Exhaust pipe 431A volvo 1992 Welding?

[vstol]

Hello all,<br /><br />I made a costly mistake and did not drain my exhaust pipes the last time i ran on the muffs and have since cracked them both due to freezing temps, my questoins are can i use a little jb weld to repair them or perhaps actually using a welder, if so what type; mig, jig, tig or do i have to buy new ones. I have heard of other people using jb on this type of application before and was wondering what the success rate was. The crack if visible and on the out side of the pipe just under were it reads volvo. I have access to several types of welders but am not sure what the pipes are made of, i am assuming they are cast iron. What do you guys think, any suggestoins on where to buy news one at if you you think JB or welding is not an option?

 

[DHPMARINE]

Re: Exhaust pipe 431A volvo 1992 Welding?

Main question is weather the manifolds leak external or internal.If they are putting water into the oil,junk them.<br /><br />DHP

 

[vstol]

Re: Exhaust pipe 431A volvo 1992 Welding?

Funny you should mention the oil, i was starting the boat to warm the motor i could change the oil, maybe i should run it a little and see if any water gets into the oil, if not then can i weld them?

 

[Bondo]

Re: Exhaust pipe 431A volvo 1992 Welding?

While Replacement is the Best Answer,.... 'Cause you never Know if there's any Internal Cracks.........<br /><br />I've gotten 6 seasons from a set of Merc. Manifolds that I welded, due to Freeze Damage.....<br /><br />I Know I've been running on Borrowed Time,+ have bought a New set from Kagee last summer,...<br />They'll be Replaced Before the start of next season.............<br />

I have access to several types of welders but am not sure what the pipes are made of, i am assuming they are cast iron.

Ayuh,.... Cast Iron it Is......<br />It's More a Question of Technique rather than Method.......<br /><br />I put mine on the BBQ to preheat them,+ Welded them with a Stick, using 99% Nickle rod,.. Little 1/2" beads,....<br />Weld a Small patch,.. Close the hood,+ continue heating,....<br />Open the hood,+ Weld Another Small bead,... Etc...Etc...Etc....<br />It took me All Day,+ then Another 4 Hours to Slowly bring the Heat Down.........<br /><br />Unless you're a Cracker Jack Welder,....... I Don't reccomend it........<br /><br />JB Weld Might be an answer,.........<br /> <br />But,....... It's Still a Roll of the Dice...................................................................

 

[Don S]

Re: Exhaust pipe 431A volvo 1992 Welding?

Even if the inside of the manifolds are cracked, they will not fill your engine full of water when running. It would have to be with the engine stopped, water leakes out of the crack through the open valves of a cylinder, and then leaks past the rings into the oil pan.<br />While running, the water would be pushed out the exhaust. If it hydrolocks, or starts missing when ideling, then you have water getting into the cylinders and probably because of cracks on the inside of the manifolds.

 

[vstol]

Re: Exhaust pipe 431A volvo 1992 Welding?

I am not against replacing them, i just am not sure if i need to or not. I have not had the boat since new and am not sure when the last time the manafoilds were changed, dont they go bad after a while anyways or is that the risers i am thinking of?

 

[DHPMARINE]

Re: Exhaust pipe 431A volvo 1992 Welding?

Good point Don,and one I haven't considered before.If an engine is running and water gets into the crankcase,it has to be on the intake side of the engine (3.0L might be different).As always you have good posts.<br />I do maintain cracked manifolds will put water in the oil.But I now think the engine has to be shut down for awhile,after running to do this.<br /><br />DHP

 

[rodbolt]

Re: Exhaust pipe 431A volvo 1992 Welding?

while a cracked manifold or leaking riser wont instanly put oil in the crankcase it will make them run funny,miss pop and backfire. then when ya shut it down it fills a cylinder.<br /> if its an older motor with a carb it has a heat crossover. usually the crossover will pull water from one bank and feed it to the other.<br /> as EFI does not worry with carb Icing most dont have a crossover.<br /> I had 4 boats last winter that busted the manifolds. only one actually leaked to the inside. last winter we had an odd cold snap before christmas and caught a few folks off guard.<br /> best I can tell you is repair it then pressure test it. if it does not leak to the inside it may be ok but I would still reccomend replacing it or getting superman to xray eyeball it.

 

[vstol]

Re: Exhaust pipe 431A volvo 1992 Welding?

Thanks for all the input, i am still leaning towards replacing them but at least you have given my a little hope that repairing them may work also.