Forming aluminum intake runner?

[jon volk]

I need to build a sheetmetal intake manifold for an application where the cylinder head port is a very elonged rectange shape. What is the best way to form aluminum like the runners in the attached picture? I know it can be done by hand with a wooden buck or perhaps making a die for a hydraulic press. Both of which are very time consuming although making a die seems like it would be quicker for making many pieces consistently the same.

Any suggestions on the best way to go about doing this...especially when having to differnt runners for various applications?

Thanks!

Picture taken from rossmachineracing.com ....i circled the piece in question.

http://www.666fab.com/runner.jpg

[rookie]

Hi Jon. I suggest carving (sanding) wood runners first then hammer/shape the runners in two pieces then weld together.

Phil

[HotRodKid]

theres not a gret number of ways to make thing like this, and you prolly listed the 2 easiest anyways

usualy wooden hammerform bucks are spent after 20 pieces, and dies can last much longer ..

so depending on how many your making ...

[anders nørgaard]

Hi Jon. I suggest carving (sanding) wood runners first then hammer/shape the runners in two pieces then weld together.

Phil

Hi Phil,
Yes... or take 2 pieces of pipe/tubing that fit the inside diameter of the runner. Bend to shape and weld together, side by side.

Press- or hammer form in two pieces (upper and lower).
Weld together.

Jon,
What gauge are we talking about.... 10....8?

[rkilgore29]

Hi Jon,

You touched on the two primary methods for forming intake runners. For just a few pieces for say a single intake you can get away with hardwood hammerforms. If you want to produce multiples of a particular manifold then making a simple push through die and pressing them on a hydraulic press is the better method. The process is still simple as long as the runners are straight, tapered runners are a different matter. They can still be done, but there is a lot more effort in making the male portion of the die.

A simple way to make the male portion for a straight runner, take that to mean the ID is constant throughout the length, is to take a length of round stock with an OD equal to the ID of the runner and heat it to bend it into the shape of the profile of the runner. If the flat of the oval is too wide to get away with just using the round section then weld on a couple of lengths of flat stock to create the flat walls. Groom and polish the male as required to give you a nice smooth part. The female portion of the die can be cut from solid plate stock or fabricated using flat stock bent to match the profile of the male and boxed in to build some strength into the die. The bad news is that these methods all take time. For that matter building intake manifolds is labor intensive, which is why many are cast even for short runs. I have built a significant number through the years and while you do get quicker on successive repeat parts, they all start out slowly.

Good luck with the project, they are very interesting to build and satisfying to complete.

[jon volk]

Thanks for all the quick input. It is 8guage aluminum that Im using. Its for an inline 6 cylinder so there needs to be at least 12 halves.....it may end up being a production piece if it makes decent power so I guess the die for a hydraulic press is definately my best option. Every good thing takes time 8)

The aluminum should of course be annealed prior to any forming right?

[rsanter]

I have always seen the wood buck the desired shape and size of the inside of the runner and then hammering the two halves over it and welding together.
I would think you could also try to find some extruded material that could be your desired size

bob

[87gtmustang]

Could you take some tubing and put it in a press to partial flatten the tube to were you need it, to make it oval? I would think that would work well, and would be fast too, once you make one or two. If it has to be bent as well, I would think you could bend the tubing either before or after, which ever has a better result. If bending before though, you would have to flatten it in probably at least 3 spots with a small area die to prevent unbending the tubing.

Brian =)

[hardtailjohn]

I was thinking somewhat on that same line, Brian...but maybe multiple passes on a roller setup with the proper profile... like a ring roller? I was told that was the way they made the oval shaped steel tubing on my Bellanca Cruisair tail feathers.
John H.

[87gtmustang]

Yes, that would be an even faster and accurate setup once one figured it out. You may be able to roll the curve, and flatten the tube all together in a roller.

Jon, Let us know if you try any of these ideas, and let us know how they turn out. Pictures are always welcome also.

Brian =)

[Boogiemanz1]

Hi Jon, lots of ways to approach this, If the part is curved, I would find some aluminum tubing with the proper inside diameter. Use a bender or buy prebent curves to get the shape you require. Take the bent tubing and slice it through the middle on a band saw or what ever means you have available.

Take your two half curves and add the correct amount of aluminum sheet metal between the halves to equal your desired part.

This probably isn't the way to go into production , but for R&D it allows you to easily change ID's and widths without building dies until you need them.

If the part is not curved try to find some soft alloy tubeing and roll a flat top and bottom.................john

[fordguyfordman]

Hi Jon,
Another idea is to use flat stock. Cut the radius you require for the sides then roll flat stock for the top and bottom. Next weld all 4 pieces together.
Might not be the final effect you want, but if it needs to be changeable this is easy to do.
o.k. that's my 2 bits. Tom

[Ron G]

Jon
The guys that owned and built a Bonneville streamliner that I used to crew on built their own manifold. They had pieces cast that had about the same curve as yours to transition from SB Chev heads to horizonal and from round tube to Chev port. They also had to be thick enough to O-ring on top for sealing. They were then welded to plate to form the manifold.
I think you could make 4 patterns of the runner interior and cast them using the lost wax process. I have no idea how expensive it is, not much to it, just needs the right equipment.
Ron