Author Topic: K&B .35 Series 75 spray bar/Dyke's ring (Read 2230 times)

Terry Caron · « **on:** June 25, 2015, 07:06:37 PM »

What is the spray bar diameter for these?
Is it turned down in the center?

Thanks.

Terry

Bob Matiska · « **Reply #1 on:** June 26, 2015, 07:18:17 AM »

The spraybar from mine mikes in at 0.160 inch. It has a single fuel hole. I believe it's a standard K&B assembly. The diameter is not reduced anywhere.

To answer a possible second question, the venturi insert has an inner diameter of 0.262 inch. And the venturi in the front casting has an inner diameter of 0.375 inch. I don't think I ever ran mine without the insert; I used it mostly in slow rat or big goodyear back in the 1970s when I was stationed near Clovis, NM. It's a nice engine, I have to put it on something...

Bob in NEAP

Terry Caron · « **Reply #2 on:** June 26, 2015, 08:28:34 AM »

Thanks Bob.
A flying bud gave me this engine with no nva, my first experience with K&B.
I put an Enya .35 nva (.155" o.d.) in it to see if it'd run (on the bench) and it acts like 2 other engines I recently resurrected which had too large a spray bar - it runs for a few seconds and dies.
Now I don't know what to think. Guess I'll play with it some more and hope it heals itself.

Terry

Bob Matiska · « **Reply #3 on:** June 26, 2015, 09:09:05 AM »

That Enya spray bar is just slightly smaller than the K&B unit, so I would think it should work. Is the venturi insert installed? Without that insert, I doubt there would be enough fuel draw the run the engine on suction. If not, you may have to get one or make one of your own, say, from some 3/8 o.d. thick wall copper tubing. It wouldn't be pretty but it would probably work.

Good luck

Bob in NEPA

Terry Caron · « **Reply #4 on:** June 26, 2015, 11:47:10 AM »

The insert's in place Bob; as you say, it should work.
I'm gonna try running it again, check fuel system, etc.
Here's hoping.

Terry

Terry Caron · « **Reply #5 on:** June 26, 2015, 12:58:56 PM »

This time I got it to run for several minutes.
On 13.5/25 fuel it turns a 10-5 APC between 8400-10400 rpm - not too impressive.
No 4-2 to speak of and from initial 1 1/4ish turns, 6-8 clicks on the Enya needle takes it from dying wet to dying lean.
A bit more research and I read that these didn't come with piston skirt ports; this one's apparently been modified to include a single rectangular port, so a wild guess is it was used previously for racing.

I've no experience with Dyke's ringed engines, but I understand they depend on compression to create a seal.
It sure has none turning by hand and's a PITA to start, easily flooded.
With the piston in the cylinder at TDC I can easily turn the ring in it's groove - OK or indicating wear?

Terry

Add: a second run and it's turning to 10.8K, very slow to break or return to 4-cycle.

Bob Matiska · « **Reply #6 on:** June 26, 2015, 03:00:17 PM »

Yes, Dykes rings depend on compression to force them out against the cylinder wall and often have little compression when cranking. I wonder of your ring is stuck in a gummed-up groove. If so, more running may help, especially with a fuel that only has synthetic lube. Squirting some solvent in the cylinder and letting it set for a day or two (with the cylinder closed) may also help loosen the ring. Of course, the ring may also be worn out.

Perhaps someone here with more experience than me with Dykes rings can chime in.

Bob in NEPA

Terry Caron · « **Reply #7 on:** June 26, 2015, 03:26:14 PM »

I'm running Omega 15% w/castor added to 25% oil, so over 50% castor.
The ring isn't stuck, as noted above, but may well be worn.
I've contacted Frank Bowman who can supply a new ring, but I'd like to know this one's bad first.
Any K&B (or Dyke's ring) gurus out there?

Seems whoever ported the piston didn't simply cut a hole - there's no noticeable vibration.

Terry

Carl Cisneros · « **Reply #8 on:** June 26, 2015, 11:13:49 PM »

Terry

here area couple of articles on that motor you have.

http://sceptreflight.com/Model%20Engine%20Tests/K&B%2035%20Series%2075.html

http://sceptreflight.com/Model%20Engine%20Tests/K&B%2035%20Series%2075%20(2).html

Carl

Terry Caron · « **Reply #9 on:** June 27, 2015, 10:48:51 AM »

Thanks Carl -

I'm running on suction with the insert, so maybe it's not so terribly wimpy after all.
I was just expecting noticeably more than a Fox or McCoy RH.

What's the engines reputation for 4-2?

Terry

Terry Caron · « **Reply #10 on:** June 28, 2015, 11:33:53 AM »

Time for a wrap-up.
Frank Bowman states the vertical gap betwen piston and ring should be .002" max; mine measures .013".
This is the critical dimension on a Dyke's ringed engine and a new piston isn't likely so I'll keep it just as a K&B exemplar in my engine accumulation.

On the off chance someone may recognize his handiwork and supply some history, this pic shows the porting job done on the piston - somewhat crude and no indication of crank rebalancing so the lack of vibration is a bit surprising.

Thanks for your interest and info guys!

regards,

Terry

Author Topic: K&B .35 Series 75 spray bar/Dyke's ring (Read 2230 times)

Terry Caron

K&B .35 Series 75 spray bar/Dyke's ring

Bob Matiska

Re: K&B .35 Series 75 spray bar

Terry Caron

Re: K&B .35 Series 75 spray bar

Bob Matiska

Re: K&B .35 Series 75 spray bar

Terry Caron

Re: K&B .35 Series 75 spray bar

Terry Caron

Re: K&B .35 Series 75 spray bar

Bob Matiska

Re: K&B .35 Series 75 spray bar

Terry Caron

Re: K&B .35 Series 75 spray bar

Carl Cisneros

Re: K&B .35 Series 75 spray bar/Dyke's ring

Terry Caron

Re: K&B .35 Series 75 spray bar/Dyke's ring

Terry Caron

Re: K&B .35 Series 75 spray bar/Dyke's ring