15 posts in this topic

Posted

Hello all, 

Not sure if I am posting this twice - just lost my sat momentarily and killed the previous post. In either case here it is again. Couple of pics below of our Subaru EA81 engine and re-drive set up. Only started flying it so too early for me to answer to many specific questions but this is what was done to the engine to modify it. Stratus profiled Cam (no longer available as far as I know, but use local engine shop), higher compression, flowed heads (flow charts to follow), stock ignition, 38 amp after-market alternator, VW Jetta radiator with stock pump and pulley regulated by 16psi cap with 190F thermostat; 

cooling works well, PCV return (right side of re-drive) line will be changed up slightly, air filter - may go bigger, wondering if it leans me a bit too much at high power settings?, electrics - simple is good and same for ignition, points are cheap..., TBI-40 works well, but it is finicki in downdraft mode,  ...and a little glimpse of the other side of the firewall. We will try to post a few more inputs as we get them over the next little while testing this set up here. If you have questions of a similar installation with the TBI, but gear driven than Willis (Marshawk) can probably give you more feedback than "moi", ..as I am only getting started flying it and testing it. 

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Posted

OOPS - dont return the cooling line (right hand side) into the Thermo-Switch port as this will only give you half the radiator. Use both outlets and cap the Switch Port or alternately use it in conjunction with a radiator fan.  

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Posted

What type of aircraft is this installed on?

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Posted

What type of aircraft is this installed on?

Larry, I think the Bushcaddy is made in Canada - donno if kit or bought finished?  EDMO 

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Posted

Yes its a bush caddy kit,R80 I think, they used to be made in Canada but like everythng else I think they are in China now, correct me if I'm wrong Willy.Really solid plane with alot of rivets :)

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Posted

How many guys who read this forum are flying a EA81 with a Dave Johnson "Reductions" drive and what is your experience with it? Seems like mine has a few machining issues which showed up in pre-mature wear (14hrs TTE) on the lower shaft - Front Crank Bearing. My lower front plate (housing) had a hump left from cutting/milling and it loaded the lower front bearing/shaft. I'm getting my plate milled and the shaft having a steel sleeve/collar placed where it slides into the bearing as the 6061T6 is simply to soft it seems to take the load. Notice the space in the enclosed photos below. While it all fit on assembly, the bottom plate was a tight fit and I believe it caused a minor misalignment of the shaft and initiated the wear. As I understand from other forums and users of the Johnson Drive, I'm not alone in this. Hence my question here!

Not looking for keyboard opinions but solid EA81 user/flyer feedback! Thanks, Willy T.  

Hump.jpg

Front Plate.jpg

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Posted (edited)

My DJ Reductions engine don't have the front lower outside plate and bearing - Starter points toward firewall and mounted near top rear of upper housing.  Was flown 75 hours with no crank bearing failure as far as I know before removed and sold to get lighter 912 for Pelican on floats.  I have not flown it since.  I know you didn't ask for this, but thought I should say that not all Reductions were built like yours.    EDMO

Edited by EDMO

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Posted

Thanks EDMO, it is actually good input as it leads to yet another discussion and thats on the benefit of the lower bearing. My first ever Johnson re-drive built from plans and parts also did not have the lower bearing, nor did several other belt drive systems such as Stratus or even Raven if I remember correctly. The biggest problem for me is the paint job, looks good but really bugs me for tolerance and ability to trust the torque settings over time. Next, and I will have to check that yet, is to micrometer the Subaru Crankshaft Flange and possible "runout" into the shaft end inside the front bearing. Let's just say that the tolerances used in the machining of the drive (way back when, 80's, 90's) are not quite CNC and what one might expect of being made today. And it's experimental and there should be a certain expectation that it will work but might need some fine tuning. And there is the fact they were built as a one of at the time and there is installation variations from builder to builder no doubt. Anyhow front the shaft has been sleeved, going to post some photos next time and hopefully some more info on the runout issue if there is any. 

Thanks again EDMO, ...hang in there! With best wishes, 

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Posted

Hi Willy,

Glad to see you are getting your Bushcaddy EA81 flying.  I am working on 600 hours on my Stratus. It does have an extra bearing on the crank to take the side load from the belt but is located on the engine side of the crank pulley inside of the redrive casting instead of on the outer end of the pulley.  The stratus redrive doesn't have the pulleys enclosed, as I am sure you know.  Hopefully yours will be as bulletproof as mine has been,

Randy

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Posted

Thanks Randy, ..it can only fight me for so long! There is definitely some machining and tolerance issue's on my drive. While minor and nearly undetectable by the common builder/non machinist it was just ever so enough to cause these problems. Hope we have the "run-out" issues corrected and it will be smooth turning from here on forward. Just waiting for the lakes to freeze up around here to provide some additional runway lenghts and option for those first "check frights" with all the new parts. Stay tuned, pictures to follow of some of the work and issues corrected.  

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Posted

Willy, is it flying?

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Posted

Hi Randy, Willy is off on his heli ski guiding adventure for another week or so, he has got a few more hours on his bush caddy and seems to have all the bugs worked out.He is looking for a bit bigger prop to get a little more cruise out of it but other than that we should be getting a lot more ski flying in ,got a huge amount of snow this year

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Posted

Hi Randy, Avidfoxflyers,

It is back in the air and its been almost too flawless, ...makes you wonder what's next? Rolled in about 5 hours thus far and lets just say every upgrade done is a positive. Changed the Rotec TBI to a Weber 34/36 and solved starting and flooding issues. Engine runs just the same and no change in power or fuel consumption is noticeable. If there is any, it seems to have a bit more pizazz overall, quicker response maybe. 

The Johnson Redrive was completely disassembled, remachined and new bearing put in place. There was numerous issues, biggest one was the crinkle paint powder coating that would allow washers, bolt heads, to wear into the paint and loose torque specification. furthermore the box structure was not true and hence the bearing/shaft alignment was in a slight V - speak a few thou and we, the machinist and I, believe this might have been the trouble of the walking belt, the overheating of the rear bearing and pre-mature wear of the bottom shaft going into the bearing housing. Make a long story short the belt sits in place through all RPM's and loads and everything runs the way it should for once. 

I have been around the Johnson Re-drives since the early 90's and recall that the plans version never called for any paint. They were straight aluminium and it was only the purchased drives that had the powder coating. If you have a powder coated drive and have similar issues, think we have a cure. But further testing is do be done. Forgot to mention that the starter bracket was also fixed and now has better clearance and alignment with the ring gear. Below photo with the spotting work done and during reassembly. 

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Here is a photo of "Nellie" with Willis' (Marshawk) Yamaha RX powered Fat Avid in the background. About the only time I've ever been a nose ahead since he converted to the new engine :-)) 

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Posted

Hey Willey just wait till I get mine over there then may Willis and I could Check out the yamahas against the Subaru ha that would be fun hope it can happen have fun you  guys from RICK 

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Posted

Great to hear you are up and running.  It looks like was a super snow year for you guys too!

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