Brazing an exhaust port on an iron head
#1056744
08/19/11 01:09 PM
08/19/11 01:09 PM
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Joined: Jan 2003
Posts: 9,670 Lima, Peru
domingo
OP
EL Master
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OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
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I know that its always said that you can braze intake ports to fix cracks, pinholes, etc because of the lower temps found in the intake port....
...but when you are taking about exhaust ports you CANT braze them due to the increased temperatures found there which would soften the bronze and it would do little to prevent cracks or pin holes from seeping water.
Now....
What if you had an exhaust port that had been opened up a tad bit too much and you would want to fill it up some by brazing and then reworking it. This is at the very end of the port opening where the gasket sits. Seems somebody port matched and went a bit overboard and enlarged the port opening a bit too much.
This port doesnt have cracks or pin holes, I just want to fill it up some at the very end of it and port match it again.
Will bronze hold up or will it melt????
Any other ideas?
Thanks!
Domingo
Last edited by domingo; 08/19/11 01:09 PM.
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Re: Brazing an exhaust port on an iron head
[Re: S/ST 3040]
#1056746
08/19/11 01:27 PM
08/19/11 01:27 PM
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Joined: Jan 2003
Posts: 9,670 Lima, Peru
domingo
OP
EL Master
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OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
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Quote:
Brazing is a very common practice for repairing exhaust ports.
really?? I always thought it was OK on the intakes but a real NO NO on the exhausts!!!!
Is there a possibility that a bronze filling actually MELT off on an exhaust port?
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Re: Brazing an exhaust port on an iron head
[Re: Hemi Allstate]
#1056752
08/19/11 05:17 PM
08/19/11 05:17 PM
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Joined: Jan 2003
Posts: 9,670 Lima, Peru
domingo
OP
EL Master
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OP
EL Master
Joined: Jan 2003
Posts: 9,670
Lima, Peru
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Quote:
I have seen exhaust ports brazed and filled on the bottom when raising them for SS etc. The intake side could be epoxied, but exhaust is brazed.
Thats exactly whay I am looking to do....kinda what SS racers do. I know they raise the exh ports on the heads and make em smaller....I wonder if they do that by brazing the exh ports. If that is the case, I know I will be 100% safe.
It'd be great if Jeff (modern cyl head) could chime in....I know he does heads for the SS guys.
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Re: Brazing an exhaust port on an iron head
[Re: domingo]
#1056755
08/20/11 11:45 AM
08/20/11 11:45 AM
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Joined: Mar 2006
Posts: 2,675 Mt. Eden Ky.
Hemi Allstate
master
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master
Joined: Mar 2006
Posts: 2,675
Mt. Eden Ky.
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Quote:
Quote:
I have seen exhaust ports brazed and filled on the bottom when raising them for SS etc. The intake side could be epoxied, but exhaust is brazed.
Thats exactly whay I am looking to do....kinda what SS racers do. I know they raise the exh ports on the heads and make em smaller....I wonder if they do that by brazing the exh ports. If that is the case, I know I will be 100% safe.
It'd be great if Jeff (modern cyl head) could chime in....I know he does heads for the SS guys.
How's this look? It may be some of Jeff's work!
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Re: Brazing an exhaust port on an iron head
[Re: MR_P_BODY]
#1056757
08/21/11 09:25 AM
08/21/11 09:25 AM
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Joined: Nov 2003
Posts: 2,715 closer to Canadian beer!
torkrules
I'm neurotic
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I'm neurotic
Joined: Nov 2003
Posts: 2,715
closer to Canadian beer!
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Quote:
If your really worried about brasing it, weld it with high content nickle rod
+1 on that. I had a pin hole in an iron head. we heated it with a torch and zapped it with a high nickle rod. I think the heads are still around to this day.
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Re: Brazing an exhaust port on an iron head
[Re: torkrules]
#1056758
08/21/11 11:45 AM
08/21/11 11:45 AM
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Joined: Oct 2003
Posts: 21,345 Marysville, O-H-I-O
70Cuda383
Too Many Posts
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Too Many Posts
Joined: Oct 2003
Posts: 21,345
Marysville, O-H-I-O
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I don't know a lot about brazing yet, but I've watched my dad do it a few times, oxy/acetylene hot blue flame to heat the metal to cherry red and touching the rod to it to melt the brass into it...that's GOTTA be hotter than any exhaust is going to get. unless you run stupid lean! but, if you're really worried, maybe look for someone who can weld cast aluminum up with steel rod.
**Photobucket sucks**
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Re: Brazing an exhaust port on an iron head
[Re: 70Cuda383]
#1056759
08/21/11 12:09 PM
08/21/11 12:09 PM
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Joined: Oct 2003
Posts: 11,678 W. Kentucky
justinp61
I Live Here
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I Live Here
Joined: Oct 2003
Posts: 11,678
W. Kentucky
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Quote:
but, if you're really worried, maybe look for someone who can weld cast aluminum up with steel rod.
I'd pay to see that trick
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Re: Brazing an exhaust port on an iron head
[Re: justinp61]
#1056760
08/21/11 12:17 PM
08/21/11 12:17 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
Quote:
but, if you're really worried, maybe look for someone who can weld cast aluminum up with steel rod.
I'd pay to see that trick
LOL.... same here
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Re: Brazing an exhaust port on an iron head
[Re: domingo]
#1056761
08/21/11 12:30 PM
08/21/11 12:30 PM
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Joined: Feb 2004
Posts: 1,093 Long Beach, CA
Mike Swann
super stock
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super stock
Joined: Feb 2004
Posts: 1,093
Long Beach, CA
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Back in the 70's, I was given a 70 Pinto with a 1.6 crossflow head that was wounded. After taking it apart, it had a burnt ex valve and cracked seat. After consulting with the wise shop owner that I worked for, I gound out the crack, we heated the head in the oven to 400F then brazed/filled the crack. Then, I had a seat put in it and ported the crap out of it. That motor got me though college and saw 7500rpm daily.
8.30's @3400 lbs
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