Datsun Roadster Forum-311s.org

spl310 wrote: Fri Apr 23, 2021 9:01 am The oil IS being slung off, but it is effectively a rope and is inducing drag on the reciprocating mass. The scraper cuts that oil off so that it effectively lightens the mass. Or so I am told...

Just as a friendly debate
That is the surface tensions aspect ...pretty minor same in the bearings
You would have a compression of air with the cranks end caps irregular shape and vacuum created passing by the plate on the back side too

Plus the plate impedes the blast of air being forced down and up the cyl

Agreed that it's probably still a theory, and the effects of a scraper likely vary a lot with engine design/internals. Depending on what's actuality happening there does appear to be some science behind it, but an internal picture would be cool. There are some before and after dyno info on the website based on one engine I think (average 3% hp increase), but it's also not all about hp.

Well, so long as it doesn't scrape, it's in there and doing its thing (or will be soon). I would love for some show like Engine Masters to do a test.

An update...
No rubbing! It appears I have a small oil leak at the crank but I have not investigated the source yet (previous leaks were a LOT worse). One thing for sure, engine temp is down significantly. I don't know if this is solely due to the scraper as the engine is running the best it ever has with EFI and the correct spark plug type (double platinum required) for the Ford EDIS system, but that system was operating before and my temps were not like this. Compression was dropped from 11.7 to 10.3, so that may be a reason as well. However I think it was theorized that the scraper puts the oil back into the pan better so it transfers heat better. Cooler oil was a target for the 7 quart aluminum finned comp pan. Even with it, my engine has always run on the hotter side. Not anymore.

I call that a win so far! If I notice anything else I'll post it.

Excellent news!

I just caught the final few minutes of Engine Masters Season 3 episode 3 about "How oil kills horse power" where they found 20hp loss with too much oil and gained 8hp with simple pan changes (I didn't see the whole episode, just the last couple minutes). This occurred at higher rpm and they talked about what they might expect with a better "windage tray" or adding a crank scraper. They also said the oil had a lot fewer air bubbles trapped in it which improved its protection.
In my experience so far, my engine temps continue to be lower and it cools off faster. Again, I do not know if this is due to the scraper or better fuel ratio control, but something changed it.