K I've have an internally gated 50Trim and going external off the manifold.

I need to get the wastegate flapper shut, how do I properly weld to the cast iron housing. Buddy of mine has a welder and that was my weekend project. but doing lil home work looks like I may run into some problems. help me out here.

 

Preheat in an oven, cool in an oven. It needs to be HOT. Then weld on it.

 

^ what he said. Best thing to do is stick it in the oven to about 200-500 degree and then weld it, after ward, quickly put it back into the hot over and let it cool down with it.

 

Or slowly turn down the temperature in the oven over a few hours.

 

is that cool in an oven before or after I weld it?
preheat, cool then weld just sounds like i'm be back to square 1, just double checking

 

No.

Preheat
Weld
Cool in an oven

 

You can put it back in the oven at the same temp you preheated at, turn the oven off and leave the door CLOSED until it cools back to room temp slowly.

 

and if you don't have an oven you can stick it in a pail of sand to let it cool slowly like they do with glass. But remember to use LOTS of heat when welding that sucker, weld it 4 times as storng as you think it needs to be.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by I4sillypwr &raquo;</TD></TR><TR><TD CLASS="quote">You can put it back in the oven at the same temp you preheated at, turn the oven off and leave the door CLOSED until it cools back to room temp slowly. </TD></TR></TABLE><TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by k24em2 &raquo;</TD></TR><TR><TD CLASS="quote">Or slowly turn down the temperature in the oven over a few hours.</TD></TR></TABLE>

Depending on the oven, this could matter. I know with my oven I would choose the second way, as mine releases heat very quickly. Some ovens are more insulating than others.

 

This is a project from back when we didn't have a fab forum. It's a good example of how easy it is to F up anything cast iron by MIG welding it. be warned. DO NOT MIG WELD CAST IRON UNLESS YOUR A PRO, or else it will have to be repaired over and over again. Hope everyone enjoys this info, i did my best to pass a learning experience on.


Just some pics of me prepping up a Turbo mani to fix some cracks caused by MIG welding cast iron.
Long crack with dimple hole


multiple cracks and someone's Fucked up mig welding trying to hide cracks. not helping the situation.


Another picture where you can see they were trying to cover cracks with some kind of epoxy. maybe JB weld. that kinda smear look at the bottom of the pic


cut channel to try and get the brass down in their.




its been brazed up, will get you some finish pics later.


update pics





its a cast iron manifold. yes you do have to preheat the entire manifold before you begin. the best way to do this is put it in the oven at like 350 or 400 degrees for an hour or so. i have seen people use like propane weed burners, but it has to be a non-carbony gas so that you don't have to reprep the iron when its hot.

While brazing it i just used normal brass fluxed rod. Not the best choice, but the only option i had. One thing that is important is trying to get an nice feathery flame. You do not want an oxygen rich flame. make sure you cut nice trenches in the iron and that you drill small holes at either end of the crack to relieve the pressure of the cracks themselves. The thing that i do like about working with brass is that i am able to go a little heavy with the rod and still clean it up relatively nice.

You also need to insulate the manifold to prolong the cooling process, once you have finished welding. i just used some mulch and dirt and it was hot for several hours. your basic fiberglass insulation from a house will work well also. Several people bury the iron in lime, and it will stay hot for days. sand also works well.

If i could do it again, i would make much deeper trenches for brazing into, and i would have probably made a better effort to remove all of the previous mig weld which was in my way making the manifold look like ****.

I would also have been more liberal with the heat before applying any braze, because once the braze is applied it is hard to reheat the metal without burning the braze.

also, a stainless steel brush helps alot in prepping the surface where you will be welding. as you grind cast iron, you get alot of graphite type material that isn't going to allow for a good weld. just some info in a learning experience to spread to others.

IF i had my choice, i would have tig welded with nickel rod, or oxygen acetalyne welded with nickel. and to all people modding cast iron for turbos or any reason, don't mig weld using normal mild steel wire, it works for a short period of time but then causes massive cracking, as what happened with this manifold. Then people try to fix the cracks with mig, causing even more problems.
Just trying to bring a little something back to life.

 

I have repaired other manfolds by brazing as well. All have held up tremendously.

Those were cracks but the same rules apply.

Pre and Post heat.

Uber clean.

DO NOT MIG. Only braze, oxy/acet weld with nickel, stick with nickel, or tig with nickel.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by snoochtodanooch &raquo;</TD></TR><TR><TD CLASS="quote">
Pre and Post heat.

</TD></TR></TABLE>

Dont you preheat or post heat?


I helped repair a large cast iron vice that cracked. We did a massive V groove on the parts. Put in into a over and let get to 500 deg F, then welded with SMAW and the proper rods.. (not me teacher did it), then we put it back in the oven. Let cooled. Inspected first 50% of welding. And heated it up then welded the rest.

Vice takes lots of stress and still holding up well

 

I have a question: I need to modify a set of steering knuckles and lower the ball joint mount by about 2 inches. The existing ball joint boss is a round hole (not tapered). I have thought of replacing the lower ball joint (in the control arm) with a spherical bearing or heim joint, and using a length of 1 inch round stock, turned down at the end to fit in the old ball joint boss, and threaded on the other end with a small step to fasten to the new ball joint. This should work fine, but it will have too much flex in it and require reinforcement. Would the same practice of preheating and slow-cooling apply when welding steel to cast iron? If done properly, will this be strong enough for a structural member? What would be the best rod/process to use in this. After reading the last post, mig is out of the question. That leaves me with stick and Gas. I spoke with another guy who did this same basic modification with a mig using stainless wire....but I don't see any good in having 3 dissimilar metals all melted together, when two isn't really desirable to begin with.

Sorry if I'm jacking your thread.

 

pre heat and slow cool was what i really ment to say, sorry about that.

 

Getting to the question at hand.
All you need to do is tack the WG flapper shut, or you can lay a small bead on the arm to hold the actual flapper shut. It'll hold without preheating, etc.
Had it done many times on diff. internally gated turbos. Good luck.

 

i don't understand what the hell is so bad about a little bit of insurance in doing it the right way, honestly...

 

yea, I dont mind the extra effort to do it right. If I did it right in the first place, I wouldn't of had an internal wastegate

 

Nice write up man im gonna try that with my manifold thats cracked

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by snoochtodanooch &raquo;</TD></TR><TR><TD CLASS="quote">i don't understand what the hell is so bad about a little bit of insurance in doing it the right way, honestly...</TD></TR></TABLE>

what exactly is the "right way?" if the flapper holds shut... it holds shut... seems to me it would be the right way... a little tack should be more than enough.. sometimes less is actually more...

 

I'm not arguing with the tack factor. its what you use to weld it, and the treatment of the material. MIG will cause cracks. Not preheating and slow cooling will cause cracks. It is as simple as that. It doesn't cost any extra money to do it, unless your counting a small amount of time as money.

 

Im not trying to hijack this thread but it seems everyone has answered this guys question so Im gonna ask one of my own. Well first of all I'm trying to modify a stock manifold for an srt-4, which has the exhaust housing cast into it, and right after the exhaust housing there is an insane "crease" in the opening. What I mean is like if you were to look straight in you would expect to see a perfect circle for good flow but instead you see a "D" shaped opening. What Im trying to do is weld up material on the outside to have pleanty of meat to port it out to a full circle. So I will actually be porting INTO the newly welded material. You guys say you can TIG this if you use a nickel rod.....will this hold? If there is a good chance this will crack Im not even going to do it. I've also heard you can only bond cast iron and not actually fuse it. Is this true? Im really trying to get as much as I can out of this while it's off the car. I honestly have zero experience welding cast iron so any help is appreciated. Thanks!