engine and prop advice

[cliff 45]

We got this old 1985 Avid back in the air a little over a week ago. It flys well but doesn't perform like the other Avid that I have flown. It takes a lot longer to get off the ground and climb rate is far less. They both have a 582 with a B box on them, only difference is he has a three blade prop, we have a very thin 2 blade. It is still fun to fly and we have enjoyed 3 hours of flight time in it so far. I am over weight and weigh in at 240, my brother is 150, With both of us on board and 10 gallons of fuel we are close to gross weight. Any how, the engine on our plane has minimal history of  it in the log books. . It is a gray head with a b box and a very thin 2 blade prop. The local airport 2 stroke guys have it set up and running fine. We just don't know the history of the engine. We have another 582 gray head that was overhauled and updated by rotax Rick about 3 years ago. It has 1 hr of test run time on it by Rick. It has a C box (3 to 1) and we have an all but new 3 blade powerfin prop, it all came off a KF IV that went 4 stroke. We were saving this engine for a Mark IV project that won't be completed anytime soon. Do you guys think we will see improved performance with the C box and big 3 blade prop? I know we will have more peace of mind with a zero time engine on the front, but with it running perfectly with this engine should we steal the engine from the other project? How long can an overhauled 582 be stored before the seals and gaskets start to get brittle? We only plan to fly local and my brother wants to finish his LS training in this plane. Any thoughts.

[1avidflyer 1983]

You could just change the gearbox and prop fairly quickly to see the performance difference.  Sometimes it's hard to get the B box gear off the crankshaft especially without the factory puller though.  What prop are you using now?  Jim Chuk

[cliff 45]

I am not sure of the make and model. It looks like a tooth pick next to this three blade we have. It does turn up the correct rpm. Next time I am at the airport I will get the prop info off it. I do have another 2 blade in my shed that is the same kind if I can find it.

[akflyer 1427]

The B gear box should pull an Ivo ultralight 3 blade 68" no problem.  I would swap to the C box if it was me just because its smoother and the rubber hardy disk helps take some of the shock load off the crank.

 

Some people run a 2 blade and they like it, but I hated the 2 blade IVO on my Avid and my brothers KF, the climb was much less than I got with the 3 blade 72" ultralight prop.

 

What RPM are you turning on take off?  What are your EGTS at take off and cruise?  even at gross you should be getting around 5-600 FPM climb.

 

I set my prop to give me 65-6600 RPM on take off as that gives me the best performance, but I have the IVO IFA so I can bump in more pitch for cruise when I level out.  EGTS should be around 1100 or so, I know you can go to 1200 max but I like a little fudge factor in there are the EGTS really just show a trend unless you are good at math and want to run the numbers while flying to give you the actual temperature corrected EGTS.  The probes are calibrated at 70 deg OAT (at the probe to instrument connection interface) so anything on either side of that for an OAT you have to correct for.  I just keep them around 1100 to 1150 and have never had an issue melting pistons.

 

Are you running premix or oil injection?  If running oil injection do you have the cable set right?  I have seen guys running really rich, so in order to get the RPM up they flatten the prop out and it kills performance.  You have to do the dance to get the prop and mixture set right so your getting the best performance but not running the ragged edge of burning down your engine.

 

Pictures of your set up would help us out a bit too.

 

[akflyer 1427]

If you need a puller for the B or C gear box (the pinion gear) I have both that I would shoot to you, but I wont be home till the 2nd to send them off.

 

[C5Engineer 1170]

Prop makes a huge difference on these little planes. Have you verified the takeoff rpm with something digital or are you using a needle tach and the grey wire off the lighting coil? That set up is notorious for being inaccurate and a few hundred rpms also makes a massive difference.

[cliff 45]

Wel I am sorry I wasted your time, My brother has decided to swap the engine with the zero time one. You all gave me good advice but he said he will feel better with an engine of known  origin hanging off the front of the plane he is finishing his  light sport training in. I support his decision and we may need more advice on setting this engine up. Thanks again, Cliff

[allonsye 85]

Prop makes a huge difference on these little planes. Have you verified the takeoff rpm with something digital or are you using a needle tach and the grey wire off the lighting coil? That set up is notorious for being inaccurate and a few hundred rpms also makes a massive difference.

Joey and all -

 

What are some of the digital alternatives over the old need/gray wire setups?

 

The OP brings up a good question. How long can a 582 be stored after an overhaul with respect to seal life?  I'm preparing to run mine. It was overhauled and pickeled 10-yrs ago. After I hung it, I serviced the G/B. Since then the oil has been leaking out of the lower weep hole. I'm hoping after it's running that particular seal will set.  Makes me wonder if this gray head will have to be pulled apart again to replace the engine seals?  I have had luck in the past rejuvanting seals by adding DOT brake fluid to rejuvante them.

 

In the meanwhile, I'm discarding the worry beads and planning to proceed w break'in and see what happens. That'll be a few weeks as I wrap up the coolant and electrical connections.

 

Paul

Edited 24 Sep 2014 by allonsye

[akflyer 1427]

re-seal after 5 years.  It is cheap and easy to reseal the engine.  One day to pull it, reseal then re-install.   I would not be putting DOT in the engine to make the seals swell up.  Your lawn mower or dirt bike is easy to pull over and fix, the plane is a bit different when you loose a seal and one cylinder goes lean and you smoke the piston.  Been there and done that, it gets exciting really quick.  I had JUST enough altitude to get back to the airport and land with a 20 mph tail wind. 

 

For 150 bucks worth of seals, I would not take the chance.  I may gamble on the RV shaft seals, but not the two main crank seals.

 

For a tach, go with a tiny tach.  I have seen the rotax analog tach from 2-800 RPM off.  Generally if a guy says it takes him 700' to get off the ground and only climbs out at 200 FPM, he is running an analog tach that is one big lying SOB!  Akflyerbob has both in his KF and at first they were reading within 60 RPM of each other.. after 50 hrs of flight time the analog tach is now 800+ RPM off.

 

I am convinced that Rotax uses the same technology for their tachs as they do for the Dream-o-Meters they say measure speed on the snowmachines.. When testing the race sleds they said we were getting 120 MPH, but GPS and radar only showed us hitting 87

 

 

[cliff 45]

We  have a  tiny tach and a rotax tach and the tiny tach reads 200 rpm less than the rotax. My brother is pulling the engine on Saturday. two of the airport guys are going to help him, all three are mechanicis by trade,and one guy has a fair amount of 2 stroke knowledge. They say if they don't run into any problems , they can have the engine swap done in one day. I am NOT a mechanic and can't see how they can get everything done in one day. Have any of you experienced guys changed an engine in one day?  Also, we bought a complete fire wall forward  (582, C box, and 3 blade powerfin prop) off  a kitfox IV. We sent the engine and gear box to rotax Rick for overhaul and never changed anything on the prop. If the Kitfox owner had the prop set right what are the chances that it will work as set with the overhauled engine? We can't find any markings on this Powerfin prop to tell us what model it is, Does any one know where the model number might be found or how to tell which blades we have. From the pictures on the powerfin website it looks like either a B or E blade. Thanks

[marksires 484]

I'm not a great mechanic, and had zero Rotax or Aircraft engine experience at the time.  I took my engine off (582 grey head) to send it for overhaul in a few hours, and it took me a little less than a day to get it put back on by myself.  Since all the 'stuff' is already run, it isn't that bad.  Most of the time I spent was running new fuel lines and oil injector lines.  Installing an engine in a new airplane would take longer since all the wires, throttle cables, hoses, radiator mounts, etc. have to be set up and then adjusted a bazillion times.

Mark

[cliff 45]

My brother ran all new fuel lines, oil lines, throttle cables, and radiator hoses to the existing engine. Only thing they need to do, hopefully, is change the engine, which has the Cbox already installed, and install the prop. I was thinking it might take a while to get the engine, prop rpm and soforth tuned correctly. I guess time will tell. 

[cliff 45]

Paul,  Nice looking plane. I would like to post a picture of ours but I have very little computer skills. I have pictures on my phone and I know how to text or email from my phone, if one of you guys want to post them for me I could send them to you. I need to get my grandaughter over to the house for some more computer lessons.

[C5Engineer 1170]

I pulled my engine and replaced the stator and had it running again before dark. A few knowledgeable guys will have no problems. Getting it set up and tuned will take some time. Hopefully it goes like a scalded dog. I know a guy who chased a power issue for months before he finally tried another gearbox which solved everything. Turned out he had a bad bearing in his box from an old prop strike which was causing excessive drag.

[akflyer 1427]

Engine swap can be done in a few hours.  Its all plug and play if its been set up before.  If you have a tiny tach, set you prop and everything by that.  Put a cover over the hole that has the Rotax tach, its worthless.

 

[akflyer 1427]

Paul,  Nice looking plane. I would like to post a picture of ours but I have very little computer skills. I have pictures on my phone and I know how to text or email from my phone, if one of you guys want to post them for me I could send them to you. I need to get my grandaughter over to the house for some more computer lessons.

 

You can email them to me.  akflyer_2000 at yahoo dot com   < I typed it that way so the bots crawling the site dont start sending me 1000s of spam mails a day.  If ya cant figure it out drop me a PM and I will give it to you there.

 

[cliff 45]

akflyer, I attempted to email pictures  to you at 1:42pm. let me know if you got them. 2 pictures before the wings went on and 1 picture of my brother and I after our first flight together. I'm the fat one.

[Guest]

This is a reply to a much earlier post in this thread that I never read.

 

While it is probably a good idea to replace seals based upon time, (I mean how can you argue with the logic??) I did not do that.  

 

I found with two separate ORIGINAL (10 yr+) Grey Head 582's that I was able to run both after many years in storage up to 600 hours before performing a major overhaul (new crank and over bore pistons).

 

However, I did tear down and clean the ring grooves piston tops and heads periodically on both engines. At first I was doing the teardowns at rotax recommended intervals, but as I gained confidence and experience with the teardowns I stretched the teardown intervals based on how the engines always looked when I tore them down. Eventually over 1200 hours of flying between both engines the way I flew them, I arrived at a 300 hour teardown and cleaning interval and a 600 hour new crank and piston interval.

 

Not advice of any kind, just my experience as one data point.

 

Chris

[cliff 45]

It is now 2:43pm, My phone is smashed against the wall and laying in peices, I thought I knew how to send email from my phone. 1 hour and 1 minute of complete frustration and I have no clue if I sent a single picture. This new technolegy is sure hard on my old brain.    PS just kidding about the phone. 

[EDMO 1078]

Cliff,

    Welcome to the Senior Citizens Club - Life was much simpler for us when we were young

- Just sent messages by beating on a drum and making smoke signals  

     My old cellphone finally lost its mind and started calling people without me knowing it - I didn't have a hammer handy, so just took the battery out and killed it that way.

EdMO

Edited 25 Sep 2014 by Ed In Missouri

[akflyer 1427]

It is now 2:43pm, My phone is smashed against the wall and laying in peices, I thought I knew how to send email from my phone. 1 hour and 1 minute of complete frustration and I have no clue if I sent a single picture. This new technolegy is sure hard on my old brain.    PS just kidding about the phone. 

 

  Your humor fits in just perfect here!  I got the email notification on my phone but I am out at the weld shop dealing with a hot issue right now (no pun intended).  When I get back to the office this afternoon I will post the pictures for you.

 

[cliff 45]

AKflyer, My email was hacked last night. Did you get my pictures?

[akflyer 1427]

Yes sir I did, but work has been insane and I have not had a chance to download them and get them posted here.  I have a 9:30 meeting this AM then I will get them uploaded here.

 

[cliff 45]

No problem. I woke up to an email mess and I was hoping I didn't spread it to you.

[allonsye 85]

re-seal after 5 years.  It is cheap and easy to reseal the engine.  One day to pull it, reseal then re-install.   I would not be putting DOT in the engine to make the seals swell up.  Your lawn mower or dirt bike is easy to pull over and fix, the plane is a bit different when you loose a seal and one cylinder goes lean and you smoke the piston.  Been there and done that, it gets exciting really quick.  I had JUST enough altitude to get back to the airport and land with a 20 mph tail wind. 

 

For 150 bucks worth of seals, I would not take the chance.  I may gamble on the RV shaft seals, but not the two main crank seals.

 

For a tach, go with a tiny tach.  I have seen the rotax analog tach from 2-800 RPM off.  Generally if a guy says it takes him 700' to get off the ground and only climbs out at 200 FPM, he is running an analog tach that is one big lying SOB!  Akflyerbob has both in his KF and at first they were reading within 60 RPM of each other.. after 50 hrs of flight time the analog tach is now 800+ RPM off.

 

I am convinced that Rotax uses the same technology for their tachs as they do for the Dream-o-Meters they say measure speed on the snowmachines.. When testing the race sleds they said we were getting 120 MPH, but GPS and radar only showed us hitting 87

 

 

AK -

 

I was thinking of a teaspoon of DOT added to the g/b in hopes that it would help the seal not to the injector oil.  

 

Anyways. We're going to proceed w/the final rad, fuel and electric connections and get that out of the way which remain to be done yet.

 

I've added the Tiny-Tach to the procurement list.

 

I valued Chris's comments about running motors that had been in long term storage.  I'd like to get this puppy up and running and everything dialed in then look at pulling it down for main seal replacements.  I'm curios if the Cbox seal will stop leaking on it's on after going through the engine ground-run break-in procedure.

Edited 27 Sep 2014 by allonsye