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Engine basics => Engine set up tips => Topic started by: Allen Eshleman on February 21, 2011, 06:02:12 PM
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I was just given a K&B 35 today. It has a sliver head. It is missing a needle valve. Three questions:
What kind of needle valve would work and where might I get one? Could I substitute a different NVA?
What kind of fuel does it use?
Were these good running engines with a 4-2 break?
Thanks in advance.
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If it's the engine I'm thinking of, it's not really much of a stunt motor. However, it's powerful and makes a great sport or racing engine. I think the original NVA is the K&B universal type, but I think you could use a ST assembly in it with no problem. Does this engine have a dykes ring in it?
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What is a Dykes Ring?
I think I do have ST 51 NVA.
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A Dykes ring is L-shaped in cross section and is at the top of the piston. If the engine has a ring, there will be like little windows in the exhaust port. If no windows, it is a lapped piston engine, probably a K&B Stallion.
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It has five windows. It looks as though it has a lapped piston. I haven taken it apart yet.
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Does it look like this?
If so, it is a Dykes ring series 75 K&B. Plain bearings. Almost any needle valve assembly will work. Fuel at 20% oil at least some castor but no need for it to be ALL castor. (5% is more than enough)
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Hi Bill. That's it! Now, I've got to get it to loosen up. It will not turn. I sprayed WD 40 on top of the piston and in the port. What should/could I do to free it up?
Did these motors perform very well? How old might they be? Is there any place where I might find a K&B universal NV. I'm aware of Mecoa. Is that still a viable business? I noticed that they have McCoy needle valves.
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If the motor has been sitting around for a long time after having been run with castor oil, it is probably totally glued together. The congealed crud (castor oil) needs to be broken loose. I suspect that a lot of the crud is around the crankshaft with lesser amounts around the piston and the ring.
Others will have good suggestions on how to un-stick a frozen motor. Heat, anti-freeze, extended soaking in solvents of one sort or another. I will let them chime in here with better advice than I can give.
The K&B 35 was a good motor for its purpose. It is probably not a good stunt motor, although it probably could be made to be one. For sport flying, it works well. And with a small amount of work, it can become a fairly high performance motor for racing or some-such (provided there is an event where it is used).
Look up MECOA on the 'net. The last I looked they were still alive. The K&B universal needle valve will work just fine in the engine although almost anything that is sized properly will work equally well.
Bill
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Heat your oven to about 250 degrees then turn oven off and throw engine into over. When cool enough to handle take out and put on a prop and engine should turn over.
If your wife won't let you use the oven, then heat with a Bernsamatic Torch.
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That particular K&B .35 is "Da Bomb" for NW "Super Sport" racing, if you have one (fairly rare and hard to get if you really want one), and if you can find a race to run it in. NW CL Regionals is about it for CL racing in District 11.
The K&B Universal NV Assy is #2918 from MECOA/K&B. I got some from them maybe 10 years ago, but haven't tried lately. I have 4ea in stock, $8ea. + postage if you want one/some. When I crash tested one, found that the NV didn't break...but the spraybar did. Nice unit if you like clicker-type NV's, and need a .156" dia. spraybar, which you do. Pretty cheap, too.
Most engines do use .156" spraybars, so if you need one at the field, the chances are better that somebody can fix you up, or vs. versa. OS and RO-Jetts are different, with most (but not all) OS's being smaller and RO-jetts are larger (from what I've been told). All that aside, my favorite NV Assy. is Randy Smith's...about double the dinero, but really sweet units. y1 Steve
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Thanks guys,
The tip about putting it in the oven (my wife allowed me - she was away) worked perfectly. I wrapped it loosely in tin foil. No stink, no fire, no juice, no problem. It is loose and oiled with after engine oil. I haven't decided to run it. If I can't scare up a needle valve here, I'll look to you Steve. I'm not in to racing but have an empty plane or two that needs engines and could be "just sport" planes. Thanks again!
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I have one similar but with throttle on it (rc) still new unrun condition . Always wondered how well it would run. Now I have to figure what to do with it.
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These are sometimes a bit hard to start as the ring seats when there is compression (when the engine fires) so you may need an electric starter until it is well broken in. If you do choose to use it for stunt it can be made to work by using a low pitch larger diameter prop like a 10.5x3 or maybe even as large as 12x3 and just running in a "wet" two cycle. They like to break into a two cycle anyway so you just prop for that from the beginning. A really great engine that will produce more than adequate power on FAI (no nitro) low cost fuel. A few years back when there was a serious shortage of nitro I flew a whole summer with one of these on a Sig Twister. It flew very well.
Bob Furr
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How much oil does this engine take?
Where can one buy FAI fuel?
I do know where to get 5% nitro fuel - Brodak, Sig and Fox.
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How much oil does this engine take?
Where can one buy FAI fuel?
I do know where to get 5% nitro fuel - Brodak, Sig and Fox.
This is a plain bearing ringed engine. 20% oil is plenty. Make sure it has some castor oil in it, 5% would be ideal. More than 5% is not needed but won't hurt, just make a mess of the model and eventually gum the engine up.
Don't worry about FAI fuel, use the 5%. Most engines made and used in this country are designed for some nitro and are easier to handle with some in the fuel. For sport flying the 5% is ideal.
Bill