CT-26, separating the exhaust housing for coating

JimR

JimR

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I'm planning to get the hot side of my CT-26 ceramic coated. To do this of course I have to separate it from the rest of the turbo.

After reading MDC's great thread on turbo rebuilds, http://www.supramania.com/forums/showthread.php?t=3991

I understand the process to get the housing off. What I would like to know is if I can simply put the exhaust housing back on the turbo after getting it coated, without worrying about any alignment issues? I don't plan to disassemble the rest of the turbo.

I've also noticed a small crack on the inside of the exhaust housing, which has been there for a while. Thoughts on this? Is it a concern?

Thanks,
Jim
 
jdub

jdub

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Heckler said:
I understand the process to get the housing off. What I would like to know is if I can simply put the exhaust housing back on the turbo after getting it coated, without worrying about any alignment issues? I don't plan to disassemble the rest of the turbo.
Click to expand...

Shouldn't be a problem...your coater is going to bead blast the part (he should anyway) and remove all rust. These coatings are only a few mils thick. If it concerns you, just have him mask the mating surface.

Heckler said:
I've also noticed a small crack on the inside of the exhaust housing, which has been there for a while. Thoughts on this? Is it a concern?
Click to expand...

That's not good...:nono: The coating will not fill the crack and when he bead blasts it, the crack is probably going to be worse than it looks right now...carbon will often obsecure these cracks completely. If you know a good welder, have him TIG it with a nickle alloy. Grind the weld down a bit then coat...I assume he will coat the inside of the snail as well? You can give it a go as is, but the crack may get worse over time.
 
JimR

JimR

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Thanks for the info. I'll see about getting that crack TIG welded, but it might be tricky because from what I remember, the crack is fairly far into the snail. I guess I'll see.

The turbo will definately be bead blasted, and coated inside and out.
 
MDCmotorsports

MDCmotorsports

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If the crack is into the snail, the housing is basically junk.

Before sending it to the coater, you need to take some sand paper and hand sand the inside of the housing's lip. Test fit back on the center section for a friction free fit. When you send it off to the coater, it should fit just fine.

You'll also want to sand any nicks or dings you made while getting the housings apart BEFORE you send it off to the coater.
 
K

KINGPIN33

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MDCmotorsports said:
If the crack is into the snail, the housing is basically junk.

Before sending it to the coater, you need to take some sand paper and hand sand the inside of the housing's lip. Test fit back on the center section for a friction free fit. When you send it off to the coater, it should fit just fine.

You'll also want to sand any nicks or dings you made while getting the housings apart BEFORE you send it off to the coater.
Click to expand...


Y is it junk??? Isn't it okay as long as the crack doesn't go through the out side of the snail? I have a crack on mine too inside. It will still hold the exhaust, not so?
 
IHI-RHC7

IHI-RHC7

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The expand and contract action of the turbo will propogate that crack to the outside of the snail very quickly. His point is not to waiste monye coating a housing that will crack through in a very short period of time.
 
MDCmotorsports

MDCmotorsports

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Well a crack 1/2" or so isn't all that bad. But Heckler is trying to get his coated. With a crack that deep inside the housing, its almost impossible to get it clean down inside the crack so that the coating will stick.
 
JimR

JimR

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On second thoughts, I don't think the crack is accessible for welding. I'll have the turbo off in a couple weeks and I'll take some pictures then.

I'll get an opinion from the coaters when I bring the hot side to them. If the coating can properly fill the crack, I should be ok. I should mention that the turbo has been running at ~12psi all last summer with no problems.

This is assuming a very small crack. If it's gotten any bigger since then, I'll be looking for a new hot side!
 
IHI-RHC7

IHI-RHC7

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I've got a few with weldable wastegate cracks with clean volutes, let me know, just pay for shipping.
 
JimR

JimR

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Well I have taken the turbo off, separated the hot-side (three hours later! frick that was a long job!), and I'm getting it coated.

The reason I am just going for coating is that I'm getting a bunch of things done at once, and the cost for the hot-side is minimal, so if it blows up, I'll just take that in stride.

I did take the hot-side to a specialty welding place in town, and I learned that cast iron welding is a fairly lengthy process and it would cost far more than a used hot-side to fix the cracks. They would have to grind out the cracks, and rebuild with fresh metal.

I have attached some pictures of the cracks in the hotside. I guess I'll just see how long this one lasts. If the coating covers those cracks, I should be fine for a while.
 

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jdub

jdub

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Heckler said:
Well I have taken the turbo off, separated the hot-side (three hours later! frick that was a long job!), and I'm getting it coated.

The reason I am just going for coating is that I'm getting a bunch of things done at once, and the cost for the hot-side is minimal, so if it blows up, I'll just take that in stride.

I did take the hot-side to a specialty welding place in town, and I learned that cast iron welding is a fairly lengthy process and it would cost far more than a used hot-side to fix the cracks. They would have to grind out the cracks, and rebuild with fresh metal.

I have attached some pictures of the cracks in the hotside. I guess I'll just see how long this one lasts. If the coating covers those cracks, I should be fine for a while.
Click to expand...

I assume a ceramic coating...it will not cover those cracks. The ones around the wastegate are not a big deal, but the crack inside the housing is not good. If I get one sent to me to coat that looks like that, I send it back :3d_frown:
 
Boss302

Boss302

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like it was said before, it's like drinving around with a burnt head light you may not get pulled over by the cops the 4th or 5th time yall pass but by golly one of them is looking for a good christmas bonus, point is the expanding and contrating is not good and it will bust. do it right the first time and enjoy it or don't do it right and curse it and yourself as your under the hood for the 3rd time.
 
JimR

JimR

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I totally agree, this is not a permanent solution. I am looking for a replacement exhaust housing. Consider this a WTB, especially if the housing is located in Canada!

Jim

Edit: All sorted. Another hotside, another trip to the coaters, and it's done.
 
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