Same problem of course with the J/ramK headers. Huge amount of cast iron in those manifolds; how does one get the whole manifold to a uniform red heat? I have a J header completely broken in two, poorly welded in the past, and so it most likely is useless.
I hear, anecdotally, about so called expert welders in various parts of the country who can fix these problems but as John stated what is the proper technical answer? I have never gotten a good answer in seven years of research. Do we have a true metallurgy
expert in the club or known to the club? These parts are scarce.
From: John Grady jkg@xxxxxxxxxxxxxxxxx [Chrysler300]
Sent: Saturday, January 13, 2018 9:07 AM
To: Fred Grossi
Subject: Re: [Chrysler300] Exhaust Manifold
I am looking at a similar / same problem .. heads up to the 300 group ,—— NEVER hang the head pipe or exhaust off the ram manifold while installing the exhaust pipe. The high leverage easily breaks off the head pipe manifold flange at about 45 degrees. Very
easy error to make . Have seen this twice . I am sure it has happened to others.
Generally cast iron cannot be welded on a bench . Unless whole manifold it taken to a uniform red heat The reason is steel of the weld rod shrinks at a different rate than cast iron and the extremely high stress while cooling due to that will crack the cast
iron right next to your new weld . Plus metallurgy changes happen there. Way it is, ignore wild claims. You can get lucky and cracking not terminal . But bad news , weak, ready to fall off .. . getting casting really hot and slow cooling ..and special “
weaker”more malleable “ rods help .but basic idea wrong at core.
I have become a fan of gas brazing for this which is not as hot as melting steel . Braze is very strong if it “takes” which gets into flux , skill etc but again needs very hot pre heat — but only needs maybe half the peak temp of welding . Welding = melting
steel . Half the temp= half the shrink
All this is specialty stuff . Point of post is not to be taken in by “I can do it” without finding out what is being done . Mine has a failed weld to dig out now , makes it 5x harder to fill in resulting gap . Or cover whole mess with braze ? Do not know.
Trying to find a technically proper answer , not an anecdote how “ Jim fixed it “ ... smile .
Great question . If we can find a guy brazing it with an oven , helps all of us on saving bad castings .
Sent from my iPhone
On 12 Jan 2018, at 4:52 pm, Fred Grossi lowtax@xxxxxxxxxxxxx [Chrysler300] <Chrysler300-noreply@xxxxxxxxxxxxxxx> wrote:
The right exhaust manifold on my 300F has a crack in it. I had my mechanic send it off to a welder who is an expert in welding cast iron. However, I have a feeling that it will not be successful. Does anybody have an idea as to where I can obtain a replacement?
Arroyo Grande, CA
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