Dial Indicating Fan Hubs ( Important)

[DavidH]

Thought I would post this method of dial indictating fan hubs that Ben Minor wrote. It is important to dial indicate the fan and have it running true so that delrin ball and the dampeners will require less maintance.

Also I will suggest to take a feeler gauge and check the distance between the fan hub and clutch driver ( Fury) or the clutch ( SE,ST, P2K). To make sure the hub and clutch or driver are square to each other. The gap needs to be between .030 to .035 between the fan hub and driver or clutch. If the gap is .032, it should be .032 at each 90 degs between fan hub and driver or clutch without rotating the fan hub. The .032 is just an example distance, the distance just needs to be the same at each place checked.
This will assure that each surface is sqaured to each other.

Now here is Ben's method for dial indicating the fan, it is simple to do.

Find yourself a 12 inch or so piece of hardwood dowel about 1/2 inch in diameter. Its use will be explained shortly. Remove the back plate and plug from your motor. I also pull the piston and sleeve to yield a completely drag free crank, but I don't force that step on people.

Lightly oil the collects and assemble the fan on the motor. Tighten the nut until the assemble JUST STARTS to draw down. Don't crank down on the nut. Dial the fan. If the fan is out more than 1 thou, gently tap the fan's face with a plastic hammer as Gordie suggested. I actually have a piece of flat aluminum with a thin piece of card glued on to it that I use to protect the fan face from dings. You don't have to tap hard at all to get the fan to dial true. The purpose of the dowel lies here. Have a friend hold the dowel against the crank counterweight and place the other end on a FIRM surface while you tap the fan face. Supporting this way makes certain that only the fan is shifted; the crank and bearings never see any force.

When you've got the fan back to 1 thou or less, tighten the nut a little more. Redial. Retap to retrue/align if needed. Never continue to tighten UNTIL you've gotten the rounout to less than 1 thou. As the nut gets tighter, I generally work harder to get to 1/2 thou or below. You might have to tap more than once. You NEVER have to hit hard AT ALL. The whole reason for tapping as you go is to keep the fan straight on the collets as the assembly tightens down. When the assembly really starts to snug up, make final tap adjustments before completely torqueing the nut. Almost without exception, if I've reduced the fan runout to 3/4 thou or less just before the final torqueing, the runout either holds stable or actually improves to drop to below 1/2 thou. My two Furys have one fan dialed at 1/4 thou and one just a hair (~1/3 thou) more than that.

As drawn out as this is to describe, it only takes about 45 minutes to do. It isn't at all potentially frustrating like the hit or miss techniques of rotating the fan and then rechecking. It's really rather pleasant to do, because you have control over the process each step of the way, and you don't proceed until things are dialing correctly.

Make no mistake. A model with a fan runout below 2 thou will likely show little perceptable vibration and certainly shouldn't crack sideframes. HOWEVER, a model with a fan running with near zero runout has a special, sweet sound, and the bearing and other component life on the drivetrain are exceptional.

Best regards,

Ben Minor


Hope this helps, it is an important step in building and maintaining.


David

[Greg McFadden]

thanks I need to do that bad

[WillJames]

Very good information David. Thanks for sharing.

[Alfred]

One of the best info I have seen.
I am going to a Funfly event this weekend. After this all my helies will have their engines pulled out and realigned according to the above suggestions.

[conrod]

How about a video ?
I know that the cool dude that did the video of balancing a fan on ice could produce such. :wink:

[Bonsai]

I started Dialing my fans about a year ago..... they are less than a thou... It really does make a big diffrence....

[WillJames]

Sweet Information. I was able to get my fan runout down to just a shade under .001 using the tap and slowly tighten method. I did not have a dowel, so I used the OS Delrin crank lock tool to hold the crank when I lightly tapped.

Thanks again Ben and David!!!

YEA!!!

[conrod]

Ok...so what are you guys clamping your motor into to hold it while you dial indicate it?
I'm using an old Graphite 60 motor mount and putting the mount in a vice and lightly snugging it up to check.
I too would like to see the Video

[DavidH]

I use a vice that goes on a drill press. The dial indicator is stuck to the vise with a magnetic base. I then snug the motor up in the jaws of the vise to hold it. I tighten up the vise just enough to hold the motor so it won't move when I spin it to check runout.

David

[Hardcarve1]

DavidH I use the same method you use with the drill press and it works great. I have also tried this method of tapping the fan and it made no difference when I did it but I was still able to get the fan down to .001.
Alex

[DavidH]

I don't use a drill press. The vice that I use to hold the motor and dial indicator is the type that is usually used on a drill press. I use the method in the first post to dial indicate the fan. The vice I use is a 6 inch flat vice, I can snug the motor in the jaws, then the magnetic base of the dial indicator sticks to the flat surface on the vice also. So both pieces are in the same piece of equipment.

David

[mevigavant]

On the Fury, do you place the DI(dial Indicator) on the top of the clutch(looking down I can see the black rubber grommets) or on the side. I would like to know so when I get my Fury next month I know what to do.

[DavidH]

The clutch is not dial indicated. It is not attached directly to the fan hub. The fan hub is what needs to be dial indicated. I check the fan hub on the inside edge where the uniball rides. The outside diameter can be used also if that is easier.
Read the first post in this thread. That is the procedure that works best for me.

David

[mevigavant]

sorry about that i meant fan.

[misio]

can you tell me where i can get chip dial indicated? What is the brand that your are using?

tom

[Robert Johns]

Check out this link for an inexpensive dial indicator and magnetic base.

Dial Indicator
http://www.harborfreight.com/cpi/cta...itemnumber=623

Multi-position Magnetic Base
http://www.harborfreight.com/cpi/cta...temnumber=5646

-robert

[misio]

Thanks for info

I just order one from Amazon.com 29.99 with stand and dial.

[marked23]

What about dial indicating the underside (bevel) of the fan? That's where I was going to try it.

Now that you mention it, the I.D. that meets the uniball is probably the most important. However, my indicator doesn't really fit in there well. I have one of those big 1" indicators.

-Mark

[DavidH]

Dial indicate the outside of the fan hub or the inner diameter. Those two locations are going to give the most accurate reading. I have a two inch dial indicator and can get the point inside the inner diameter of the hub just fine. The tip of the indicator can be at an angle. Just try to keep the angle as least as possible.

I would not dial indicate the fan at the bottom. It could be perfect at the bottom and then be out on the end that connects to the clutch.

David

[marked23]

Waaaa!

It didn't work for me. I got it down to .001 then tightened a little. Then recheck, good. Tighten more, still good. (several iterations)... One last crank down... then .003.

Now the dang thing is on there tight, and loosening the nut gives me nothing. I can't tap it in again with my hammer.

Did I maybe over torque it? I'm just holding the engine in my hands. I figured I couldn't torque it too much that way.

Where do I go from here? (new collets and a fan puller?)

-Mark