Magnum Exh manifold machining.
- Thread starter Cuda416
- Start date
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69_340_GTS
Well-Known Member
Unless these are somehow special, you can buy a pair of new aftermarket (Dorman, etc...) ones for around $200-$250.
Cuda416
Well-Known Member
I have an idea what might work. Thinking about the flattening jigs woodworkers use for getting a table top or other surface flat using a hand router. Basically they build a movable gantry/carriage in which the router sits, then they simply place it over the work piece and pass the router over a billion times and end up with something that matches the plane of the carriage.
I could mount a 4" grinder onto a carriage like that and as long as everything is locked into place, just keep sliding the grinder back and fourth until the material is removed. Like a hillbilly surface grinder.
-=C
I could mount a 4" grinder onto a carriage like that and as long as everything is locked into place, just keep sliding the grinder back and fourth until the material is removed. Like a hillbilly surface grinder.
-=C
69_340_GTS
Well-Known Member
Well that's a lot more than I'd imagined. I thought you were just trying to get them flat? edit:"Shave", to me, means a few thousandths, like 0.005" or something.
Yep, a 1/4" is a lot.
Cuda416
Well-Known Member
They have the 2-1/8" outlets so in a way, they are "special". Using them for a magnum into a 65 valiant swap. Everything I've read where people have done it, they "wish" they;'d taken more off than say 3/16. That's where the 1/4" comes from.
69_340_GTS
Well-Known Member
I think there are parts of the head, or even the block, that may interfere if you take 0.250" off those flanges. I know I had to grind a little on my LH head for clearance, and I'll bet we only took .020" off my manifolds.
Cuda416
Well-Known Member
gzig5
Well-Known Member
Stranger things have been done, it could work. You should be able to hog most of the material by hand and use the fixture for the last bit, but it will take some time and you'll have to nibble at it. I've seen guys grind hardened lathe ways by mounting a grinder on a sled and running it up and down the less worn tailstock ways. Those jobs ended up at a couple tenths of thousandths over several feet.
Cuda416
Well-Known Member
Sort of my thinking as well. Should be "good enough"...
Parks engine service. Seguin, Tx
830-379-4562
They have resurfaced exhaust manifolds for me before.
Cuda416
Well-Known Member
Cuda416
Well-Known Member
Called them and they mentioned they'd done it before. Gonna bring the manifolds in on Monday and see what they say.
Thanks!
-C
No problem. That is where I get all my machine work done. Been going there since the mid 90's.
Jmill67
Well-Known Member
Just wondering how your exhaust manifold machining turned out?
Cuda416
Well-Known Member
It's been put on hold. We're going to use the 273 manifolds for the time being.
Jmill67
Well-Known Member
My son James is working on his first Mopar and needed some manifolds. I happened to have a pair in the shop. The left side was machined because it was so close to the steering column. The thing is, you can’t take too much off because of the center bolt hole mounting flanges. They’re only 7/16” thick. We ended up taking .150” off.
Jmill67
Well-Known Member
Cuda416
Well-Known Member
Yup, my estimate above of how much I need to remove was way off. Probably more like .180 to .200
Jmill67
Well-Known Member
Ported the center divider as well.
Cuda416
Well-Known Member
Jmill67
Well-Known Member
This is in his 69 Dart, 318 with manual steering. Since the pic was taken, he made a small aluminum heat shield. So far so good. He might do the lower bearing upgrade later on. NOTE: before the machining, the corners of the steering coupler were just barely touching the manifold. Not any more.
69_340_GTS
Well-Known Member
You could also try moving the column over. There is a ton of slop, usually.
Jmill67
Well-Known Member
That’s good to know. We’ll give that a try.
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