Bill Ball

Mike: I appreciate the info.

RyanPerrella

Bill,

Did this engine fail under racing conditions. This is a race car correct? Or did this happen under street driving?

Bill Ball

Race. 7 laps. The track (Thunderhill) does have two moderately long sweepers.

SwayBar

Drilling the crank, etc are all good ideas of course, but a drilled crank and it's bearings will still fail if the flow of oil is interrupted, or if the oil gets overly aerated by not controlling the oil and keeping it around the sump. Since a dry-sump is out of the question, then the next logical choice for oil-control would be a crankscraper and windage system such as Ishihara-Johnson's:

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

Scroll down and look for the Dutch Stallion yellow 928 (..quote from link):

"Rob Van Kol, owner of Havik Racing Solutions in Houthalen-helchteren Belgium and his brother, Jean-Paul, campaign the Dutch Stallion Porsche S4 Evo. The engine ran the season at typical rpms of 6800 and is now run at 7200 (..RPMs) for a total of over 43 hours of racing with stable oil pressure and no engine damage whatsoever. This was accompanied by a 10 degree Celsius drop in coolant temperature from the previous years engine which had less power. This years engine is NA and develops 420 rwhp. It is important to note that without the windage system the previous years engine failed in two days running at 6300 rpms -- this is a critical rpm for the wet sump engine and to break through it reliably absolutely requires comprehensive windage and oil control."

That is a compelling story. According to Dutch Stallion, the I-J system has warded off 2/6 failure for over 43 racing hours with a redline of 7200 RPM!

I too have the full I-J system installed on my brand-new wet-sleeve motor and have run it once so far at Road America, and there is no doubt it really works.

http://www.roadamerica.com/images/maps/ra_map_2006.pdf

Going through the Carousel, my oil pressure remained stable whereas before I-J, the oil pressure would bounce around. Braking hard into Turn 8 the oil pressure remains stable whereas before it would bounce around. Those are the only places I'm able to take a peek at the oil pressure.

The most telling clue though was the temperature of the Accusump, or lack of temperature, after coming in from a 20-minute session; it was barely warm to the touch whereas prior to the I-J system, it would be blazing hot at engine temperature. Apparently the I-J system did such a good job keeping oil around the sump that the Accusump did not have to discharge and recharge too much, and that's on a really fast, heavy braking, high-g cornering track.

I think that without a doubt, the two most important things to do is to install the I-J system, and drill the crank. Those two items with a properly setup Accusump should eliminate another 2/6 catastrophe from happening due to oil starvation/aeration.

Oil control, oil control, and more oil control.

GregBBRD

Thunderhill has always been hell for both 951's and 928's. The off camber stuff just kills the oil slosh issue. I had a customer with a 951 that loved the off camber stuff and could go really fast on that part of the track. He killed his engine every time he went to Thunderhill, until we dry sumped it.

I've been full grooving the bearings in the engines with the Chevy drilling. There doesn't seem to be a downside. The main bearings never fail or have wear issues, so the surface area doesn't seem to be of any concern. The oil pump can deliver plenty of volume, so that is not an issue. And, of course, you need Amsoil. Don't need to pour it into the crankcase, just put a can behind the seat and everything will be fine (sorry Mark....couldn't help myself!)

Even dry sumped engines will kill rod bearings. There are many different reasons for the bearings to fail.....two if them are the drilling and the pan pick-up issues. There are a couple of more.....which makes the entire issue way more complex than it seems on the surface. The latest version of windage trays that we developed completely eliminated oil coming out of the head breathers. This means that the oil is staying in the pan. We were not able to detect the accusump even working at Fontana with the latest stuff. Fontana is not Thunderhill, however. If Thunderhill was my home track, I'd look carefully at a dry sump system, or get the best windage tray set-up you can find....and pray.

The factory rod bearings provide greater bearing clearance than the ones you buy from Glyco. We use the factory bearings, even though they are more expensive. The other alternative is to have the crankshaft "micropolished" longer a bit more than normal.....

Have fun!

gb

mark kibort

Amzoil: 6 seasons with lots of 2:02 laps at Thunderhill, almost 100 race hours on the 928 engine.
Probably the fastest dependable race car in the world to date! all stock components.

all packed up and ready to hit Thunderhill tomorrow and sunday. Knock Knock! Dont jinkz me Downtown GB!

mk

Bill Ball

Swaybar: The I-J windage and scrapers are under discussison.

Greg: You mention a windage tray. Your own design, different from the I-J setup? As an aside, I think I need that, as I'm throwing a lot of oil out the filler breather in open road racing at very high speed. Thatnks for the vote for Chevy drilling and main bearing full grooving. And Dennis is going to carry a bottle of Amsoil in the car for now on.

GregBBRD

Bill:

Don't think I've seen the I-J (?) set-up. I've seen a few, but all that I've seen seem to have the same problem...they don't leave enough area for the oil to escape back to the pan. They almost seem to be designed to keep the oil in the upper part of the engine. We tried a scraper/windage tray/different pan set-up on Mark's engine once. The rod bearings almost lasted for the entire day....and that was with a dry sump. When you rev the engine up to 6000 and the dry sump tank slowly looses volume....there is something wrong.

gb

Fastest928

Bill - check the wiring, and as suggested, remove the electricly actuated valve for fool proof operation. Dont forget to renotch the dipstick. Also, clean, clean, clean.

Yes, the dry sump pan is ready for testing. We can now build the test engine

Dave/Shartskin, what are you taling about with the bearings???

The 928 has been run on the track for almost 10 years hard...with the same engine. And as far as I can tell, after running a stock engine up to 8000 rpm on adynohjet, the oil feeds to the rods never failed as long as their was stable un aeriated oil feeding the crank.

Cheers,
marc

Fastest928

Oh, Louis' scrapers are about eh best I haveseen to date.

GregBBRD

Louis's scrapers are indeed works of art. I can't imagine the time it took him to build them, trimming off little bits at a time to make them fit that well. He's a genius with patience...a rare combination.

gb

Bill Ball

OK, rereading...

Greg, I see you have developed your own windage. I don't suppose you offer it to other builders.

It looks like Louis is using the I-J scrapers. He links to them. They have Louis' custom touch (a drip edge). The trimming/grinding and tight fit is part of the I-J installation. Louis has his own windage design , but notes it is still experimental. What isn't in this car?

Thanks for the comments. Even more would be appreciated, especially about Chevy drilling of stock (non-stroker) cranks.

Bill Ball

Further word from Jim Morton - Dennis' crank is bent like a pretzel into an S-shape. All the mains are toast, of course.

lorenolson888

Hi Bill, Dennis...

Great thread... I am at home these days with the new future rennlister... my boy Alexander...

Let me know if youy need a hand... I can come by and do some menial tasks, take some pictures etc... I would love to helpout with some engine teardown and assembly!!!

Loren

lorenolson888

Wow..

bent crank!!! I guess once the bearings go the crank will go whatever direction it is pushed in huh...

I hope you guys find a good core soon... Did dennis pay for this engine that blew up so quick... was it refreshed in anyway before the tortuous 7 laps at thunderhill... this makes me rethink the idea of racing a stockish engine///