Crank Scraper

L

loperdw

New member
Purchased a crank scraper (Teflon version) over the Christmas break and now finally have time to install. I was wondering if anyone has done an install, how bad was it, did it take a while to get seated?

Also should I expect an improvement and how should I look for the improvement? Dyno time is obviously the way to go for real numbers, but if the general consensus is that there will be an improvement, then I don’t see a point of a baseline dyno? If there is there a potential for a marked change in power at certain revs I want to know where that is, i.e., dyno is useful, but only afterwards, not before and after.

Some people swear by them, that’s why I bought it, just looking for some practical advise and experience. Hopefully when its done I’ll be saying “thank the IT gods this is legal”

Thanks
 
Generically, it (along with a windage tray) does a lot to keep the oil in the pan where it belongs. On my car I've never been able to measure a difference before and after on a chassis dyno (too many variables over too long of time), but I could notice a more stable oil pressure gage.
 
The purpose of a true "scraper" is to be a knife that shears the oil off the rotating parts, such as the crankshaft and rod. Oil has weight, and all that weight has to be accelerated. The end effect of a scraper is the same idea as lightening the flywheel. The improvements will be seen best in those RPMs where the acceleration rate of the engine is the largest.

Scrapers, when designed properly, will be within fractions of a millimeter from the rotating parts. Sounds like your Teflon one may be intended to "wear" into place, or at least be tolerant of interferences.

That difference will show up on a dyno that measures rate of acceleration (e.g., DynoJet) but will not show up on a dyno that measures torque (e.g., DynaPack).

Then you've got windage trays, as John describes. Those are usually plates that sit below the crank and keep oil (windage) from bouncing/jumping up from the pan and slapping into the rotating parts. Any collisions with liquid/spray oil will slow down the crankshaft.

Finally, you have trap door in the pan, which will keep oil at the pickup so it doesn't starve during cornering/accel/braking.

These three functions can be separate parts, or incorporated; here's an example of one fo rthe Golf engine that does all three: http://www.techtonicstuning.com/viewpart.a...artnum=115.110L
 
so we can install something that can scrape the oil off of the crank, and it's legal?! cool. so, where does one find such a device and what colors do they come in?

hoop
 
hoop...

2007 GCR:

GCR - 126: (Defenitions)
Scraper - A passive internal attachment to an oil pan whose purpose is to control the return flow of lubricant by removing it from the rotating crankshaft.

GCR - 296: (Improved Touring Category Specifications)
h. Oil pans, pan baffles, scrapers, windage trays, oil pickups, lines, and filters are unrestricted.

Prod cars can do it too.
 
Well, I tell all my competitors that crank scrapers will add absolutely nothing to their WHP. ;)

Seriously, when I added a custom crank scraper fitted specifically to my crank/rod setup (I made the template and Kevin Johnson at crank-scrapers.com made one to my template) the DL1 data showed a 3-5 hp improvement at the wheels and 2-3 mph gain on the top end at Road Atlanta's back straight, with no other changes. And that was with WORSE air conditions (ambient temperature was higher, humidity was higher, and density was lower) when I went back to Road Atlanta after fitting the scraper. (March national vs. June national). This is on a full prep G-Production 1.5L Scirocco, making about 120 WHP at the time.

I'm convinced. :birra: If my competitors are dubious and not convinced, that's even better! I wish I had known about them when I raced ITC! :eclipsee_steering:

MC
 
im interested, too.

are any being made for the 84-87 1.5 engines?

the d15/d16 ones they list im pretty sure are for the later d-series engines...
 
If you make a template, Kevin will make you a custom scraper in just a couple of days. Making a template isn't too complicated, just some sturdy cardboard or other heavy material is required. Then just keep whittling the cardboard away until the rotating parts are just .030" or so from the template when rotated.

Give him a call, he's a great guy to work with. http://www.crank-scrapers.com

MC
 
Yup, I'm with Mark Coffin, I wish I had known about crank scrapers back in my ITC days as well. They are worth every penny, and Kevin does excellent, quality work. I also have to agree that if anyone doesn't believe they work...good for them (and that means I have a couple of extra ponies that they don't have)! B)

Some of the cheapest extra horsepower out there IMHO.

Now if I could just get Coffin to admit he has 150 WHP, I'd feel better about him beating me all the time. :P

Mark
 
Crank scappers have been around for a long time. They work best with dry sump systems.
You have to be careful that the oil that the scapper is pulling of the crank shaft is channeled away from the chank shaft. This is so it is not building up and becoming a wad of "taffy" that the crank has to cut though with each revolution.
I remember reading a dyno test in Hotrod magazine back in 1975. In that test they got a drop in horsepower with a scapper until the put a bumpout in the oil pan to give the oil a place to go after it came off the crank. They also put a dry sump pump vaccum line in that area of the pan.
In that test they were trying find out what horse power could be gained with just a changes in the oil pan.
On a basic 350 Chevy they got impovement with everything they did to get the oil away from the crank. The only drop was when they put a scapper in with a deep sump pan which had no place for the oil to drain. It was building up on the scapper and then was being struck by the crank shaft. They got 50 HP increase at the end.
 
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