Welding on Cast iron with nickel rod....

Ronn

Well-known member
Ok, I have an intake plenum thing going and need to weld tubing and plates to the log. Needs to be fairly strong..actually nice and strong because it will have to support a Holley 500 or 350, plus about 3 more pounds of aluminum. With road vibrations and heat..Nickel rod would be the way to go right? I am a welder/fab guy of sorts but cast iron is a whole new realm. Must I heat the area to be welded with a torch and what nickel rod and amp do you suggest? I have a stick box, goes to 175. I don't want to crack this head all up, whats the scoop on welding these heads and what kind of metal/steel/iron is best welded using the nickel? I need it to be able to burn in nice on both surfaces for maximum strength. All help is needed.

I was going to drill and tap for 4- 5/16 studs for each inlet but just in case the log is too thin after milling flat..I may need to weld instead.
 
Ronn, rick wrench had a website where you don't have to prehead the head. www.muggyweld.com take a look & see what you think.
I had my head preheated then the low spots on the log were brazed in.
Another choice would wait till the aluminium head is available from FSPP.
If i had to do it again the money spent on modifying the cast iron log head could have paid half the cost of a superior flowing aftermarket head.
till these heads are ready to the buying public the modified log is a great step forward. William
 
Yep, seen them before. Pricey. Might just have to try those rods out.

I know I could wait but it's something to do. And it's hard. I like it that way! Actually if the plan works out I won't have to weld at all and I could re-produce these plenums fairly easy. Just using a couple different peices of standard aluminum stock with some angled cuts and some welding, it may be able to be bolted on. Instead of 6 runners it will have 2 big ones and mounts to the side of the log so clearance of the hood will no longer be an issue with the carb of choice. The top of the plenum will actually sit about 1/4" below the top of the log and will follow the same angle as the original 1 bbl surface. That hole will be capped. With this plenum and the added volume and distribution..I am still wanting to add the gas to it :twisted: I can mount the 2 nozzles on each side of the carb pointing down....oh say a 35 shot is all. Got the pills already 8) :twisted:
 
don't forget wether you have to preheat or not after the mods you will need to have a value job and prob a deck job to make sure everything is true still.
 
When we were ruining crossflow conversion blocks we learned a lot about how not to weld cast iron.

Preheat is important. If possible, you need to get the whole head to about 500 F before welding. Cast iron is prone to cracking at the weld otherwise. One way to do it is to set it in a glowing charcoal pit, do the weld, then cover it and let it cool slowly overnight.

Use a nickel rod. They are expensive, but really the only good, machinable choice. Keep the area to be welded clean and make sure all the oils have been leached out by the preheat. Cast can be like a sponge.

Go slowly and stitch the parts together. That way you don't build up any localized hot spots.

Have fun. It ain't easy, but can be done.
 
welding iron is a real art. especially on used components. there are about 20 ways to screw it up and you will most likely stumble upon at lest one or two of these. even something simple as repairing the exhaust ears isa challenge. If it looks like it is holding it probably isnt.

my "new " hardseat-head had brazed helicoiled repairs on both corner ears( from the rebuilder). both seemed like good repairs but both failed within 20K miles. as well as the nickel rod welding on my port divider had let loose during this same period; this had been done by a reputable head shop. I took my head this time to a welder who specializes in iron/ductile iron/steel welding and fabricating. he used a different approach for the ears vs the port divider. the whole part was heated to degas, then additional heat locally to the areas, special flux on the oxidized areas and use of a henrob torch and special rod.

the head was normalized then resurfaced and finally valve grinding done. the resurfacing at the ears shows the metal to be one homogeneous part.

Try to avoid welding if possible. in the port divider area you can weld it and also mechanically stake it using small set screws in the seams is good assurance if you have any doubt about the integrity of the welds

frankie
 
A place called fastenall, it's a chain supplier, has a product that is like an epoxy, comes in a can and is made with aluminum and bonds to any cleaned metal and they have 2 temp ranges. One goes to 550 the other goes to 1500 degrees and is machinable, tappable and all that, I may buy that to install the divider.

Yall are scaring me. I may just forget the whole welding thing unless I can scroung up some junk cast peices to practice on. Thanks for the info!
 
hi,
as a guy with several years welding under my belt including cast iron, I have not found a way to make a strong joining weld on cast, especially when trying to join a dissimiliar metal. I have burned a lot of nickel rod on cast but it was to build up a worn surface, large pump housings and such.
Cracks can be ground out to a wide bevel and sucessfully filled with nickel and hold pretty good, I just never had any luck joining two separate pieces and making it last. Yeah you need to heat it up first, slowly, and cool it just as slowly.
Oh Yeah, if you are new to nickel rod, be careful, unlike regular welding rod, the flux is conductive on these, they will arc out anywhere along the rod, not just on the tip, not cool in a tight spot!
 
Thats what I'm coming to beleive just looking at how cast reacts even with 60/13. Breaks right off.

Oh well, guess it's drill and tap time. :? I think actually I'm going to use 4 1/4" counter sunk allen bolts with a washer and locknut on the inside of the log. I'll have the end caps off so my 8" needle nose vise grips will be able to hold the nut while I tighten. flow won't be messed with because the air will be sort of bending or flowing in an arc around the corner for the first 1" or so. I think it will work but welding would have been a lot more professional looking if I could have. Grinding the welds to look as if it's part of the mold would be nice but I think this bolt on will work good.

Thanks again.
 
Ok, I'm stumped here. I've got a fairly ghetto Lincoln Electric handy mig welder. When I cut the log off my extra head, I figured I'd practice welding cast iron with the scraps left over. I used the standard wire that came with the welder, I forget what it is, without gas shielding. I turned the welder up to the highest setting and went welding away. I welded one piece of 18 gauge sheet metal to a piece of cast, a 1/4" bar of steel to a piece of cast, and two pieces of cast together. I don't know why, but they went together well. I've beat both the 1/4" bar and the two cast pieces with a hammer and put them in a vice and done all kinds of mayhem to them and can't get them break apart or crack. the sheetmetal also held well to the cast piece. Is this some kind of fluke or what?
 
You might have a good "feel" for welding, too - in the way some people are natural artists or musicians. Thermal cycling is one issue, as is the length of a run - especially if you are going the length of the log.

Ronn - Can you drill and wire those nuts as well? I keep thinking about one coming loose!

Regards, Adam.
 
I did the same thing PutPut6, It seemed fine to me but I will only know when I get it back from the Head shop. I did hear one mild pop duing the last spot weld I made......so it is likely it did crack. I think the cracking is probably most likely to come about when you run the engine and the cast expands and the weld expands at a different rate. But I am a novice, so we'll see. I have the lincoln 135 mig and L56 wire---I did use an argon/carb mix. :?:
 
darwin":aulg1bng said:
I did the same thing PutPut6, It seemed fine to me but I will only know when I get it back from the Head shop. I did hear one mild pop duing the last spot weld I made......so it is likely it did crack. I think the cracking is probably most likely to come about when you run the engine and the cast expands and the weld expands at a different rate. But I am a novice, so we'll see. I have the lincoln 135 mig and L56 wire---I did use an argon/carb mix. :?:

Welding cast iron is best left to the pro's but if you insist on trying then weld short beads and when it is still hot take your slag hammer and pein it lightly and rapidly with the pointy end all over the bead until it cools. This will help relieve the stresses that develop as it cools. Good luck.
Joe
 
PutPut, you have flux core wire. If it worked that good for you...flux core is something I have and am actually certified in 70 and 71 series flux core so maybe..just maybe it will work. I'll try it on scrap first then heat it up to 250 degrees in the oven to simulate engine heat and then see how it does.

Addo, yes, those nuts are going to be well fastened for sure because...well, now that you got me thinking, I may just run the bolts from the inside and nut the outside lol. I don't want my baby to be rattling with a nut bouncing around the piston :lol:
 
Just to follow-up on this topic. I called my head shop guy and told him I wanted to bring in my E0 head and he said don't bother--it will be a waste of your time. He said he knows if I heard any kind of pop or crack the head is trash... I said "really" He said "absolutely" then replied you need to get that thing up to about 900+ degrees to do it right and then even with experience you run the risk of ruining it. So I took his word, ran right out and pulled a 77 head at the yard...So how hard will it be to adapt that 2 barrel to the log of the 77---that is if it turns out to be a good head????

Because I got all four of my heads cheap 30 bucks each, I wanted to try my luck with them in everyway, I will use one for practice welding with different rods, at different temps and with my MIG. Two are still good but I have hacked the log on both of them, one is a 65 and the other is a 78. My thinking is experience is a good teacher and if I can learn to weld these cast iron heads...priceless. :lol:
 
Well, it can be somewhat easy and pretty hard.

One way which has been done by a few is to take that new head and have the log where the one barrel bolts, milled flat so you can use an aluminum adapter as a base plate you would have to drill and tapp 2 holes diagonal, cut a gasket for it to seal to the log, then use studs to mount the carb onto a second adapter that has been milled to give back the angle so the carb site level while on the engine. OR have a custom billet adapter made to give the angle.

Something like that anyway.
 
Back
Top