Hey guys, not sure where to really post this but being the age of this engine I decided to post here, I am restoring an antique Chris Craft boat (1952) with a Hemi in it and I have cracked exhaust manifolds. The manifolds leak water only when the engine gets to operating range and I want to seal the manifolds. I am a somewhat experienced welder and am wondering what you guys suggest I do to repair this... Should I just grind out the crack and "stitch" weld the grind? Preheat the manifold? Any help will be appreciated, thanks, Shaun
You can weld or braze it yourself or if you have a couple of bucks to spend you are not too far from the premiere cast iron welding shop in the nation. He is in Kelseyville Ca Lake Co. He has a large oven to heat it then he gas welds it and lets it cool slowly. When he is done you can machine it. Last time I was in there he had to Dusenburg engines and heads shipped from back east there for him to weld. He was in the process of welding a 327 double hump matching number Corvette head. And had just finished a big block matching number A C Cobra block. His phone # is 707-278-0223 or 1-866-935-3227 fax 707-278-0222.
That is a good place to use brass. If you can't do it yourself, ask around for someone that can. Maybe find a local trade school and ask the instructors for leads to local repair shops that have the expertise. I hate to see stuff like this welded, as in most cases you will get more cracks than you started with.
NEVER NEVER EVER use brass on cast iron. The rule is to use filler that is the same as the base metal. I have been using a Henrob torch to weld cast iron exhaust manifolds for 14 years and none have had any problem. The cast iron melts like butter and is extremely easy to weld with the Henrob and a cast iron filler rod. It is easy to dress and drill and tap.
My Dad welded a lot of it. We are in Amish country lots of cast iron stove grates , plates etc. etc. He would light a bed of charcoal , pre heat the part, weld it hot , bury it in sand and uncover it the next day when it was cool & used a nickle rod
If the manifold isn't cracked inside where the exhaust is separated from the water I would look into the Devcon products. They have been around for ever. JMHO.
I welded the cast water jacket on my woodburner in the house, like your manifold it heats up and cools and also has to be water tight. As the water jacket/boiler is cast into the main burner body as one piece I couldn't move it or pre heat it easily. I was advised to use high nickel content rods and weld it cold and keep it as cold as possible. Apparently time had moved on since the pre heating days . I gave it a go, I v'ed out the crack and welded it very slowly tack at a time, building each tack up onto the one before it. Kept it cool hammered and stress relieved each tack. It welded very well, didn't crack anymore and didn't leak. That was almost 3 years ago and it's in full use every winter for at least four months running 24/7 with no issues. Might be worth looking into. Paul.
Go on YouTube and search cast iron welding.There is a young guy on there who tries three or four different methods,but the best is a good,even pre-heat,with a nickel rod,crack fully ground through and vee-ed out for proper penetration,the buried in a bucket of sand and allowed to cool very slowly. You can do it,just take your time and do your homework before you jump in,and you will be fine. Scott Posted using two Dixie cups and a medium length piece of string.
If you want to braze it, check out you tube for Keith Fenner Turn Wright Machine. Man brazes lots of cast iron. Watch and you will believe, you really should watch all of his stuff, he's awesome.
just welded up an exhaust manifold for a cummins 300....got cast rod from Ebay and put manifold in a wood fire we built on the ground. After having lunch we pulled it out, welded it up and put it back in the fire. Overnight the fire died and cooled slowly so the next morning we had a warm freshly welded manifold with no cracks or leaks.
http://www.amazon.com/gp/product/B0000DD6HY/ref=oh_details_o02_s00_i01?ie=UTF8&psc=1 This is the rod I used but unfortunately the pics i had of the welded up manifols were lost with my other phone saturday. I got tatoos, they just look like scars......Funny thing Seb..I have a 24 in scar that looks like a tatoo
Good question. I have been researching this for awhile. I have been researching it because I have a cracked block that I want to repair. All of my research says the best method is preheat, use high nickel rod, and allow to cool slowly and evenly. I have brazed cast parts and had 50/50 luck. I have cold welded with a nickel rod and had 50/50 luck. For smaller parts like your manifold, I like the thought of the charcoal method of preheating. Not too many have an oven that will bring a part up to red hot. I saved a section of cast iron tub to practice on before I try to weld the motor. My 2 cents, Good luck, Dan
From a swedish 1964 O/A welding handbook: Objects with complex shape needs to be completely heated to red heat, i.e. glowing red. Simpler shapes allowing for free movement with changing temperature may sometimes be welded completely w/o preheat - although some preheat with the torch is recommended - and semi-simple shapes may be locally heated making them expand prior to welding and thus shrink again as the weld cools down. (One example is a six spoke cast iron wheel with one spoke broken. The spokes on both sides of the cracked one and possibly the outer edge of the wheel is heated forcing the crack to widen before welding so it all shrinks uniformly after welding.)
Bolt it to a 1/2" plate first , to keep it from warping. When it cools , slowly , it will keep it from cracking. An electric oven and nickel rod seem to work best. The sand burial is something I haven't heard of , seems like it would help.
Here is what I did on my manifold (352 FE), not preheating just brass welding. Probably I just had luck, worked all summer and still no cracks.
Sorry flatred 53 but welding is joining (melting ) the parent material together. Brazing is attatching the parts with another material. You brazed it you didn't weld it and it looks dam good. JMO.
I have had good luck with Pre heating in a kiln to nearly red hot ( I like the campfire trick and will use that next time) welding it with Nickle rod and then back in the kiln to SLOWLY cool down. The bucket-O-sand trick would do the same thing, evenly and slowly cool it.
Pre-heat the hotter the better. Red hot is about 1400-1600 F. You need a lot of heat to get that hot in an open fire. That is why a real furnace is best, not only control the temps, but it has insulated sides and top to keep the heat inside the box. Slow cooling is also good. Sand is good, but can also use insulation, just make sure it can take the temps. Nickel filler is used because it is more ductile. Peening the weld right after welding is done to help the shrinkage stress. Shrinkage of the weld is what causes cracking along the fusion line, the most common welding problem with cast iron.
I brazed a SBC head with good success, but it all depends on the cast iron. I have used a MIG to weld antique cast iron factory style caster wheels, like the ones that came on factory carts, also have ARC welded various cast iron parts with no problem. I guess it all depends on the cast iron and the materials you are using to weld with i.e. nickel rod etc. I have also found that the pre-heating helps.
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