exhaust manifold rust tolerance?

CheapboatKev

CheapboatKev

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On my 68 120 mercruiser, the manifold block off plate rusted through and leaks..I did find a replacement..But am thinking I am putting my motor at risk by not getting a new (or dang near new but used) exhaust mani..

There is a lot of rust in the 42 year old mani..is there any set thickness like rotors, at XXXXX mm's they are shot?

Is there any rustproofing/coating/miracle in a can cure for the red cancer inside the manifold?
 
Don S

Don S

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62,321
Re: exhaust manifold rust tolerance?

Since the thinnest part of the manifold is in a place that can't be seen or reached by normal methods you wil have to cut the manifold into sections to find it.
The minimum thickness allowed is 1/32" or .032".


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In other words, if you have doubts, replace it. You can't see all the places that can go bad.
 
Bondo

Bondo

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Re: exhaust manifold rust tolerance?

Is there any rustproofing/coating/miracle in a can cure for the red cancer inside the manifold?
Click to expand...

Ayuh,... It's called Replacement,... Comes from a Checkbook, not a Can....:D
 
A

a70eliminator

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Re: exhaust manifold rust tolerance?

Saltwater eats them 3 to 1 is what I've heard, fresh water manifolds last a long time, usually it's improper winterizing that takes them not rot. I've never heard anyone talk about sonic testing if replacements aren't available.
 
CheapboatKev

CheapboatKev

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Re: exhaust manifold rust tolerance?

Bond-o said:
Ayuh,... It's called Replacement,... Comes from a Checkbook, not a Can....:D
Click to expand...

Get to the point Bond-O...whatcha trying to say? ;)

I'll save my pop bottles and go shopping
 
Bondo

Bondo

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Re: exhaust manifold rust tolerance?

Get to the point Bond-O...whatcha trying to say?
Click to expand...

Ayuh,... If there was a Miracle drug in a can that Stopped/ Prevented Rust in manifolds,....
We northerners would be dippin' our pickups in the stuff.....
We fix our pickups with the Same Tool I mentioned.....;)

Best I've found is Grease,...
'course,.. That won't work in a manifold,....:D
 
A

adeneo

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Messages
107
Re: exhaust manifold rust tolerance?

Volvo recommends replacing manifolds every four years if run in salt water, I'd say 42 years is a good run in any set of conditions.

Buying a new maifold is usually a good investment, if it rusts thru, water can run back in the engine, and eventually a new engine is the only option.
 
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