YYC - Resurface turbo exhaust manifold

PeterT

Ultra Member
Premium Member
I think having the abrasive attached to the surface would be the preferred way. You could check into sanding belt like 6" wide by whatever length & split so its a continuous uninterrupted abrasive surface for the entire push pull stroke. You could just use felt pen cross hatching across the manifold surface to monitor how the removal is going. I'm not an auto expert but guessing cast iron might be significantly harder on the abrasive than some of the vids showing alloy heads. So maybe not all belts would make the grade?
 

phaxtris

(Ryan)
Premium Member
Premium Member
On man your going to be at that for a month of Sunday's with 120g by hand and It'll probabaly just make it real shiny

Cast iron isn't aluminum, 120 is hardly going to make a scratch never mind take off half a mill

I suppose a guy could do it in two passes on a smaller mill, just a lot more setup time

Or just pay an engine shop 100$ to do it
 
On man your going to be at that for a month of Sunday's with 120g by hand and It'll probabaly just make it real shiny

Cast iron isn't aluminum, 120 is hardly going to make a scratch never mind take off half a mill

I suppose a guy could do it in two passes on a smaller mill, just a lot more setup time

Or just pay an engine shop 100$ to do it
What nobody here has a mill at home?

I still would prefer to keep this within the hobbies community. but yeah Cast iron a much harder material than aluminum
 

terry_g

Ultra Member
What is the exhaust manifold off? What is the maximum allowable warpage? Looks like a Cummins ISB manifold.
Two piece manifolds you measure the two sections for warp individually. The joint between the two sections has a lot of "give" to it.
Cummins spec is .008" for the long section.
 
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phaxtris

(Ryan)
Premium Member
Premium Member
@digitalbilly I would say most of us have a mill, but I don't know how many have 59cm of x travel, i could do it in two passes, but don't have the time or enough fixturing stuff to set it up

Does it actually leak ? Or do you have it apart and checked it finding some warpage, as @terry_g said that 2 piece part has a good bit of flex to it
 

Dabbler

(John)
It will take longer to set up the piece on a mill than to lap it on a glass or granite plate. If you have to do 2 passes, you have to take *extra* care to make sure the two cuts are coplanar. That will more than double the setup time.

Lapping is the best way to go.
 

Susquatch

Ultra Member
Moderator
Premium Member
Don't know how I missed this thread.

How do you know the exhaust ports on the head are planar? If you are not going to do the head then you might help or hurt the exhaust manifold fit.

Since I don't read anything in the thread about doing the head, I assume that isn't in the plan. Therefore, before I touched the exhaust I'd check the fit between the two. Just put them together with no gasket and use feeler gauges. You might be pleasantly surprised to find out how well it fits. Or you might discover it's worse than you anticipated looking at the manifold alone and your simple job just got a whole lot more complicated. But better to know than not.

Assuming there is nothing in the way, you can also use a straight edge on both parts.

If you really have to do this yourself, I am in @Dabbler's court on how to flatten it. I think you will probably be disappointed in how a milling job turns out even with a big mill table. But just for the record, I personally recommend bringing it to a good engine shop. It's peanuts in the big picture. Many of those shops will do it in exchange for a donation to their coffee fund or some cash on the table.

My two cents for what it's worth.
 

Degen

Ultra Member
Look even with a small mill it could be done, would I no, for the simple reason to get a good result the set up time(s) alone would far exceed the time to do it hand to get the same result.

Know your tools, maximize the results for minimum effort in the shortest time.
 

DPittman

Ultra Member
Premium Member
Many of those shops will do it in exchange for a donation to their coffee fund or some cash on the table
Wow I don't think you'll find that sort of deals with any good engine shop around here! I imagine shop rate is at least $150/hour and minimum charge must be at least that as well? That's alot of donuts.
 
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Susquatch

Ultra Member
Moderator
Premium Member
Wow I don't think you'll find that sort of deals with any good engine shop around here! I imagine shop rate is at least $150/hour and minimum charge must be at least that as well? That's alot of donuts.

You might be right. The Windsor/Detroit area is the collective motor city. There are engine shops and hotrod shops everywhere. It's like a hobby for a lot of them. Some of them don't even do it for a living. There is a race track 5km away from me and a racing car in a garage on every block.

You are probably right, it might be a lot different out west.

It doesn't change how I think though. Setting up to mill an exhaust manifold and then actually milling it with good results is no piece of cake in a hobby shop. That's why I prefer sanding on a flat block.

On the other hand, engine shops do that kind of work regularly and are setup to do it quickly. But they typically do entire engines or short blocks or complete cylinder heads. Mounting and resurfacing an exhaust manifold should be an easy side job for them. Finding someone to do it at an affordable price might not be so easy out west. You might have to pay through the nose. But at least that way, you could expect them to stand behind their work.
 

terry_g

Ultra Member
I had a couple exhaust manifolds off a 1976 Tucker Sno-Cat with a 318 Chrysler engine that had shrunk
and warped quite badly. They were leaking badly and we needed the machine. I took the manifolds to
two machine shops and neither one wanted to do the job. I finally talked the second shop into doing them.
Resurfacing the manifolds helped but did not fix the problem as after a few hours the gaskets started
leaking again.
I ended having to remove the cylinder heads and have the manifold gasket surface on the heads resurfaced as well.
 
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Degen

Ultra Member
See some on the group has done it.

 
I did it and it came out great for it within 0.04 pretty flat for my needs
6B6A7323-86D2-4368-8351-31763FBE15A8.jpeg
 
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