Brass brazing cast iorn monifold?

[alamantia]

1987 wellcraft elite 222 XL with a chevy 350, older boat but appears to have low hours, good compression, no overheating issues etc. basically a good running, clean boat. Long story short one of the valve covers was rusted and seeping oil on the head last year, so I put new valve covers on it last fall. I was cleaning the boat over this past weekend and while doing so I shined a flashlight on the heads to check for any dripping oil as an indication that I did not torque the valve covers down enough on the cork gaskets I used. Luckily for me, I saw no oil but I did for the first time notice rust marks on the inside of one of the exhaust manifolds which appear to be water seeping from about a 2? long crack on the inside front of the manifold just under the riser. I ran the boat and could not see any water dripping out, but it must be for the rust trails to be present. I have only had the boat for 2 years now and prior to both winters I completely drained the manifolds. I suspect that at some point of the boats 23 year life before me that maybe some ice built up in the manifold and cracked it? Aside from this crack, both the manifolds and both the risers look, for lack of better terms, new, from the outside anyway, no visible rust. I removed the manifold with the crack last night and brought it to work with me today. I just went down to our welding department and see a stick welder and some ?cast iron? sticks, but I have no experience with that and don?t want to get involved attempting to weld the crack. I do see about 3 TIG welders and some brass rod. I think I am going to attempt brazing the crack after work today before I go home. Have any of you done this before? Any tips would be appreciated.

 

[RCAnderson]

Re: Brass brazing cast iorn monifold?

If it is cracked, there is no harm trying, but what does the inside of the manifold and risers look like ? If they are 23 years old, chances are that they are probably corroded from the inside out. The material between the exhaust section of the manifold and the coolant section of the manifold will most likely be very very thin, and if the manifold develops a crack between the two, you will end up with water intrusion into the cylinders. It may not be cracked now, but may crack from the heat\distortion of welding or brazing. It's up to you, but you might want to start looking for new manifolds and risers.

RCA

 

[Bondo]

Re: Brass brazing cast iorn monifold?

1987 wellcraft elite 222 XL with a chevy 350, older boat but appears to have low hours, good compression, no overheating issues etc. basically a good running, clean boat. Long story short one of the valve covers was rusted and seeping oil on the head last year, so I put new valve covers on it last fall. I was cleaning the boat over this past weekend and while doing so I shined a flashlight on the heads to check for any dripping oil as an indication that I did not torque the valve covers down enough on the cork gaskets I used. Luckily for me, I saw no oil but I did for the first time notice rust marks on the inside of one of the exhaust manifolds which appear to be water seeping from about a 2” long crack on the inside front of the manifold just under the riser. I ran the boat and could not see any water dripping out, but it must be for the rust trails to be present. I have only had the boat for 2 years now and prior to both winters I completely drained the manifolds. I suspect that at some point of the boats 23 year life before me that maybe some ice built up in the manifold and cracked it? Aside from this crack, both the manifolds and both the risers look, for lack of better terms, new, from the outside anyway, no visible rust. I removed the manifold with the crack last night and brought it to work with me today. I just went down to our welding department and see a stick welder and some “cast iron” sticks, but I have no experience with that and don’t want to get involved attempting to weld the crack. I do see about 3 TIG welders and some brass rod. I think I am going to attempt brazing the crack after work today before I go home. Have any of you done this before? Any tips would be appreciated.

Ayuh,.... Bein' a pretty darn good Welder myself,... I suggest skippin' the weldin' altogether, 'n goin' straight to the Epoxy,...

Weldin' cast iron is rather Tricky at best, 'n usually a coatin' of epoxy is necessary, anyways, to seal up the weldin' porosity's,...

 

[alamantia]

Re: Brass brazing cast iorn monifold?

I never took the riser off to look inside. I see plugs in the bottom I guess I could try to take out and look inside I suppose. Other than that, how can I tell if they are 23 years old or 3 years old? I never thought to ask the previous owner if he had any knowledge of changing them. I am guessing they are original as this boat was supposedly only used on lakes. I use it on a lake and sometimes take it to the hudson river north of tarrytown. I dont honestly know if it ever had any exposure to salt. Is there any sort of way of finding a build date on a manifold like you can with a block, I doubt it right? Anyways, i was intending on filling it up with water after It cools and check for leaks. If I see any water drip through the exhaust ports then I would suspect that I did as you said and brok through the lining. Either way. Its probably worth a try before spending what $100 - $150 on a new manifold right... ha!

 

[alamantia]

Re: Brass brazing cast iorn monifold?

Bond-0 - Thats a thought. What epoxy do you reccomend?

 

[chimmike]

Re: Brass brazing cast iorn monifold?

I don't see how any epoxy or adhesives are going to work on a cast iron manifold that does get pretty hot.

For a crack like that, in order to weld it properly you'll need to grind it out pretty good, and use something like NI-55 rod to weld it. Not the best, but better than buying new manifolds.

 

[Bondo]

Re: Brass brazing cast iorn monifold?

Bond-0 - Thats a thought. What epoxy do you reccomend?

Ayuh,.... JB Weld, or whatever ya want,...

I mix my own outa resin, 'n fillers,...

Chimmike,.... manifolds don't get nearly as Hot as ya think, lest not the outer jacket,...

 

[achris]

Re: Brass brazing cast iorn monifold?

.... manifolds don't get nearly as Hot as ya think, lest not the outer jacket,...

Ayuh,..... you should be able to hold your hand on them with the engine running....

And don't even think about manifolds for $150.... They'll be cheap Chinese rubbish. Go for OEM, or something like Oscos or Barrs.... Definitely not GLM, Sierra or Mallory...

If you're going to weld it, grind out the crack, use a MIG at a reasonable current and put in very small amounts of weld over a long period of time, never let the parent metal get too warm. Weld for about 2 or 3 seconds, wait 10 minutes for it to cool, then in for another 2 or 3 seconds, 10 minutes off, until you're done..... That will work, and be stronger than the original metal....

Chris.....

 

[alamantia]

Re: Brass brazing cast iorn monifold?

So I got one of the welders to stay late last night and braze the manifold. He used a TIG with brass rod. As he heated it the crack elongated from the original 2" to about 4" he filled the entire crack. I grinded it down and we say a few little pin holes so we plugged them up on a 2nd pass. I once again grinded it down and painted it with some engine paint. I never took the rizer off so that son of a ***** was pretty hard lugging home and back into the boat. I threw it on in about 20min and put the muffs on and fired it up and saw a worse drip coming from a different area. Figures... I took it back off and brought it back to work and we zapped it again and buffed it down, this time I mixed up some JB weld and filled in the pin holes, let it sit for about an hour, scuffed down the JB weld and painted it and reinstalled it a 2nd time. I ran it for about 20min till the engine got up to running temp and let it sit over night. I figured if there was an internal crack that water wojuld leak back into a cylinder and I would hydrolock it. This morning I started it up (probably to the chigrin of my neighbor) and it fired right up and ran fine, no leaks. What a process. But at the end of the day, I have a fully repaired manifold. I am glad I took the time.

 

[chimmike]

Re: Brass brazing cast iorn monifold?

Glad to hear it's all fixed.

Trick with welding cracks, regardless of the metal, as we said is grind out the crack entirely, then fill with new material. As the parent metal heats, a crack will just expand. Kinda stinks. Now I know what I can do if mine crack though!