Oil drain backs

[digger]

Has anyone modified the M20 block to fix the drain back from the head from landing on the rotating assembly?

anyone got any bright ideas as to how get it to drain back straight to the pan like the modern engines?

i thought about some small mandrel bent tubes pressed into the underside of the deck that travel down the block skirt and a receiver on the crank scraper? could probably weld to the inside of the block but dont know how well that'd work

[zaq123]

Has anyone modified the M20 block to fix the drain back from the head from landing on the rotating assembly?

could it be done intentionally by design due to the lack of oil squirters, unlike in modern engines?

[digger]

No I don’t think so. It’s still going to be chaos with oil being splashed around everywhere but the aim is so it’s a bit less

[zaq123]

No I don’t think so. It’s still going to be chaos with oil being splashed around everywhere but the aim is so it’s a bit less

I think your idea should be pretty straight forward if there is enough room to run tubes.
If I recall correctly S52 oil pan (one of the best i6 engine designs IMHO) had drain cutout in the windage tray so the oil goes all the way to the sump

[digger]

9/16" alloy tube 0.035" wall that is bent to clear a few things would work. not sure on the fixings though

[zaq123]

9/16" alloy tube 0.035" wall that is bent to clear a few things would work. not sure on the fixings though

I would use steel tubing and tig them with a high NI rod to the block

[digger]

my concern with welding is the porous casting has been in oil for 30 years so getting a good welding on the inside of the block is questionable

[zaq123]

my concern with welding is the porous casting has been in oil for 30 years so getting a good welding on the inside of the block is questionable

if you are really set on this idea and don't mind redoing intermediate shaft bearing, hot tank it.....will get all that oil out.
also maybe there is a possibility to arrange/weld all those down tubes to one flange and secure the flange only to the block somehow (drill/tap??)

[Andre3127]

I wouldn't mess with it. If you want to experiment with improving the design of older engines (which I highly encourage) there are better places to start on this engine. M20's can make some serious numbers (albeit, not as easily as others), so I would just leave it.

I've torn apart 250k mile m20's with wrist pins that still fit the pin bores and rod pin ends perfectly, so I am led the believe that the bottom end oiling system of these motors is pretty spot on IMO.

[digger]

leaving it is an option but its an obvious improvement BMW seem to have implemented with M50. with a big stroker crank thats going to spin up a bunch more than your average stock b25 i don't want everything being churned up unnecessarily which could hurt the engine bearings. I'll be using a scraper/windage tray & baffle but it makes sense to start more from one of the root causes where possible