Crank scrapers or plate...?

nm9stheham said
If you have other reasons to use them, then I am all ears, particularly on the aspects of how stroke and displacement impact the usefulness of scrapers. So hit those notes! I have read the IJ site BTW, so that good has come of this.

Everything is has a cost/benefit aspect, and knowing what the results are is worth the conversation IMO. It is $80 for the cheapest IJ scraper set for the SBM, and they have pricier ones. But, how many HP and other benefits will be gained in the application versus that cost? Is it 1 HP for cruising at 3,000 RPM, or 10 HP? That answer makes a BIG difference; that cost/benefit needs to be balanced by everyone to their own satisfaction; IMHO, it is more helpful to just give people the facts, point out the good and the bad, and let them decide, and avoid judgments on the individual decisions.

When I get a minute I'll see if I can find that notebook. May be out in the shop.

Some things don't always show up as power on a dyno. What if you dropped your oil temp 15 degrees with a scraper? What if you picked up 10 pounds of oil pressure with a scraper? What if you observed both?

That's why I detest calling certain parts "race" parts and others just parts. They are inanimate objects. They serve a purpose.

For me, running engines at 8500 and higher when I know, KNOW for a fact (especially when data logging became standard) that very few people actually made power at those RPM's, let alone actually spun them that tight. Oil control becomes a serious issue. What I also learned was that as the stroke length gets longer, the RPM gets significantly lower where entrainment becomes problematic.

I know there are people who calculate crankcase volume, and have an empirical formula they use to determine the volume needed in the pan. While the pan may have enough internal volume to run 10-12 quarts of oil, they may run 5. You can't do that without scrapers and trays and some a out of crankcase vacuum.

Dry sumps are very good at controlling oil. The latest pans are segmented. And they still use a scraper. A Pro Stock engine has a stroke of ~3.6ish depending on the bore. If you figure the surface feet per minute of the crank, even at 11000RPM, it's very close to the same as a 4.5 stroke at 7000 RPM IIRC and I don't want to do all the math but maybe AJ will come along a do some ciphering on SFPM on crank strokes.