This is a exhaust manifold off of a 292 six cyl Chevy. Saw this crack while changing out intake. It is not leaking now. Any ideas what would be the best way of welding this to stop the crack. These things are hard to find and would like to try and save it.
you need to find someone who can weld cast iron , or at least get the stuff to do it yourself. a quick search (cast iron welding has been discussed on here many times) brought up a few threads that may be of help to you http://www.jalopyjournal.com/forum/showthread.php?t=182671&highlight=cast+iron+welding http://www.jalopyjournal.com/forum/showthread.php?t=302535&highlight=cast+iron+welding
I always heard you should drill a hole at the end of each crack to keep it from spreading. As welding goes take it to a pro.
I've used high nickel content welding rod (arc welded) after heating the manifold to a dull red with a torch, then slowly let it cool. It'll still warp some.
You could always do it the way I go about things. Do some research, study what others have done. Take your time cleaning the manifold. Practice welding on some scrap cast. Weld the manifold like a pro. Worp, drop, make bigger crack, or just completely screw up the manifold in some way that has never been dreamed of. Go buy a new or used one.
It's best if you have a high temp oven to slowly heat and cool the manifold. When heated it's best to use a scarfing tip to chamfer out the crack then oxy weld it with a nickle rod and use the oven to slowly bring it back down to temp. Probably a job for a pro with the right tools and know how?
Heat the whole manifold, tig it up with ni-cad rod or tig-tech rod, peen or wire brush the welded area while hot, warm it back up and wrap it in something to keep it from cooling too quick. Insulation works or i purchased heat resistant blankets from Insultech to slow down the cooling process.. I have welded lots of cast iron and this is very sucessful 95% of the time..
I had an exhaust flange that needed turned 1/4 turn and rewelded. I cut it off, ground the edges on a 45 deg, and took it to a local machine shop. He welded it with low heat nickle rod and hardly burned the paint. I asked him if it was strong, He laughed and said drop it on the floor. No I didn't, but that was 4 yrs ago and the car has been sold and I'll bet its still holding. Do it right the first time. Ice man
Hey dude, C-clamp a piece of heavy channel to the mounting face, then drill a 1/8 hole at each end of the crack, preheat it slowly for 35 minutes abd braze her up................
If you weld, others have made good suggestions. If you have to pay for the welding, It'll go over a hundred to do it, probably not practical. If time isn't a deal breaker, I would drill/tap/plug with cheap 1/4 inch screws, using jb weld on threads. Plant one, grind off the head, drill next to it with a very thin overlap of edge, etc. etc.
Gouge that crack, heat crack with rosebud torch & arc weld it up. High nickel rod like mentioned above. Carl Hagan
if i was going to weld it with arc and nickel rod i would def preheat and slow cool with peening during the welding part. i sometimes use tub of ashes from stove. i have had mixed results with it. i have had it looks so good you couldn't hardly see where it was welded, i have also had it crack right next to the weld. i think brazing is better because the cast doesn't have to reach the high temps. i really want to improve my cast brazing in the coming year. another important factor is cleaning the weld after you grind your v and before you weld. cast leaves a graphite residue unless the surface is preped well which makes good penitration harder. i would personally look for one off a 250. they interchange and are a lot more plentiful. i have sold them for as little as $25. good luck.
Well here is my 2 cents, Its already broke so you have a 50% chance of repairing it. All of the the methods are good and have worked with some success. I would pick a method and try it. I have used most of them at one time or another. Don't be surprised if you get spider cracks. Keep your eyes open for a replacement . Good luck with the method you chose.
Drill it and braze it...read about the Dillon/Henrob torch...I saw a guy by the name of Art Dyrdl do a demo of one of these torchs...he busted a pc out of a manifold and welded it right back up....oxy acy...old school !
I've repaired many exhaust manifolds by grinding a vee into the crack, and tig welding with inconel 82 wire. Use preheat, and postheat.
V grind crack ,pull out gas grill cook manifold 20 min. on high with lid closed,remove ,weld nickle rod (I have used mig with stainless worked well), place back on grill,re heat on high 20min ,lower heat 20 to30 min, lower again ,then turn off gas DO NOT OPEN LID let cool . have fun rtp
Drill holes at each end, vee the area to be welded. Heat area with a torch not red hot, weld with a nickle rod using an old style buzz box then cover with sand to promote slow cooling. Worked for me.
take it to a engine machine shop. Have them pin repair it. at our old shop, when customers had cracked heads or blocks and didnt want to spring for new ones, we pin repaired them. never had any issues with the repairs.
heres what i use quite often, arctec #3, http://www.arctecalloys.com/app/prodlist.asp?action=2&mtID=1
I would grind the crack out preheat it to 400 degrees tig weld it using utp 8051 filler matieral and post heat to about 800 degrees
If were brought to me I would grind and clean up the crack, drill stop holes at the end of the crack and tig weld cold with a rod called MG200. This rod is machineable and works amazing. The only draw back is that it's expensive. When you start the weld keep the rod in contact with the manifold and start the arc on the rod and not the cast. Keep the rod flowing on to the cast until the crack is covered and then go back and fill the rod covered "v". When your done you can grind off the excess and powder coat manifold and thw weld will disappear for all purposes. When welding do it in short periods or either heat the whole thing to keep heat stresses out.
V shape grind then stop drill the ends of the crack. Put it back on the engine & start it up. Let it get hot then shut it off & weld it right on the engine. As sone as the weld is done start it back up & let it run. Figure on a little success and you won't be disapointed.
Tell ya what.....you mount that to the motor & weld, chances are the current will flow through every moving part of that motor. Most of the time....your ground will kinda stick to the area you place it, due to the process......you don't want some internal engine part like "Piston ring" to arc to the cylinder wall do ya....... Carl Hagan
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