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Author Topic: Enya 29 woes  (Read 2473 times)

Offline Dane Martin

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Enya 29 woes
« on: November 02, 2020, 01:50:47 PM »
One of my free flight companions was having issues with his enya 29. The one with the square black venturi insert. It was hard to start, and down on the power.
So we pulled it off and it was noticeably binding just turning by hand. We suspected a bent crank. I took it home for disassembly.
 Spun the crank in the lathe, just fine. What I found was, from always using a starter, the prop drive was worn into the case. It was worn enough to allow the crank to make contact with the rod, and it bent the rod. I was able to put two gauge pins in each hole, and press the center of the rod until the pins were parallel. I also turned the back side of the prop drive to rid it of that nasty, sharp ridge it developed. So now there's a little more gap between the drive and the case. Reassembled the engine and now it seems completely normal.

Here's the question... I'll assume this engine would continue to be operated the way it has been... with that starter. Also, there was enough clearance to allow the crank to contact the rod. And now there's more.
 Would a steel thrust washer be advisable between the drive and the case?
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Offline Tim Wescott

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Re: Enya 29 woes
« Reply #1 on: November 02, 2020, 02:29:47 PM »
I dunno Enyas, so what's the prop driver made of?  If it's aluminum, then yes, a steel washer would probably be a big help.  If it's steel, then I'd use a bronze washer.  Whatever washer you use, make it as smooth as you can get it.

If it's an aluminum driver on an aluminum case, you're just asking for things to wear out.

I've got a Cox 049 engine that I used a starter on -- what I thought was sparingly.  Just half an hour of cussing at a Cox Babe Bee with a starter will chew it up.  I'm thinking of capping that case with a brass or bronze end-piece, to space it out where it belongs and provide a dissimilar metal for the aluminum drive washer to ride on.
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Offline Dane Martin

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Re: Enya 29 woes
« Reply #2 on: November 02, 2020, 03:47:33 PM »
Tim, it's an aluminum drive and nothing between the drive and case from the factory. So the little prop drive was worn excessively. The case showed some wear, but nothing that couldn't be cleaned up. It's a nice engine. But it does not enjoy the starter!
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Offline Dave Hull

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Re: Enya 29 woes
« Reply #3 on: November 02, 2020, 04:20:35 PM »
Danish,

It gave you the electric finger, eh?

Yer gonna need a spacer behind the drive now, of some sort, else'ns the crank pin gets shoved into the back of the case. The OS's use a precision steel washer for this....not sure about them YenYas.

Measure the endplate or use something like Plastigauge to figure out the thickness of the washer now required. I'd prolly shoot for something like .010" crankpin clearance.

Divot
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Offline Dane Martin

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Re: Enya 29 woes
« Reply #4 on: November 02, 2020, 04:54:16 PM »
Oh it's made contact. Haha. Because there's no removable back plate, it's just gonna have to get a minor clean up so there's no metal flakes floating around in there.
But yeah, there's gonna have to be something. It's gappy!
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Offline Dane Martin

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Re: Enya 29 woes
« Reply #5 on: November 02, 2020, 04:55:00 PM »
Where the crank met the rod
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Offline Brett Buck

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Re: Enya 29 woes
« Reply #6 on: November 02, 2020, 08:30:31 PM »
Good diagnosis and fix.

   What I cannot understand is how, when most stunt and combat people get nearly instant start without even bothering to flip it through compression, and other guys have  grind and grind on it with an electric starter long enough to cause this sort of wear.

     Brett
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Offline Dane Martin

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Re: Enya 29 woes
« Reply #7 on: November 02, 2020, 09:16:41 PM »
Interesting aside to that, is everyone looked at me funny when I first started flying with these guys, as I hand start my engines. Haha.

I believe it's a free flight thing? I mean, these guys know what they're doing for free flight. So I would never take away from their expertise in that. When he mentioned he was having issues, I thought back to my youth.
 I had an enya 35, this same case. I got it used for dirt cheap. And, it was because it was hard to start and ran with very little power. I disassembled it, and found this same failure. Now, as a kid I cleaned it up as best as I could with some of dad's tools, but I don't know if it was really better or not. But, I could hand start it. I put it on a trainer and that's how it lived out life. Knowing what I know now, I would bet money that one had a bent rod also. I just didn't know enough to know.
 So at least now I have the tools to put engines back to their OEM specs for myself and friends!
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Offline Dane Martin

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Re: Enya 29 woes
« Reply #8 on: November 02, 2020, 10:36:04 PM »
Ha! Thanks for making that simple MM. I was considering a few things, but that sounds like a nice easy approach
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Offline Brett Buck

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Re: Enya 29 woes
« Reply #9 on: November 02, 2020, 10:57:03 PM »
Quote from: Dane Martin on November 02, 2020, 09:16:41 PM
I believe it's a free flight thing? I mean, these guys know what they're doing for free flight. So I would never take away from their expertise in that.

   That is a bit surprising, FF guys know what they are doing, in general. This seems like classic RC Club Dork stuff.

       Brett

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Offline Reptoid

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Re: Enya 29 woes
« Reply #10 on: November 03, 2020, 01:17:10 AM »
Must have ground the hell out of that thing. A normally fit rod on an Enya or any other engine for that matter can not travel forward on the crank pin far enough to hit the counter balance on the crank. If it could it would do so while running. Normally the fit of the rod in piston and on crankpin is such that it stays centered in the bore with enough clearance to reduce drag but not enough to allow damage. In some engines the rod may move enough to make faint marks on the backplate. Competitive free flight folks generally know what they're doing but many that indulge in free flight are somewhat famous for "Starter Abuse". Bent and broken rods are not uncommon, and damaged front ends on bushing engines abound. The Enya's bent rod likely occurred from a flooded engine starter insertion. The rubbing on the counter weight was likely induced by the bent rod.
 
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Offline C.T. Schaefer

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Re: Enya 29 woes
« Reply #11 on: November 03, 2020, 05:20:18 AM »
McMaster has steel shims in inch and metric. Come in assorted thickness. affordable.

PS   I am working on that Sterling  S-8  109 that I got from you!
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Offline pat king

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Re: Enya 29 woes
« Reply #12 on: November 03, 2020, 10:20:15 AM »
Dane,
Two things, the rods on those engines do not have the beam portion centered in the ends. The side with the clearance goes forward toward the crank. The crank pin should hit the back end of the crankcase before the counterweight hits the rod. On the next models the Model 5225 engines the back face of the prop driver is counterbored and they run a hardened steel washer in the counterbore. The washer is hard to see because it only protrudes about .005 beyond the face of the prop drive. Make a washer out of something harder than mild steel and lap the faces so they are exceptionally smooth. You probably don't have a lapping plate, so just use a piece of plate glass. We used plate glass and 400 grit valve grinding compound "in the day" to lap motorcycle heads and jugs. That was the only way I got my 650 Triumph to hold. It kept blowing head gaskets. I guess it objected to 12 to 1 CR.

Pat
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Offline Dane Martin

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Re: Enya 29 woes
« Reply #13 on: November 03, 2020, 11:02:49 AM »
Thanks for all the help gents.

The bent rod could be 100% from a flood and the starter. That makes sense. The crank pin is definitely hitting the back plate, so now that'll be my focus to finalize the fix. I appreciate the assistance on making the thrust washer. Got a call from Uncle Pat and I got a handle on making and lapping it now. Larry will get a like new running enya 29 back!
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Offline Dane Martin

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Re: Enya 29 woes
« Reply #14 on: November 03, 2020, 11:05:17 AM »
Quote from: Reptoid on November 03, 2020, 01:17:10 AM
Must have ground the hell out of that thing. A normally fit rod on an Enya or any other engine for that matter can not travel forward on the crank pin far enough to hit the counter balance on the crank. If it could it would do so while running. Normally the fit of the rod in piston and on crankpin is such that it stays centered in the bore with enough clearance to reduce drag but not enough to allow damage. In some engines the rod may move enough to make faint marks on the backplate. Competitive free flight folks generally know what they're doing but many that indulge in free flight are somewhat famous for "Starter Abuse". Bent and broken rods are not uncommon, and damaged front ends on bushing engines abound. The Enya's bent rod likely occurred from a flooded engine starter insertion. The rubbing on the counter weight was likely induced by the bent rod.

Don, that makes sense. It must have bent towards the crank weight, and then pushing the heck out of it with the starter contacted the rod. The crank pin hitting the back of the case probably prevented the crank from hitting the rod more! At least it's all salvageable
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Offline bob whitney

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Re: Enya 29 woes
« Reply #15 on: November 03, 2020, 11:23:27 AM »
one of my biggest pet peeves is ANYONE who puts a motor in a starter and grinds til it starts or doesn't.
 it is the same people who cant get a one to 3 flip finger start that cant get a bump start in a starter. Racing and combat guys can get one flip starts because they know how to prep the engine before trying to start it, the same thing needs to be done before using a starter.the. speed guys do the same before using a starter.
 most stunter engines are inverted and need to be primed and the fuel brought up to the motor before bumping it with the starter.an exhaust prim is out if it has a muff so flip plane over and put two or 3 drops of fuel in the venturi  flip it over three or 4 times  hook up batt and see if u get a bump ,if so dis connect batt flip back over .using your syringe or a fuel bulb (u remember what those are right) force .

some air into the uniflow tube ,connect batt and bump it with the starter .if using a stand up start dropping the nose down just a bit will help getting fuel to the engine .every setup is diff so u need to take the time to find out what yours wants

free flight has become a one man operation  so hand starting is almost non existant as it normally takes two to hand start a FF model so a starter is almost a must . RAD
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