crankshaft counterweight shape

[strokersix]

Perhaps the notches might wash out FEA hotspot somehow.

So now there are three suggestions. Nobody will claim an aero, pumping, or oil shedding effect next to the conrod?

[SchmidtMotorWorks]

Perhaps the notches might wash out FEA hotspot somehow.

So now there are three suggestions. Nobody will claim an aero, pumping, or oil shedding effect next to the conrod?

It probably would make more of a CAE hot spot, it is rare that you can remove material and reduce stress in a crank.
Those same notches exist on some cast iron cranks since the 70's on cranks of similar proportions.

[Kevin Johnson]

Sometimes it is best to slowly dole out information to see where the dynamic narrative leads us. Cough.

Here we have a cast 4-6L DOHC crank next to a forged steel 4-6L DOHC crank. It is fortuitous that the profiled leading edges of the counterweights are clearly visible.

I am sure the little notch on the steel crank counterweight is for balance and not indexing QA after violent forging operations.

crankshaft-comparison.jpg

http://www.mustangandfords.com/featured ... mmer-time/

[SchmidtMotorWorks]

Sometimes it is best to slowly dole out information to see where the dynamic narrative leads us. Cough.

Here we have a cast 4-6L DOHC crank next to a forged steel 4-6L DOHC crank. It is fortuitous that the profiled leading edges of the counterweights are clearly visible.

I am sure the little notch on the steel crank counterweight is for balance and not indexing QA after violent forging operations.

crankshaft-comparison.jpg
http://www.mustangandfords.com/featured ... mmer-time/

That notch is not the same as the others discussed in the previous posts.
That is a qualifying feature typically made in the 1st or second operation depending on the equipment used.
(has nothing to do with QA).
The need for indexing is a sign of a poor process. Much better to index on the rod pin.
If one is going to put in some kind of indexing feature, it would not look anything like those balancing notches.

It isn't clear from that image or the article that crank is forged.
They claim that it is "steel" but Ford has often called some variants of ductile iron "steel"

[Kevin Johnson]

Note:
This information was available to you in previous posts but as is your history, you rarely do very simple follow-up research.




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Brand: Ford Performance Parts

Manufacturer's Part Number: M-6303-D46

Part Type: Crankshafts

Product Line: Ford Performance Parts SVT Steel 4.6L Cobra Crankshafts

Summit Racing Part Number: FMS-M-6303-D46

UPC: 75612268534

Rear Main Seal Style: 1-piece

Engine Stroke (in): 3.542 in.

Crankshaft Material: Forged 4130 steel

[SchmidtMotorWorks]

If it is this crank, yes it is forged.
The flat is for indexing but has nothing to do with QA.
Apparently the knife edges on the cranks you posted were done as an afterthought, perhaps by Sean Hyland Motorsport.

[Kevin Johnson]

If it is this crank, yes it is forged.
The flat is for indexing but has nothing to do with QA.
Apparently the knife edges on the cranks you posted were done as an afterthought, perhaps by Sean Hyland Motorsport.

My Father worked in Quality Assurance for a large corporation for many years -- by large I mean it was broken up by the Federal Government for being too large. You have a very limited idea of what that entailed.

You are also forgetting that my first degree and profession involved casting of precious and non-precious alloys. I know what as-cast surfaces look like with a wide variety of refractories or even with dies.

Keep trying.

[SchmidtMotorWorks]

If it is this crank, yes it is forged.
The flat is for indexing but has nothing to do with QA.
Apparently the knife edges on the cranks you posted were done as an afterthought, perhaps by Sean Hyland Motorsport.

My Father worked in Quality Assurance for a large corporation for many years -- by large I mean it was broken up by the Federal Government for being too large. You have a very limited idea of what that entailed.

You are also forgetting that my first degree and profession involved casting of precious and non-precious alloys. I know what as-cast surfaces look like with a wide variety of refractories or even with dies.

Keep trying.

That notch is used to set the crank in the machining fixture.
At the quality stage measurements would be made from center-line datum on the ground journals.

You posted the part number. I just posted an image of what came up.
It had a crank with the notch on it but on a non knife-edged crank.
Maybe you can find a picture of a complete crank like that that is knife edged stock, (if that is what you are arguing is the case).
Even if you find it, the late model cranks don't have those knife edges, one would wonder why they stopped using them if they worked.

If I remember correctly your casting experience had something to do with dental work.
You are not your father, and you have not said what his experience was relative to crankshaft manufacture.

Try find anyone with experience in design and manufacture both high-end racing cranks and OEM that will disagree with me.

[Kevin Johnson]

The link is for a motorcycle engine. I don't think they run vacuum systems on them. And if you look at any old factory stock high rpm motorcycle crankshaft they are not fancy looking at all. I still say there is no need for counter weights to be aerodynamic, they are not flying into static air. The air flow would be more radial I feel, from the centrifugal pumping effect.

I see dry sumps being used and the efficiency of the stages usually dictates whether a depressed atmosphere or vacuum results. It is a fully machined crank benefiting from the atomizer effect. You could question them as to whether they were aware that was beneficial or glad happenstance.

Here is a video of a BMW s1000rr run up to over 14k rpm so the cams are running at half of that. The "smoke" you see drifting out is actually minute oil droplets generated by the engine.

https://www.youtube.com/watch?v=nsa6kq-qqIE

If they are not drawing a depressed atmosphere, here are windage losses they can extrapolate from:

http://www.wseas.us/e-library/transacti ... 54-646.pdf

oil droplets in air windage losses in gears.jpg

[Kevin Johnson]

That notch is used to set the crank in the machining fixture.
At the quality stage measurements would be made from center-line datum on the ground journals. ...

I can read quickly too and you missed the part in the handbook where raw forgings are evaluated prior to expensive machining time being expended.

... You posted the part number. I just posted an image of what came up.
It had a crank with the notch on it but on a non knife-edged crank.
Maybe you can find a picture of a complete crank like that that is knife edged stock, (if that is what you are arguing is the case).
Even if you find it, the late model cranks don't have those knife edges, one would wonder why they stopped using them if they worked.

The picture that you (and I) found is on many vendor's sites. It is not high enough resolution and did not display the leading edge of the counterweight well (the crank rotates clockwise in this engine). A bit more searching was required for a nice quality pic.

... If I remember correctly your casting experience had something to do with dental work.

That is correct. I worked with my Grandfather (a master technician) for several years prior to earning a degree in the field and becoming certified. The non-precious alloys are what are commonly described as super-alloys. There was a variety of alloys used.
I also ran a small side business making precision brass castings for hobbyists to replace fragile Styrene components.

... You are not your father, and you have not said what his experience was relative to crankshaft manufacture.

No, but we discussed his work. He visited production plants around the United States and followed up on problems in machinery lines, filling equipment, rodent infestations and many other areas. Maybe the most interesting incident is when he tracked down a mafia controlled can supplier who was disassembling printed cans and reversing the shell. That led to product contamination at the higher end of the periodic table. He subsequently ran the West Coast plant in Vernon (your neck of the woods). He had a bright red caboose that would be brought in on a rail spur in front of the plant in last place with quality problems.

... Try find anyone with experience in design and manufacture both high-end racing cranks and OEM that will disagree with me.

You simply ignore people. You have been presented with a longitudinal crankshaft history ranging from 50 years ago to the present with present OEM engines exceeding race engine output of years prior (and at high rpm) accompanied by comments from an OEM engineer of same engines. By chance, what I presently do involves looking at hundreds of different engines from dozens of marques and following particular engine series or architectures development over time. I apologize if it makes my spidey-sense of BS detection go off periodically.

[SchmidtMotorWorks]

You simply ignore people. You have been presented with a longitudinal crankshaft history ranging from 50 years ago to the present with present OEM engines exceeding race engine output of years prior (and at high rpm) accompanied by comments from an OEM engineer of same engines. By chance, what I presently do involves looking at hundreds of different engines from dozens of marques and following particular engine series or architectures development over time. I apologize if it makes my spidey-sense of BS detection go off periodically.

Get involved in actually designing, making and testing them and your views will align with mine.

[Kevin Johnson]

I guess Kevin forgot you worked at Bryant, and are a design person.

No, you've only been on the forum for six years. Jon and I have both been on eight years prior to that.

[SchmidtMotorWorks]

I guess Kevin forgot you worked at Bryant, and are a design person.

Speaking of Bryant. I walked to his house this morning we were talking about usual stuff and I asked how he liked his V12 BMW I had not seen it being driven in years. He gave it to me, 60k miles like new condition. Started up perfectly after at least 2 years indoors.

[Kevin Johnson]

That's very nice of him to do that. I know you have suggested many times that BMW and Mercedes make nice engines that people could swap in to projects.

[SchmidtMotorWorks]

That's very nice of him to do that. I know you have suggested many times that BMW and Mercedes make nice engines that people could swap in to projects.

It is like this one, 750 IL V12

https://www.youtube.com/watch?v=5H0W-NE4Cqs