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-   -   What is Crank Scraper (https://www.team-bhp.com/forum/technical-stuff/18130-what-crank-scraper.html)

Just came through crank scraper.....its a metal piece connected to the bottom of engine slightly away from rotating parts......when engine crankshaft rotates a kind of rotating mass of oil is produced which softens the rotating motion because engine has to overcome this cloud of oil.....scraper strips excess oil without touching the rotating part so drag is reduced while rotating which imparts more rotating power.....

Although this technique is very old.......Does current generation of vehicles has anything like this?.....

http://www.crank-scrapers.com/index.html

Enjoy....

Yes, most modern engines have some form of this technology -- now even diesel engines. Its use has increased greatly over the past 45+ years. On the web page listed above is a modern patent abstract from General Motors mentioning the use of crank scrapers in the manner described -- this technology is considered well-proven by professional automotive engineers around the world and this patent is one excellent example of that acceptance.

Kind regards,

Kevin Johnson

Ishihara-Johnson Crank Scrapers

Hi kevin,

Thanks for your input.....I just want to ask that is the benefit quite noticeable using crank scraper?......means in terms of power & FE gain.........I m interested if scraper imparts power with gain in FE........

Enjoy.....

Finetuning This seems interesting, but How is one gonna get this done?

Is this crank-scraper the same as a counter balancer in the crank to reduce vibrations?

Dear turbo_v12,

Crank scraper is differenrt from counter balancer.........this is infact a metal sheet fitted at the bottom of engine....its edges are just few mm away from rotating crank......crank normally rotates inside oil pool so with more rotation this mass of oil produces a rotating cloud of oil.....crank has to overcome this drag whic is loss of certain precious BHP......crank scraper simply strips oil from crank in each rotation so that there is no drag on crank during rotation....more closer it is to rotating parts more effective it will be......this free ups BHP & improves FE too as per studies........also it is very easy to fit....you can check link in my first post....

Enjoy......

Typical power benefit seems to be about 2-3% of a normally aspirated engine's output (at peak rpms). That percentage could be much larger when the engine is in motion and a great deal of oil is splashed onto the crank.

In modern engines the rotating assembly does not normally hit the surface of the sump oil so the 2-3% is simply from the windage cloud that evolves from the spinning crank and rising and falling pistons.

You can gain fuel efficiency because the internal parasitic power loss is reduced hence the increase in output. Most people, however, end up using this increase in power for quicker acceleration or higher top speed.

I think many racers get the products to help ensure a consistent supply of oil to the pump. Some engines also have a severe problem with aerating the sump oil which can reach dangerous levels and harm the bearings. On the website there is a mention of a system for the Porsche 928 V8 engine -- that engine and the straight fours developed from it in the 944 and 968, have a severe problem with aeration at high rpms leading to damage to the rod bearings. Rod bearings generally cannot tolerate more than 30% entrained air.