Idea: DIY crank scraper

The other thread about the BMW crank scaper got me thinking...how hard is it to build one yourself? My 4AGE is still apart, a crank scraper would be nice but the I-J parts are a bit too rich for my blood. Sheet metal's cheap, sheet teflon's not terribly expensive in the amounts needed, no advanced fab tools should be necessary...anyone done it?

Edit: I'm not the first to think of it (hooray! It's easier when you're not the first)

http://www.dsmtuners.com/forums/newbie-forum/384441-diy-crank-scraper.html

http://forums.rennlist.com/rennforums/928-forum/603531-nylon-diy-crankscraper-good-idea.html

Nothing I didn't expect, the big problem is tight clearances. Would it be safe to have a teflon contact surface that's a little on the too-tight side and let it "wear in?" That would make things easier and I imagine better than trying to get the clearances exactly right, which I would imagine would take a lot of test-fitting and modification.

Really, you only need to be close enough to everything to strip of the oil that is being flung like monkey poo. There is no need to be so close to need anything teflon.....

GameboyRMH wrote: The other thread about the BMW crank scaper got me thinking...how hard is it to build one yourself? My 4AGE is still apart, a crank scraper would be nice but the I-J parts are a bit too rich for my blood. Sheet metal's cheap, sheet teflon's not terribly expensive in the amounts needed, no advanced fab tools should be necessary...anyone done it? Edit: I'm not the first to think of it (hooray! It's easier when you're not the first) http://www.dsmtuners.com/forums/newbie-forum/384441-diy-crank-scraper.html http://forums.rennlist.com/rennforums/928-forum/603531-nylon-diy-crankscraper-good-idea.html Nothing I didn't expect, the big problem is tight clearances. Would it be safe to have a teflon contact surface that's a little on the too-tight side and let it "wear in?" That would make things easier and I imagine better than trying to get the clearances exactly right, which I would imagine would take a lot of test-fitting and modification.

BMW S52 motors come with one from the factory that is more tray than scraper but would be an excellent starting point for any of the M50/52 family motors as it has the bolt pattern and "fingers" in place already.

There's a company that makes both types for Miatas - a "close enough" steel one and one with a teflon piece that wears in. Easy enough to do yourself, just tedious.

I'm more interested in teflon for safety. If something moves somehow there's less potential for further carnage.

If I want to go with a "close enough" design, how close is "close enough?"

I seem to recall the Miata ones were around 1mm away. Seems to me it would be easy enough to make sure that nothing moves.

1mm should be safe enough for my ham-fisted DIY fabrication techniques...I'll keep that option open, because I don't want to admit it but I'd probably have to import a common teflon sheet if I want one.

One perspective.......

Another - I've NEVER seen Loynings use a crank scrapper....

Ok, dumb question - I know what crank scrapers are and why they're good, but what part of the crank are you trying to recover the oil from? The edges and end of the counterweight/journal/con-rod?

Edges of the counterweights, webs and conrods, and you want to block any oil from being flung back upwards - like the rear mud guard on a bike keeping the crap off the rider's back.

Why would that be an issue? Going to come down eventually right?

Enyar wrote: Why would that be an issue? Going to come down eventually right?

The fact that it's up there isn't much of a problem, the problem is that it's not down in the pan where it's needed. In hard corners that can be important.

Think of the weight of that oil being slung around a crankshaft at high RPM. Also, what happens to oil when it is abused like that?

It reduces the amount of weight being rotated.

It reduces the potential for oil foaming.

It increases the amount of oil in the pan.

All of which helps for consistency and longevity.

I won't comment on Loynings other than to say they build motors based on customer specs/available funds. They aren't known among the spec racing community for their consistency or their documentation.

turboswede wrote: I won't comment on Loynings other than to say they build motors based on customer specs/available funds. They aren't known among the spec racing community for their consistency or their documentation.

27 SCCA titles(and a few land speed records @ Bonneville) tells me they build winning engines

Interesting, good to know.

There's also a fair bit of aerodynamic drag on the crank, and the thick semi-oil atmosphere of the crankcase makes this worse.

oldeskewltoy wrote:

turboswede wrote: I won't comment on Loynings other than to say they build motors based on customer specs/available funds. They aren't known among the spec racing community for their consistency or their documentation.

27 SCCA titles(and a few land speed records @ Bonneville) tells me they build winning engines

Not debating that. I'm stating that they aren't the end-all be-all and that in any build there is almost always room for improvement, but usually their client's budgets and/or rules create limits that cannot be moved.

They are literally down the street from where I live and I've been to their shop fairly often. It is a small outfit of great folks that work hard and are proud of their work. However, speaking with FF guys who paid upwards of $15-20K to have them build a Kent motor to win a championship and finding that it made less power than the one built in a guys garage was frustrating, especially when asked about dyno plots or blueprinting documentation on the motor they just built. Or worse, the first motor is a 120hp flyer while the second one barely puts out 112hp. In FF that is the difference between the front pack and the back of the pack.

not quite down the street.... they are about 3 miles from me.... they do all of my machining.

I don't doubt what you heard....... the internets is full of heard this's and that's. Can any of what you heard be substantiated? Have both sides spoken on the subject?

$15 to $20 large will get you a full dry sump Atlantic engine making over 240hp... The same coin is required for a Kent??? I find this a bit hard to swallow......

Finally... getting this thread back on track.... the point of my response was......... some folks who build engines use crank scrapers... and some do not.

As far as keeping more oil available for lubrication... get a larger sump pan. Other things you can do to improve oil flow back to the sump is completely remove all the casting surface from inside the block... also fitting a drain to the intake side of the head.

I was wondering about this last week. I can agree with all the stated benefits (they should help to some degree). However, what about piston cooling? On an engine that's running high CR or high boost, or both, I would imagine that having all this oil slung up onto the back side of the pistons is probably very advantageous. It's basically working as oil squirters, wouldn't you think?

Good point, but in the case of my 4AGE specifically, I already have oil squirters

Got a question for oldskewltoy and anyone else familiar with 4AGE internals: Is there any way to attach one of these other than a "second gasket" around the oil pan?

JohnyHachi6 wrote: I was wondering about this last week. I can agree with all the stated benefits (they should help to some degree). However, what about piston cooling? On an engine that's running high CR or high boost, or both, I would imagine that having all this oil slung up onto the back side of the pistons is probably very advantageous. It's basically working as oil squirters, wouldn't you think?

If it wasn't a whipped frothy mess, you would have a case.

GameboyRMH wrote: Got a question for oldskewltoy and anyone else familiar with 4AGE internals: Is there any way to attach one of these other than a "second gasket" around the oil pan?

?? I'm guessing with "second gasket" in quotes... you also mean without using Toyota's recommended installation procedure using FIPG(Form In Place Gasket)

Another point... at least in a 4AGE... stock rods are drilled to provide a squirt of oil each rotation to the thrust side cylinder wall. If using an "H" beam racing rod(Carrillo, TRD, just about everones)... these are NOT drilled for oiling the thrust side.... so you may want a bit more oil flying around to aid in lubricating the cylinders. Again, this is in a 4AGE... your engine may be different

No I mean without needing a metal piece going all the way around between the oil pan and block...in some other engines I've seen the scraper bolted directly into the block or tying into the crank bearing caps so there's no difference in oil pan installation. This would make it easier for me to design and build and reduce the chance of leaks later.

I'm using the stock rods with the oil squirters.

GameboyRMH wrote: No I mean without needing a metal piece going all the way around between the oil pan and block...in some other engines I've seen the scraper bolted directly into the block or tying into the crank bearing caps so there's no difference in oil pan installation. This would make it easier for me to design and build and reduce the chance of leaks later.

From memory... some one makes/made a block stiffening plate that ties all the mains together... and I think also goes out the the blocks edge. This device, the one I'm thinking of, was not designed as a crank scrapper.

The original 4AGE did have a windage try mounted under the rotating assembly... and this was mounted out on the blocks flange... the FSM says to FIPG each layer... I believe they recommend a 2mm wide bead. Recently a friend had to reseal his pan... we did it a bit differently then usual. We applied the layer of FIPG to the windage tray using the bolt alignment from that. then we also FIPGed the pan and then bolted it all together...