Smart K100 frame question. How to solve?

[touchwoodsden]

As this Frame Related Topic thread has been a little quiet (it seems the last post was December 2014) I have posted this here and also on my own build thread.
I thought that fitting the engine in the frame was going to be relatively straightforward.
Think again, although, in the whole scale of things, it’s probably not that much of a problem.
Because the BMW engine lies flat on its side, the crankshaft and therefore the gearbox input shaft is also over to one side. In the BMW there are various idler gears but in the whole scale of things that makes no difference because the original BMW engine has gone and we are stuck with what we have.
20160126_234418
Anyway, because the gearbox input shaft is not central in the gearbox and the crankshaft is central in the engine it means that the engine is offset to the right as you sit on the bike (why did I never think of this before... Stupid man)
So the upshot is that the engine which is now bolt upright fouls the top right hand (as you sit on the bike) frame tube. You can see it on the left in this picture.
20160126_234508

I was going to have to remake the mounting here anyway but didn’t want to really do any tube manipulation. Here is another view of the offending tube which, in this photograph would need bending towards you where it crosses the top frame rail and then bending away from you a little further down.
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I could slant the engine over slightly towards the left-hand side (as you sit on the bike) which is to the right in the pictures of the front of the engine that would probably balance the whole thing got better and give me a little more clearance around the frame tube which is fouling. It would still need modification but I would probably get away with not bending it. It would also mean that the gap between the engine block and the other side engine mounting would not be quite as big. I reckon that about 5° would be about what it needs although 5° is quite noticeable. If you look at this photograph, it would be moving the engine around the axis of the crankshaft a few degrees and to a position more central between the two short front frame down tubes.
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It would mean me remaking the gearbox adapter however which is about three quarters finished. However apart from time, the cost is only another 50 quid for some plates.
The potential problem with sloping the engine over is that it was designed to run at an angle of 45° and it’s already moved from that angle to vertical and if I move it more, it’s actually going the opposite way. I guess that it’s easy enough to cut the triangular gussets out and remake them and to re-bend the offending frame tube.
I’m just wondering, which alternative all the experts on here would themselves choose.
Although psychologically, having wait a little more central makes more sense, in everyday riding it makes no difference because, after all, Lambretta never had a problem with it and nor did (and their situation was even worse) Vespa.
Thoughts?

[touchwoodsden]

This is the Lithuanian builder’s front engine mounting.

9

his engine is slightly further back than mine (about 25 mm) because his adapter is slightly shorter. This is in turn because he has an earlier flywheel which is thinner. The later flywheel is easier to adapt to the BMW clutch but cannot be made thinner. I won’t bore you with the details as to why, you just have to accept that.
Hence, whereas the Lithuanian front tube clears the front of the cam box, mine is just to the rear. The cam box rear engine breather is also in a slightly different place and that also potentially interferes with the frame. That is less problematical because I could always relocate it.

RH view of frame

I am not going to rush into deciding which way to go and before I start bending frame tubes I’m going to do some more pondering. The more I look at it, the more likely I am to remake the adapter and to slope the engine over by just a few degrees to the left as you sit on the bike.

I will keep you updated.

[Mouse]

I'm not to familiar with the internals of the smart engine but tilted the VW engine over rather a lot in my Dnepr conversion.

My biggest fear with tilting the engine was the oil pickup being relatively central in the sump after tilting it. I performed several crude experiments to check this out. The most telling was to remove the sump and mockup where the sump pickup was located in it and then fill with water and tilt over to the desired angle. Lucky for me that it made little difference to that engine and I did not have to alter the pickup tube.

Also note that for some engines there is a certain amount of lubrication for the pistons / bore performed by the splash of the crank in the sump oil. So if the oil level suggests the crank dips into it it will be peace of mind to check that you maintain this when repositioning the engine.

This is the best photo of the engine tilt in my bike I have. Like you I was avoiding a clash with a frame tube. I also hung the bike from an engine hoist to check the balance and centre of gravity which were spot on after a bit of tweaking.

[touchwoodsden]

Also note that for some engines there is a certain amount of lubrication for the pistons / bore performed by the splash of the crank in the sump oil. So if the oil level suggests the crank dips into it it will be peace of mind to check that you maintain this when repositioning the engine.

SNIP...

the engines which rely on splash to lubricate the internals generally have a sort of finger which hangs from the big end bearing And dips into the oil.
There can be a problem if the crankshaft dips into the oil because it can whip the oil into froth and starves the big ends.
There is a story that the old Austin 1800 “Land Crab” had exactly that problem when it first came out. Evidently the problem existed worldwide but not in Australia by and large.
The oil level on the dipstick was set too high and the crankshaft dips into the oil and turned into froth which subsequently starved the big ends and they got knocked out. The problem didn’t happen in Australia (allegedly) because the Australians neglecting their cars didn’t top the oil up to the top.
I don’t know whether it’s true but it does make sense.
When the crankshaft is spinning, the oil feed to the big ends spews out everywhere and by centrifugal force flies up the inside of the cylinder bores and under the pistons lubricating the bores, the little end, and cooling the piston crown.