Head design and casting cost?

General engine tech -- Drag Racing to Circle Track

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SchmidtMotorWorks
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Re: Head design and casting cost?

Post by SchmidtMotorWorks »

mekilljoydammit wrote: Mon Nov 05, 2018 9:54 am https://imgur.com/a/kgTkdG0

Just something I was working on, speaking of reverse engineering cylinder heads. The fun trick will be turning the slices into a 3d model but I'm pretty sure I have a way to do that without too much work. edit: Well, I suppose I should say "too much trouble" - every step of this is a lot of work.

If you're dedicated enough, you can DIY the foundry work too but I have no doubt that getting to routinely acceptable head castings will be a learning process. There's a lot of technical literature out there to let you crib off of what people have done before. Patterns and stuff are even more easily DIYable.

I am not, however, sure how to get any money out of any of this, but it keeps me out of trouble. :lol:
There is a big difference between a 3D model, and one that is useful to make foundry tooling.
Simply lofting a bunch of sections won't develop a usable parting line.
There is no alternative to developing the CAD skills and foundry tooling knowledge if you want to be competitive.
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Re: Head design and casting cost?

Post by Steve.k »

Yes and that adds up to alot of heads to sell for returns. Could take many years depending on what style engine.
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Re: Head design and casting cost?

Post by volodkovich »

SchmidtMotorWorks wrote: Mon Nov 05, 2018 5:11 pm If you plan to make as-cast ports or chambers that are competitive with todays OEM designs, you need the best tools.
SolidWorks is better suited to machinery.
You've said an OEM spends up to $400k on modeling. I don't think its reasonable to expect a low-volume aftermarket head to compete with this level, and likely not what this thread is about. I am sure Solidworks is usable for the majority of cases, especially with aftermarket CNC porting being easily available these days to shape chambers / ports as needed.

Image
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Re: Head design and casting cost?

Post by mekilljoydammit »

SchmidtMotorWorks wrote: Mon Nov 05, 2018 10:47 pm There is a big difference between a 3D model, and one that is useful to make foundry tooling.
Simply lofting a bunch of sections won't develop a usable parting line.
There is no alternative to developing the CAD skills and foundry tooling knowledge if you want to be competitive.
Oh, I'm not naive enough to think "3d model representing what's there after all machining processes" is anywhere near the same as something usable to make tooling - the head slicing is just an experiment in very low buck reverse engineering.

Fortunately I'm not really intending on being commercially competitive at any point in the foreseeable future - I don't even know if there's any market worth pursuing for aftermarket DOHC heads if I had salable product - but heads are an interesting thing to work towards, for me.
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Re: Head design and casting cost?

Post by hoffman900 »

It would seem to me the water jackets are harder to design than the ports. At least, effective water jackets.
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Re: Head design and casting cost?

Post by Keith Morganstein »

So when a company introduces a casting... Whether Brodix, Dart, Sniper, or some offshore, etc ...
Do they have the same cost every time? Even if it's for the same engine family?

With a high production head such as a LS pushrod head or SBC head. Is that an easy or complicated casting to make.

I've watched countless YouTube videos on casting... they make it look easy
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Re: Head design and casting cost?

Post by Newold1 »

Water jacket shapes and placement are a very difficult part of cylinder head development. There very intricacies and tangled shapes when sized, placed and constructed are probably one of the most difficult design features of a good cylinder head. Just making the sand cores and keeping them placed in the core boxes and handling them after fabrication in sand is a challenge. Creating the sand mold to make the cores is as difficult as the water jacket cores themselves. These are big reasons why the OEMs have gone over to lost foam and pressure casting to help them cast heads cheaper and faster but the investment in the equipment and plants to do this type of casting is beyond HUGE!
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SchmidtMotorWorks
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Re: Head design and casting cost?

Post by SchmidtMotorWorks »

volodkovich wrote: Mon Nov 05, 2018 11:16 pm You've said an OEM spends up to $400k on modeling. I don't think its reasonable to expect a low-volume aftermarket head to compete with this level, and likely not what this thread is about. I am sure Solidworks is usable for the majority of cases, especially with aftermarket CNC porting being easily available these days to shape chambers / ports as needed.
I have never seen a good head or manifold model made in SolidWorks.
It is an ordinary day for me to remodel a casting designed in Solidworks so that shapes can be improved and foundry tooling can be made cost effectively for it.
Even using CATIA or NX, there are compromises made that are determined by the capability of the CAD software.

With regards to CNC porting, this is where most people do it backwards:
They do the following:
1. Shape a port with die grinders
2. Scan the port
3. Fit surfaces to the scan
4. CNC program to the scanned surfaces

A vastly better way to do it is:
1. Model the ports in CAD (it is easy to improve on a hand-shaped port in CAD)
2. Cut a split port box to evaluate the shape by eye and flow bench if you have one.
3. Run CFD if you have it
4. CNC program to the CAD
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SchmidtMotorWorks
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Re: Head design and casting cost?

Post by SchmidtMotorWorks »

Keith Morganstein wrote: Tue Nov 06, 2018 8:54 am So when a company introduces a casting... Whether Brodix, Dart, Sniper, or some offshore, etc ...
Do they have the same cost every time? Even if it's for the same engine family?

With a high production head such as a LS pushrod head or SBC head. Is that an easy or complicated casting to make.

I've watched countless YouTube videos on casting... they make it look easy
Mostly, it depends on how good they are at reuse of CAD.
If they are not good at it, reuse actually takes longer.
If they are good at it, they can save 80% the design work.

Reusing one part of the tooling to make two different castings is almost always regretted by the time the project is done.
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Re: Head design and casting cost?

Post by volodkovich »

SchmidtMotorWorks wrote: Tue Nov 06, 2018 11:09 am
I have never seen a good head or manifold model made in SolidWorks.
Challenge accepted!
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Re: Head design and casting cost?

Post by digger »

Round pipes flow quite well, can SW draw circles ?
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Re: Head design and casting cost?

Post by Kevin Johnson »

Jon knows what he is talking about.
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Re: Head design and casting cost?

Post by Newold1 »

Yep , he gets a little past my mathematical and technical knowledge base, but he does for a good reason, it's his training and his profession to do just such! He knows cylinder head design and methods because that's his job! Glad he can help keep our wheels on a straight track once in awhile. We need industry experts like this on this forum and we may disagree with all his thoughts and ideas but I am glad he is here to inject knowledge and actual expertise.
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SchmidtMotorWorks
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Re: Head design and casting cost?

Post by SchmidtMotorWorks »

digger wrote: Tue Nov 06, 2018 9:34 pm Round pipes flow quite well, can SW draw circles ?
You are closing in on the point.

Solidworks can sweep a circle section just fine, and some people would consider that a good port.

A properly shaped port has more complexity than a circular section
and
It must be easy to modify the section of the port at any point along the port in ways that are:
1. Quantifiable
2. Repeatable
3. Transition with the desired smoothness vs locality to the surrounding surfaces

How high-end CAD systems differ from general purpose CAD systems.
High-end CAD systems = control of shape by surface poles
General CAD systems = control of surface by sections and guides

If anyone is Interested I can make up some images to explain the difference.

When it comes to water cores, there is no "good-enough" CAD system.
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Re: Head design and casting cost?

Post by mekilljoydammit »

SchmidtMotorWorks wrote: Wed Nov 07, 2018 12:31 pm If anyone is Interested I can make up some images to explain the difference.
If it's not too much trouble, please do. From what you're describing and from other things I've worked on, I think there's ways to work around the issues with SW you're talking about, but I'm not sure if what I'm thinking and what you're talking about are the same. As someone interested in this stuff and trying to home-game things for personal use, I'm grateful for hints from people who actually know what they're doing.
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