Shimming Crank Pulley?
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From: Jackson County
Shimming Crank Pulley?
i have a set of march under drive pulleys, crank and alternator. i'm using an eletric water pump so it isn't driven by the crank. i hav a morosos alternator bracket #63482. with this bracket the two pulleys are off set about an inch. i was thinking i could make a shim to move the pulley on he crank out, but was concerned about the extra weight on the crank. i then figured i could make some bushings to move the pulley out. what are your thoughts on this? my other option and i guess the correct thing to do would be to buy the alternator drive kit #63843 from moroso and give up on the march underdrive pulleys. bad thing about that route is i'll have a new set of pulleys i can't return because i've installed them. thanks
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ICON Motorsports
1st & 3rd
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ICON Motorsports
1st & 3rd
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Joined: Jul 1999
Posts: 18,457
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From: Loveland, OH, US
Car: 4
Engine: 6
Transmission: 5
I don't think the weight would be a concern, if anything it would help make the balancer balance better. However if you wan tto be on the safe side you could make your spacer out of aluminum. Just be sure it's balanced so it doesn't cause a vibration.
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"So many Mustangs, so little time..."
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"So many Mustangs, so little time..."
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Ed,
Not to burst you bubble or anything, but have you seen the dyno numbers on the underdrive pulleys? Not the ones from the March guys, but independent numbers.
If you think about it, the alternator is still going to electrically load the engine with whatever wattage output it takes to keep the battery fresh. That's what the regulator does. The A/C compressor is not usually on during peak power runs, so the only load is from the free-wheeling mass of the clutch sheave. The A.I.R. pump takes a little over one HP at 4,500 RPM, so any improvement there will be negligible. And the PS pump doesn't require any power until the steering box valves open and stop bypassing the pump lines. A direct-drive radiator fan can be a big power consumer at any RPM, so the best idea there is an electric fan setup, eliminating the problem. A viscous fan clutch helps a little if you have the direct fan.
IMO, the biggest advantage of the March sheaves is that they are aluminum, allowing the engine to spin up a little bit faster. The diameter reduction is not that big an improvement in power. On the down side, the aluminum sheaves will wear out faster, allowing the belts to pull down in the grooves and slip/slack off.
For my driving, a lightweight steel set of sheaves would do just as well. Since you're stuck with the setup, a spacer would be acceptable, but will change the harmonic dampening of the balancer, but probably for the better. I would avoid using aluminum for the spacer, since it is a somewhat fluid metal unless you can heat treat it after machining. If the metal flows away under the pressure of the crank bolt, the damper can become loose. I'd stick with a good steel spacer machined flat on the ends and radiused on the inside to clear the radius on the crank snout. The little extra mass on the snout shouldn't be a big problem, and will just about offset the weight advantages of the aluminum sheaves. just make sure that the length of the snout remaining is at least 1-1/2 times the diameter to provide good bearing area, or the balancer might start wobbling on the snout and wearing the crank.
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Later,
Vader
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"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0
Not to burst you bubble or anything, but have you seen the dyno numbers on the underdrive pulleys? Not the ones from the March guys, but independent numbers.
If you think about it, the alternator is still going to electrically load the engine with whatever wattage output it takes to keep the battery fresh. That's what the regulator does. The A/C compressor is not usually on during peak power runs, so the only load is from the free-wheeling mass of the clutch sheave. The A.I.R. pump takes a little over one HP at 4,500 RPM, so any improvement there will be negligible. And the PS pump doesn't require any power until the steering box valves open and stop bypassing the pump lines. A direct-drive radiator fan can be a big power consumer at any RPM, so the best idea there is an electric fan setup, eliminating the problem. A viscous fan clutch helps a little if you have the direct fan.
IMO, the biggest advantage of the March sheaves is that they are aluminum, allowing the engine to spin up a little bit faster. The diameter reduction is not that big an improvement in power. On the down side, the aluminum sheaves will wear out faster, allowing the belts to pull down in the grooves and slip/slack off.
For my driving, a lightweight steel set of sheaves would do just as well. Since you're stuck with the setup, a spacer would be acceptable, but will change the harmonic dampening of the balancer, but probably for the better. I would avoid using aluminum for the spacer, since it is a somewhat fluid metal unless you can heat treat it after machining. If the metal flows away under the pressure of the crank bolt, the damper can become loose. I'd stick with a good steel spacer machined flat on the ends and radiused on the inside to clear the radius on the crank snout. The little extra mass on the snout shouldn't be a big problem, and will just about offset the weight advantages of the aluminum sheaves. just make sure that the length of the snout remaining is at least 1-1/2 times the diameter to provide good bearing area, or the balancer might start wobbling on the snout and wearing the crank.
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Later,
Vader
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"No matter how hard you try you can't stop us now"
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From: Jackson County
vader, i had to buy pulleys anyway, didn't have any with the little engine and wanted to run a flat belt. i don't think i'd buy them if i didn't need a set. there isn't any PS on this car and the water pump is eletric so that isn't a problem. i have an eletric fan, my engine is so far back from the radiator a regular fan wouldn't do much good. the more i've thought about it the more i think i'll buy the alternator drive kit from moroso and set it up the way it's suspose to be and try to sell my pulleys before they end up on my sons engine.
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ICON Motorsports
1st & 3rd
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ICON Motorsports
1st & 3rd
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Ed,
If you're using the aluminum shaves with a poly 'V' belt ("serpentine") the life expectancy should be better than with a regular 37° 'V' belt. Still, I'd be a little wary of getting the balancer sticking out another inch. I suspect you had concerns as well, or wouldn't have posted the topic. Since the "little engine that could" will probably be pushed to make more power than most V-8s, you'll need all the advantages you can get in strength.
You've installed the March set but not run them, so you might have a little leverage in returning them. It's worth a phone call.
------------------
Later,
Vader
------------------
"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0
If you're using the aluminum shaves with a poly 'V' belt ("serpentine") the life expectancy should be better than with a regular 37° 'V' belt. Still, I'd be a little wary of getting the balancer sticking out another inch. I suspect you had concerns as well, or wouldn't have posted the topic. Since the "little engine that could" will probably be pushed to make more power than most V-8s, you'll need all the advantages you can get in strength.
You've installed the March set but not run them, so you might have a little leverage in returning them. It's worth a phone call.
------------------
Later,
Vader
------------------
"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0
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