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Hi all,
I was wondering if anyone else has had excessive con rod wear on their 7-77? My 7-77 has about 4 hours run time on it, and last week my engine quit in flight. The T-28 is no longer, but while cleaning up the dirt on the outside of the engine, I decided to take off the back plate and see what was doing inside. I'm glad I did. I found most of the con rod pins connecting the main rod to the smaller rods super loose. further inspection showed excessive wear in both main and secondary rods at just about every location. I have no idea how this happened, as I've religiously ran the engine with the recommended oil concentration with castor. I always shoot a ton of after run oil after each session, so I don't know if I'm just the lucky guy, or I'm missing something? Ughhhh. Adrian was no help with parts, so I just contacted UMS to see if they have parts. Crossing my fingers.. -Richie https://cimg0.ibsrv.net/gimg/www.rcu...2928c71fb1.jpg Buh bye T-28! https://cimg4.ibsrv.net/gimg/www.rcu...d45f735b8f.jpg https://cimg9.ibsrv.net/gimg/www.rcu...098b7b6e44.jpg |
Can't post without a title? So title. lOL
Originally Posted by RadialWacko
(Post 12744543)
Nice landing! Looks like it does great on grass. I thought my 90cc was a lot, 125 must really fill out the cowl space!
Here is my flight from last week... I had an emergency in flight... At first I thought it was just the engine running rough as the temperature has been cooling off since I last flew it. Then I thought maybe a push rod was rattling. But once the noise got real bad I knew I had to come down. So word of warning to everyone... Be sure your cowl is SECURE! I had at least one loose and one missing screw next to each other and the pressure inside the cowl pushed the cowl forwards into the back of the prop. I was amazed it didn't bring the plane down. After taking the prop off I noticed that the burning/melting epoxy actually kind of laminated the damaged spots of the propeller which is probably what kept it in one piece and saved my butt. Besides the time and effort I put into customizing the cowling and making the baffles, overall not a huge issue. Not that this plane would be that difficult to float back to the airfield... HA! Please don't judge my take off or landing.. It was only my fourth flight and my worst one yet all around. Wow Tom? I know you only as RadialWaco. Just saw this. Awesome flight !!! Nothing to be said but congrats on a great piloting job there! Emergency forced landing too. Flawlessly done on tarmac which is tough at any time. My cowl was not as tight either between flights and I have it secured with bonded washers to cut down on vibration. I inspect the wing fasteners religiously every flight too. They have also shown looser than when it went up, even on short five minute flights! Naturally I feel the major overpowered 125 cc powerplant is just going to have this effect on this lightly built ARF. Thanks for the link. I will hit the like thumb and subscribe. Please post more flights I when u can Love this stuff Dude! Your flying site is AWESOME !!!! Aaron- https://www.youtube.com/watch?v=bJnhocQIp5k&t=68s |
Originally Posted by MYHELL99
(Post 12745289)
Hi all,
I was wondering if anyone else has had excessive con rod wear on their 7-77? My 7-77 has about 4 hours run time on it, and last week my engine quit in flight. The T-28 is no longer, but while cleaning up the dirt on the outside of the engine, I decided to take off the back plate and see what was doing inside. I'm glad I did. I found most of the con rod pins connecting the main rod to the smaller rods super loose. further inspection showed excessive wear in both main and secondary rods at just about every location. I have no idea how this happened, as I've religiously ran the engine with the recommended oil concentration with castor. I always shoot a ton of after run oil after each session, so I don't know if I'm just the lucky guy, or I'm missing something? Ughhhh. Adrian was no help with parts, so I just contacted UMS to see if they have parts. Crossing my fingers.. -Richie https://cimg0.ibsrv.net/gimg/www.rcu...2928c71fb1.jpg Buh bye T-28! https://cimg4.ibsrv.net/gimg/www.rcu...d45f735b8f.jpg https://cimg9.ibsrv.net/gimg/www.rcu...098b7b6e44.jpg I may be able to help with this situation. Aaron- |
Hyjinx, WOW, I have never seen anything like this on the glow radials! I have hundreds of flights on mine with no wear. Bad materials?? I hope you can get parts and sorry to see your plane ruined. -Tom
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Originally Posted by Maxam
(Post 12745343)
Hyjinx, WOW, I have never seen anything like this on the glow radials! I have hundreds of flights on mine with no wear. Bad materials?? I hope you can get parts and sorry to see your plane ruined. -Tom
I think he is on track for a good solution to the failure. Regards Aaron- aka Hyjinx |
Yes, I'm going to try to find parts first. I was thinking about the idea of bushing the rods a little bit more. My concern with adding bushings to the rods is the rod wall thickness will be greatly reduced and hence, creating a potential failure point.
If anyone has a crash damaged 7-77 or other means of parting out serviceable con rods, please PM me. I'm in no hurry to sell my engine as is, but if I get a fair offer, I could be persuaded. :) Does anyone know if Mr. Ramaraj still a best contact for UMS? Thanks, Richie |
Hello thread users. I have decided to sell some of my radial engine collection. There will be several to go. Among them is a Evo 7-77 that the use of has been documented earlier in this thread. It uses the original carburetor and has not been modified in any way. The engine has been involved in two crashed planes, but had not experienced a frontal prop strike. It has been stored indoors in a climate controlled area.
It has not been opened to inspect for rust. It can be started by an interested party as it is currently mounted on a ready to fly Balsa USA Newport 28. I don't want to sell my engines to the general public. I do not want to deal with people not involved in these RCU Radial engine threads. I am located in southeastern Michigan. All sales will be face to face. All engines will be sold for cash currency in 100's and fifty dollar bills in my bank parking lot in Chelsea Mi. 48118. Before transfer any and all bills will be scanned by the banks loan officer. I will not ship any engine any where for any one. I will not accept any electronic payments or hold deposits. I want 800 for this engine. I may sell three engines in one sale. This is one of the three. I may be contacted initially at [email protected] . |
Hey just a quick stupid question, where are we supposed to be putting the after run oil on the engine exactly? I've just been using a paint brush to brush it onto the pushrods and heads near the valves. Am I missing something else?
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Originally Posted by RadialWacko
(Post 12745599)
Hey just a quick stupid question, where are we supposed to be putting the after run oil on the engine exactly? I've just been using a paint brush to brush it onto the pushrods and heads near the valves. Am I missing something else?
Put it in the Crankcase. Remove one of the upper pushrods and remove the lifter pin , Squirt 5-10cc or so in and put the pin and rod back. Turn the prop 5-10 times, then remove a bottom rod and lifter and black oil will pour out. that will keep the insides from gumming up and rust. |
Originally Posted by TimD.
(Post 12745610)
Put it in the Crankcase. Remove one of the upper pushrods and remove the lifter pin , Squirt 5-10cc or so in and put the pin and rod back. Turn the prop 5-10 times, then remove a bottom rod and lifter and black oil will pour out.
that will keep the insides from gumming up and rust. I get good service from all my motors. Regardless of manufacturer. Aaron- |
UMS still has parts available for our older engines!
Contact: UMS Technologies Private Limited T. Shanmugavel - SGM Operations; email: [email protected] He has replaced Mr. Ramajaj. I'm getting new con rods for my 7-77. Hooray! -Richie |
Originally Posted by myhell99
(Post 12746273)
ums still has parts available for our older engines!
Contact: Ums technologies private limited t. Shanmugavel - sgm operations; email: [email protected] he has replaced mr. Ramajaj. I'm getting new con rods for my 7-77. Hooray! -richie |
Hello
some time ago I bought a new cam ring from UMS. it was time for a change on my 7-35. https://cimg2.ibsrv.net/gimg/www.rcu...936618d842.jpg New and old https://cimg3.ibsrv.net/gimg/www.rcu...0f3b0705f5.jpg New https://cimg4.ibsrv.net/gimg/www.rcu...d0afce7443.jpg Old My 7-35 is from 2010 but I got chambering from the new version. which is made in one piece, which makes it more precisely round. They make valve adjustment a little easier. Lars |
Lars, did you get your Sonictronics #302 glow plugs? -Tom
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hi tom
I'm waiting to order until next spring. It's windy autumn and soon winter and snow will come. so it will be airplanes with skis Lars |
Oh OK Lars, I found a Great Planes Super Stearman and I will be installing a UMS 7-35 new version on it. The new version can swing a Fiala 19x8 at 6400 RPM! -Tom
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Quick update on my 7-77 with the worn con rods. I finally got the parts from UMS and the engine is back together! Planning on running it soon. I've recently acquired the Cline regulator and I'm going to try it out to help with keeping fuel mixture at a better constant and will report out once I get it going again.
Now, to find another home for it... -Richie |
I had a chance to run my 7-77 after replacing the con rods. It ran well, but now I hear some clicking on the front end around the cam area when I rotate the prop slowly. Unfortunately, I'm done with this engine and decided to sell it. Moving on.
By the way, I found the Glow Devil 302 glow plug for sale at $8.95 each at Radical RC. https://www.radicalrc.com/item/Glo-D...for-Non-OS-115 Cheers, Richie |
Richie, that is too bad about your engine. I am totally stumped as to what happened. I thank you for the glow plug info!!! -Tom
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Tom, thanks for all of your tips and experience throughout this thread. I'll definitely get another radial in the future. The sound is purely addictive.
-Richie |
Been a while since I last posted here with my Evolution 160 still going strong in my Corsair after a new ignition, pump and carb.
I have a UMS 7-50 to go into Seagull Skyraider (cowl has been slightly enlarged to get it to fit). Iv also posted this question on anothe UMS thread as not sure if this is for more recent UMS gas engines now. I m running-in the engine. Starts OK, high speed needle works fine, good pickup and getting around 5500rpm on 20x8 prop (like Timbers black spray all round!). Trouble is I just cannot get the engine to run at much less than 2500 rpm without stopping. I tried setting the idle needle but if I lean too much (screw clockwise) s the engine is hard to start and if set rich then engine stop just after throttle is half closed. If I get the engine somewhre near to idle then the high end is too rich, which obviously is no good at full throttle. This engine has the UMS glow type carb which too me seems almost impossible and super sensitive to setup , never had this problem before with my engines. Any thoughts or should I just junk this carb. Also, the fuel Fuel draw is almost zero even with choke closed and hand starting but once started pulls fuel OK. Tank is level with carb and fuel line just 10cm. If this carb is so bad as some peoiple say they why do UMS supply it on this engine only in their range? I ve stripped the carb and cannot find anything wrong. I m wondering if air is leaking in to the crankcase around the carb body as its not a great seal in its sleeve. Should there be a gasket or something here? |
Loose intake manifold pipes?
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Everything is tight, engine seems to runs smooth enough and temperatures all OK
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