That appears to be wear from throw out bearing pressure applied to a standard transmission clutch plate. ________________________________ From: KRnet <krnet-boun...@list.krnet.org> on behalf of Max Power via KRnet <krnet@list.krnet.org> Sent: Wednesday, December 25, 2019 8:44 PM To: KRnet <krnet@list.krnet.org> Cc: Max Power <maxpow...@gmail.com> Subject: KR> Confusing engine wear EA81 direct drive
EA81 Subaru thrust bearing wear https://imgur.com/gallery/DooQjEm Image gallery link above. Story: New to me kr2 acquired 4 years ago, had 18 hrs on the clock all ground run. I've flown for almost 4 and brought total to 26 with a little bit of crank endplay I assumed was normal but one day I was getting what seemed like a misfire and when looking thru the prop in the air I could see it's actual shape for a split second when it would skip or misfire which I chalked up to the endplay as it moves in and out upon rotation of the prop. I've grounded it since sept '16 So now 3 years later and a plan to vastly improve many aspects of the craft I split the case of the Subaru EA81 to examine the thrust bearings and what I found was the opposite of what was expected. The prop is on what would be the rear of the engine in a car. I don't know the history of if it had been rebuilt prior to conversion but the wear isn't what I would expect to find in a car either. These are worn down to nothing on the wrong side, the prop was pulling away from the worn side and technically I could've just left it alone. I don't know if any of this is useful info, It's been so long since I've run it I don't remember any data from gauges but I know it was very slow and I had to keep it at WOT nearly the entire flight time. I had a crazy long rollout, well more then half a 3000ft runway, this has hydraulic retractable tri-gear that I never raised and I know that was most of my speed issue. It is set up as direct drive and the prop should be putting pressure on the thrust bearing, I'll measure the new ones to determine how much was actually worn off that face that still is good. I can only imagine this if it was involved in a front end collision while in a car still to have actually put any significant force in that direction but it would've pushed the drive pulley back first hard enough to score the engine case and there's no evidence of anything like that. Just wondering if anyone else has seen wear like this on any engine really? It's going to a machine shop to get bored, shaved, and a cam regrind to bump hp for a shorter rollout. I'm reengineering some pieces from steel to aluminum. Dropping the radiator and it's draggy "in the breeze" mount to a double or triple stack of motorcycle sized radiators with a naca duct and a 2 speed fan or something similar after extended testing, reengineering some aluminum parts like coolant reservoir to plastic. Will be lighter and more powerful when complete. A 3-D printer is extremely helpful in building a better aircraft, I'm building a complete intake system to bypass the coolant passages in the original intake manifold that cost me some HP that will eventually be rebuilt in machined aluminum parts but it's great for dryfitting things to see how they would fit. Thanks in advance for any and all information. I'm so glad to be a part of this group. _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
