Aluminum dust around blower belt area...

Ive got around 10 passes and a bunch of warm ups on the engine now, and just noticed very, very fine aluminum particles on my fuel pump, and on the bracketry on the front of the engine. I'm pretty sure what I'm seeing has accumulated over time. It seems to be generated by the blower belt. The inside of the blower belt is covered with the same stuff. I checked the idler, and it is turning OK.

Is this normal?

Should the inside of the belt be lubricated with something?

Thanks,

-Brian

 

Aluminum Dust

You may need to check the alignment on your belt. It may be rubbing the side of the idler, creating the dust. Does your belt run off your top or bottom pulley? Look closely at your alignment and make adjustments as necessary. Also look at all of your front brackets to be sure the belt isn't rubbing one of them.

 

Its normal to see belt dust, but I've never seen aluminum. That might make me nervous
enough to start looking for the source.

After about 5 passes on our new belt the front of our motor turned purple.

Are you sure that your belt and pulleys the same profile, gt vs htd?
Are your pulleys anodized or plain?

 

The belt is rubbing the front of the idler. At first glance it looks like there is an air gap, but I cant get a feeler gauge all the way to the bottom, so that might be the source.

So is it as simple as just putting more pressure on the front side of the idler to persuade the belt back where it belongs?

Also, I don't know how to tell if the pulleys are anodized or not. They are plain aluminum color.

-Brian

 

The idler may need to be shimmed to correct any mis-alignment.

I think forcing the belt using the idler is going to cause more problems. The belt should align itself freely and be centered on both pulleys, the idler should be only to just adjust belt tension.

If the belt wants to move either forward or backward, it would seem that the pulleys are not aligned to each other.

 

Make sure your bottom pulley bolts are not to long also.

Mark

 

shim it. the idler is machined with a crown..Dave

 

OK, I took the idler off to shim it and the front lip is not abraded, it's nice and smooth. So where I thought it was rubbing it really wasn't. At least not enough to make dust. The main face of the idler, where the belt rides, is rough (matte). I'm certain this is the origin of the dust. When I checked the belt it was looser than I would like, so I'm thinking the belt may have been "skidding" on the idler. I probably just didn't get it tight last time I tensioned it, probably 6 passes ago. I'm gonna clean everything up and re-tension the belt and watch it at the next race.

Bottom pulley bolts are not hitting. The belt isn't hitting anything. It has to be the idler or the pulleys making the dust, and I don't see anything that looks like wear on the pulleys. We'll see weekend after next.

-Brian

 

You might check your fuel pump shaft standoff clearance to your timing wheel if your fuel pump is in the front of the motor.

 

don't use any solvents or carb or brake cleaners on the belt..Dave

 

Pretty sure I'm good there, but I'll check it anyway. These are very fine particles. I just happened to get some direct sunlight on the front of the engine Saturday and saw some glistening on the fuel filter, fuel pump standoff, etc...

 

check that the bolts holding the upper pulley aren't bottomed out and rubbing on the end of the blower snout

also check that the lower bolts aren't bottomed out and rubbing on the front cover.

 

check that the bolts holding the upper pulley aren't bottomed out and rubbing on the end of the blower snout

also check that the lower bolts aren't bottomed out and rubbing on the front cover.

 

Idler

Check to make sure the idler bracket is square to the motor and has no flex.
This is more common than you might think.

Check top and bottom pulley alignment. Belt wear marks on pulley should show if it's trying to run off front or back of pulley. Don't automatically rule out a bad belt.

Final thing to check is the idler itself. It's a subjective call, but it should be very free to turn.

Bob

 

Thanks for the input. I'll check all those things next time I'm in the shop. I'm pretty sure It was just a loose belt. I was able to grab the idler and turn it by hand with the belt on. Even though the idler turns freely with the belt off (about the resistance you would expect with a couple of sealed bearings), with the belt that loose it was almost certainly "skidding".

I blew the front of the engine clean yesterday so it'll be easy to spot if it comes back.

Thanks for all the suggestions. I wouldn't have thought of some of them.

-Brian

 

Did that one