Need Single-Groove Billet Crank Pulley...

[66 Restomod]

I officially give up on the March underdrive crank pulley -- seems to be too small for my application and the charging system doesn't charge enough until 3000rpms... I've been through two batteries, two alternators, and on my third voltage regulator. But I do like the water pump and alternator pulleys that came in the kit. Anyone know of a stock diameter billet crank pulley on the market? I haven't been able to find a March pulley in this stock diameter (single-groove, three-hole) anywhere but I may call them tomorrow. Thanks!

 

[Rusty67]

What alternator are you using and how much underdrive did you get ? I think there are usually different ratios for under drive pullys. Maybe ask them if they have one with a closer to stock ratio ?

 

[iskwezm]

March offers a few different options like a stock size set up and one for "super cooling". I threw mine away i had on both my trucks for the same reasons.

 

[66 Restomod]

I'm using a newly rebuilt 61amp alternator that's kinda a ringer I guess, because the testing card that was attached to it shows 68amps at 5000rpm. I have no power anything, no AC, no radio, but do have all lighting, gauges, heater/blower, and a single electric fan from Old Air. This might not be a problem if I had a 100amp alternator or larger, but I couldn't even imagine if I had the stock 40amp alternator. The pulleys do look good though.

I'll see if they can sell me a stock size crank pulley. The others are pretty much the same size. Hopefully this is my charging issue, and soon will be fixed...

pulley+compare.jpg (image)

 

[htwheelz67]

your alternator may be the problem, elec fans use some power. I had the same prob on my 408, my fan stayed on after the eng was off though. I removed it and no more probs and my alt is 140 amp. You can find a smaller alt pulley which may help.

 

[66 Restomod]

your alternator may be the problem, elec fans use some power. I had the same prob on my 408, my fan stayed on after the eng was off though. I removed it and no more probs and my alt is 140 amp. You can find a smaller alt pulley which may help.

I was concerned about the fan's drain on the electrical. I have it wired to turn off with the engine off, which helps. I think what's mainly causing the issue though is the 22% or larger drop in alternator output due to the small crank pulley. If I can get the crank pulley back to 6.5 inches in diameter I should be charging again, but we will see. If that doesn't fix it, I then will go to at least a 100amp alternator...

 

[66 Restomod]

update

March doesn't offer a stock size crank pulley for their 1550 kit, but they do offer the 131 alternator pulley which is 2.1" instead of 2.7" for the 137. I'm thinking of trying that. Also found a local OE 1 groove crank pulley which needs sanding and painting...

 

[htwheelz67]

try that, but I have never been able to run an elec fan with a stock style alternator