Exhaust Manifold - Fix it or trash it???

[RonKrifchin]

To All,

I'm in the painful process of reassembling my 3.0l and can across something I'm just not familiar with and hope someone can shed some light on it for me...

The head has been machined as well as a valve job, new seats and valve spring spacers! WOW it looks terrific!!! I also had the exhaust manifold pots as well and the head machined for a clean installation. However, as I was looking at putting the erector set back together I noticed something troubling in the exhaust manifold specifically, where it joins the exhaust elbow. Looking into the manifold it appears one of the petition wall in t he manifold has melted? I've posted a couple of pictures to better illustrate the situation. Left one is the elbow right one is the exhaust manifold port...

The question is:
1. What the heck happened?
2. Should it be fixed. eg machined down to where the petition is in contact with the gasket
3. Can it be used as it is?
4. os there any danger to additional damage to the motor?
5. Replace it?

I know this is a lot to ask, but any input would be greatly appreciated.

Thanks,
Ron

 

[alldodge]

Number 5, replace

 

[GA_Boater]

Number 1 - Not melted, it's rusting away. What does the riser look like?

Proceed with Number 5.

Welcome aboard, Ron.

 

[Scott Danforth]

hit it with a sledge hammer to break into pieces so you are not tempted to use it, then proceed with number 5

 

[RonKrifchin]

Thanks to everyone for your help. MOD EDIT - Not permitted.

GA-Boater, the rises looks reasonable. Rusty as yo might imagine but good. No cracks or broken pieces....

Regards,
Ron

 

[Scott Danforth]

I would get a new elbow as well. no sense toasting a motor because the gasket joint fails and fills the cylinders with water

 

[Scott06]

What happened that you needed a valve job for? If it was water in the cylinders this is the root cause.

 

[Lou C]

Exactly. That was way past its expiration date and so was the elbow. Take it to the cast iron recycling place like I did with my old OMC batwings and get some money for it.

 

[wingless]

Welcome to the forum.

Toss the exhaust and replace.

Going out on a short, sturdy limb, the exhaust is raw water cooled and the boat is operated in salt water.

Under those conditions the OEM exhaust parts last three to four years. That system requires unbolting the parts annually to inspect for sufficient SOLID wall thickness between water and exhaust.

My salt water raw water exhaust would last three to four years before requiring replacement.

My exhaust retained salt water 24/7/365 w/ no way to drain and no way to flush. At the last replacement I redesigned my exhaust, so now I drain, flush w/ fresh water, soapy water, Salt Away, then drain bone dry.

My latest inspection, after exhaust disassembly, after three years of flushing and draining, reveals the internals still looking brand new.

My guess is that the exhaust service life will now last the life of the boat.