Subaru EA81

[bcbushcaddy 27]

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. 

[bcbushcaddy 27]

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.  

[LSaupe 123]

What type of aircraft is this installed on?

[EDMO 1078]

What type of aircraft is this installed on?

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

[marshawk 82]

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

[bcbushcaddy 27]

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.  

[EDMO 1078]

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 15 Nov 2017 by EDMO

[bcbushcaddy 27]

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, 

[SuberAvid 617]

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

[bcbushcaddy 27]

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.  

[SuberAvid 617]

Willy, is it flying?

[marshawk 82]

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

[bcbushcaddy 27]

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. 

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 :-)) 

[RICK Pingert 2]

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 

[SuberAvid 617]

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

[bcbushcaddy 27]

Spring 2022 Update

Well it's been a little while since I've posted in here and this is just a little update on our Subie. It's still attached to Nellie's airframe and as of a few days ago, moving it off the ice and back onto wheels we've put in 70+ hours. The engine in itself has performed flawlessly and run without a miss ever since installed. The Crux of the system going from automotive to aviation, despite it's original aviation design on the EA8, is with all the sub systems from belt drive, right up to carb heat. If you decide to build any automotive conversion yourself, remember that you can't just roll on over to the next Autozone and pick up, ..let's say an alternator mount for the new light weight 38amp unit. Or get a carb heat box for your Weber carb upgrade. Or maybe grab a new engine mount dampener off the shelf while you're there. No Sirreee, you will have to design, build and source way beyond what Tony Bingelis may have put in his book on engines and your version 1.01 might not quite cut it the first time around the patch. Back to the drafting board you go, only problem being, most likely you're also the test pilot in all of this. Well now, just how brave (smart) are ya? How many more "Check - Frights" do you in you? In either case if you're sole determination is to build a cheap automotive conversion to save some dollars on your project you may want to do some serious Soul, yes thats with a U fool, and not the $ole ($$$) $earching before entertaining such an endeavour. I would highly recommend, for starters, to follow tried and true more so than thinking you'll re-invent the whole homebuilt world of how to set up automotive engines and that history and those you came before you just simply got it wrong. Now, if everything you've just read thus far doesn't stop your resolve to build your own engine conversion, go ahead, read on.  

Do I still stand behind the Subaru? Absolutely 100%!! It is a solid, reliable, time proven option and all of my encountered issues were not as much Subaru Engine problems but "me-chanic induced problems" more so, with the biggest issue, getting all the items you attach to it running in tune with the engine. Perfecting the mounting, air intake, fuel delivery, exhaust flow, cooling, and last but not least the reduction drive/propeller system. Don't expect for a moment that you can just add a new part and it will fit and operate perfectly. I got bitten big time by a new water pump installation, despite the fact that way back in 2006 I've printed and filed a builder report pertaining to the three (3) YES THREE different water pump options that all will fit the EA81 Subie, but all are slightly different in heights and not necessarily in alignment with your stock main crankshaft pulley. But that's a whole another story in itself. And after all the installation woes, it will take some time tweaking, I thought I had it at 15hrs, then for sure at 30hrs, definitely at 40 and now at 70, with the last 30 rather flawless I'm still finding myself doing little adjustments tweaks here and there. If it were a Lycoming these would be done most likely by the local AP at some great cost (cutting into the fuel budget) and not really furthering the understanding of my engine. Which brings me to the true reason for me to build, to do what I (we) did, and that is to "experiment", "learn", and being able to proudly say, "Yup we built this!" 

To say this whilst sitting around a backcountry fire with a good friend, cooking some Connoisseur blue collar tube steaks, ..PRICELESS!!

Best regards, Willy T.