koenvlieg

I started to use the pump on my 215 a few years ago. The reason was that there came regularly grease in the tube to the carburettor. At that moment the engine didn't run well anymore and the tube was necessary to clean. After, I bought the 250 and I saw almost no grease came into the tube, it meant they already solved that problem. As the 250 was for an acro plane ( pitts python from c-arf ) I also installed the fuel pump : result was prop hanging without any engine problems.
About one and half year ago I installed the turbulator on the 215 : result was a perfect smooth running engine with about 50-100 rpm more, less fibrations and less fuel consumption. I didn't do it on the 250 becaus of mounting problems in the Python, but it would have been a big improvement for the gas response.

My conclusion is :

- the engine runs well and reliabel as it comes from the factory
- my first investment would be without doubt the turbulator
- I doubt the necesarity of the fuel pump wen there are no high demands like long distance between fuel tank and engine and long vertical manoevers.
- The perfect running radial in all circumstances is of course with turbulator and pump
- But it's as important to keep the engine in good condition : regulation of valve settings, oiling the valves every fly-day, to take minimum 1.5 minutes of idle and than slowly go to hi rpm, ...
- As I always use Aspen premixed fuel, the engines are both clean inside. As I mentioned a few weeks ago, this aspen fuel burns so clean that the lubrification of the cylinders becomes worse. So for me it's very important to know if the black coal that can come inside an engine is from the oil or from the fuel. One thing is sure : I will not take the risk anymore from using premixed Aspen !

It will be :

1/ Aspen ( Stihl ) pure + synthetic oil of high quality 2 %
2/ 98 % octane from the pump + synthetic oil of high quality 2 % : only if the black coal is not due to the pump fuel, in the other case I take option one with the Aspen that's more than twice expensive

I hope somebody can give me this information

fg

koen

affas

I ended up installing the engine a little twisted with the cylinder that was recomended topfront a little more twisted to the right when I am in the front of the engine. This just to have the exhaust at a better angle out on the righthand side of my AT6.

Does this matter? Should I turn it back to recommended from the manual?

Thanks,
Alf (first time Moki owner...)

ram3500-RCU

My Feedback: (221)

Fuel system for our CARF Corsair.

germrb

My Feedback: (3)

Alf,

The slight rotation of the engine will not make any difference in performance. No worries.

WARBIRDRCER

My Feedback: (22)

Did you ever buy this project MOKI 250? If not, was this on a CARF F4U belonging to Brian. If so I now have this 250, but if not, I would like to buy it for the parts. If anyone knows of another please let me know.

Thanks,

Warbirdrcer

TJPro351

My Feedback: (8)

I have a Moki 215 and had to replace #1 cylinder head and having problems with exhaust ring. I loosened all exhaust elbows from each head. Turned the exhaust ring clockwise and all exhaust elbows removed from each head. I replaced #1 cylinder head and turned the exhaust ring counter clockwise to install the exhaust elbows into each head. I ensured all the washers were still installed on each head. My problem is that when I tighten the exhaust nut (head side) on each head, all the bolts tighten up but the elbow on all heads are still loose. I can grab the exhaust ring and move it clockwise and all exhaust elbows move back and forth. What am I doing wrong? Why are all the exhaust elbows not tightening up? Am I suppose to change the washers inside the exhaust port on the heads?
Help!!!

Tim

WARBIRDRCER

My Feedback: (22)

TJPro351,

The washers inside of the cylinder heads located in the exhaust and intake ports, as well as the opposite ends of the intake tubes on the aft case assembly are “crush� washers. They are thick when installed and designed to crush when the component is installed. That may be what caused your looseness.

You will find them listed at most aircraft supply companies as AN900 (MS35769)
Also, known as annular copper-asbestos gaskets that will withstand temperatures up to 500 F, and pressures up to 200 PSI.

First call Vogelsang Aeroscale at 919-533-6275. They are the U.S.A. resource for MOKI.

If you have trouble finding them, let me know and I will assist you on locating some.

TJPro351

My Feedback: (8)

Ok, I will give Goetz a call on Monday. I do see the washer on the head side but it is pretty flat Thanks for your help.

Tim

WARBIRDRCER

My Feedback: (22)

I think the size you need is a AN900-6, and the MS number is MS35769-6

JRSmith

My Feedback: (47)

Hello guys, I am going to buy a Moki 250 once they are back in stock (within two weeks) at Vogelsang Aeroscale and have a couple of questions and my first contribution to the thread hopefully. The motor is being installed in a Hempel Yak 55M 170cc.

Little history.....The plane was originally built around the SL/PRM 150 in Italy and 6 months after returning it for repairs I still have no motor then just got a E-mail that states he "sold the designs to another company and they would be in touch". I have a feeling I will never see that motor or a refund, so that was a big mistake, tough pill to swallow, but I need to move on and buy the Moki like I should have done in the first place! There is a build thread on FG that details the problems if you guys ever want to read it. Enough about that and sorry for the quick rant!

I have done my best to read through the thread and avoid asking these questions again, but if you guys don't mind...

Looking to get advise on prop selection for break-in and normal operations once broken-in. I really want to run a three bladed prop on the airplane but two bladed will work just fine also.

I already have five gallons of 100LL AVGAS mixed 50:1 with Castrol Power RS TTS 2T oil and Metalon C2 that I was using in the SL/PRM engine and would like to continue using it with the Moki unless you guys feel premium pump gas would be the better option even with the ethanol that is currently blended it? I have a friend that works a FBO locally so logistics are not a problem to buy the AVGAS.

The fuel pump from Vogelsang Aeroscale is already plumbed in the system and I was using it with the SL/PRM engine and it works great. I have a smoke system installed in the airplane and any considerations as to smoke tap location, oil preheat (if required), etc would be appreciated.

Any other tips or considerations that I have not addressed, please let me know.

I do want to share a item I though would help in maintenance intervals and tracking for the SL/PRM engine that will also work with the Moki or any other gas engine for that matter. I thought if full scale airplanes have a engine hour meter, why not our model engines. After doing some research on meters, I found a unit from ENM from Chicago that meets the specs in our installation. The LCD meter operates on 4.5 to 60 VDC and has a operation current of .5mA @ 4.5V. It has EEPROM memory, is epoxy encapsulated and is very light weight. I am running two Powerbox Spark switchs (one ignition and one fuel pump) and built a lead that runs in-line with the output from the spark switch to the ignition unit. The meter turns on and off once you flip the switch for the ignition. I designed a mounting box for my installation and cut it out with the laser cutter. If I would have thought of the meter earlier on I would have been able to incorporate it into the other sub units I built into the airplane for a little cleaner look, but this one work fine for now. If this is something you guys might be interested in for your motors please send me a PM, e-mail, or give me a call. I can make the mounting box, lead, and engraving to your specs. I have not bought any more meters yet to see what the interest is first. Pricing TBD.

Thanks Scott for starting the thread! What a great place to find info on the motor. Take care guys and all the best.

Jason

affas

How do you adjust the valves easiest? Moki is new for me and this thread is a bit long. I have searched without finding a good solution.

Here is my second day with my AT-6:
http://www.youtube.com/watch?v=sBcV3SpChiI

Thanks,
Alf

WARBIRDRCER

My Feedback: (22)

I hope this helps with valve adjustments.

Four stroke basics:

1. Intake Stroke – Intake valve opening while piston is traveling down causes a suction drawing the air fuel mixture into the cylinder.

2. Compression Stroke – Both valves are closed while piston travels back up to top of cylinder compressing the air and fuel mixture into the combustion chamber of the head. Piston is at Top Dead Center (TDC) at full piston up travel at maximum compression. (Remember this position for intake and exhaust valve adjustments)

Note: Because of a delay in spark and flame travel, most ignition timing is set to fire just Before Top Dead Center (BTDC). This allows the 3rd stroke, called the Power Stroke, to receive the explosive power of fuel and air ignition to happen as the piston starts on the way down. Think of pushing on a bicycle pedal as it rotates around. If you wait to apply down pressure as the pedal goes beyond TDC all of your force is converted to power for the full stroke of the pedal. If you apply pressure BTDC you fight the rising pedal, if you push to late, or After Top Dead Center (ATDC) you loose power. An engines ignition system is designed to take advantage of this rotating motion. So, the third stroke is the Power Stroke.

3. Power Stroke – Expanding exploding gasses pushing piston to BDC.

4. Exhaust Stroke – Piston returning to TDC with the exhaust valve opening allows the burnt gasses to be pushed out of the cylinder just prior to the next intake stroke of that cylinder.

Note: In some 4 stroke engines, there is a brief moment when the piston reaches TDC of the exhaust stroke that the intake valve starts to open. This allows incoming cool air to assist in pushing all of the remaining hot air charge out of the cylinder prior to the exhaust valve closing for the intake stroke cycle. (See item 1)

Valve adjustments: There are other methods to follow, but applying the knowledge from the above items will assure you get it right every time.

1. This engine has a close motion between TDC and valve movement. So my recommendation is to start by removing your spark plugs.

2. Pick a cylinder to start with. It does not matter which, but continue in one direction clockwise or counter clockwise. This will assist you in not missing a cylinder.

3. Now, find that cylinders compression stroke. There are two ways to determine the piston is on the compression stroke.

First you can put your finger over the spark plug hole and feel for the pressure build up as the piston is on the way up on the compression stroke.

Second you can place two fingers on the tops of the rocker arms for the cylinder you are adjusting the valves on and find when there is no valve movement and the piston is on the way up as described above.

Either way, place a non-metallic tool (small dowel, plastic tube, etc.) into the spark plug hole and feel for the rising piston. Once the piston reaches TDC of the compression stroke there will be a point where the piston does not move up or down as you slightly rock the prop back and forth. Both valves will be fully closed and ready for adjustment.

4. Using your feeler gauges, select the recommended range sizes first. Now select a feeler gauge .001 smaller than the tightest fit you are wanting, and one .001 larger than the greatest gap you are wanting. So, if you are looking for a .005 gap, .004 should be loose (no friction on the gauge), and .006 should be tight (feels like binding). However, a .007 should not fit into the gap. Remember, Using feeler gauges is just that, feel. Your feel and my feel will be slightly different. Once you become a custom to how it feels to you, go with it. With the feeler gauge slid between the valve stem top and the rocker arm tighten or loosen the screw, then lock the jam nut and recheck the feel. It may take a little back and forth to get it where you want it, but you will get it.

The following photos may help in understanding what is going on inside of the engine.

The first and second photos show the MOKI 250 ring/cam gear. The lobes you see protruding from the sides are the cam lobes.

The third photo is a side view of the cam gear. You can see the two rows of lobes. The row furthest from the gear teeth is the exhaust side, and the one nearest to the gear teeth is the intake side. Each side has 2 lobes.

As the cam ring rotates, it causes the cam followers/lifters to push up to open the valves. As the lobe passes by, the valve spring pushes the cam followers/lifters down against the cam ring allowing the valves to close. The flats, or area of the ring that has no lobes is where the cam followers/lifters are when you are adjusting your valve lash.

The forth photo is a parts layout of the Cam Ring, Cam Follower/Lifter guide, Cam Follower/Lifter, and the pushrod.

Photo five is an assembly photo.



I hope this helps.

Scott Prossen

That's fantastic WARBIRDRCER! Thank you so much for another super helpful contribution[8D][8D][8D]. Please keep it coming when you have time.

You have our full appreciation,

Scott

affas

Thanks for great information and helpfull explanations and pictures!!

ram3500-RCU

My Feedback: (221)

First start for our new Moki 250.

Oiled all the heads at the recommended (6) points.
I left the cowl off for the three times we ran the engine this day.

-380 pump
-50cc tank
-1800 mah A123 battery regulated down to 5.1v on the ignition, switched
-1800 mah A123 on the pump, switched
-32/1 gas/oil mix using Klotz 100% synthetic

We used a 24v started for this run. It started right away and ran flawlessly. Could not be happier with this first experience with these wonderful engines!!

mogman

Hi Gary.

Finally got the 400 on an airplane! 40% Waco, started 1st. Feb. Finished on JUly 10th. Going to fire it up in the driveway today (I have run the engine before) regulated 5.2 V on the 380 pump and ignition. 50-1 synthetic (Stihl ultra)
Maiden will be in a couple or 3 weeks. (we just lost our field[&o])

If all goes well will be at Monster planes again this year, are you going again?? Looks like it will be "Radial City" this year
Cheers,
Dave.

DENTO

HI DAVE
Just a bit of trivea I have friends that live in the same block as the GILLNETTER . PS sorry to bust into the forum.
REGARDS
JOHN

mogman

John,
PM sent.

nine o nine

My Feedback: (1)

Beautiful work and you'll love the 400 on her. Only thing I'd like to advise for your maiden......don't even think of going over 3/4 throttle on the take off. In fact 1/2 WILL be plenty. Too much throttle until you're used to the take off characteristics of the Waco and you'll have a tiger by the tail. Let it fly off the ground when it's ready and you'll be rewarded with a huge grin instead of gut wrenching terror. Good luck, Mitch

ram3500-RCU

My Feedback: (221)

What a wonderful looking plane Dave. Yes, we are planning for Monster Planes 2011. My brother planned his vacation around the first week in October, but he thinks he has that problem solved.

Hope to see (and hear) your 'monster plane' in person.[sm=thumbs_up.gif]

PS I love your color scheme. A real eye catcher.

mogman

Gary.
That's great. See ya there.

Mitch.
Thanks for the advise. First flight will be somewhat cautious. The field where I will be conducting the maiden has a very long runway so plenty of room to work up the T/O speed.

Cheers,
Dave.

RichardGee

My Feedback: (156)

[X(]HELP!
I am looking for intelligent opinion, or better yet, first hand experience with my question/problem![]

On flight #4 of my Thunderbolt, the Moki 250 began to run rough, missing and such... mostly at high throttle settings, but clearly something was not quite right with the engine. Upon taking the airplane apart for transport, I found the ignition module was quite loose on the back of the firewall as one of the 3 screws had come out and the module could literally flop around against the firewall.
I assumed this was probably the culprit as the engine had been running perfect earlier (and YES, I checked the carburetor pump/pressure line - it is clean)

Upon further inspection at home I found another problem... one exhaust outlet has broken off my collector ring!!!

As I have a warbird event in one day that I REALLY, REALLY would like to fly, can anyone give me an intelligent answer as to whether or not flying the engine like this will be a bad thing?? Other than the hot exhaust spraying inside the cowl[], what else might be a potential issue that could risk my engine or plane?

No doubt the collector ring must be removed to repair?? YIKES!
[][][]

glazier808

My Feedback: (1)

Ouch

RichardGee

My Feedback: (156)

Dave,
Where are getting the beautiful flexible exhaust tubing?

germrb

My Feedback: (3)

Richard,

You already know what the intelligent answer is. Don't fly it!!!!!

Theory: The excessive vibration of the loose ignition module was enough to interrupt the ignition firing sequence and pistons were firing at random creating more vibration. It was apparantly severe enough to fracture the exhaust ring.

In any event, its a matter of mind over pocketbook.

Good luck,