Plane Power Alt. Install Problem

[Indiana Larry]

While I wait to hear more from Plane Power alternator folks, I thought I would post an issue here to see what I might learn.

I am installing the Plane Power 60A with Boss mount on an O360 A1A. After everything is mounted and torqued I have found the pulley on the alt. to be about 75 thousands aft from where it should be to be in perfect alignment with the ring pulley. I am sure it will run in this position but it should cause extra friction and wear on the belt and perhaps less than a long life alternator. PP folks have been nice in receiving my call and the pictures I emailed of my install. I suspect I have done something wrong. But, Small world I guess, it just so happens the fellow next to me is installing PP on his plane and after I mentioned it to him, we found his to be just like mine.

I would like to hear from anyone with ideas or experience on this issue.

Larry in Indiana with Yellow RV7, SunSeeker 240 hours.

[gmcjetpilot]

75 thousand, 0.075.....humm are you a machinist?

I say make it perfect; other wise you won't be happy.

Perfect both in fwd/aft alignment and angles will make the belt last longer, run cooler and cause less drag. How much, who knows. The advantage of V-belts is they can take twist and miss alignment with out noticeable loss of life or reliability.

Can you get out a little "persuader and tap the bracket? (that might get you 0.075")

Can you file oh so little of the bracket or alternator mount ears and shim?

Can you elongate the bracket mount holes ever so slightly and slide it forward a bit?

If you can stand back and see it, it's too much IMHO. If you're getting out the straight edge, vernier calipers, micrometers and laser level to measure it, than ............

The way I do it, put the belt on the flywheel, mount it, put the alternator on, adjust it so the belt looks straight and untwisted, by eye. There's always some play in the brackets and alternator bosses. Most brackets are set up to shim fwd/aft. There's nothing wrong with taking say 0.040" off the alternator ears with mr. file; that would put it within 0.025", now that surly OK. Make your self happy.

Their is nothing wrong with being picky; it can't hurt. It sounds like you have it installed right; PP tried to cut it so no shim was needed. However alternator cases, flywheels and the case mount boss on the engine all have tolerances that can stack up in one direction.


PS: Don't make the belt too tight or you will toast the alternator bearing.

[newtech]

Originally Posted by Indiana Larry

While I wait to hear more from Plane Power alternator folks, I thought I would post an issue here to see what I might learn.

I am installing the Plane Power 60A with Boss mount on an O360 A1A. After everything is mounted and torqued I have found the pulley on the alt. to be about 75 thousands aft from where it should be to be in perfect alignment with the ring pulley. I am sure it will run in this position but it should cause extra friction and wear on the belt and perhaps less than a long life alternator. PP folks have been nice in receiving my call and the pictures I emailed of my install. I suspect I have done something wrong. But, Small world I guess, it just so happens the fellow next to me is installing PP on his plane and after I mentioned it to him, we found his to be just like mine.

I would like to hear from anyone with ideas or experience on this issue.

Larry in Indiana with Yellow RV7, SunSeeker 240 hours.

I am not sure how much mis-alignment is too much. Mine, on exactly the same configuration as yours, is out of line by just over 1/8". 1/8", over a distance of 5 1/2 inches between the points where the belt is tangent to each pulley, seems to be a lot to me..

Steven Eberhart
RV-7A, Genuine Lycoming O-360-A1A and still waiting for my Catto to be delivered.

[Indiana Larry]

I got an email from PP today that they agree the alternator pulley is out of alignment with the pulley on the gear ring from my pics and I do have the alternator properly installed. PP indicates they have always found this condition to be caused by not indexing the gear ring correctly on the crankshaft.

I will check that tomorrow and if you do hear anymore from me on this, that means it resolved the problem.

Thanks to all those who responded. This forum is great.

[Radomir]

I checked mine tonight and I did not notice any mis-alignment... everything looks fine.

[gmcjetpilot]

Originally Posted by Indiana Larry

I got an email from PP today that they agree the alternator pulley is out of alignment with the pulley on the gear ring from my pics and I do have the alternator properly installed. PP indicates they have always found this condition to be caused by not indexing the gear ring correctly on the crankshaft.

Something does not sound right? Not picking on you Larry but the fly wheel is one piece cast aluminum. It slips on the crankshaft dowels and is sandwiched by the prop There is no possible miss alignment, in my mind.

The RING GEAR is steal part that press fits on the OD of the aluminum flywheel/pulley. This part engages with the starter only. The ring gear has nothing to do with the pulley or alternator.

So I am confused. Now there are some "experimental" non PMA or non OEM Lyc flywheel's that someone cast. I bought one on eBay and got rid of it. It was OK but had some porosity in the casting, ie holes. It was probably structurally OK, but decided not to use it, sold it and bought a used Lyc flywheel/pulley/ring gear assembly.

It's possible the flywheel was made, machined a little off? However the PP mounting should have some latitude in adjustment.

[Bill Dicus]

If indexing is incorrect it's possible the pulley/ring gear assembly is not seated fully. If it is mis-indexed and the prop is torqued fully the pulley assembly and the stud on the crank can be damaged - bad news. This was done to a friend's RV-8 by an A&P who should have known better. It would be worthwhile to check! Consult a local mechanic if there's any question. Bill

[szicree]

Originally Posted by gmcjetpilot

the fly wheel is one piece cast aluminum. It slips on the crankshaft dowels and is sandwiched by the prop There is no possible miss alignment, in my mind.

Unless the person putting it on didn't know about the dowels. This would push the ring gear forward by about ... maybe 0.075 inch?

[Indiana Larry]

PP folks were very congenial. They addressed two solutions to the problem that only I and someone else has had in many installations. They suggested filing .075" off the forward inner edge of the U bracket to move the alt. forward and add a shim at the back of the U bracket to make everything tight. Also a shim of .075" is added behind the top belt adjusting bracket to move it forward. That solution will not void the alt. warranty.

The other solution is to file off at the front of the alternator mount tube that the AN7 bolt goes through. The alternator mount tube is made up of a front part (smallest), middle part which is the alt. casing, and a back part. I was able to remove the front part by twisting it after applying some WD40. Due to availability of AN washers with a thickness of .062", using a milling machine I removed .062" from this front sleeve that actually fits over a thin tube that is inside to keep it together. You can see this readily after you twist off the front sleeve. I also had to file away about .062" from this thin inside tube so it would not bottom out when the front sleeve is reinstalled and torqued down within the U bracket. I added a .062" washer to the rear at the U bracket and under the upper belt adjustment arm to keep everything in perfect alignment. It works fine after a couple of runups and flights. Of course, I have voided my warranty according to PP by going this way but I know the belt is running without additional torture to it and I have not weakened any parts which I would have done by filing away on the U bracket. In addition, the alternator should be happier without that extra twist that would always be there while it is running. The alternator looks great also.