OK Super 60 woes..

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OK Super 60 woes..

Postby zeek » Sun Sep 05, 2010 4:07 pm

G'day all!

I have a wonderful OK Super 60 that I purchased about 12 months ago and currently have perched on a Lanzo RC-1. I use a Larry Davidson transistor ignition, coil and lead set with a 3.7v NiCD pack. I use 98 octane unleaded gasoline and castor in a 4:1 mix. It was all running very well up until yesterday when it decided it din't want to start.

I have spark and fuel but it won't start. It will kick and backfire off a prime but won't keep turning. Tryed another (working) plug; advanced and retarded the timing while turning it over;opened and closed the needle valve;flushed the tank;flushed the spray bar;tryed different fuel;cleaned the points;checked the wiring;all no go.

Getting desperate and a little confused as I have had this engine singing sweetly over many flights and none of this makes any sense. Hoping someone can point me in the right direction - oh and a photo of a OK Super 60 NVA would be appreciated. I suspect mine MAY be damaged but I don't have any pictures or another engine to compareit with.

Many thanks for any assistance..
zeek
 
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Postby raglafart » Sun Sep 05, 2010 7:12 pm

The seal between the crankcase and cylinder barrel is an area I'd be looking at.
These engines are getting very old now and the stress of running can blow these old well baked base gaskets. You will get a similar situation to the one you have described if the gasket is leaking, ie it will run on a prime but won't continue to run.
The barrel is spot welded in place and it can't be taken apart and reassembled without special spot welding equipment that also pre loads this base gasket!
There are guys in the US that do have this gear but one flyer here in Sydney used dental floss to make an effective seal along with I believe a fluid gasket material. I guess you could also use a bit of JB weld too :roll: at a pinch :?
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Postby chiefss » Sun Sep 05, 2010 7:49 pm

I think you will find the OK Super 60 as well as all the other OK 60's have the cylinder bolted to the crankcase. At least mine does as do all the ones pictured in the American Model Engine Encyclopedia.

Now the Ohlssons were spot welded together and can't be taken apart. Terry Toops in San Diego used to repair Ohlssons but he passed on several years ago.
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Postby Jim Kraft » Sun Sep 05, 2010 7:56 pm

If you have a spare coil I would try that. You have done most of the things that would keep it from running, so it gets down to the electronic ign., or the coil, if you have a good ground, and wiring is OK. You might want to switch over to a condenser just to see if it will run on that. I have a couple of extra ign. systems that I use on my test stand, that I can hook up to the engine in the plane to check it out. If the coil from Larry is one of the very small ones, it will probably not work with a condenser. Make sure your batteries are charged. You should have about 4 volts with them fully charged, and when they get down to around 3.6 they do not put out enough current.

I know you said you are getting spark, but I have seen cases where you would get spark each time you turn it over, but it would not fire fast enough to run. It was a bad electronic ign. system. Also seen coils do the same thing. Hope some of this helps, and let us know how it goes. One other thing, I would run a 3 to 1 mix as these old engines need at least 25% oil.
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Postby raglafart » Mon Sep 06, 2010 4:22 am

chiefss wrote:I think you will find the OK Super 60 as well as all the other OK 60's have the cylinder bolted to the crankcase. At least mine does as do all the ones pictured in the American Model Engine Encyclopedia.

Now the Ohlssons were spot welded together and can't be taken apart. Terry Toops in San Diego used to repair Ohlssons but he passed on several years ago.


Oops, you are of course correct, :oops:
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Postby zeek » Mon Sep 06, 2010 3:51 pm

Thanks for all the help people! Much obliged!

Using a combination of swearing and violence I managed to get the OK to start and keep running yesterday. I found that it is a VERY tempramental beast that is sensitive to the slightest adjustment (must be female).

I started by priming the engine (finger over the carb, 4 flicks of the prop),retard the spark 5 degrees, carby out 2 1/2 turns and switches on for start. The first 2 flicks - nothing. The next 3 it popped and banged and blew flames out the exhaust - classic signs of too advanced spark. Normally I would retard it further but after doing that countless times in the last couple of days with no effect, I resolved to keep flicking through the backfires. After a dozen flicks it started and shutdown almost immediately.

This wasn't unusual - it has done this several times over the past couple of days and still won't keep running. My normal response was to open the needle valve, re-prime and start again until my arm got sore and I started reaching for the matches to set the whole thing alight. This time I re-primed and started flicking again. After 5 flicks it started and died. Therafter, I went in to a "2 clicks on the needle, prime and flick" regiime until, 20 mins later it actually kept firing long enough for me to adjust the needle and spark to settle it in to a steady run. WOOHOO!!!

Over the next couple of hours I played with it some more and came to some conclusions:

1. I Had the spark too far advanced - it now sits at about 40 degrees.
2. I had the mixture too lean to start. It seems to need a quarter turn rich to start and then leaned out once it starts to run. This is the same whether its hot or cold.
3. It has a pathological dislike of being flooded. I was priming and flicking and using the starter so much that It was pumping raw fuel out the exhaust. With the spark so advanced it was firing this "exhaust charge" erratically and causing the engine to stop during the ignition stroke.
4. My ignition batteries were degraded. I switched to a replcement set and things started getting lively.
5. The combination of the above, multiple changes between starting attempts and lack of familiarity with spark motors meant that I was the primary cause of the OK's issues.

So I have worked out a starting formula which I will test over the next couple of days:

1. Timer set to 40 degrees
2. Needle 1 quarter turn rich from running position
3. Three priming strokes
4. Switches on
5. Flick

Absolutely NO direct prime through the venturi or exhaust or alteration of any settings until it fires.

I will let you know how I get on..
zeek
 
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Postby Jim Kraft » Wed Sep 08, 2010 5:00 am

Glad you got her going Zeek. I have found battery voltage to be very important. I run three NIMH batteries, and when they drop below about 3.7 volts, things become iffy. I think this is partly due to the drop through the electronic ign.. I think what happens is that when the voltage drops to that point, the batteries do not have enough current to drive the module, and to charge the coil. I have actually run engines on 2 nicads or NIMH batteries that were fully charged even though the voltage was only about 2.7, but still had plenty of current.

I have been playing with ign. engines of all kinds for the last 15 years, and I think I have had every ign. problem known to man. One thing that drove me nuts for awhile was that I would have intermittent spark on Orwicks, Super Cyclones, and Anderson Spitfires. In every case it was the point in the movable arm being loose. I now solder all of them. You won't have that problem with the OK, since it is a different point setup.
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ok super 60 woes

Postby collie » Fri Jan 14, 2011 12:32 am

Hi been there done that .took 3 months to find the problem on mine ,tries ,points ,coil ,fuel ,nicads and mNImh batteries ,even got a mate to wind me an extra hot coil,put the problem was simple ,once i found it .the web underneath the crankshaft that goes to the bottom of the crancase id very thin ,and willcrack down the side thus venting the crankcase and making the motor hars to needle and in worst case stop the engine ,cure is get the case tiged up each side of web<,
pull the backplate off the engine and look underneath the grankshaft at bdc and if u lucky u see a thin black line running vertically down there is ur problem,i have 3 ok super 60and all three were cracked.hope this helps. collie
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oksuper 60

Postby collie » Sat Jan 15, 2011 4:00 am

i have never ben able to get mine to run more than 32 deg timing btdc as any more just makes it run hot .Same with Mccoy 60 ,i heard 45/dec btdc but i never found any advantage beyond 32 deg,but this might because i using a propeller at slower speeds than a tethered car.
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OK Super 60 leaking fuel around the rear points cam

Postby jprimrose » Fri Mar 16, 2012 1:50 pm

Hi,

it seems that my OK super 60 will run but gradually cover the points with gas/oil and stop running. The seal around the rear bearing where the cam protrudes is not so good. Can I make good this seal somehow, with an o-ringlet into a (new) groove or somesuch? any solution?
I have been trying to see if I can protect the points somehow. The leak is not enough to lose crankcase compression, everything else seems to be fine.

btw; two of my spark engines run OK but on the bench get hotter and hotter until they stop well before the fuel is used up. I am using colmans gas and 1/3 oil (60 Harley bike oil). Should I go to methonol FAI fuel ?

cheers
Jim
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Re: OK Super 60 leaking fuel around the rear points cam

Postby De Hill » Sat Mar 24, 2012 2:31 pm

Try using Fox fuel: 29% castor, 5 % nitro, and the rest, methanol. It might cure your overheating.

De Hill

jprimrose wrote:Hi,

it seems that my OK super 60 will run but gradually cover the points with gas/oil and stop running. The seal around the rear bearing where the cam protrudes is not so good. Can I make good this seal somehow, with an o-ringlet into a (new) groove or somesuch? any solution?
I have been trying to see if I can protect the points somehow. The leak is not enough to lose crankcase compression, everything else seems to be fine.

btw; two of my spark engines run OK but on the bench get hotter and hotter until they stop well before the fuel is used up. I am using colmans gas and 1/3 oil (60 Harley bike oil). Should I go to methonol FAI fuel ?

cheers
Jim
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Postby jprimrose » Tue Mar 27, 2012 9:02 pm

Hi De

I shall certainly try that, and will post here on how it goes.

Also I see somewhere in the forum that three nicads (NiMh ?) wont burn out the coil because the volts drop under load -- that may help with the contacts getting smothered.

javascript:emoticon(':idea:') Maybe glow fuel is better for that problem as well!

cheers
Jim
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Postby oldtimer 1993 » Thu May 17, 2012 4:37 am

G'day Zeek.
If you haven't already sorted your OK , here are a few suggestions . this is one of the most popular engines for Oldtimer Antique competitions in OZ. and we have them pretty well sussed.
Firstly the 2 cylinder screws tend to come loose and are very short, replace them with longer ones that utilise the full thread length in the crankcase ,use some locktite sparingly. check the gasket as they blow if the screws are loose, but you will see fuel bubbles at the join if it is blown.
Check that the points are not siezed on the shaft , clean and lubricate.
have at least 15thou point clearance, not critical, visual is ok.
Not sure of the 40 degree thing with timing, points opening just before TDC is ok for initial run.
Sometimes the driver for the camshaft turns on the shaft. or it has been fitted incorrectly to the crankshaft- 3 choices. if youremove the rear housingand check the flat on the camshaft it should line up "äpproximately" across 2 holes.
Which hole you put on the crank pin depends on which of the 3 positions youfit the timer assembly, just make it so the points open BTDC.
Good batteries are essential but dont go over 3 cells or you will cook your coil..a single 15 -20c lipo is good.3.7v
Lastly the fuel we use is 4:1 CoolPower and methanol. no nitro,or you probably wont stop it ...dont need it anyway. they run too hot on petrol and there is a risk of fire as they flood and spray fuel everywhere.
Dont run it lean it will over heat , slow down and run like a glow on a red hot spark plug
dont over advance the timing ,use a tacho and watch the rpm.
Good luck ..these are very good engines.
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Postby oldtimer 1993 » Thu May 17, 2012 4:40 am

Oh I forgot we use starters on these engines (carefully).
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