Using a finer screen for oil pump pickup?

[sr50r]

It's 5:41 AM and I just woke up with this idea.

A fine screen like say, from a permanent coffee filter?



Thoughts?

[Dandy Dan]

Hmm....interesting idea. I wonder if this would be more or less effective than just using a magnetic drain bolt?

[sr50r]

I got the idea from my ruined oil pump.

Ideally, one would have a magnetic drain plug, but since that can only catch what comes near it, I figured a fine screen should work well in concert.

It would probably have to be cleaned out frequently...

[chanito]

A screen like that would be a great idea, sadly the screen is a weird shape, so doing one will be kind of hard, but is the best solution to the oiling problem and as you mention it will require to be clean at every oil change, also epoxying a magnet to the oil screen cover is way better than one on the oil drain
My two pennies

[sr50r]

I've made the screen.

I used a 10mm long box wrench over which I folded the screen into a kind of basket shape like the original, then held it's shape with a tie wrap while I folded a flat flange at about the corrent length, cut it round, and massaged in some Permatex Right Stuff into it to build up a gasket.

I'll take a pic today

[chanito]

Looking forward to that pic

[sr50r]

Ooops! I wanted to get really up close since it was a cell phone pic, but the tiny screen didn't tell me it was THIS out of focus

[Dandy Dan]

Hmm....this could be good. Tough to say. I wonder if this works better or worse than a drainbolt magnet? And does it add too much resistance to the oil flow? It might cause difficulties on cold mornings?

[sr50r]

Too bad we don't have a spot where we can measure the oil pressure

But I don't think it'll restrict flow much, afterall, the original screen is just so coarse, the coffee filter is fine, but not too fine for oil... I've seen screens that fine on systems that dealt with much thicker oil.

[chanito]

Actually there is a spot to measure oil pressure, is on the side of the block, on the passage use to send oil to the head, sadly is after the crank so it is use to measure available flow of oil to the head and the pressure is very little (4-5 psi)
That screen should be fine, even in the cold morning (unless you are not using multiweight oil), just make sure you clean it at the 600 miles oil change ;D
Congrats on a great idea, and yes it does work WAY BETTER than a magnet as it filter "all' the oil going into the oil pump, WEATHER THE FOREIGN PARTS ARE MAGNETIC OR NOT, BUT THE MAGNET ON THE DRAIN PLUG, CAN ONLY COLLECT THE PARTS THAT BY CHANCE FLOW BY IT CLOSE ENOUGH TO BE ATTRACTED TO THE MAGNET, AND IF IT IS NOT MAGNETIC (like aluminum parts from the block or stainless steel from the main bearing) YOU ARE OUT OF LUCK

[Dandy Dan]

Very interesting stuff.....it does seem like you're on to something here.

[sr50r]

I've got another screen (cut out the two sides of a cone-type filter) so I'll probably try to perfect the idea down the line, probably when the engine's back in the bike and I've had time to chop on mine for a change of pace.

Meanwhile...



It's starting to look like an engine!

And on that note, I've been wondering something... OK I've fitted a '06 timing chain lifter, but here what I'm wondering: Do I leave both hoses to breathe freely and rely on the turbulence from the timing chain to carry in enough fresh air through the new breather, or, I have a check valve I could use so that the varying pressure in the crankcase makes it breathe only through the chain lifter and expel only through the valve cover vent.

[chanito]

A PCV valve is actually a high flow check valve, so you can use that on the chain tensioner side, and relay on the intake to suck air from the valve cover ;D

[sr50r]

Well yeah, if you check the above pic, besides the McD coffee is genuine PCV valve off of a hyundai accent 1.5 sohc

Though the second half of your post I think is missing a word or two... and relay on the intake to suck air from the valve cover... Well, the way I'd go about it is dump the hose from the valve cover on the airbox nipple that's just over the intake tube, and have the fresh air hose to the chain lifter grab clean air behind the filter (through a PCV valve acting as a check valve)

Oh, also, massive progress tonight

[Dandy Dan]

The up and down movement of the piston is what creates the airflow through the case. As the cylinder volume changes, so does the crankscase volume, so you're pumping out 49cc of crankcase air everytime the piston comes down. You want a check valve in the fresh air hose so that fresh air makes it into the engine case without being pushed back and forth everytime the engine case exhales. With no check valves, you'd suck 25cc in from each hose and then push 25cc back into each hose. Because each hose holds a lot more than 25cc you'd end up breathing the same air over and over....hence the need for check valve. Even with a check valve in the intake, it's still going to suck in 25cc of fresh air and 25cc of dirty air, but then it will expel 50cc of dirty air so you do get flow through the engine. If you put a check valve in both then you'd breathe in 50cc of fresh air and expel 50cc of dirty air which would be ideal, but probably overkill.

[sr50r]

Well not only that, but forcing the engine to breathe 50ccs of air through a hole as small as the one on the chain lifter would probably put a lot of drag on it, seeing as the engine needs a hole as big as the intake port to breathe that much on the other side of the piston.

One check valve on the fresh air side would be enough, and I'd even wager that it won't even breathe 25cc of fresh air, probably more like 10 or something, as the hose diameter is the restrictive factor here.

Still, going at a few thousand revs, only a few ccs of fresh air on each stroke will be enough to completely renew the crankcase's air volume many many many times a minute.

[Dandy Dan]

That sounds completely correct. I suspect that most of the 50cc of potential airflow is absorbed just by compression/expanding the air that's in the case. 10cc of flow sounds more realistic.