Making my own EFI intake... The casting begins!

[Derek]

Now that the design stage is done It's time to start the casting process. If you need to come up to speed on this here is the original post. http://forums.hybridz.org/showthread.php?t=121021

I''m going to make a separate pattern for the front manifold and a separate pattern for the rear manifold.

I'll also make a core box for each as well. Here's a picture of the cope (upper) side of the pattern.

And here's a shot of the drag (lower) side

 

 

 

The gold colored areas are the core prints and cores. Cores are what makes a casting hollow. Prints are what holds the cores in position. The magenta areas are gates and runners. Normally I try to put these in the drag portion of the mold but because of the orientation of the part I need to have them in the cope. Most foundries like to do their own gating so I'm not sure if this will be the final design. Sometimes you have to pour one to see what you get. The metal will enter in the magenta section just behind the head flange. I'll cut this pattern with a ball end mill so all joints will have a fillet. For that reason I don't take the time to draw them in.

 

 

As a side note can any one tell me why I can't post attachments? I've sent several messages through the contact link at the bottom but haven't received a reply.

 

 

Thanks

Derek

[240Zed]

 

As a side note can any one tell me why I can't post attachments? I've sent several messages through the contact link at the bottom but haven't received a reply.

 

 

Thanks

Derek

 

 

Maybe the image size is too big, or the file size is too big.

try resizing them to a smaller image.

[Derek]

Maybe the image size is too big, or the file size is too big.

try resizing them to a smaller image.

 

Actually I just looked down at the bottom and it now says "you may post attachments" and it used to say "you may not post attachments" so I'll try to edit the post.

Thanks for making me look!

 

Derek

[Chemicalblue]

Are you going to make this a production pattern or just a test plate?

What media are you using for a mold and core?

[Derek]

Are you going to make this a production pattern or just a test plate?

What media are you using for a mold and core?

 

The pattern is plastic on wood which would put it in the low production category. The foundry I'm using on this job molds with Olivine sand which will give me a really fine finish. The cores will be done cold box with a Furan bound sand. He's going to hand work the core seams before he pours so the part line on the inside of the throttle body will be minimal. If there's interest I'll make the raw castings available. I'm not set up to do production machining so I'll only be offering unfinished castings.

 

 

Derek

[Chemicalblue]

Cool , I was going to suggest pep-set with a acetylene smut on the surface, but a good molder can make a pretty fine finish. What do you want for your as-cast parts? Sounds like fun.

[Derek]

Cool , I was going to suggest pep-set with a acetylene smut on the surface, but a good molder can make a pretty fine finish. What do you want for your as-cast parts? Sounds like fun.

 

The guy doing the molding has over 30 years molding experience. He doses awesome work. This is such a declining industry so good hand molders are just not that common anymore. I won't have any prices until I get the first one cast.

 

 

 

 

Derek

[Derek]

Your looking at the bottom of the front manifold. This is the final roughing cut ready for the finish passes. The pattern is mounted to a sacrificial bottom plate. I'm using corian scraps (free) for the pattern material.

 

 

Derek

 

[Tony D]

Coooool!

[Derek]

Here is the pattern after the finish passes.

 

 

Your looking at about 7 hours of machining time just for the finish machining. You CNC types out there might be interested to know there's over 300,000 lines of code!

I still need to fill and sand a couple spots but I'm really pleased with the way it turned out. I'll rework my cutting strategies for the top sides so I have a better finish. Here's a shot of the bosses.

 

 

The large one is for the throttle shaft bearing. The smaller ones on either side of it are for the idle air bleed fittings and the outer ones are for a heat shield. I put drill points on the smaller ones because I don't plan on doing a bottom setup on the machining so I'll use a hand drill on those.

 

 

Derek

 

PS You may notice the Corian colors don't match the first picture. Well I had a bit of a problem with a cutter and it was just easier to start all over.

[Tony D]

You were right, Derek! I stumbled across a small foundry in Costa Mesa that was agreeable to do the pours if I can supply decent forms or cores. So my job just got a bit easier as well! Thanks for that suggestion on finding one---strange thing was I found it looking at a Citroen DS, that revealed three Renault R5 Turbos, a Twin Turbo Motec'd Diablo, and an LT-1 conversion in progress on a Ferrari 412...as well as a complete 510 Racer that was up for sale. While looking at the 510, they started knocking out sand, and it was like "Oh, hey, that's a short-run foundry!" Right there, passed it countless times but never ventured to the back of the complex to check anything out. But that DS was calling me....LOL

[Flexicoker]

Wow! That looks really cool! What size endmill did you have to use for finishing? What did you do the programming with?

[Derek]

You were right, Derek! I stumbled across a small foundry in Costa Mesa that was agreeable to do the pours if I can supply decent forms or cores. So my job just got a bit easier as well! Thanks for that suggestion on finding one---strange thing was I found it looking at a Citroen DS, that revealed three Renault R5 Turbos, a Twin Turbo Motec'd Diablo, and an LT-1 conversion in progress on a Ferrari 412...as well as a complete 510 Racer that was up for sale. While looking at the 510, they started knocking out sand, and it was like "Oh, hey, that's a short-run foundry!" Right there, passed it countless times but never ventured to the back of the complex to check anything out. But that DS was calling me....LOL

 

 

That's great Tony

The most important thing to look at is “are they pouring scrap or ingotâ€.

If there's piles of old wheels and pots and pans around then use caution. The two main foundries I work with use nothing but virgin ingot. This plays a big part in end quality and machineability. Nothing worse than putting a few hours into finishing a casting only to hit a piece of crap.

 

 

Derek

[Derek]

Wow! That looks really cool! What size endmill did you have to use for finishing? What did you do the programming with?

 

Thanks

I used a 1/4†ball mill for the finish pass. I used Rhino to design the part and Visual Mill for the cam programing.

 

 

Derek

[Sven]

Derek, that is awesome. I'm very interested in how much this will cost you. Is it going to be remotely affordable for you? I've had some indeas for things I'd want cast, but always assumed it was out of reach for the ordinary joe.

 

Very impressive.

[Derek]

Derek, that is awesome. I'm very interested in how much this will cost you. Is it going to be remotely affordable for you? I've had some indeas for things I'd want cast, but always assumed it was out of reach for the ordinary joe.

 

Very impressive.

 

Hi Sven

I would normally charge around $5000.00 minimum for a set of tooling of this complexity. Probably more considering I'm doing all of the concept and design work as well. But everything is relative in that I'll have a ton of time in this before I'm finished. I'm lucky in that I have enough free time on the machines that I can sneak it in a little at a time.

 

Fortunately the first set of castings are free because I'm friends with the foundry. After that I'm not sure what they're going to charge.

 

 

Before I started doing patterns I assumed I needed to pour my own metal because none of the foundries would want to mess with me. Then I came to find that there are quite a few small foundries that are more than happy to pour small runs. Especially if you pay cash! The only thing is they can be leery of working with novice pattern makers. If he gives you a price on a piece and they have to ram it up 3 or 4 times just to get a good mold they're not going to be very happy. Most small foundries are hurting right now so you won't have much trouble finding one that will work with you.

 

 

Derek

[MONZTER]

Hey Derek,

Nice pattern. Do you have to account for shrink by making the pattern oversized? If so by what percent? It always looks like the Cannon manifolds have shrunk and are too short when you try to line them up with the ports. Could this be why?

 

Thanks Jeff

[Derek]

Hey Derek,

Nice pattern. Do you have to account for shrink by making the pattern oversized? If so by what percent? It always looks like the Cannon manifolds have shrunk and are too short when you try to line them up with the ports. Could this be why?

 

Thanks Jeff

 

 

Thanks

 

Yea shrink can be a real problem. Sand casting metal is still a black art. There are many areas that can affect the size of the part. I usually use 3/16†per foot for shrinkage. Old school “saw and sand†pattern makers use shrink rules that are oversize rulers. I simply scale my model in 3D space and I'm good to go. Hitting all six ports on the first try with a single manifold would be tough. On something like that I would put in extra money to adjust the core box after we poured a few. This is why I'm casting mine in two separate pieces. I also made the final diameter where the port meets the head a little smaller. I'm going to machine a jig plate out of steel that will match the ports and bolt pattern of the head. I'll clamp that to the manifold and use it to drill the mounting holes and match the ports. If I cast anymore manifolds to sell I'll adjust the core boxes accordingly.

Most patterns need a little adjustment after the first pour. I do a lot of replacement parts for old cigar making machinery. The plans I get are from the 40's. I'll make the pattern exactly like the print and the final part will always be off a little. I think there were a lot of changes made on machines back then that were never reflected on the plans. Probably a case of the machinist walking over to the pattern maker and saying “ move this boss over .050†and never telling engineering!

 

 

Derek

[MONZTER]

Thanks for the reply,

Sounds like a case were there is no substitution for experience, and patients

Jeff

[e_racer1999]

nice! i await the result!