franchi

I recently purchased a MVVS 2 cc Diesel engine. Upon checking it prior to starting the engine, I noticed that I is very tight at tdc when being turned over by hand. Quickly flipping it over, the tightness appears to be normal

Should I proceed to break it in in this condition? If so any things that I should do like add extra oil to the fuel. My standard mix is 35% ether, 25% castor oil 1.5% DiII the remainder kero.

Suggestions/Comments

Tia,

Franchi

1967brutus

That tightness is normal AFAIK, and you should not do anything to remove or lessen it. when the engine is at operating temperature, that tightness will be more or less gone.
The tightness feels normal when flipping because that happens quick and the oilfilm between piston and liner has no time to get squeezed out. When turning over by hand, the oilfilm does get squeezed out and that is what you feel as tight. Engines with a tapered liner should not be turned over slowly by hand, especially not in cold condition.

1QwkSport2.5r

I would question the liner construction. Being MVVS, I’d suspect it to be ABC, but if it’s ferrous, add extra oil and run a giant prop. Run numerous heat cycles on tight ferrous engines.

franchi

Hi All:

Thank for the prompt replies.

I am planning to run the engine just as you suggested. I have a 10-3 plastic prop that I am planning to use for initial break in. It should work very well. If not, back to a 9-4.

For actual sport C/L flying, perhaps an 8-4 or an 8-5 will be the hot setup.

Stay well

Franchi

franchi

It is not an ABC engine. Looks like iron on iron.

1QwkSport2.5r

it would be meehanite iron piston and steel liner then. Use the heat cycling outlined at adriansmodelaeroengjnes.com. Tight ferrous engines need careful running in if you want them to last.