IcemanG17

its also helps that I disconnected all of the breather lines that used to go into the intake too....just one large K&N filter on top of the oil filler for crankcase breathing....it gets damp with oil, but thats about it..... I'd guess my relatively low RPM makes the crankcase issue much less severe....I NEVER go past 6000rpm and typically only even hit that twice per 2:10 lap.....

I wish I had the funding to pursue a killer Doc engine......

Oh well I will continue testing how long my 4.7L can live....since its about all I can contribute...well other than smart a$$ remarks here and there

mark kibort

Mark drove Joes fan for hours and hours, he has actually driven my car too (holbert racer) , we have all seen the videos and THANKS, but i dont think im doing any thing that different. i might be a little easier on down shift, but look at the times. Mark was driving your build 928 at world challenge, making just insane videos at road america before the monster engine, yet running 1:40.1 at laguna two years in a row. I run the same set as that original car, with 25 to 40 less hp (I think it was around 400 to 420rwhp at the time) to a time of 136.1 on the same kind of tires, so i dong think he could do anything that differnet , unles he didnt warm the car up properly before getting on the track (one of my theories for failure)
we had the same times in the rain race, and in the lemons racer drivng the same car. I dont think he is doing anything that different than i am. however, i dont think i could drive his car as fast as he could , without a lot of practice. (there is yet another level of racing which is driving FAST cars fast, besides a car fast)

anyway, not to digress. Joe didnt have any oiling issues, so im still not convinced there is an issue. brians car is racing, mine have been for many years, scots, all my old racers, etc etc.

since we know the clutch and transmssion has a limit of about 400rwhp, thats where i would stay. making it up over 6500rpm with a custom intake might be a way to do it, and maybe even loose some peak torque, which as you said, busts things, and that happens down under 4000rpm. since you can make the hp goal much higher, the stock stuff might be alble to survie 400rwhp and not require a custom set of rotating components.

i might of missed something, but does the new rotaing assembly solve for any oiling issues? new drilled holes? etc?

blown 87

Wow Mark.

GregBBRD

Mark versus you....it's not a debate I'm going to get any deeper into....

Yes, the crank is definitely "surface" drilled. They call it "high speed oil hole drilling, in the crankshaft world, BTW.

This is also the way that Porsche Motorsports had the 944 GTR cranks drilled, once they raised the rpms limits to 7800, before they "solved" the "rod spewing" problem.....also "systemic" in those very similarly oiled engines, BTW.
You might also note that they used "different rod bearings", for those engines...not the stock rod bearings.

Hmmm.

"If you don't resist looking at the obvious, sometimes you can learn something. This can be difficult to do, if you think you already know everything and keep your eyes closed."

BC

You are still surprised Greg?

Exactly. And change is the only constant - which behooves us to look at what may have changed with what we already know.

blown 87

Nope, just trying to convey my thoughts with out actually saying what I really think.

BC

Indeed.

GregBBRD

If you never contribute more than the fact that the "early 928" oil pick-up works much better than the "later 928" oil pick-up, you've already done more than your share....

86'928S MeteorGrey

brutus

What model year did they change ?

justaguy

If you never contribute more than the fact that the "early 928" oil pick-up works much better than the "later 928" oil pick-up, you've already done more than your share....

Brian
Now that's a compliment!

mark kibort

greg, greg, and others,

Look, im only asking what was differnt with the new cranks. I do believe there is a small problem, not a huge problem with the oiling of our 928s. I dont think the new pickup vs the old pick up is the issue. both work fine and have their advantages. I have seen no oil pressure drops with the race cars i support, build or have driven with the old style. Fan still has the old style.

However, interesting to hear about the new drilling and other mods that make the cranks safer for the higher revs. (and bearing materials).

Greg, there is a certain thing regarding imperical testing that is going on here. dont be so quick to dismiss sucess. as someone that migh be serious about solving problems, you look at those sucesses and learn from them or replicate them, to improve on the engine and its performance.

oh yeah, im just lucky and drive slow. i forgot.

go watch a video and get back to me on that.

Rob Edwards

PET sez the spring pickup and screen setup was used 78-82 only.

mark kibort

really? sometimes change can be bad , very bad. just look at all the folks that really have re-invented the wheel here. most have got in big trouble. some , like GB are the minority. a long time ago, 100s of race hours ago, i found someone that was sucessful and did what they did. its not to say i didnt improve on those things, but i started fom a point of sucuess. others try and jump to the end point with little or no knowledge of what they are really doing.
its one of the reasons my car is as fast and reliable as it has been.
now you can poke fun at amzoil, my "bogus" mobil 1 low oil pressure reads at temp, but in the end, whos cars are still running with out being torn down ?


Its not a debate. However, i did want to know what was differnet with the cranks and how the would solve the high rpm bearing issues. which i still think are present under certain conditions.

you know what ive done and lap times my car runs. you also know i dont have any thing modified in the engine but a strengthened pressure plate and a stroker. (no coolers, no breather mods, etc).

you cant dismiss driving style or orer all on track and off track technique as well as the oil properties.

i toss that car around a lot, off line on line, mixing up gears im in and g's im applying. I dont buy its a smoothness thing either. i truely believe its a combination of the oil and proper warm up . i think a ton of racers just get in their car ,and beat on them from the start without being warmed up. our cars might be even more senstive to that, as well as the oil pressure issues.

look at brian for example. he is ringing that 4.7 out right now, withonly a pan spacer. he ran a 2:05 with real racing slicks. think about it... only 220 rwhp and running a 2:05. the cornerng speeds and gs are very high to run that time without power. why is he not seeing any issues.

Ive raced at willow springs, buttonwillow several configurations, RA (on crappy tires) laguna , sears, thunderhill and havent seen any bearing issues in 17 years of this stuff? 100s of race days??? common, give me a little credit!

namasgt

MK,

Don't want to go off topic, but did you use the cheaper OEM rod bearings or the expensive Genuine ones for your stroker?