MVVS 120 twin boxer
 

Can the cylinders exaust be turned upwards so they point the same way as the carb.
See picture

RE: MVVS 120 twin boxer
 

TP,


This is an MVVS...

All the .15-.91 displacement cylinders (this engine has .61 cylinders) can be rotated, to have the exhaust port pointing in any of four directions...
This is best done before the engine is ever run, so new wear-patterns are established on pristine surfaces of new piston and sleeves.

However, the carburettor probably cannot be turned 90º, so I cannot see how you would allow it to work properly.

RE: MVVS 120 twin boxer
 

are you saying it can not be done with this 120 engine ?

RE: MVVS 120 twin boxer
 

No, TP.


Just that an extension would probably need to be fabricated, to use the Walbro carburettor on your engine...

Its solid parts will otherwise clash with the exhaust...

RE: MVVS 120 twin boxer
 

Yes you can rotate the cylinders. I never got the carb you have installed to run properly. No mater how far I backed the needles out, I could not get it to run rich enough. Most of my problems with this engine were solved by replacing the carb. The new car does not interfere with the mufflers but the linkages is not as simple as I'd like. You will have to install the mufflers the other way around.

One cylinder ran considerably hotter on my engine. I did some work internally to direct the fuel/air and now they run withing 5 deg of each other.

I haven't flow this engine yet but I have run it a considerable amount on the bench. I would solicit other opinions and or run this engine on the test bench some before you build a plane around it. My engine is running very well now but it didn't come out of the box that way.

Bill

RE: MVVS 120 twin boxer
 

Hi!
It can be done ...but don't lay down too much work on the MVVS 1.20 as it doesn't work too well!
Both the 1.20 and 1.24 twin was something the MVVS would likely forget today( These engines are no longer in production).
The twin engines doesn't run well. Ok ! They run but they cannot be run rich, don't idle too well without battery glow and don't throttle too well. Can you live with that then go ahead! But please don't use them in a scale plane.

RE: MVVS 120 twin boxer
 

hi! i'm from pr and i have this engine, but the cylinder exaust is looking upwars to the carb. this engine only ran 2 tank and in the first tank it stop radically, i have to losen the bolts to liberate the propeller. when i tighten the bolts again and the propeller losen freely i run the second tank and run very well.(i run the tanks in a bench). do i turn the cylinder exaust just 1/2 away to have the exaust like is in the first picture? and what kind of muffler are that? thank for the help. i will try to take a picture of my engine the next time.

RE: MVVS 120 twin boxer
 

http://www.bissonmufflers.com
This company makes the mufflers that were on there i believe .
The motor was sent to my friend and the exaust was turn 90 deg facing down

RE: MVVS 120 twin boxer
 

Quote:

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ORIGINAL: abnerdjesus

...Do I turn the cylinder exhaust just 1/2 away to have the exhaust like is in the first picture?

---

Abner,


According to MVVS, one can only determine the position of the exhaust BEFORE the engine is first run...

However, according to my own experience with MVVS, after two tanks it is still possible...

You will need to redo the break-in... Since the piston(s) will now be at either 90º or 180º to its previous orientation; so the wear patterns must be reestablished.

RE: MVVS 120 twin boxer
 

Hi Fellows
I now need parts for this Boxer 120
Carb # WYK41D5
Of course all help is appreciated
Sparky

RE: MVVS 120 twin boxer
 

What carb did you end up using? And what internal mods did you do?

RE: MVVS 120 twin boxer
 

Strange that MVVS never build simmilar size petrol engine twin cyl

RE: MVVS 120 twin boxer
 

I have received assistance from a fellow owner of these engines, who kindly gave me some very helpful information.

Here is mine, wearing diesel heads

Once I sort out the gas flow into the reeds and put on a new carb (a replacment Walbro able to flow enough fuel) I will run it in with the glow heads on. If I succeed in obtaining reliable running, I will post my findings here.

RE: MVVS 120 twin boxer