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View Full Version : Crank Scrapers....load of crap?


indierthanthou
09-05-2007, 05:02 PM
http://cgi.ebay.com/ebaymotors/Crank-scraper-BMW-M10-NEW-Dual-M20-M30-M50-M52_W0QQcmdZViewItemQQcategoryZ46098QQihZ010QQitem Z200147537612QQrdZ1QQsspagenameZWDVW
I dont know anything about them, do they work and have any effect, or just a bunch of nonsense?
Barney Paull-Edwards
09-05-2007, 05:13 PM
Not a load of crap but really for competion engines where every HP counts,I suppose if you have your engine in bits and the money then fine.Attention to detail and balance will get you more power for free.
Bin_jammin
09-05-2007, 05:18 PM
Not a load of crap, but usually comes with a windage tray too. Add a stud girdle to the mix and have the crank knife-edged, and you're on your way to a built bottom end. Top off with an accu-sump and you're ready to race.

In fact, when I start piecing my turbo setup together, it's totally getting an accu-sump. Cheap way to insure my turbo is always oiled.
indierthanthou
09-05-2007, 05:31 PM
Ok, I remembered hearing about them awhile ago, and just ran across this one today on ebay, so i thought I would find out. thanks guys
Jon K
09-05-2007, 08:39 PM
Once you add the cost of knife edging, baffling, windage tray and crank scraper, you could almost go with a dry sump setup.
Bin_jammin
09-05-2007, 09:19 PM
Once you add the cost of knife edging, baffling, windage tray and crank scraper, you could almost go with a dry sump setup.


John K, I can't believe you said almost. I figured you'd have something that ridiculous either planned or installed ;)

Knife edging is fairly easy to do, but not cheap if you have someone else do it, and obviously rebalancing is necessary after. I'm going to need to build a pretty stupid m30 in the next year, I'll probably be doing all of the above. Anyone know of stud girdle for the m30, or am I going to have to make one?
Jon K
09-05-2007, 09:54 PM
Thing is - I have been told by various reliable sources, that the crank is damn near perfectly balanced from the factory. Knife edging the crank will obviously free weight, which can be good or bad depending, but additionally, your whole rotating assembly will be off.

I had mine dynamically balanced but no knife edging as its just not that critical in my build to have 0.5hp more for that.
Bin_jammin
09-05-2007, 10:12 PM
Thing is - I have been told by various reliable sources, that the crank is damn near perfectly balanced from the factory. Knife edging the crank will obviously free weight, which can be good or bad depending, but additionally, your whole rotating assembly will be off.

I had mine dynamically balanced but no knife edging as its just not that critical in my build to have 0.5hp more for that.


Hah, no I meant dry sumping your motor.
Jon K
09-06-2007, 03:47 PM
Hah, no I meant dry sumping your motor.

that's typically where the line is drawn from a street car to a full blown race car.

yes the new M cars have dry sump or semi dry sump, and LS1 stuff is the same way, but those are factory setups. To dry sump an M50 would be.... a lot of time, and even more money.
Ross
09-06-2007, 05:31 PM
that's typically where the line is drawn from a street car to a full blown race car.

yes the new M cars have dry sump or semi dry sump, and LS1 stuff is the same way, but those are factory setups. To dry sump an M50 would be.... a lot of time, and even more money.
But Jon, think of all the bits you could powder coat.
E34 530
09-06-2007, 05:55 PM
my friend just bought one for the m20 stroker I'm building him, we'll see how it goes. ;)
Bin_jammin
09-06-2007, 06:41 PM
my friend just bought one for the m20 stroker I'm building him, we'll see how it goes. ;)


Oh I have GOT to see pics of that.
E34 530
09-06-2007, 07:28 PM
Oh I have GOT to see pics of that.

Should be putting in the pistons and head tomorrow

Here's the initial thread I made about it, but we've made TONS more progress since then...

http://www.bimmer.info/forum/showthread.php?t=32914&highlight=project+e30+begun