Carl Fausett

My Ishira-Johnson Crank Scraper and Windage tray arrived last week and I put it in this weekend.

I'm happy to report that the workmanship was very good, and the fit better than I had even hoped. More importantly, I liked the engineering that went into it - the design is sound - it should do the job nicely.

That being said - there is a fair amount test-fit, grind a little here or there, wash, test-fit again, etc. that goes on. That can't be helped, and the fit was correct in most places to begin with.

Crank scrapers are not new - about 50 or more years old near as I can tell - and just another way to pick up about 5 to 10 HP on a V8 other than a knife-edged crank (which tries to solve the same problem a different way). The side benefits of a crank scraper system over a knife-edge crank is that the oil usually runs cooler when crank scrapers are used (knife-edged cranks have no effect on this) and the crank does not have to have a lot of extra metal welded to it like a knife-edged crank does.

Of course - my motor is not installed and running yet - so I have no performance numbers or anything yet. But I do have pictures - here is the process in over-simplified sequence...

Carl Fausett

BTW - the reason I have Picture 3 in there - it just shows the shield in front of one Head-and-cam down-drain and next to it the normal down-drain. This is where the oil that gets pumped up to the cams comes back down into the crankcase - and unfortunately is aimed almost right at a crank counterweight whipping by. We know the 928 puts up quite a windage cloud and I think this is the key.

Some have spent lots of time on their windage tray in the belief that the windage cloud on the 928 is created by oil rising in cornering or braking and getting whipped into a froth by the crank. Although I'm sure that to some extent that is true, I think the outlets for our down-drains are more likely the cause.

Anyway - the Ishira-Johnson crank shield with the optional windage tray system came with these deflectors so that when the oil from above enters the crankcase it is deflected around and outside of the counterweights whipping by. Smart.

Airflite40

So. wadja pay for that set up? Looks nice...

heinrich

Carl please be very careful and remember ONE THING. This is my humble opinion . When you get low or zero oil pressure, or when you get abnormal heat .... remember the scrapers. They could be the cause.

BC

I have one on the way as well. But with Teflon. Should be fun. This can be installed with most of the important nuts torqued down on the girdle beforehand right?

heinrich

Actually the tray more than the scrapers.

BC

H - your thought is good - but I think I know what you are getting at, ala Louie's site - and this system would probably avoid whatever caused that low oil pressure problem. The movable trap doors will allow more movement and proper drainback of the oil.

But we will be carefull. ;0

DR

I have been thinking of getting this setup also, especially after my recent testing using clear hoses to monitor the oil vapor issues on the 32v engines and seeing the amount of oil that is slung up on the passenger side.

But, after seeing these closeup pictures I am a little concerned of the quality level. I know my good buddy Mark sent the donor motor to get these made and says nothing but good things about these guys and I trust his opinion completely. I just don't understand why the cuts are so rough/crude looking (see photo) below. I would think they would use the precision of a waterjet for cutting these things. But looking closely it seems they are using a plasma cutter or a torch to cut them out. This bothers me and makes no sense because waterjetting is not expensive at all and makes about as perfect a cut as possible without putting extra heat into the base material (notice discoloration etc in the photo from the heat). For those that have this setup, are the cuts as crude as they look or is it just an optical illusion? Is this possibly part of the reason for the grinding and fitting?

After noticing this I went to their website and after looking closer it seems this is the norm (see second photo) as seen on their home page, I don't understand.

Also Heinrich, you sound like you know something I don't concerning these gadgets. I trust your knowledge and would like to know the scoop before I plunk down my $$ and go thru the intense installation because it really seemed to me like a good product. If you don't want to discuss this here, PLEASE e-mail me as enquiring minds want to know :-)

Tony

DR, that was the first thing i noticed on that picture also.
I always thought that to be completly effective the tollerances have to be pretty close.
I also thought the teflon edges were better in case your tollerences inadvertantly got toooooo close for what ever reason while the engine was operating?.

hmmm..My wife has a few extra spatulas around that she wont miss.

DR

Hi Tony,

I noticed it back months ago when they were first being talked about and attributed it to the fact those photos were probably prototypes and basically forgot about it. But, seeing actual shipping product that looks like that has made me rethink my strategy. I still would like to give this product the benefit of the doubt and hopefully some of the guys who actually have them can speak up. Carl's setup could have been an early version so maybe they will get better. I hope so because I still think the product has potential. If not maybe we can pay them a licensing fee for the drawings and have my (or someone else's) waterjetters do the cutting. Minus the material cost it shouldn't cost more than $100 (most likely a lot less) to have all of those pieces waterjetted properly in quantity. Just a thought, because we need more products like this for our beloved 928s.

Brendan, please let us know how yours look when you get it, if you don't mind.

PorKen

End user final fitting?

FlyingDog

That's what I was thinking at first, but the S-shaped cuts are also ragged. It looks like they just used 2 C shapes to make an S and they don't line up.

BC

Well, I will DR. I'll take pics when I get them of the edges. I was hoping to get around any sort of metal problems by getting the Teflon so that it can wear into the crank for much closer clearance.

If its not a super-close tolerance NEED, then its not a big deal to me what it LOOKS like, as much as what it DOES.

Also, I had my 36-1 Crank trigger wheel for my Megasquirt (www.msefi.com) made by water jet at www.emachineshop.com and it looks about the same, but more uniform. It was a steel part and its not perfect by any means by visual, but Taylor machine in whittier had to fit it to a 928 flywheel and true it, and it was very close.

Anyway, my point was that my experience was water jet was not good looking, but good tolerance.

heinrich

Dave, I've seen some very careully-designed oil pickup modification, and I've seen them cause oil starvation. I'm saying, let's be careful the design is good. Solving the windage problem may cause other issues.
Best,
Heinrich

Tom. M

Do you have any more detail on the oil pickup modification H?....

Thanks,
Tom
89GT (contemplating the windage tray..)