Strange crankshaft wear pattern

[modok]

Although it has a lot of boost it is still has a throttle yes?
Do you close the throttle when shifting gears? Then for that moment it is at max rpms and no boost.

[4vpc]

Although it has a lot of boost it is still has a throttle yes?
Do you close the throttle when shifting gears? Then for that moment it is at max rpms and no boost.

And where are you going with that?
(I'd assume it wasn't your normal manual change and the gears were shoved in at high speed with little dip in the revs)

[modok]

I don't know, why I asked. he figured there would not be much force on the PULL side due to it being so much boost, which would be true with a diesel, heck you could leave off the caps it would still work until you shut it down
but not necessarily true with this because it has a throttle.

[ptuomov]

I always try to listen and learn from the experts in the manufacture and use of very high performance racing parts. They spend tremendous amounts of money and time making product and performance better including durability. If those experts and extreme condition users say that cross drilled crankshafts are not ideal and they don't use them so I am going to follow their lead and advise and not use them. Why sit here on Speedtalk and ague with their experience, successes and extremely expensive technology, testing and results and try to justify cross drilling crankshafts ! Spend more time listening to free great advise and help and stop trying to justify things work that don't work well. I know there are a few on here who would argue that water isn't wet, but I don't want to hear their sometimes ridiculous opinions. JMO

Stuff evolves. There was a time when piston rings were 5/16" wide. My forties-design 61 c.i. Vincent twin had 2" 'primary pipes in race trim. Full groove main bearings were once the norm. Cross-drilled cranks are in the same category.
On top of all the other potential issues raised above, the bearing eccentricity still looks too low for the application.

Why sit here on Speedtalk and argue about this stuff? Good question for each of us. Personally, I'm just trying to understand why and keep thinking out loud doing that. If anyone does anything to his crankshaft based on what I write here, he deserves what he's got coming!

Right now, I think that car factories making crankshafts understand a lot more about making crankshafts than aftermarket "racing" crankshaft manufacturers. That's not a diss on the aftermarket, just a statement about relative resources, especially computing budgets. So if one wants to talk to someone about cross drillings and how things have evolved, I'd head in the direction of car companies.

Also, I think that if someone is talking about just cross drilling mains without specifying what kind of cross drilling they are talking about, they are out to lunch.

[pamotorman]

i would guess GM cross drilled the BBC HI PERF cranks because they found they needed it because it added to the cost in a industry where they look to save pennies.

[Warp Speed]

I always try to listen and learn from the experts in the manufacture and use of very high performance racing parts. They spend tremendous amounts of money and time making product and performance better including durability. If those experts and extreme condition users say that cross drilled crankshafts are not ideal and they don't use them so I am going to follow their lead and advise and not use them. Why sit here on Speedtalk and ague with their experience, successes and extremely expensive technology, testing and results and try to justify cross drilling crankshafts ! Spend more time listening to free great advise and help and stop trying to justify things work that don't work well. I know there are a few on here who would argue that water isn't wet, but I don't want to hear their sometimes ridiculous opinions. JMO

Stuff evolves. There was a time when piston rings were 5/16" wide. My forties-design 61 c.i. Vincent twin had 2" 'primary pipes in race trim. Full groove main bearings were once the norm. Cross-drilled cranks are in the same category.
On top of all the other potential issues raised above, the bearing eccentricity still looks too low for the application.

Why sit here on Speedtalk and argue about this stuff? Good question for each of us. Personally, I'm just trying to understand why and keep thinking out loud doing that. If anyone does anything to his crankshaft based on what I write here, he deserves what he's got coming!

Right now, I think that car factories making crankshafts understand a lot more about making crankshafts than aftermarket "racing" crankshaft manufacturers. That's not a diss on the aftermarket, just a statement about relative resources, especially computing budgets. So if one wants to talk to someone about cross drillings and how things have evolved, I'd head in the direction of car companies.

Also, I think that if someone is talking about just cross drilling mains without specifying what kind of cross drilling they are talking about, they are out to lunch.

Way different goal sets and challenges. I understand your point about the level of oem resources, but do you honestly think the time they spend in this subject is more than all the professional race teams put together?!?
The "TOP" aftermarket crank vendors know what works and what doesn't when the factory strategies fail.
According to the paper you posted, our strategy wouldn't work at all. The fact is that it does, very well, at way more abusive criteria than the oems use, with less pressure!
About all I can say about that.........

[Warp Speed]

i would guess GM cross drilled the BBC HI PERF cranks because they found they needed it because it added to the cost in a industry where they look to save pennies.

They probably thought it was an advantage......in the 70s and 80s.
It seems we beat this to death every couple of years.......kinda like tq vs hp! LOL

[ptuomov]

What factory crankshaft design strategies "fail" in the intended use? My impression is that when a major car company makes a crankshaft, it meets all the design requirements without a fail. I'm talking about the fully computerized era of the last ten to fifteen years.

[Warp Speed]

What factory crankshaft design strategies "fail" in the intended use? My impression is that when a major car company makes a crankshaft, it meets all the design requirements without a fail. I'm talking about the fully computerized era of the last ten to fifteen years.

And why do these not work in proffesional motorports.......in the fully computerized era of the last ten to fifteen years?!?

[ptuomov]

What factory crankshaft design strategies "fail" in the intended use? My impression is that when a major car company makes a crankshaft, it meets all the design requirements without a fail. I'm talking about the fully computerized era of the last ten to fifteen years.

And why do these not work in proffesional motorports.......in the fully computerized era of the last ten to fifteen years?!?

Are you talking about a situation in which the car factory designs a crankshaft for requirements X, it fully meets the requirements X, then someone like a motorsports team takes that crankshaft and switches the requirements to Y, and the factory crankshaft that was designed for requirements X doesn't meet the new requirements Y? I can see that happening. I can also see a situation in which a small subset of aftermarket manufacturers can design a new crankshaft that meets these new requirements Y. What I can't see happening is a car factory designing a crankshaft for requirement Z and it not meeting the requirements Z.

Perhaps we don't even disagree about anything on this one.

[Newold1]

Reminds me of another old song "And the times they are a changing" There are a lot of things OEM's do and don't do to engine parts and development and in today's corporate automobile world its done from an NOI and sales basis. If it is cost effective, meets regulations, will sustain itself at or longer than the warranty period and it will sell to the user, that's the way it's done.

In racing, cost is a small aspect, there is NO Warranty! and they don't care if it sells or not. It's whatever it takes to survive and WIN!

Speed and racing has now shown and pretty much proved that cross drilling the crankshaft to deliver oil is not a successful method in racing and high rpm power adder uses on an engine and that's what this post is about. We are not talking about what OEM manufacturers are doing in their world with their crankshafts.

If you think or believe aftermarket crankshaft manufacturers don't produce some of the best crankshafts in existance, perhaps you should come out of your CAVE and put a Winberg or Bryant racing crankshaft down on a table next to a GM or Ford or other OEM production crankshafts and make some keen observations and analysis.

Ask Cadillac/ ER Racing Engines Daytona prototype LSX engine that just ran 30,00 miles in 24 hours at Daytona at rpms in excess of 7,000rpms. It wasn't no stock GM crankshaft!

If one does these it will become quickly apparent that some pretty choice product comes out of the aftermarket in these crankshafts "AND THEY AIN'T CROSS DRILLED!" and there is no OEM crankshaft that will stay with them and survive in today's super power and rpm professional racing uses.

Enough said I'm done here.

[user-23911]

Professional motorsports people tell lies on purpose to put the opposition off track. DV even made a topic on that.

The aftermarket parts industry is interested in selling lots of low quality low performing parts.

The OEMs are interested in selling complete vehicles which need to last a reasonable length of time without problems.




That needs thinking about.

[Zmechanic]

The “problem” comes from the fact that the required supply pressure of a T style drilling is proportional to the square of the main journal diameter and to the square of the rpm. At some rpms, this gets a ridiculously high if mains have large diameter.

I don't disagree with the math, but everyone has been looking at this very idealistically..
Bearing clearances are a controlled leak. How much pressure do they bleed off at the bearing interface between the oil holes?

And all the gallerys are a maze of restrictors and other controlled leaks. How much pressure is actually at the main bearing oil hole?

[MadBill]

Professional motorsports people tell lies on purpose to put the opposition off track. DV even made a topic on that.

The aftermarket parts industry is interested in selling lots of low quality low performing parts...

So the $5,000 cost of say a Winberg or Bryant crank, much less some top-of-the-top $10k+ pieces, is just a sales gimmick to distract us dim racers from the sub-par reality of their cheap and nasty stuff?

[hoffman900]

Professional motorsports people tell lies on purpose to put the opposition off track. DV even made a topic on that.

The aftermarket parts industry is interested in selling lots of low quality low performing parts...

So the $5,000 cost of say a Winberg or Bryant crank, much less some top-of-the-top $10k+ pieces, is just a sales gimmick to distract us dim racers from the sub-par reality of their cheap and nasty stuff?

It's always the same handful of people too.