Intake Manifold Forming Aluminum over Wooden Buck

[bahtenduh]

Hello everyone. Looking for a little advice from the experts. I am attempting to make a custom intake manifold for my engine. The stock manifold is a 2 part with a lower part with long runners and an upper plenum. I am hoping to replicate something like this.




I have made a wooden buck to use to form the aluminum over. I was thinking of 3/16 or 1/4 for the top part which will be formed over the buck and 3/8 for the base plate that will bolt down to the lower piece. The base plate will need to have some machining done. These 2 pieces will need to be tig'd together. This is a boosted application so it will see at the MOST 30psi. I doubt i will ever push anything like that but better safe than sorry.

So my questions are what alloy would you guys recommend and do you think my thicknesses will be suitable. I was thinking of 6061 but then i was quoted by an online metal supplier to go with tool and jig plate. However i read somewhere that this tool and jig plate is not good for vacuum/boost applications. I am also curious about tempering the aluminum. My father mentioned that after tempering the aluminum it becomes softer and easier to form. If anyone has any links or advice about this i would really appreciate it.

Here are some pics of the wood buck from various angles to show what kind of bends will need to be made.













Thanks in advance.

Matt

[tstom]

Most sheet metal manifols are made from 3003 H14 We use .090" for naturally aspirated I think you will have trouble forming anything as heavy as 3/16" and up by hand The only way I think you can form 6061 is to use T0

[bahtenduh]

Thanks for the reply.

Annealing was what my father was talking about. That would get the metal to the T0 temper correct? If i did anneal the 6061 i would have to take it somewhere to get tempered back to the T6 or so temper for strength correct?

I am not set on any certain alloy so i appreciate the input for the 3003. I really want to get as much research done beforehand before i purchase some AL to beat on. I read somewhere (maybe on here) that someone used a pneumatic hammer with delrin hammer ends on it to help shape the metal. Not sure if that would make the thicker material that much easier to form or not.

[tstom]

I don't think you'll find a hammer big enough for 3/16-1/4 material
think if you design it right .125 should be plenty even fo 30 lbs boost
scroll down on the page linked here to see some V8 manifolds we have done
http://www.hemphillracingengines.com...ll_engines.htm
I don't thing the T6 condition is a big concern and may be a detriment.....can crack easier from engine harmonics ..especially in a 4 cyl.

[ViperTX]

I would opt for hallowing out the maple block and doing a sand casting and fabricate and weld the base plate and flange.

You might save some time if you made your model from foam and did a lost foam casting.

Paul

[mc-motorsports]

Good reading:
http://www.cnczone.com/forums/showthread.php?t=73019

Will answer most of your questions, and .090" 6061 is your best bet, probably go 3/8" for the bottom plate that needs machined.

[bahtenduh]

Hey thanks for the replies guys.
I think i have decided on 3003 H14 0.125 for the part that will be formed and then 3/8 6061 for the base plate that will bolt to the lower runners. Did a little more reading on the annealing process and my father just got his acetylene torch gassed up again so i will have that at my disposal also. Gonna try and go to the local metal supermarket maybe tomorrow and pick up some material. I'll update with progress.

[mc-motorsports]

3003 is not heat-treatable. Can't anneal something that isn't hard. And yes, .125 is good for 3003, it's not as strong as 6061.

If you want to use all 6061 and your worried about the temper, heat it to 980* and drop it in a bucket of hot water, will go right back to T4. Artificially age it at 350*F and you'll get T6, but it's not going to matter that much.

[bahtenduh]

From my understanding from doing some research last night is that the 3003 alloy can be annealed and then it will be "work hardened" as it is getting shaped from the forming process.

[mc-motorsports]

And how's it going?

[bahtenduh]

Going to pick up the sheet on wednesday. I'll see how it goes from there. I'll post some pics either way it works out. I ordered 3003 .190 for the part of the manifold i'll be forming and 6061 T6 for the base plate. I have Wed-Fri off so i should get somewhere with it. Thanks for asking.

[svenakela]

If it gets too troublesome to form the alu, you could form it halfway and then add the sidewalls separately. What I mean is to shape the domed part as one piece, the sides as one piece that you wrap around the wood sides and then weld the dome on top.
I hope you understand what I'm trying to explain.