mick15

Here is a copy of the email I received from the factory through the dealer, and my response.

"In English:
These tolerances fall within the permissible framework and have no influence on the running characteristics and motor life.

Within an engine to run various temperature-related parameters are constantly changing, this includes the valve clearance.

It is important, not too tight adjust the valve clearance so valves close for sure!"

"Ok ********, I will no doubt have to accept what the factory has said. I do feel though that is a poor substitute for a properly engineered component after all 0.1525mm discrepancy in precision engineering terms is a bus ride!

Incidentally none of my other Mokis (of which I have three) exhibit this problem.


Thanks for your efforts regards Mick".

Obviously the cam grinding equipment is wearing out and they cannot be asked to replace it!

m

PS> You would have thought they would have offered me a new cam ring at least. I know where not to spend my money in future..

Maxam

My Feedback: (62)

Not good and a true blow off. Not acceptable. Period. -Tom

affas

Hi,

Nobody with experience on a well suited 3-bladed propeller?

Detlef Kunkel

Mick,
although I wouldnt be happy either, I dont think that that is a serious problem if you care for not having too little clearence at the tightest point.
When there is a bit too much gap 2 rpm later, it will not affect the engine. The valve train of the moki is everything but that of a race engine, meaning it will work with that big clearence, too.

But I admit it would have been smarter to to please the customer and replace that part.

GaryM

My Feedback: (14)

Hansen, I had Zoar make me a 26 x 14 3 blade and it hauled my 51 lb. corsair nicely.

G.Masters

Hello all, I would just like to introduce myself to this forum.My name isGlenn Masters, long time warbird fan and accomplished display pilot on the United Kingdom and some european show venues. I have recently taken the plunge and acquired a used 215 from Stuart Mackay - a friend and flying colleague for a good few years ! With his tuition and also the help within the pages of this thread, I have had a successful first experience with the Moki radial. My 215 is intalled in a 30% Harvard (AT6) and 25 flights later, it has proved to be totally predictable and reliable. I have, so far, not used any aftermarket add-ons such as pumps or turbulators and the motor appears to be just fine. I am achieving 4100 rpm on the ground with a Menz 32 x 18 prop. With a little energy management, a very scale-like flight performance is possible. I have a question to ask of any 400 owners regarding 2 bladed propellor choice. I have purchased the starboard Moki 400 engine from the 1/3 scale B25 Mitchell belonging to Marcus Berger of Germany (have a look on UTube - its a stunner) He has upgraded to Valach 420s - I intend to eventually fit the engine into a 1/3 P47 but first, I will befitting the 400 into my nearly finished 1/2 scale Gee Bee R1 and I would welcome suggestions for the best size 2 Blade Prop to suit 400 and the flying characteristics of the R1 ? Many thanks regards Glenn

mogman

Hi Glen.

I have a 400 in an AMR 40% Waco....big draggy bipe. I'm using a 40x18 Biela 2 bl., turns 38-3900 on the ground, but very seldom fly at over 3/4 throttle. I also have a 40x22, but have not tried that yet as I don't need the speed.

Perhaps Scott, the originator of this Moki thread will chime in here as he is running a 400 in a 29% (I think) P47 and it motored along very smartly. Perhaps a 38x22 or the like.
Also Phil Clark, Fighteraces, (Ali's big Skyraider) might have a suggestion as they ran a 400 in that originally.

Cheers,
Dave. ( LMA # 2296)

RichardGee

My Feedback: (156)

Glen, welcome!
Your story piqued my interest when you mentioned a 50% R1?! Being a Gee Bee fanatic, I hope you will introduce a new forum about your giant GB so that we can all enjoy!
I have no experience with the Moki 400, but lots of experience with Gee Bee's... if it were me, I would go with the recommended range propeller that provides the most pitch. That said, the recommended 38x18 will certainly fly your Gee Bee, but only flight testing will determine the ideal prop. Lots of speed is impressive, but a fast Gee Bee will eat up the sky at an alarming rate and you may want to develop some familiarity with the plane before you go down that road...
Best of luck!
Richard

Brian Rawcliffe

Glen welcome to the forum,it's nice to see that you have at last fitted a decent engine into the Harvard.Looking forward to seeing it flying at
Cosford. ps.Scott, if you are reading this post my regards to you and Greg.I remember our meeting in 2010 on your visit to Cosford, and I am still flying the Tempest mk11 with panache, although I will be 81 on the 25th of October. Brian.

affas

Thanks. But that small? I am running 28*14 four bladed now and it pulls approx 4200rpm at ground. I can see Biela offering 32" for Moki 250?

mick15

I'm running a Biela 32x12 three blade "Extra" prop on my Sea Fury, working on the assumption this prop is designed for low speed pulling power,
also working on the assumption that the scale speed of a 1/4 scale Fury should have a maximum speed of 100mph.

m

darryltarr

My Feedback: (2)

Mick,

I honestly don't think that that 12" is enough Pitch. I am running a 30x18 Three Blade Menz on my 250. I have also tried a Biela 32x16 Three Blade and will NOT go anything with less pitch than that.

The MOKI is a High Torque motor. Also make sure you do OPEN the throttle all the way. Yes, there won't be much increase in RPM from 60% to Full but at least the motor will get the required airflow and cooling.

An electric fuel fuel pump (Emcotec) is the only way to go.

Good Luck.

Darryl

butlern

My Feedback: (15)

Alf,

I think Gary was under the impression that you had the 150cc (which Gary had installed in his 51 lb Corsair), not the 250cc...

You're right, 26x14 is way too small for the 250cc.

mick15

A 32x12 seems to work just fine to me, like I keep saying most folks fly their warbirds far too fast.

http://youtu.be/MPJnt0ogOz8

G.Masters

Thanks for the warm welcome . . . I think I will run with your advice richard and go with the stock 38 x 18 prop. Sorry, but I never really became involved in a build thread of sorts but I will try to upload a few photos of the project so far . . . Brian, can you remember Mr Tappin, open mouthed and drooling when my Gee Bee appeared at the new project symposium at Haigh Hall ? my goodness - that must be 7 or 8 years ago !! Time it was finished. In the meantime I enclose a few piccies of the P47 project which will eventually have the 400 installed . . best regards Glenn

Detlef Kunkel

Hi Glen,
 its a small world, nice to meet you here.

I remember your last P47 when we talked about it in Duxford, a lot of years ago, and the sad news one year later.
Nice you build another one

heraldoboldrin

I need some help with my MOKI S7 250.
I already did 3 flight using 40/1 of oil and a Biela 32x18.
My moki works great, but is to hot.. and i think because of that is loosing a lot of power. The fuel misture isn't lean.. and is on a stermann so has no cowl.
With a reach fuel mixture, the engine get more or less 4000 RPM, but after a few minutes the RPM drop to 3300 RPM


Some people said that Biela is to heavy for break in, and because of that the engine is getting hot. (some times 230o F)

Straightleg

Hello helaldrobrolin !


I do not think our prop is too big for break in. Just take it easy
Regarding Your drop in rpm, have you tried to lean it when it gets warm ?

Use environmental fuel 50:1. I recommend Stihl pre mixed for Chain chaw engines. Aspen will also do.
Gas from pumps contains a lot of crap, and Your engine will have a carbon build up inside.

/Straightlegger

heraldoboldrin

Straightlegger

Thanks for your tips.. do you think I could go to 50/1 direct?
I open the mixture more or less 1/8 from the factory default. When get hot I should lean the misture?

regards

Heraldo

Straightleg

No prob. I have used this fuel (Stihl 2%) from day one on all my radials.
Try to adjust the engine while it is running. To do this, you need to silver solder a brass tube on your needles, to prevent the screwdriver to slide away.

/Straightlegger

heraldoboldrin

I can't acess the fuel mixture with the engine running.

mick15

Set the main needle to a turn and a half and the L needle to a turn and a quarter, should be very close at those settings.

m

wphilb

My Feedback: (10)

One thought, instead of silver soldering on the needles, perhaps a small piece of fuel tubing over the needes should also hold the screwdriver blade in place while tuning. Then you don't have to remove the needles from their current position and you can adjust from this point.

heraldoboldrin

Straightleg

How much RPM do you think i can get on the Biela 32x18?

Straightleg

I do not know the seven cylinder,but I will guess around 4400....