|
#1
|
||||
|
||||
March pulley question
I am thinking about getting a March underdrive system. I am nervous because I don't want my engine to run hot. The enigne is a 440, 12.5:1 compression, Fully ported Indy SR heads. .650 lift cam. Howe radiator. 4500 stall converter, 4.33 gears.
Thanks for the help |
#2
|
||||
|
||||
It wont run hot. Actually that's one of the reasons for underdriving. As rpms get higher the pump will start to cavitate. Somewhere around the 4,000 mark. With it under driven you can turn the engine more and the pump about 20%less which aint much less. This helps to keep the water moving and the cooling system working just right. We run much bigger under drive pulley's on our race car than march makes and it runs around 190 all night long. See the circle track section. Sanborn did a real good piece on cooling systems. I think he mention pump cavitation in there.
|
#3
|
|||
|
|||
I think March sells a street and race underdrive ratios now. I have one of the older pulley kits and the underdrive is on the edge of not being streeetable. The alternator won't keep up unless the engine is ar 1,200 RPM or above and the car runs hotter in stop-and-go traffic. The cooling problem is more related to the fan pulling less air, not the waterpump speed. The good part with the pulleys is my belts stay on at 7,000 RPM. With the stock pulleys I was throwing belts all the time.
|
#4
|
||||
|
||||
make sure your cooling system is up to par, or you will run hot. it does turn the pump slower, so at low rpm, where most cooling problems occur, you could have trouble. it depends on your starting point. If you currently run cool, you will be ok. If you are on the edge now, they could put you over into boiling territory
|
#5
|
|||
|
|||
march also claims that because the pump is turning slower, that the water spends more time in the radiator, cooling it more, supposedly.
i used a higher output alternator on my 340 and no problems after a year of use on the march set. (30% under driven) |
#6
|
||||
|
||||
I run the 33% under drive March on a 12.5:1 440 with a .590 cam. It ran HOT, but I had other issues with my cooling system. Currently I live in Chandler Arizona (it's 107 out right now!). Last month I swapped to a 2 row 1" tube Aluminium rad, Flow Kooler pump, MP Aluminium housing, and I'm searching for a good fan set up. The car will be on the road in a couple of weeks so I'll let you know how it works!
Later, Greg |
#7
|
|||
|
|||
Hi guys, maybe you can help. I have 67 cuda with 72 440 for race only, I have aluminum mopar water pump and gm 1 wire altenater. My problem is the pulleys don,t line up with the fluid dampner, the fluid dampner is recessed a small amount so i shimmed the water pump pulley to line it up and it is better, except there is only about an 8 th of an inch gap between water pump pulley and crank pulley, is that enough? I,m wondering what set up would work. I will phone march pulleys tomorrow and see what they have to say, thanks Tim Walton
|
#8
|
||||
|
||||
If it's race only put a Moroso electric pump drive on it and just run the alt belt off the crank. That will free up some horse when you stop the water pump from running off the crank.
|
#9
|
|||
|
|||
Okay thanks 43 maybe that is the way to go, I was trying to set it up yhe other way as i have the parts, but I can get more, Tim
|
#10
|
|||
|
|||
dwc43. after looking at set up on there web site, would i need a dual pulley for my gm 1 wire altenater? Defintetly looks like it would solve my problem, and I take it it just bolts onto the stock location of my mopar aluminum water pump? Thanks again Tim
|
#11
|
||||
|
||||
Not sure what you are getting at there. You might need the double grove pulley to use belts on the crank pump and alt. But if you are getting the moroso pump drive it only runs the pump. It can not run the alt too. The alt would nrrd just one belt to the crank. I still would use this set up. Less head ache in aligning pulleys. 'cause if they are not just so so perfect the higher the rpm goes the greater the chance of throughing the belts off.
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
March Alternator pulley | mopartodd | Rear Wheel Drive - Parts for Sale | 0 | 02-10-2006 08:36 PM |
March Pulley conversion | 71SATELITE | Performance Talk | 3 | 09-20-2004 08:14 PM |
March pulley question | dram1500 | Ram Truck Chat | 1 | 07-16-2002 02:35 PM |
march pulley | JoeM08 | Performance Talk | 2 | 06-19-2000 01:29 PM |
March pulley's from Summit | Joe Bump | Performance Talk | 0 | 06-10-2000 03:18 PM |