So got my new Mechman alt in, just curious is if this common/how to fix?

[Syphlyn]

Hey guys!

First off I want to say what a great experience this has been ordering from Mechman, they're always there to answer questions and have great service.

Now I put my new 240a mechman alt in my 2000 f150 today and everything went smooth! I kept the original belt on (I do have a gatorback that is 3/4 of an inch shorter here just in case. The belt seemed to fit good, although it is a bit more lose than it was on the stock one, but not much. I should mention my truck has 40k kilometers so the belt isn't worn out or stretched or anything. Did some driving and everything seems good but I have two concerns:

1) When my truck warms up to operating temp the alt whines, it doesn't come through my speakers and I opened the hood and it is for sure 100% the alt itself. I was told the alt could be noisy as the bearings "break" in so to speak. I was told they are square to start and they wear down to a circular shape after time.

2) When I stop at a red light or stop sign ect... or slow down while in D (drive) my rpms drop to 600 and the alt turns off completely and my voltage drops to 13.0 while slowly draining lower every second. If I put the truck in park it goes back up to 650-700 and the alt engages. How can I stop this as it's going to suck having to turn down my amps/volume every time I'm about to stop or slow down. Would the shorter belt work?

Thanks guys, was just curious to see what you fellas thought about these minor issues, although the second one could be pretty annoying.

[hdorre]

1) The alt bearings squeal to "break in?" Thats... New.. LOL..

Anyway, it sounds like belt slip to me.. considering that your belt is looser than stock.

2) How could you stop this? Bigger alt pulley (easiest route), or different sized crankshaft pulley. Just note that you'll lose a bit of idle output with a larger alt pulley.

[Syphlyn]

1) The alt bearings squeal to "break in?" Thats... New.. LOL..

Anyway, it sounds like belt slip to me.. considering that your belt is looser than stock.

2) How could you stop this? Bigger alt pulley (easiest route), or different sized crankshaft pulley. Just note that you'll lose a bit of idle output with a larger alt pulley.

I don't know mechman told me that today when I called but yeah maybe I'll try the new belt tomorrow if I have time. I did ask mechman if it would operate at idle and they told me yes. I mean it's so close it's ridiculous, probably 25-50 rpm off engaging while driving. You think the tighter belt would fix it?

Edit: TO CLARIFY they never said it would squeal but they said it would be "noisy".

[Broke_Audio_Addict]

Since you already have the new belt It doesn't hurt to try it so just give it a shot see what happens.

[SLYentist]

How does your belt drive maintain tension? spring tensioner? If so, maybe the belt is on the longer side now with the smaller alt pulley, and the tensioner is hitting the stop on the one side causing a clatter at lower RPM. My tensioner clatters, two HO alts, but the belt is tight and doesn't slip. Voltage difference is smaller at idle for me, but it's not as low as battery resting voltage.

[Soccerballzs]

If you have never replaced the belt tensioner in 14 years that could be a issue also weak spring. New tensioner is what I would replace it should have pulley.

[Kyblack76]

Ho hum....

wont charge at idle..

Meh.. most dont care about that anyway...

[Syphlyn]

How does your belt drive maintain tension? spring tensioner? If so, maybe the belt is on the longer side now with the smaller alt pulley, and the tensioner is hitting the stop on the one side causing a clatter at lower RPM. My tensioner clatters, two HO alts, but the belt is tight and doesn't slip. Voltage difference is smaller at idle for me, but it's not as low as battery resting voltage.

If you have never replaced the belt tensioner in 14 years that could be a issue also weak spring. New tensioner is what I would replace it should have pulley.

Ho hum....

wont charge at idle..

Meh.. most dont care about that anyway...

The tensioner is fine. The belt is nice and tight and no slipping is occurring.

I care if it charges at idle lol....so I'm driving down the road come to a red light or a stop sign and am listening to music what do I do when my voltage instantly drops to 12.6 or so?

I have a saz 2000d and a pdx f4.

[Kyblack76]

I know bro. It was a funny.

I hear all the time how "i only care if it charges a shit load at 2k anyway, i dont care about idle"

I was just clowning......

[Syphlyn]

I know bro. It was a funny.

I hear all the time how "i only care if it charges a shit load at 2k anyway, i dont care about idle"

I was just clowning......

Haha well it went over my head . It's been a stressful last couple weeks...having to rma my zv4 12 (which went great, no issues...sundown great c/s!) and now my alt isn't working properly (. Seems to be charging fine when above 750-800 rpm but I have yet to put a real load on it with my 2000d...

The tensioner feels fine as my new belt is just as tight as the stock one. Truck only has 40k kilometers so everything is pretty new, even my stock belt looked new...