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Kodiak Exhaust Manifold Update

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Kodiak Exhaust Manifold Update

Postby Enduro4fun » Sat Jul 18, 2020 10:02 pm

I got tired of leaks between the manifold and riser on my Kodiak manifolds so I pulled them off broke out the welder and welded up the water holes and added an external hose. Very happy with it and no more worry About them leaking back into my engine.

I’m wondering about the winter time with the old risers they will drain back to manifold, but with them welded up the external fittings sit in such a way that about an inch of water will remain in the bottom part of riser. I’m assuming since there is air space above that water that I’m not going to have a freezing issue? I always drain my manifolds when I get out of the water when freezing is possible.
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Re: Kodiak Exhaust Manifold Update

Postby Riverjohn » Sun Jul 19, 2020 9:04 am

Enduro4fun wrote:I got tired of leaks between the manifold and riser on my Kodiak manifolds so I pulled them off broke out the welder and welded up the water holes and added an external hose. Very happy with it and no more worry About them leaking back into my engine.

I’m wondering about the winter time with the old risers they will drain back to manifold, but with them welded up the external fittings sit in such a way that about an inch of water will remain in the bottom part of riser. I’m assuming since there is air space above that water that I’m not going to have a freezing issue? I always drain my manifolds when I get out of the water when freezing is possible.

All the new ones are made the same way. I did the same thing you just did several years ago to mine. They will drain back thru the hose you installed. :Drink: :Drink:
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Re: Kodiak Exhaust Manifold Update

Postby viking » Sun Jul 19, 2020 10:21 am

My 460 risers had drains on the under side of the exit. Whenever I opened them, water exited. So there was water inside. But I don't know that they are necessary. The water will freeze, but it seems that damage will depend on the geometry. Air above is probably helpful, but I don't know if this is sufficient to prevent cracking. Internal geometry is probably very important.
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Re: Kodiak Exhaust Manifold Update

Postby Akclassic » Sun Jul 19, 2020 11:42 am

wait a min...could we start over for a moment?
I am very interested in this mod...
Is there a more detailed breakdown of how and why this is done?
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Re: Kodiak Exhaust Manifold Update

Postby Riverjohn » Sun Jul 19, 2020 12:11 pm

Akclassic wrote:wait a min...could we start over for a moment?
I am very interested in this mod...
Is there a more detailed breakdown of how and why this is done?

The Reason I did it to mine was that I kept seeing water leaking out the sides at the Riser to Manifold connection. It also made me wonder if it was leaking out it may be leaking in and might find its way into the engine.
I also saw that all the new ones were being made with only the exhaust going thru and the cooling water going thru a bypass hose. (I am not sure if the mfg's did this because of this or there desire to put antifreeze in the manifolds.) At any rate I had the Manifold and the Riser water passages welded up and then machined flat on the ones I have in "The Rat" 502. I bought new ones for "The Rodent" 383 because they did not have the bypass bungs to use the hose. (I will be selling these if anyone is interested. They are Kodiak Aluminum ones.) Hope this answers your question. :Drink: :Drink:
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Re: Kodiak Exhaust Manifold Update

Postby Akclassic » Sun Jul 19, 2020 1:43 pm

thanks. Ill be adding bung/hoses to mine tomorrow! I got it all apart now anyway. (Lifter failure repair).
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Re: Kodiak Exhaust Manifold Update

Postby Akclassic » Sun Jul 19, 2020 1:48 pm

I guess there's no need for a specific gasket? Seems like rtv or the right stuff would work?
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Re: Kodiak Exhaust Manifold Update

Postby Riverjohn » Sun Jul 19, 2020 2:19 pm

Akclassic wrote:I guess there's no need for a specific gasket? Seems like rtv or the right stuff would work?

I don't know whose manifolds you have. The old Kodiak's and the new Kodiak's take different size gaskets. I think both the same width one is longer than the other. RTV will probably work though. :Drink: :Drink:
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Re: Kodiak Exhaust Manifold Update

Postby Akclassic » Sun Jul 19, 2020 3:16 pm

Riverjohn wrote:
Akclassic wrote:I guess there's no need for a specific gasket? Seems like rtv or the right stuff would work?

I don't know whose manifolds you have. The old Kodiak's and the new Kodiak's take different size gaskets. I think both the same width one is longer than the other. RTV will probably work though. :Drink: :Drink:


I have the kodiak manifold and riser. I have the smaller of the gaskets. I have a few sets so I'll use them up with rtv.
What size bung did you weld in?
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Re: Kodiak Exhaust Manifold Update

Postby Riverjohn » Sun Jul 19, 2020 3:59 pm

Akclassic wrote:
Riverjohn wrote:
Akclassic wrote:I guess there's no need for a specific gasket? Seems like rtv or the right stuff would work?

I don't know whose manifolds you have. The old Kodiak's and the new Kodiak's take different size gaskets. I think both the same width one is longer than the other. RTV will probably work though. :Drink: :Drink:


I have the kodiak manifold and riser. I have the smaller of the gaskets. I have a few sets so I'll use them up with rtv.
What size bung did you weld in?
They were already cast into them. Yours must be like the older small block ones that I have. I think the ports are 3/4" pipe thread.
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Re: Kodiak Exhaust Manifold Update

Postby Enduro4fun » Mon Jul 20, 2020 6:44 pm

viking wrote:My 460 risers had drains on the under side of the exit. Whenever I opened them, water exited. So there was water inside. But I don't know that they are necessary. The water will freeze, but it seems that damage will depend on the geometry. Air above is probably helpful, but I don't know if this is sufficient to prevent cracking. Internal geometry is probably very important.


I think I’ll take them apart before winter and Add a drain right at the bottom of the riser to get that last little bit of water out.
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Re: Kodiak Exhaust Manifold Update

Postby Enduro4fun » Mon Jul 20, 2020 6:46 pm

Riverjohn wrote:
Enduro4fun wrote:I got tired of leaks between the manifold and riser on my Kodiak manifolds so I pulled them off broke out the welder and welded up the water holes and added an external hose. Very happy with it and no more worry About them leaking back into my engine.

I’m wondering about the winter time with the old risers they will drain back to manifold, but with them welded up the external fittings sit in such a way that about an inch of water will remain in the bottom part of riser. I’m assuming since there is air space above that water that I’m not going to have a freezing issue? I always drain my manifolds when I get out of the water when freezing is possible.

All the new ones are made the same way. I did the same thing you just did several years ago to mine. They will drain back thru the hose you installed. :Drink: :Drink:


I was worried about the 1/2-3/4 inch of water left below the hoses, but that’s encouraging if you haven’t had an issue.
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Re: Kodiak Exhaust Manifold Update

Postby Enduro4fun » Mon Jul 20, 2020 6:49 pm

Akclassic wrote:wait a min...could we start over for a moment?
I am very interested in this mod...
Is there a more detailed breakdown of how and why this is done?


The reason I did this is I always had a problem with water weeping at the junction of the manifold and riser. I always worried it way going to leak internally and cause a problem. All you have to do is weld up the existing ports, Machine flat, add a new gasket, fittings and hose for the new water routing.
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Re: Kodiak Exhaust Manifold Update

Postby stevenal » Sat Aug 01, 2020 10:42 am

It's not just hypothetical. Mine leaked internally and hyro-locked the engine. Mercruiser makes a "dry joint" system that sounds similar to the mod described here. Any possible leaks are external where they are visible. I also looked at converting to fresh water cooled manifolds, but that wasn't an option with my fuel injection system in the way. I ultimately went with the Hi-Tech stainless jointless system.
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Re: Kodiak Exhaust Manifold Update

Postby BigRodney » Sun Aug 09, 2020 8:14 am

Wait what! Now I have another problem I didn't know I had? If you weld these up how does water get injected into the hose out the exhaust, won't the hose burn up? And where's this bypass hose I'm reading about? Could you show us more pictures of this mod please? Thanks.
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Re: Kodiak Exhaust Manifold Update

Postby Riverjohn » Sun Aug 09, 2020 8:28 am

BigRodney wrote:Wait what! Now I have another problem I didn't know I had? If you weld these up how does water get injected into the hose out the exhaust, won't the hose burn up? And where's this bypass hose I'm reading about? Could you show us more pictures of this mod please? Thanks.

Look at the OP's first picture with the bypass hoses. Older ones don't have the bungs, The newer ones do. Not sure how you get them into the older ones. :Drink: :Drink:

You really should get one of these :RTFM: for this post ;) ;) :Laugh1: :Laugh1: :Drink: :Drink:
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Re: Kodiak Exhaust Manifold Update

Postby BigRodney » Sun Aug 09, 2020 8:55 am

Riverjohn wrote:
BigRodney wrote:Wait what! Now I have another problem I didn't know I had? If you weld these up how does water get injected into the hose out the exhaust, won't the hose burn up? And where's this bypass hose I'm reading about? Could you show us more pictures of this mod please? Thanks.

Look at the OP's first picture with the bypass hoses. Older ones don't have the bungs, The newer ones do. Not sure how you get them into the older ones. :Drink: :Drink:

You really should get one of these :RTFM: for this post ;) ;) :Laugh1: :Laugh1: :Drink: :Drink:


Ok, thanks. So I see the hoses now. My manifolds don't have bungs like that in them so maybe they're older versions. If it's not one thing it's another.
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Re: Kodiak Exhaust Manifold Update

Postby Akclassic » Mon Aug 10, 2020 11:15 am

Here's a closer picture. I just did this mod on mine.
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