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FAQ




1. What fuel should be used for MVVS glow engines?
Good quality fuel with ricinus oil in ratio 1:4 ( 20% oil ). This ratio is suitable for run in also. Please don´t use untried synthetic oils.

2. What fuel should be used for MVVS gas engines?
The suitable fuel is 95 octane gasoline with Mobil Racing 2T oil or some different full synthetic two stroke engine oil for racing use. Right ratio is 1:40 (for run in 1:30)

3. What glow plugs should be used for MVVS engines?
Glow engines 2 - 4.5 ccm:   Novarossi C5S
Glow engines 6.5 - 35 ccm:   Novarossi C6S
Gas engines :   NGK CM-6

4. Can nitro be used for all glow MVVS engines?
Nitromethane can be used up to 5% without any engine modification, if using more than 5% (5 - 15%) it´s necessary to change the compression ratio. An extra shim has to be added under cylinder head. During max. RPM running and after unplugged supply for glop plug, the RPM can not fall or rise. If RPM falls the compression ration is too low. If RPM rices the compression ration is too high.

5. Why the piston do not go smooth over top dead center (TDC) in glow engines?
The MVVS glow engines are ABC style. ABC engine has bigger piston diameter than liner at TDC. This is not fault and piston is never seized for this reason, when is used good fuel with ricinus oil.

6. Why the engine has angular clearance?
Slide bearing need about 0.04 mm clearance for creating oil layer. This clearances of piston pin and con-rod pin are add to crank-shaft bearings clearances. All of this make final angular displacement.

7. The crank-shaft is free motion in the bearings and it has axial clearance.
Free motion of crank-shaft is normal and it´s necessary for temperature differences.
For engines up to 40cc volume: The axial clearance is delimitated after propeller final tighten.

8. Is it possible to turn nozzle on the carb?
No, the characteristics of carb would be changed. Right position of nozzle is necessary for good carb work.

9. How care for glow engine after using?
Especially when engine will not run longer time. It is important pass through the engine some paraffin and after used conservation oil. This is really needed, when fuel with nitromethane is used. The rest of ricinus oil in the engine can cause crank-shaft and bearings corrosion.

10. How can I know right engine idling speed?
When you close throttle from wide open, The RPM go down, after 1-2 sec. little bit increase and than stay constant.

11. The engien has a lot of carbon on the piston and exhaust port and engine is heated fast.
Reason can by using engine at very low RPM, which are below recommend RPM for muffler. The lighter propeller is needed.

 

MVVS, spol. s r.o., trida Kpt. Jarose 35, 602 00, Brno, Czech Republic, Tel.:+ 420 545 211 683, Fax.:+ 420 545 211 418