Any fix for a cracked exhaust manifold?

[98FWDSM]

ok, i have had a crack in my exhaust manifold for months and it finally broke all the way through and is leaking a tiny bit....but i imagine if i can feel it leaking air at around 2500 rpms then it is probably losing a nice hunk of power on the higher rev....JB Weld says that they only recommend their stuff for things under 500 degrees....how hot does the manifold get? could i weld or sauter it??

Thanks

 

[XtremeGST]

get a new manifold, JB weld stinks! it stinks i tell ya! no literally it stinsk when it gets hot, ul want to throw up. get a new manfiold or get it Brazed shut or sottered (brazing is a better way of sotering) i would get the new one (ported EVO III i suggest) or melt copper into the crack if u got a simple propane torch and long nose plier and a penny ur set

 

[98FWDSM]

i forgot to mention that mine is ported....that is one of the main reasons that i do not want to get rid of it

 

[XtremeGST]

try my ghetto penny idea, ive done it on a friends *bites his knuckle* Mustang on the exhaust, its still holding today! its been 1 year+

 

[98FWDSM]

or melt copper into the crack if u got a simple propane torch and long nose plier and a penny ur set

so do i just hold the penny with my needle nose pliers about a inch or two above the crack and then heat it up and let the drips of copper fall onto the crack?

 

[Masakari]

dude, just go to a welding supply store and buy a tube of brazzing rod...you need to get teh kind that has the flux on the wire...the flux is important to making it a long term repair....next , find a buddy thta has an oxy acetelon welding torch...run about 10 pounds of acetelon and 35ish pounds of oxygen..tune the torch to where there is a small intense white flame about 1/4 shooting from the end of the torch( dont concern yourself with the larger blue flame..all your interested in is this little white flame, you will bring the tip of this white flame into contact with the manifold) the torch should have a mellow sound to it ( it shouldnt sound like a jet engine) heat the area of the manifold around the crack up till it starts to turn red and then start adding the rod...add it a little bit at a time and work the torch around the puddle in a circular motion..then dab the rod a little bit more...if you think your getting the manifold to hot then back off a little with the torch.....keep adding the rod little by little till you seal the crack


:edit: if you dont have access to an oxy acetylon rig, the penny trick will work....or you can use a clothes hanger..if you can get one of the older gold tinted ones....this is refered to as "junk" welding...so dont expect it to be a permanent fix, but it will work...and as stated might last many years...or might last a few months, dont expect longevity from doign it this way..

 

[nickcampbell]

Braze it closed like the post above says with flux covered brazing rod, make sure not
to form a puddle or the braze will crack. 35 psi O2 and 10 psi acetylene are WAY WAY too
high, though, should be more like 7 and 7.

Or, find someone with a stick welder. You can buy electrodes made specifically for use on
cast iron that people repair exhaust manifolds with all the time.

 

[Masakari]

good luck with those cast iron stick welder electrodes.....run like hammered dog poo

 

[dave99gst]

yer s'posed to tig weld and ping the metal while your welding to relive stress on cast iron.
Not very fun stuff to weld ( but it can be done )

 

[Masakari]

never tig welded cast....i think you need a special tungsten because if you arc up with a standard tungsten it will eat itself....im going to go try this right now and see what happens


weird, it worked...the arc jumps around liek a madman but you can do it....if the crack is a small one you wont even need filler metal, just fuse the crack back over

 

[98FWDSM]

the crack is about a inch long but is only leaking out of one spot but i would like to cover the whole crack...so what is the best way to do this?? i tried the penny thing but i couldnt get the copper to stick

 

[XtremeGST]

did u clean the surface? sanded it down to polished cast iron? a clean surface is needed! with no rust, because rust makes the bond alot worse, and the penny must be clean, if you dont have muratic acid to soak it in just use coca cola try it again with proper preperations, if you already did the proper preperations, sry that it didnt work.

 

[98FWDSM]

nope...definetly didnt do the proper preparations...but am i supposed to just sit the penny flat on the crack and heat it up or heat it up with just a side of the penny touching the crack or what...i have the proper tools but dont know what to do with them ~bangs head~

 

[Masakari]

its also important that you get the header hot,the goal is to get the header hot enough to keep the copper molten long enoug for it to soak into the pores in the headers metal...you will want the penny in contact with the header...it would be much easier to use a coat hanger, you will have more controll over it this way...but if your bent on using the penny then hold it with a set of needle nosed pliers and hold the side of the penny over the crack and melt it in a way that it is flowing from the penny straight onto the headers surface...after you get a little copper onto the header, pull the penny away and wash it into the crack using the heat from the torch

 

[Defiant]

Cut your losses. Replace it.

 

[wret]

American pennies have been copper clad zinc since 1983.

 

[flinguist]

Get an EVO manifold. They're on sale right now, and it's a good deal.http://www.dsmtuners.com/forums/showthread.php?t=163542

 

[gsx951]

good luck with those cast iron stick welder electrodes.....run like hammered dog poo

That's because people leave them out. The flux coating on the rod absorbs moisture from the air and needs to be baked in an oven to dry them.

This is a repair that a competant welder can do in ten minutes; I used to get cracked manifolds from the dealer and fix the as practice.
Seek out someone in your area who can actually weld and discuss the repair or better yet just buy a new EVOIII manifold and call it done.

 

[gsx951]

never tig welded cast....i think you need a special tungsten because if you arc up with a standard tungsten it will eat itself....im going to go try this right now and see what happens


weird, it worked...the arc jumps around liek a madman but you can do it....if the crack is a small one you wont even need filler metal, just fuse the crack back over

TIG works fantastic and you should use filler. It's designed to be very elastic and to fight cracking.

 

[nickcampbell]

It's funny how we got into this discussion on how to correctly repair cast iron manifolds
and seem to have totally forgotten that the guy who started the thread obviously wants
to do his repair in a jerry-rig fashion.
All that being said, I'm wondering how many decent welders are on the boards here and
if any of you guys read the Hobart or Miller welding boards?

 

[gsx951]

It's funny how we got into this discussion on how to correctly repair cast iron manifolds
and seem to have totally forgotten that the guy who started the thread obviously wants
to do his repair in a jerry-rig fashion.
All that being said, I'm wondering how many decent welders are on the boards here and
if any of you guys read the Hobart or Miller welding boards?

I have been welding professionally for 15 years. Starting in 1990 as a production welder and spending the last 5 as a machinist/fabricator.
I've never been to the hobart or miller boards.

 

[Masakari]

i have been a pipefitter for 6 years, mostly carbon steel and stainless work though with a little mig and flux core occasionally....oxy acetylon welding and cast fittings are all but gone in my trade.... i went to lincoln electric to learn to weld..but they didnt focus on cast to much...my posts have been from my personal experience with playing with cast

 

[funniegus]

Has anyone ever tried using exhaust patching compound? Mine has a crack and is leaking also. Just need something that will hold for 2 or three months until it gets nice outside for me to replace it an SBR manifold hopefully.

 

[Defiant]

Has anyone ever tried using exhaust patching compound?

It'll cook off a DSM manifold like bread in a barbecue.

 

[kelvinb]

When welding cast iron heat it slowly, and when done let it cool slowly. throwing water on it or putting it outside in the snow (if you have it) will make it crack again. get a bucket and fill it with some sand and then when your done put the manifold in the bucket and cover it with sand. This will be sufficent in letting it cool slowly. Hope that helps ya