Maybe on thin ice on this job.

[GK1918]

The job is a 6cyl cast iron exhaust manifold comming in as soon as they remove it. Another can not be
found. These were always sent out to be surfaced, hard to beleive there is nobody around doing that
anymore. Game plan, I think a fly cutter is out. Use and end mill. Come up with special shop made
clamps. Use plywood on the mill table. I have got a junk manifold first to try on. I already have made
several tall machine jacks and 5/8 tee nuts. I do not think it doesnt have to be perfectly trammed, just
close, cause I plan to mill all three exaust ports along with intake ports, as long as it is fairly flat. I looked
at it and a couple exhaust ports they doubled up gaskets. (so its a gasket blower). I asked around
as far as using plywood or sheet metal strips I dont want this rusty thing on my table, and most say it
should be ok. Or maybe knock down the high ports with a flap disk getting rid of most of it? This is not
an operation we do. Shame 20yrs ago Napa did this all the time. IH gas job tractor looks like a Chevy
6. I figure to level it on its ears with jacks/ blocks and wedges underneath / blocks and jacks have to
work together to clamp so not to break the ears. Take my time, light cuts. Can anyone add an idea
samuel

 

[R_Audano]

Good Luck... it's always frustrating to spend hours to set up for a 10 minute cut. I do know some folks have better luck with a horizontal on a manifold of that size as it provides more leveling and clamping surface area. I once made a fixture to surface a bunch of 8v Detroit manifolds but the one-off jobs dont justify that! If you have the table area and z axis space, think about large angle plates and plenty of clamps. On short manifolds, many shops are using belt grinders with a large platen. If You go with the belt grinder method, remember the ends always get more attention due to the inherent dwell time.

Robert

 

[Ray C]

Have never done one before but here's a thought...

Do it in two stages... Build a fixture that you can bolt the manifold to just as though it were on an engine, but leaves half the ports exposed for you to work on. Clean-up the first half then re-mount and catch the other half. Of course, the fixture would be made to easily clamp to the table. There would be a little "eye-balling" on the first setup.

Just taking a WAG... Dismiss as needed...

BTW: I've done a couple cylinder heads and I never hesitate to TIG fill if it makes the overall job easier.


Ray

The job is a 6cyl cast iron exhaust manifold comming in as soon as they remove it. Another can not be
found. These were always sent out to be surfaced, hard to beleive there is nobody around doing that
anymore. Game plan, I think a fly cutter is out. Use and end mill. Come up with special shop made
clamps. Use plywood on the mill table. I have got a junk manifold first to try on. I already have made
several tall machine jacks and 5/8 tee nuts. I do not think it doesnt have to be perfectly trammed, just
close, cause I plan to mill all three exaust ports along with intake ports, as long as it is fairly flat. I looked
at it and a couple exhaust ports they doubled up gaskets. (so its a gasket blower). I asked around
as far as using plywood or sheet metal strips I dont want this rusty thing on my table, and most say it
should be ok. Or maybe knock down the high ports with a flap disk getting rid of most of it? This is not
an operation we do. Shame 20yrs ago Napa did this all the time. IH gas job tractor looks like a Chevy
6. I figure to level it on its ears with jacks/ blocks and wedges underneath / blocks and jacks have to
work together to clamp so not to break the ears. Take my time, light cuts. Can anyone add an idea
samuel

 

[rgray]

I would leave the intake out of the the set up or mill it seperatly. not sure if you ment mill them at the same time or not...that would be a nightmare.
They don't have to be the same height....(maybe stating the obvious)
That old cast exhaust is going to be rotten and brittle most likely.sometimes they just crumble.

 

[8ntsane]

I have resurfaced many cast iron manifolds, and have found the belt sander does a nice job, and quick to do.
Im talking about the belt sanders that are mounted on a stand, not the type you hold in your hands.

 

[Tamper84]

I'm in. I would love to see how this is done. Often wondered, but I would like to learn

Chris

 

[schilpr]

I have resurfaced many cast iron manifolds, and have found the belt sander does a nice job, and quick to do.
Im talking about the belt sanders that are mounted on a stand, not the type you hold in your hands.

Yes, large belt sander is the answer

 

[GK1918]

Thanks all, I actually spent more time back and forth to the hardware store, for more 5/8 threaded stock.
I then used three standing ,up, tee nuts washers & lock nuts. Blocks wedges, put a level- got it good.
clamped it. Then made reference to the highs and lows / 1/2 end (4) end mill. I didnt use an indicator
(dont want it on that) Raising the knee sneaking up on the highest, manually took that one down,
then the next and so on until I got a not bad. Here goes- dialed in about .020 power feed on, let her
rip. My kids insisted on fly cutter, no, I have more control with end mill cause things happen to fast with
fly cutter. I probably took a good 1/8 off.> lowest good port is reference point. Now with nice finish I put the dial ind. and all are right on target. I did cut pieces of rubber to put on the table. I took pics. and
here we go again. (no camara detected ) as soon as I figure dastardly PC ill post them. Good thing is
I end up with more tee nuts bolts and stuff.

 

[GK1918]

Beleive it or not, but these pictures took longer to get that to machine the part. Been working 3hrs just
for a couple pics. Seems I download or upload whatever its called, I want to send to "My Photos"
and it sends itself deep in the bowels of this thing. I do it again its says photos already exist. OK so
where. Do it over and over till the batt. goes dead. finnally anyways job came out well, pretty simple
setup. My leveling setup is using 1/2 of the tee nut threads to adjust then tighten locknuts until all are
even and level, I know my table is level so that got me in the ballpark by using a common level across the
ports.

 

[george wilson]

I had to machine a NOS International Harvester manifold for a local guy. The manifold had warped so that the openings were not well aligned. I carefully clamped it to my Bridgy so as not to warp the pipes,and managed to mill them flat. I didn't have a large belt grinder that would encompass its length.