Casting small engine parts

[wgipps]

Hello all - first post here. You come recommended from a guy i found in a google search.
Anyway - i have a rare car engine that has some fancy valve rockers. Being rare - there are no others. I would like to cast some spares.
They are fairly small - each rocker is in 2 pieces and each piece will fit inside your hand. Ive attached an image of it all together but i dont expect you to make too much sense from it.
Does anyone know where i could get these pieces cast?
Thanks
Glenn
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG0179.jpg

[bollie7]

Glenn
Welcome
do you know what the material is? Cast iron or Cast steel? If iron you should be able to find someone down your way who could and would be able to reproduce these. If steel then it might be a different story. I can't help you with who though unfortunately.
There are still a few commercial foundries around but I believe a lot of them are not interested in small volume work. If the rockers are Cast Iron then you best bet would probably be a backyarder who knows what he's doing. Someone else here will probably be able to add more to this.
Whats the car?

regards
bollie7

[wgipps]

Thanks bollie
Its a Ford model T racer. photos attached.
Now im gonna let you see something that not many people get to see - my ignorance! i have no idea what they are made of. :B
I would need someone to have a look. Personally - does it matter what they are made of?

http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG0450.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG0452.jpg

[Master Splinter]

An alternative option could be to take a stack of photos, and use an image-to-3D service (see this post (http://www.woodworkforums.com/f170/free-3d-model-service-142700/)) and create a CAD file of the part (confirm critical measurements and tweak the model to fit).

You then have something you can keep against future need, and when required, either get the part CNC'd in a moulding foam to make a part for casting, or CNC'd directly from billet - CNC Machine Shop | Custom Waterjet, Plasma, Laser Cutting | eMachineShop.com (http://www.emachineshop.com/) .

[nadroj]

Wow - four valve heads! How old is that engine?

I wouldn't be surprised if the rockers are forged steel, like the car's front axle.
Not easy to replicate in the home workshop.

Jordan

[wgipps]

Nadroj - its actually 16 valve. 1917 was the year of manufacture. Peugot made the first multivalve engine but this is considered so different to the Peugot model that this engine (called a 'Roof type A') is considered the first 16 valve car engine. They were an after-market engine solely for the Ford Model T.

Is there a difference between cast steel and cast iron? again showing my ignorance but would it make any difference for this type of application?

Ive seen the ability to take digitial measurements of pieces and turn them into plastic replications - is that the sort of thing in need here to start with?

[franco]

Nice looking car.

Looking at the photo, the rocker assembly seems to be a mixture of castings and forgings. I'd be surprised if any of the higher stressed bits were cast iron in that application - could be wrong though.

Are you a member of the MTFCA (Model T Ford Club of America)? I am not, just a former T owner, but a friend and current owner of an OHV speedster (not a Roof head) passes on his MTFCA magazines for me to read. Within the last year or two there was a long feature article on the history of the Roof company and detailed description of the Roof heads.

Frank.

[nadroj]

Nadroj - its actually 16 valve.

I mean 4 per cylinder. Most V8s have 16 valves too, but only 2 per.

Jordan

[wgipps]

Hi Franks
I am on the MTFCA discussion board and am aware of 3 other Roof type A heads still going, and 1 in a museum somewhere. I read an article about them a while ago - i will see if it is one and the same.
Castings? Forgings? now youve got me stumped.

[Stustoys]

Hi Glen,
What sort of rpm do you have in mind?
I guessing not many so maybe cast would hold up?

Which ports are split? 2nd and 5th?

Stuart

[RayG]

Hi Glen,

I do a bit of backyard casting, but I'm not sure I can help. It's hard to see the shape clearly with the pictures, and I think making the pattern might be a bit tricky.

As for material, the sample part doesn't look like cast iron, it might be a cast steel alloy?

I wonder if silicon bronze would be suitable?

Any chance of a few pictures showing the shape a bit more clearly?

Beautiful restoration by the way.

Regards
Ray

[BenM78]

We get small run castings done at work, not cheap but I'll find out who does them if you like?

[.RC.]

Is there a difference between cast steel and cast iron?

Cast steel is exactly steel, but rather then rolled into beams and rods and billets is instead cast into shapes...

Cast iron is well, cast iron....

There is a third and fourth option..... They could be drop forged... But I would well imagine drop forging back then would have been a very expensive thing to do if it was even invented back then... Drop forging is the forging of steel between machined dies...

The fourth option is malleble iron castings.... Malleble iron is items cast as cast iron, then they go through a heating process in controlled conditions where most of the carbon is removed... resulting in a ductile iron metal...

[jhovel]

There is a foundry in Bendigo that does ONLY cast steel. If you get the pattern sorted out, I could get a quote.
To put the difference of cast iron vs. cast steel vs. forged steel into perspective for this application (and simplistic terms), cast iron is brittle and won't tolerate much in the way of bending or shock before it cracks and falls apart, whereas cast steel has the ability to tolerate both bending (and will spring back up to a point) and shock.
Forged steel is "pressed" into the shape very hot by either a huge press or hammering. It has more inherent strength than the steel it was forged from because none of the 'grain' of the metal is cut or disrupted in the process and it is made 'denser' by forcing the molecules closer together.
None of this is technically entirely correct, but in practical terms it makes some sense.

Joe

[wgipps]

Thank you guys. Ill tell you what im thinking.
1 - Get some better pictures of the parts.
2 - look at getting some 3D modelling and/or rapid prototyping done
From there, i can identify what process i need to employ and get some quotes.
How does that sound?

[matthew_g]

I have a mate here how has not long sold his "T" Ford. I have just emailed him this thread, If he has any info he will get back to me and I can pass on Phone numbers and things.
He restores many classic cars and has a nack of finding rare bits and pieces..I spose it helps that he ownes a car yard as well...He also does a bit of importing in that area as well.

[franco]

Cast steel is exactly steel, but rather then rolled into beams and rods and billets is instead cast into shapes...

. They could be drop forged... But I would well imagine drop forging back then would have been a very expensive thing to do if it was even invented back then... Drop forging is the forging of steel between machined dies...
..

.RC.

Drop forging was alive and well long before 1917. If I can find it I'll e-mail you a copy of a description of drop forging Overland crankshafts from an Overland publication from 1912. It would really make a modern safety officer's day!

At least the pedestal in the photo which supports the rocker gear on the head looks like a forging to me.

Frank.

[4-6-4]

Dear WGGIPS ifr you want you can come and see me at Newport Railway workshops one Saturday and I will fill you in. The major problem here is a pattern If I can see the bits then I would be able to advise you. The problem in using existing castings for patterns is firstly the rate of contraction. ie the new casting would be slightly smaller that the original. Secondly the method of casting. Foundries do not like being mucked around. It is all pace now and I would be able to tell you the methods of making it easier for the foundry. to let you know my background I went to RMIT Patten Making and Foundry school for 13 years. I also worked there as a pattern maker and a Moulder. I ran my own non ferocious foundry so if you want advice contact me. Yours 4-6-4

[wgipps]

if you want you can come and see me at Newport Railway workshops one Saturday and I will fill you in.
I would be happy to take you up on that. i hope to get onto the engine tomorrow and pull one of the rocker sets apart and photograph it.

[wgipps]

All
As promised. Its 3 pieces not 2.
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2724.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2723.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2722.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2721.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2720.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2719.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2718.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2717.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2716.jpg
http://i658.photobucket.com/albums/uu304/wgipps/Model%20T/CIMG2715.jpg

[franco]

Nice clear photos. My guess having seen the individual bits is that they are all cast steel - will be interested to see what the experts say. The heads must have been fairly expensive to produce.

Frank

[Stustoys]

My guess is the rockers are forged but the pillar(?) is cast, because I think the thickness change around the mounting holes(can't remember what thats called atm) would be hard to forge. Could the be bronze? its a funny color around one of the holes it you zoom the picture up a little.

Still what I know about forging would fill a very small book :D

Have you put a magnet on them?

Stuart

[eskimo]

is this a possible alternative..
do they need to be cast?...if all the geometry is right for bearing and contact surfaces etc etc......could'nt they be machined from a solid piece?

going by some of the machining pics I see on here it certainly should be possible for you guys to do this to keep that beautiful old racer on the road

yes I know it wont look like the original...but it may get you out of trouble

and if you are in accord, you can remove the existing originals and use the machined stuff now, while allowing for re-installation later so that you can at least say the "engine has all working original parts"

[wgipps]

the pieces are magnetic

[RayG]

Hi Glen,

I can see parting lines on some of the pictures, so the originals were cast, but from what?

Best guess would be a steel alloy of some sort, but the shiny colour is a bit confusing, is it possible they have been chrome plated, or nickel plated? Before plating they usually put a layer of copper down, that might account for the colour Stuart is seeing in one of the holes.

Have a talk with 4-6-4, he knows more about casting and pattern making than just about anyone, he will have some ideas as to how the pattern was made... too complex for me.. :)

Regards
Ray

[Pete F]

the pieces are magnetic

They're certainly cast and I think they would be cast steel in that application. Have you read through this article, I haven't had a chance to read it through as yet, but I would think it may contain the answer.

http://www.nwvs.org/Technical/MTFCA/Articles/1804OHVs.pdf

Pete

[Stustoys]

Hi Ray,
Chroming sure would explain the funny color :doh:.



Don't forged parts have flash/trim(?) lines?

The motor on page 23 of Peter's link has "drop forged steel rocker arms"(its not the same rocker though, 14hp!)

Stuart

[RayG]

Hi Stuart,

Hmmm...could be drop forged I guess? Just going by the rough surface finish (in the areas that aren't polished) looks like sand cast and the placement of the parting lines looks like it's a casting.

So the process might be...
1. Cast from a heat treatable alloy, ( I see mention of high tungsten steel in that article, so could be a type of HSS)
2. Heat treated hardened and tempered
3. Ground and sized.
4.Copper plated, then Chrome or Nickel plating
5.Probably lapped to final dimensions..

I tried to work out what the patterns would look like to see how they could be cast, It would be a pretty complex multi part pattern and several cores.... (4-6-4 Help!)

If it's a function replacement that's required, I think I'd be going with a cnc machined part from some suitably tough alloy and heat treated.

On the other hand if it's a replica part, that's required.... :)

Regards
Ray

PS... Seeing as it's only a few required, I wonder if lost wax, might be a better approach...

[Pete F]

Hi Stuart,

Hmmm...could be drop forged I guess? Just going by the rough surface finish (in the areas that aren't polished) looks like sand cast and the placement of the parting lines looks like it's a casting.

Agree ray, the rough texture sure looks cast to me. Also the cast in number and flash. I was wondering what the shrinkage is like on a part this small? Would it be possible to coat the part with something to increase its volume and then use it as a pattern? There's no real details to be lost and I think it's only a few percentage anyway. While it may not be quite perfect, I would guess it could be made relatively close.

Pete

[.RC.]

Another vote for cast...

[wgipps]

Have you read through this article, I haven't had a chance to read it through as yet, but I would think it may contain the answer.
]http://www.nwvs.org/Technical/MTFCA/Articles/1804OHVs.pdf

Aside from the casting and the issues on this thread - thanks for this article Pete - i recently saw a Laurel 16 valve engine and started quite a discussion on it on model T land - nobody had seen or heard of a Laurel 16 valve engine before. This article identifies them and their genesis!! Thanks again.

[clear out]

Have you thought of making a mould from these and you could then get them investment cast when/if needed.
Add a bit of machining by supergluing on some ply to the appropriate faces, you can even lead or wax wrap bits re contraction.
A mate in Brisbane was making moulds for the waxes in epoxy filled with Al.
He made a few woodys tools, squirrel tailed planes in bronze and stainless,trammels and a marking gauge.
Called himself the Bowsaw Tool Co.This was in the late 80's early 90s.
This was for production you may get away with silicon if boxed properly for a few off.
Hicast? here in Sydney does a range of metals. This process is used in the defense and aircraft industries so the strength and tolerences are achievable.
H.