AC2

My Feedback: (34)

Being a Maintenance supervisor and knowing first hand how critical parts/availability to parts are, this deeply concerns me, givin the initial investment.

This cannot be correct can it?

I looked at other engines on youtube and no other make that I found had the same sound. Similar to a Harley Davidson,,,, they come close but fall short.

Seems as though they know they got you by the balls once you buy a Moki..... not interested an anyone squeezing my balls ..



An interesting side note, that G62 (from link) with gear reduction swinging that 30+ inch prop had quite a unique sound as well. Hmmm..interesting.

Greg Wright

My Feedback: (6)

https://youtu.be/F6Wt9zGK3M0

Greg Wright

My Feedback: (6)

AC2,

A moki 180 would fit into a Ziroli Hellcat with no problem.

It's the same size as the 150 that it replaced in the line of moki engines.

There is a video of one flying on youtube.

Here's the video:

https://youtu.be/MHQZKYfwSqs

AC2

My Feedback: (34)

Damn, maybe a little squeze won't be so bad...ugh!! That sound is like a freaking drug. How did you know I had that Ziroli in mind!! That is not nice!

affas

Hi,

Long thread but could not find the best and reccomended way to adjust the valves for my Moki. Anyone with link or copy of the text?


Thanks!

Some motivation in the meantime:

https://www.youtube.com/watch?v=ZVhA9mkQoZU

marksp

My Feedback: (9)

Better yet, a video would be awesome!

Greg Wright

My Feedback: (6)

I just figured that the Ziroli was a nice size for one person to handle is all..

samparfitt

My Feedback: (43)

Affas,
My notes on the moki 250's:

cylinders (counter clockwise 1,2,3,4,5 facing engine)
firing order: intake: 1,3,5,2,4
exhaust: 3,5,2,4,1
feeler gauge gap (.007:0.05mm to 0.08mm ) when engine cold.
VALVE ADJUSTMENT: rotate prop until valve is just starting to go back down and then rotate prop 360 degrees and check for snug fit with feeler gauge.
(distance between two flat spots on locking nut is .007).
High/low needle settings: about 1.5 each.
Needle settings: L: 1 ¼, H: 1 ½ and usually keep it there. Just adjust the low needle by 1/16” turn at a time. Idle 700-800, High 3600-4000, 3[SUP]rd[/SUP] cylinder should be 160-165 degrees. Top cylinder max 220 degrees. John recommends red line or echo oil. Oil should be ISO or JASO FD/HD properties.


solo prop: 3-blade 32X16, idle: 800, full throttle: 3660
spark plugs: NGK CM 6: plug gap is 0.3mm to 0.4mm

fuel: 1:50

engine festo fitting: Industrial specialties mfg, connector: part # 6512-3-m3
After every flying session clean and lightly oil the rockers, push rod ends and valve stem.

The valve stem under the spring is important as without a regular lube carbon build up on the valve stem could eventually cause the valve to stick resulting in the possible loss of a push rod.

Check all external nuts/bolts especially the exhaust collector ring gland nuts
as they take ages to bed in due to the Teflon seal.


Sam

Maxam

My Feedback: (62)

Sam, a critical point with valve adjustments. The cam ring is not perfectly concentric. On many radials you will find that once you adjust the valves you will discover that when the prop is then rotated two turns you will find the valves to be either tighter or looser. If tighter they must be readjusted. The Moki's have two sets of cams on the cam ring so the valves must be checked twice. Two of my 215's are very concentric, one is off but still in manufacturing spec. The one that is off concentricity a bit, the valves must be adjusted to the higher cam pair thus insuring the valves fully seat so yes the valves will be a bit more loose on the other cam pair. Also as said earlier in the thread, brake cleaner with the carbon tetrachloride is perfect for cleaning the carbon off the external portion of the exhaust valve, but do not forget to oil right away! Brake cleaner removes ALL oil. -Tom

samparfitt

My Feedback: (43)

Thanks, Tom
Sam

GeorgiaFlyer

In reference to valve adjustments, earlier in this thread (post #209 and #213) have information on it. The additional information about the cam ring that Maxam mentioned in his post above is very useful as well, Thank You!

Here is my Stearman I just put a 250 on it, first flight with this motor on it.

https://www.youtube.com/watch?v=tKAB2HIqODA

Hinckley Bill

My Feedback: (569)

Awesome Marc........nice 'touch and go' too

Hinckley Bill

My Feedback: (569)

Sam and all.....thanks so much for continuing to educate everyone on the Moki radials.....I've got a 215 on an older AMR Waco that hasn't been run in years and right now I'm more than a little nervous about getting it running again. I may opt to send it in to have it checked out and adjusted before anything else

Your thoughts would be most appreciated.

Bill

Greg Wright

My Feedback: (6)

Depends on how long a few years is. But i would still send it in to have it checked out. It could just need the carb rebuilt to be back to running condition.

Gas will dry out the diapham if not kept wet same with the fuel lines in your gas tank. I'd go thru that and rebuild it with all new hoses and clunk/filter.

Jaketab

My Feedback: (2)

Maxam,

Regarding your post 3709 above, I have discovered your post to be good advice. School me if you would as I have never seen the inside of a radial. The Moki radial has 2 cam rings - one for intake valves and one for the exhaust. Question - on each cam ring are there 4 cam lobes ???? If so, does it take 2 revs of the crank for the cam lobe to rotate 1/4 turn to the next lobe ??? So is each valve being lifted in turn by the 4 lobes on the cam ring which accounts for the slight variance in the valve lash ????

FYI - Regarding Moki 250 props, in the video posted below my engine is tuning a Xoar Laminated 32 x 18. Seems to be a very good stiff prop for this combo other then it may slightly over-rev the engine if not managed. Has anyone tried the Biela 32 x 22 on the 250 ????

https://www.youtube.com/watch?v=1bvQ3ApFfT4

Regards - J Tab

samparfitt

My Feedback: (43)

Bill,
This past winter, I just sent my two moki 250's to TBM (where I bought them) and had them PM'ed. PM of each was about $120-$150, the 'kicker' is mailing (with full coverage) 60 bucks each way, but when considering the lost of a 4K engine (plus plane), it was worth it. I had carbon buildup and John recommended: use red line or echo oil. Oil should be ISO or JASO FD/HD properties. I had over 300 flights on planes and of all engine types with no problems but I got carbon build up on the moki's. I'm guessing the single piston gas engine operate at a higher temperature (and faster RPM's) than the moki's so the single piston engines burn off excess oil a lot easier.

Also, in my previous post of a low pass, the engine is at full power. In my opinion, if your engine and/or prop sounds louder than this, then you need more pitch. For me this is about the 'ideal' sound of a moki flying by at full throttle on a low pass.

https://www.youtube.com/watch?v=5u1RRUYQ7Tc

Sam

Hinckley Bill

My Feedback: (569)

Sam and Gregg....

Been over 4 years since the last time the 215 was run, been attached to the airframe hanging in my garage since then.......so I'll take your advice about getting it gone over......far cheaper than damaging it and having to repair/replace it.

Just curious are the guys at TBM the 'go to' guys for Moki radial maintenance?

Bill

samparfitt

My Feedback: (43)

Bill,
Not sure if TBM will take engines that they didn't sell and, also, they have seemed to switched over to selling mostly high end multi-rotor stuff. John is the Moki tech at TBM. You may have better luck with Vogelsang as I hear he also does excellent work.

I've taken apart my single piston engines to work on them but 'no way' on the radials :[]

Sam

Maxam

My Feedback: (62)

J-tab, there is one cam ring with two tracks. One is for exhaust and the other for intake. Each track has two cams Therefore the ring is running at one rotation / four rotations of the crank. My 7-77 has 3 cams on each track so it rotates at 1/6th crank speed.

To all; If you find fascination with radials may I recommend two books that are a great read. 1. R-2800 Pratt & Whitey's Dependable Masterpiece 2. R4360 Pratt& Whitney's Major Miracle. Both are written by Graham White. I have learned a great deal about engines from these two books which can get technical but still of great interest. Also Development of Piston Aero Engines by Bill Gunston has great insight into overcoming failed valves, overheating and improving power to weight ratio etc. Good stuff! -Tom

samparfitt

My Feedback: (43)

A simple explanation of how radials work

http://blueballfixed.ytmnd.com/

Sam

Jaketab

My Feedback: (2)

Max,

Thanks for the explanation. So each valve is lifted by opposite (2) lobes on the cam ring.

Thanks - J Tab

Maxam

My Feedback: (62)

Yep! Way early in this huge thread is a photo of the cam ring. Cannot remember where.

AC2

My Feedback: (34)

So are any of you using Gyro's to help avoid any mishaps as added protection for these Golden eggs?

GeorgiaFlyer

No I do not use any Gyros. Its all in the thumbs

Greg Wright

My Feedback: (6)

I use Gyro's in all of my planes...

But don't get the idea that a gyro is going to save or help you fly or save your plane from crashing.

Because everyone that thinks that, they are totally wrong in there deception on what a gyro is there for.

I will just leave it at that cause i don't want to get into it with any of the none believers.