fan Kit soon. So I have a few questions first of all how many companys are making underdrive pulleys for the truck and does one seem to be better than the other and if they are all pretty much the same which one costs less and where is the best place to buy? Since I do have the tow package and I do tow a boat in the summer I read in a previous post something about slowing the waterpump down I DO NOT want this since cooling is very important for me for towing. So which underdrive pulleys would best suit my application?

Thanks,
Richard D.



https://www.f150online.com/galleries....cfm?gnum=2479

 

For a newer truck like yours, I would go with the 2 piece ASP set.