exhaust elbow question

[SeaDuty]

will be replacing mixing elbow and had a question in regards to the threads.

do i need to put anti seize or something on the threads ?

thanks in advance.

(haven't taken it off yet - looks fun though)

got the replacement and gaskets - waiting on a good time.

 

[rochepoint]

Dont think that I would use a nylon hose barb and that one looks very small for the injection hose, our Perkins hose is a lot bigger like yours is in the first photo........

 

[SeaDuty]

Nylon barb

Dont think that I would use a nylon hose barb and that one looks very small for the injection hose, our Perkins hose is a lot bigger like yours is in the first photo........

Probably carry over the previous fitting to match existing setup or replace with newer if needed.

Not sure why it came with it

 

[diver dave]

I think i might reuse the old bronze barb and use PST sealant on the threads.

 

[RT Firefly]

Greetings,
Mr. SD. Looks fairly straight forward to me with little to no rust on the 3 flange bolts. Start application of PB Blaster or similar, now. Anti-seize may help with disassembly in the future.


I concur with Mr. r. (post #2). No nylon and bigger hose.


"...waiting on a good time." No time to lose Mr. SD.

 

[SeaDuty]

"...waiting on a good time." No time to lose Mr. SD.

 

[catalinajack]

Greetings,
Mr. SD. Looks fairly straight forward to me with little to no rust on the 3 flange bolts. Start application of PB Blaster or similar, now. Anti-seize may help with disassembly in the future.


I concur with Mr. r. (post #2). No nylon and bigger hose.


"...waiting on a good time." No time to lose Mr. SD.

No on the nylon. Get a Groco hose barb. I agree that those flange nuts look okay but, looking at the new part, I do not understand why the flange must be removed. The elbow obviously threads into that flange. Looks to me that the old elbow must be screwed out of the flange and the new one screwed in. However, there is mucho rust there and I would anticipate a lot of difficulty getting the old elbow out. Leave the flange in place and use a big pipe wrench? If it won't budge, get a new flange. Those nuts ought to come off easily with an impact wrench.

 

[Comodave]

Whatever you end up doing I would start ASAP soaking it in PB Blaster or the like to start breaking the corrosion on the threads. Start shooting the solvent on it and then tap it with a hammer to vibrate it so the solvent can penetrate better.

 

[SeaDuty]

. Leave the flange in place and use a big pipe wrench? If it won't budge, get a new flange. Those nuts ought to come off easily with an impact wrench.[/QUOTE]

plan A

thanks !

 

[SeaDuty]

"Whatever you end up doing I would start ASAP soaking it in PB Blaster "


wd-40 at the moment - haven't used pb blaster .. hmmm
won't know until the pipe wrench gets on it ..
trying to finish out the season first -- hopefully it'll last till then..
risking it .. i know

 

[SeaDuty]

" I agree that those flange nuts look okay but, looking at the new part, I do not understand why the flange must be removed. "

hoping it'll come off without having to pull the flange and put it in a vise.

- grabbed them just in case - hope they fit -- plan B

 

[Tator]

I thought you were asking if you should use Never-Seize on the elbow threads. Is this so?

Tator

 

[twistedtree]

I thought you were asking if you should use Never-Seize on the elbow threads. Is this so?

Tator

That was indeed the question.


And what are the materials involved? I can't tell if the elbow is stainless or cast iron, but based on the pictures of the old one at least the threads appear to be steel. Any idea what the mating part on the manifold is made of?


If steel on steel, I'd be inclined to use an anti seize, but carefully check the MSDS to see what temperatures it can tolerate. Unjacketed exhaust parts could be 700-1000F

 

[SeaDuty]

That was indeed the question.


And what are the materials involved? I can't tell if the elbow is stainless or cast iron,



Zinc plated malleable iron


I plan on leaving the flange in place , unless i can't get the pipe off.

anti-seize or pipe sealant with high heat application.
- not sure on that part..

 

[RT Firefly]

Greetings,
Mr. SD. I've usually found it's easier (sometimes MUCH easier) to work "on the bench" rather than leaving parts in situ. Personally, I would remove the elbow with the flange.

 

[Marco Flamingo]

This might be a good place to use graphite powder. Just powder, not one that has an oil or other carrier. It can definately handle the temperature.

 

[Oeanda]

Was in the same situation last year with identical looking elbow. The bugger was seized up solid where it threads in. After unbolting the flange/elbow and bringing it home, I threw everything I had at it for two days- tiger torch, various sprays, beatings, hot and cold waterboarding. In the end I carefully hacksawed through one inner side of the elbow at the threads and hammered it to crumple it inwards. After that things got easy. I wish I’d just taken a hacksaw blade to it first thing.

We did put anti-seize on the replacement as I recall, but I don’t expect it to make much difference when the time comes to replace it again in the glorious future.

 

[SeaDuty]

Cool - thanks !

going to try the in boat replacement , but thinking it'll have to go home with me.
doesn't come off - hacksaw it is

 

[Oeanda]

Yes if I did it all over again I would just cut the elbow off around somewhere in the middle of that rusty section, leaving a rusty ring threaded inside the flange. Leave enough of the rusted elbow protruding that you have something to beat/grip on. Then put the flange in a vice, put a hacksaw blade through the hole, assemble the hacksaw handle, and cut most of the way through the ring. Then start beating and fold it inwards, possibly using some sort of cold chisel or other random object to help direct the beating. If for whatever reason a hacksaw isn’t going to make sense in your situation then you can probably improvise with a small Dremel tool cutting wheel or whatever. In my case as soon as the ring folded inward slightly, it lost all its grip and easily unscrewed.

What Marco F said above sounds better than applying anti-seize. Good luck.

 

[catalinajack]

Greetings,
Mr. SD. I've usually found it's easier (sometimes MUCH easier) to work "on the bench" rather than leaving parts in situ. Personally, I would remove the elbow with the flange.

RT Firefly, do you really think you can get as much stability in a bench vise than simply trying to wrench that elbow off in place? I rather doubt it. With the torque that might be needed to get that thing off, you are not likely to have it hold in a vice. Perhaps, but why go through all that when you know it will hold on the boat. Plus, if it does come off, now you don't have to mess with cleaning the flange surfaxe and reinstalling.

 

[catalinajack]

Yes if I did it all over again I would just cut the elbow off around somewhere in the middle of that rusty section, leaving a rusty ring threaded inside the flange. Leave enough of the rusted elbow protruding that you have something to beat/grip on. Then put the flange in a vice, put a hacksaw blade through the hole, assemble the hacksaw handle, and cut most of the way through the ring. Then start beating and fold it inwards, possibly using some sort of cold chisel or other random object to help direct the beating. If for whatever reason a hacksaw isn’t going to make sense in your situation then you can probably improvise with a small Dremel tool cutting wheel or whatever. In my case as soon as the ring folded inward slightly, it lost all its grip and easily unscrewed.

What Marco F said above sounds better than applying anti-seize. Good luck.

If it were I, I would just buy a new flange if were not wildly expensive however that term is defined. Expensive to me might not be to others. Then there is the time and knuckle-busting factor.

 

[Oeanda]

In our case we tried but hit the ‘wildly expensive’ threshold. Can’t remember the exact price but somewhere around $800 for the flange comes to mind. I did spend a lot of time on it before getting out the hacksaw, but if I had to do it all over again knowing what I know now... it would be easy.

 

[diver dave]

If this was a muffler shop, it would be demo saw with metal blade on the threads, followed by a air hammer with cutter tip to get some anti-clockwise rotation on the remaining piece.
A marine shop would have u buy a new flange.
To rotate the mixer, u want impact and a low mass piece.

 

[RT Firefly]

Greetings,
Mr. cj. Re: Post #20. On engine VS bench. IF there is enough room to swing a wrench, I don't see too much of a problem trying to loosen things up (after copious application of your favorite rust release solution) with the elbow in place BUT close quarters are a recipe for skinned knuckles and injuries, IMO and combustion hazards if fire becomes involved.



Working on the bench with a vise WILL allow more even heating with a torch, if necessary and cutting to one's hearts content with saws/chisels. Secure clamping can be accomplished with a bit of jury rigging.



Different strokes, and all...

 

[FlyWright]

I did this on my Perkins 4.236 about 10 years ago and paid ~$300-350 for the flange. No doubt it's more today but they're also not hard to fabricate locally in a weld shop.

YMMV

 

[Finestkind]

Rust Buster…

KROIL!!
- Look it up. Best ever.
IF you are Not willing to purchase a product you will LOVE and share (in Small Amounts!) with good friends & family…
OR… Go Cheap & mix 1/2 ATF & Acetone. Store well secured & treat the threaded area once or twice a day for a few days. *There is a lot of surface area on those threads!!*
Then give it a go. Then repeat as necessary. You will prevail!!

 

[Newtrawlerowner]

will be replacing mixing elbow and had a question in regards to the threads.

do i need to put anti seize or something on the threads ?

thanks in advance.

(haven't taken it off yet - looks fun though)

got the replacement and gaskets - waiting on a good time.

I would use some teflon tape and/or some pipe dope, available and at hardware store. That will lubricate for future disassembly and help seal.

As far as disassembly several have suggested some lubricant prior to taking it apart. I might also suggest painting the new parts once installed to prevent rust.

 

[Lepke]

Whenever I assemble threaded components as part of an exhaust system or anywhere there is a possibility of corrosion, I use an anti-seize compound. It makes future disassembly simple and easy.
$800 flange? Any welding/machine shop should be able to make a similar flange for about $100. A block of steel cut, bored, threaded and 3 drilled holes... it's not rocket science. Probably the flange and elbow could have been made out of stainless for less than the cost of the replacement elbow.

 

[Oeanda]

Whenever I assemble threaded components as part of an exhaust system or anywhere there is a possibility of corrosion, I use an anti-seize compound. It makes future disassembly simple and easy.
$800 flange? Any welding/machine shop should be able to make a similar flange for about $100. A block of steel cut, bored, threaded and 3 drilled holes... it's not rocket science. Probably the flange and elbow could have been made out of stainless for less than the cost of the replacement elbow.

The ‘around $800’ quote was from Cummins. Or actually - from my girlfriend, who called them. We asked around locally but no one here could machine a new one. So it was definitely preferable in our case to save the flange. Cummins just got us for the price of a new gasket and a couple bolts.

Yeah I know late reply… ha ha but the subject is on my mind because it came up in discussion today