B
Bogstandard
Guest
To all those who now have elbow engines 'in storage' under the bench.
I have done a few mods to my engine today.
The first was to make a recess around the inlet ports on the baseplate for the upright block and the horizontal one and inserted a small 0 ring into the resesses rather than having to seal with a compound. Just made the recesses about 20 thou shallower than the ring thickness. This makes adjustment dead easy because when you undo the holding screws slightly the rings still make a seal rather than air blowing everywhere, then having to strip down again to reseal which defeated the object in the first place.
I also tweaked my step and shoulder holding screws, left about 2 thou clearance, makes all the difference to smooth running.
These last ones were an observation.
This engine has now run about 3 hours so when I looked at the pistons they showed a unique wear pattern but also they were very 'wobbly' in the cylinder holes, so it looks like you can loosen your tolerances slightly to give yourself more free play. This engine is running better now than when it was first made.
I also did a small experiment with oils.
When I set the engine up, I set it so that I can turn the flywheel and the horizontal cylinder turns in sympathy without being touched, if your engine will not do this I think you are on to a loser. Anyway, as I was rebuilding I could not get the engine to turn like above, then I noticed I had used the wrong oil, 10 sae instead of my usual 20/50 multigrade. So I did a little experiment. No air, just turning flywheel by hand.
Put my multigrade on, engine turned straight away, blew off oil and put on 10 sae, the engine turned once and locked up, again blew oil off and put on 30 sae, after a little 'rocking' the engine started to turn again but locked after about ten revolutions, again oil off, put on multigrade and away it went with no further problems, running better than ever with the mods done.
So it looks like this engine requires a thickish oil from the very beginning, not the thin 3 in 1 type that I think was recommended. It must be something to do with the piston side loads that require a heavier 'film'.
Hope this might help those that are having problems.
John
I have done a few mods to my engine today.
The first was to make a recess around the inlet ports on the baseplate for the upright block and the horizontal one and inserted a small 0 ring into the resesses rather than having to seal with a compound. Just made the recesses about 20 thou shallower than the ring thickness. This makes adjustment dead easy because when you undo the holding screws slightly the rings still make a seal rather than air blowing everywhere, then having to strip down again to reseal which defeated the object in the first place.
I also tweaked my step and shoulder holding screws, left about 2 thou clearance, makes all the difference to smooth running.
These last ones were an observation.
This engine has now run about 3 hours so when I looked at the pistons they showed a unique wear pattern but also they were very 'wobbly' in the cylinder holes, so it looks like you can loosen your tolerances slightly to give yourself more free play. This engine is running better now than when it was first made.
I also did a small experiment with oils.
When I set the engine up, I set it so that I can turn the flywheel and the horizontal cylinder turns in sympathy without being touched, if your engine will not do this I think you are on to a loser. Anyway, as I was rebuilding I could not get the engine to turn like above, then I noticed I had used the wrong oil, 10 sae instead of my usual 20/50 multigrade. So I did a little experiment. No air, just turning flywheel by hand.
Put my multigrade on, engine turned straight away, blew off oil and put on 10 sae, the engine turned once and locked up, again blew oil off and put on 30 sae, after a little 'rocking' the engine started to turn again but locked after about ten revolutions, again oil off, put on multigrade and away it went with no further problems, running better than ever with the mods done.
So it looks like this engine requires a thickish oil from the very beginning, not the thin 3 in 1 type that I think was recommended. It must be something to do with the piston side loads that require a heavier 'film'.
Hope this might help those that are having problems.
John
