End Play when hand turning prop

[jfuerst]

I just purchased a waiex (AeroVee) and have been going over it in my shop before I start flying. I have noticed a small amount of end-play on the crank shaft when I turn the prop by hand and have made a short video that shows what I am talking about. Is this normal? If not, guesses on what the cause and fix will be?

Video is here http://youtu.be/0fZyUmoO3L0

Thanks!

[marsolgp]

Looks like crank was not shimmed correctly…. when you move the prop, have someone watch the flywheel. If it's moving too, then shimming will need to be checked. Crank end play should be between 0.003" and 0.006 per build manual. How many hours are on this Aerovee? Any oil leaks at flywheel seal?

[MichaelFarley56]

As much as I hate to say it, I do agree that it appears the crankshaft shims under the flywheel were not calculated and/or installed correctly. That "forward/aft" movement that you pointed out should be between 0.003" - 0.006" total, and yours looks to be much more than that. As 'marsolgp' said, if you see the same movement on the flywheel then you will need to calculate how much fore/aft movement you have and add additional shims as necessary to acheive the proper crank end play.

The bad news is that, in order to reach the shims, you will probably need to remove the engine off the X casing, remove the alternator and ignition shaft assembly, then remove the flywheel gland nut and then the flywheel. The good news is that the shims will fit through the rear crank seal without the need to remove it, and once you've added the shims you need, you can put the flywheel and gland nut back onto the crank by following the engine instructions. At that point, check the crank play again and if it all looks good, reinstall the ignition shaft, remount the engine, and reinstall the alternator.

I'm not sure what the long lasting implications would be if you left this as is. Sort term it may be okay but I don't know about long term. I would also recommend you call tech support at Sonex before you start to see if there's anything to be careful of when performing this work. Be sure to include the link to your video as well so they can see what it looks like.

I know this stinks but it really shouldn't be too bad to accomplish. Hopefully it will only take a few hours all said and done. And, if your engine by chance hasn't been modified by the newest AeroVee Service Bulletins, this is the perfect time to do tht as well. Look at www.aeroconversions.com for more info.

[kmacht]

That is way too much endplay. Depending on how new this engine is it may be as simple as needing to pull the gland nut and re shim it or if it has a lot of hours on it with that much endplay you could have ruined the thrust bearing and likely damaged the case. In either case I wouldn't fly it until you have it figured out.

Keith
#554

[MichaelFarley56]

Depending on how new this engine is it may be as simple as needing to pull the gland nut and re shim it or if it has a lot of hours on it with that much endplay you could have ruined the thrust bearing and likely damaged the case.

Scary thought! Hopefully it would take quite a number of hours to cause that sort of damage. I'll keep my fingers crossed this can be fixed by adding shims and calling it a day!

[jfuerst]

Thanks guys, that was quick confirmation of what I suspected from glancing through the build manual. Of course I'm worried about damage here and I don't really know the history of the plane/engine.

Looks like crank was not shimmed correctly…. when you move the prop, have someone watch the flywheel. If it's moving too, then shimming will need to be checked. Crank end play should be between 0.003" and 0.006 per build manual. How many hours are on this Aerovee? Any oil leaks at flywheel seal?

Here is a video of the flywheel movement (actually a few different views) http://youtu.be/86uTRqcFvOg really just in case someone else runs into this they can have a comparison...

I have noticed a very small amount of oil under the cowling but have not been able to narrow it down to where it is coming from. It seems to concentrate and drip off the carb, but it's such a small amount it's hard to know.

That is way too much endplay. Depending on how new this engine is it may be as simple as needing to pull the gland nut and re shim it or if it has a lot of hours on it with that much endplay you could have ruined the thrust bearing and likely damaged the case. In either case I wouldn't fly it until you have it figured out.

The engine has 300 hrs on it...

[rizzz]

I would first of all check with Sonex but I fear that, like others have mentioned, that is way too much end play. The 0.003 to 0.006 as required is normally hardly even noticeable on the prop end.

If it's just a matter of adding a few shims, it's not as big a job as you might think. Yes, you will have to remove the accessory case, alternator, fly wheel, etc. but I think you could knock all this over in half a day or so. You might want to find someone in the neighborhood who has assembled their own AeroVee before to help you with this.

The only thing you might struggle with is removing the gland nut. If it does not come off easily, an impact wrench is the tool for the job here, BUT, it is strongly recommended not to re-use it if that was indeed required.

One final issue is measuring the number of shims for the correct end play, Sonex has you do this when the case halves are not joined yet, this is easy. Measuring this now will require a specialized tool, you can either make this yourself: http://www.aircooledtech.com/end_play/, or buy one: http://www.ebay.com.au/itm/VW-ENGINE-CR ... 1073312139

Now here's what I believe may be the bad news:
As I mentioned before, that is A LOT of play, seriously. I'm not even sure you can install enough and/or thick enough shims to fix this problem if that is really the only cause of the problem. I fear something else (more serious) might be wrong here.

BUT, before you do anything, contact Sonex.

[rizzz]

Excessive end play on a VW (not an aero engine in this case but it does not matter):

..In other words, see if the crankshaft can be push-pulled long-wise through the case. If you can see/feel more than the tiniest motion (0.006"-- same feel as a normal tappet movement), the end-play is excessive, usually due to the bearing. If the bearing has been spun, you can NOT compensate by shimming more...

Read the full story here:
http://www.vw-resource.com/endplay.html

From what I can see in the video, I fear you might have a similar issue.

[jfuerst]

Excessive end play on a VW (not an aero engine in this case but it does not matter):

..In other words, see if the crankshaft can be push-pulled long-wise through the case. If you can see/feel more than the tiniest motion (0.006"-- same feel as a normal tappet movement), the end-play is excessive, usually due to the bearing. If the bearing has been spun, you can NOT compensate by shimming more...

Read the full story here:
http://www.vw-resource.com/endplay.html

From what I can see in the video, I fear you might have a similar issue.

I think you are right. I sent sonex an email and will be pulling the engine in December when I return from a 3-week trip abroad :?

Thanks guys.

[MichaelFarley56]

If you don't mind, please let us know what Sonex tells you.

My gut tells me that, if the engine was just rebuilt and only had 10-20 or so hours on it, you may be fine by simply adding shims as needed to elminate the crank movement.

It seems like the problem could be wear over long term. If your engine has 300 hours on it and it's been like that the entire time, my first thought is that this problem can't be too major or else the previous owner would have had oil pressure issues, but my guess is Sonex will tell you to split the case and install all new crank bearings.

Just a guess though...