End Play when hand turning prop

[kmacht]

A little tip to help with the engine pull. You can remove the engine but still leaving the accessory case on the engine mount. It can easily be done and makes it so you don't have to pull all the wiring off for the p-leads and electronic triggers. You are going to have to pull the accessory case off anyways to work on the motor so you may as well leave it on the mount.

Keith

[GWMotley]

I had to rebuild my engine this summer due a similar amount of play. But, I also had some oil leak and about 300 hours on the engine. It turned out that the prop hub bearing had gone bad and was severely gouged. My engine still had the restrictor plug in the the galley as this suggested mod came out after I had already hung my engine. I now see that in the latest service manual edition that Sonex recommends not only removing the oil galley restrictor plug but to also up drill the oil hole in the bearing itself. I do hope that perhaps you find someone just didn't install the end play shims but you may have to break the engine down to be sure.
Sorry to there about your problems. I know it a bummer.

[vwglenn]

you may be fine by simply adding shims as needed to elminate the crank movement.

A VW has 3 shims. No more. No less. If you can't get the correct amount of end play with those three shims, something else needs to happen.

Judging by the amount of endplay in the video, you'll probably have to break the engine down. The good news here is your case and crank are probably fine provided it hasn't gone too far or been machined too many times in the past. A little machine work and some new bearings will probably do the trick. Cheap but rather labor intensive.

A good rule of thumb when it comes to VW endplay without measuring is you should be able to feel it sort of click back and forth but barely be able to see it move if at all.

[SonexN76ET]

I am going to disagree with some of you on the "play" you feel when hand turning the prop. I verified this with Kerry at Sonex. You will feel the prop move in and out a little when you turn it by hand. This is due to two things. The first, is that the movement is more noticeable because with the prop on you are feeling it with a 54x44 inch disk on the front instead of a four inch pulley as you would in automotive trim. The second is that the crankshaft and camshaft have the intermeshing gear with angled gear groves. So if you move the prop one way, then reverse the movement and move the other way the crankshaft is being pushed forward and then backward by the interlocking of the angled groves on the prop and camshaft. This movement will feel to be more than what the crankshaft endplay is set at. It "feels" like it is 1/16th or an inch or so versus the .006 inches the crankshaft endplay is set at.

However, in the video link provided in your example, that does appear to me to be excessive movement and you need to check with Sonex on their recommendation for your particular situation.

[gammaxy]

A VW has 3 shims. No more. No less. If you can't get the correct amount of end play with those three shims, something else needs to happen.

Just thought I'd point out that the Aerovee Assembly manual says "Select any combination of three to five shims which most closely equals the 'Shim Thickness' determined in step 10".

[vwglenn]

Just thought I'd point out that the Aerovee Assembly manual says "Select any combination of three to five shims which most closely equals the 'Shim Thickness' determined in step 10".

Sure thing. Still, adding shims when the end play is out of whack on a running engine is not fixing anything.

[radfordc]

Sure thing. Still, adding shims when the end play is out of whack on a running engine is not fixing anything.

Can you explain further? Isn't adding shims the correct way to control end play? If you have an assembled engine that has too much end play how would you fix it other than adding shims? What else needs to be fixed?

[kmacht]

I think the point was that of you ruined a bearing and beat the thrust faces of the case that adding a ton of shims shouldn't be used to try and fix the problem. You can fix a 1/4 inch of endplay with shims but that doesn't mean you should.

Keith
#554

[corton]

Did you ever hear back from sonex? I have some play as well, but nowhere near what you have. I never sent Kerry a video ( good idea though!) but from my description I gave him, he said it was fine.

Part of the issue is that the crank/cam are beveled gears. To just push and pull on the crank without rotating it, you're fighting the gear mesh as well. And, at the point in assembly when you're setting end play, everything is so tight you usually can't rotate by hand without some leverage. So, I've been led to believe that setting the endplay as per the manual may result in some rotational variation to be observed.

When I assembled mine, I used a rubber mallet to gently tap the hub and flywheel to see how much play I really had.

[jfuerst]

I have heard back from Sonex. In general they confirmed what the group said. Unfortunately I am out of the country for the next couple of weeks and won't be able to pull the engine until mid December. I'll post a follow up for those that might stumble upon this in the future. Lots of great input on this so far though, and for once a forum agreed with the factory (I find that rare with most of my toys).