sen2two

for the first real post in this section is kind of a tough one. but maybe someone will know...



im going to make a turbo manifold for my car. lets say i wanted to make that same exact one again because it cracked, or my other car needed one, or i sold it.



how would i go about making a Jig to duplicate that same exact set up?

mazdaspeed7

For any jig, you want it strong enough that the piece you will be welding on it will not cause the jig to flex or deform. It may not be noticable at first, but the problem will snowball, and after so many pieces, the jig will be so far out of tolerance that any pieces made on it will no longer fit. Fiberglass molds are especially susceptable to this, which is why most aftermarket fiberglass body kits dont fit worth a crap.



For a turbo manifold, especially stainless, Id stick to 1/2" plate for where the flanges go, and something very strong between them. The exact design will be determined by the header design, i.e. you dont necessarily want to use 1/2" plate to span the distance between the flanges if you are making a manifold where the turbo sits a foot away from the engine. But it would work well for a stock fitment manifold. for longer reaches, a few pieces of heavy wall tubing(1" OD x .120 wall for example) would work well.



The easiest way to make a jig is have a part already that fits. If you are doing a custom piece, like my engine mounts were(the truck mounts), make the first set to fit. I had the engine sitting in the truck where i wanted it, and I cut and trimmed and welded and repeated until the mounts fit like i wanted. Then I made a jig off the first set of mounts so I could reproduce them quicker and easier. For the FC REW mounts, I assembled a mock block with an fc center iron and an FD rear iron. I built a jig that bolted to the center iron that mated up with the mounting surface of the stock mounts. Then I drilled through the jig where the slot in the stock engine mounts was so I could mark where it needed to be on the new mounts. Once the jig was done, I unbolted the stock fc mounts, mounted an FD oil pan on my mock block, and I use that for making my mounts. The engine is a very rigid base, so I never have to deal with flexing. It also dissipates heat quickly so i dont have to spend a lot of time waiting on the mounts to cool. But even still, I only tack weld the pieces on the jig, and take them to my welding table for final welding.



The purpose of a jig is to offer fixed "hard points" so any pieces made on it will fit predictably. Hard points are external things that define the fitment on the piece you are making, such as bolt locations, exhaust port locations, turbo flange dimensions, other mounting points, and things that need to accounted for to achieve adequate clearance. I usually use pins of the same diameter as the bolts to locate bolt holes on the jig. You can either drill the jig slightly undersize and tap the pins in, or you can drill it and weld the pins from the backside. Either way works well, the latter probably being a little stronger in the long run, but harder to replace if the pin gets damaged.



For your specific manifold, I would cut out some 1/2" plate to relatively the size of both the manifold and turbo flanges. A little oversize, but not so big as to get in the way. Mark those flanges for the bolt holes, and install the locating pins. With both of the flanges done, clamp them to their respective locations on the part, and determine exactly what you need to do to span the 2 jig flanges(or more if an external wastegate is used). Be sure the locating pins are not located such that the part will not be able to be removed. In some cases, you may need to have the pins easily removable to be able to get the piece out. A good option for that case is to drill and tap the jig flanges, and actually bolt the part to it as its being fitted and welded.







Here is my jig for the FC REW mounts, with a set of the mounts in place.

sen2two

thanks! thats some good info. nice work too...



i have a basic idea in my head now too. i just have to build it. thanks again for the informative responce.

sen2two

check this out... http://www.hobartwelders.com/weldtalk/show...ed=1#post327820



for making a tubular style jig. pretty simple...