I know that cast iron is normally not easy to weld, but since the cracks are very fine would I be able to "seal" them off by running a simple mig weld down the inside of the crack?

 

If you are a good welder that shouldn't be a problem. The problem is going to be machining the surface once your done. Take it to a good machinist and see if they can mill that surface once you weld it.

Please note that "machining" doesn't mean hitting it with a grinder after welding. I paid to have an exhaust manifold repaired and machined once and that was the guy's idea of a good job. Anyways, I never took another job to him.

 

I'm sure you could, but... Why?

1. That's a dime-a-dozen EGR 4-barrel manifold, which people will pretty much give away.

2. One of those cracks is between the barrels.

3. The other crack is so small that it may be effectively sealed with paint, and left until you find another manifold that somebody is throwing away.

- Eric

 

My opinion is to use them as is unless they were leaking. I think the weld will give you more grief than those minor cracks. If they crack worse then replace them. They're not hard to replace once they've been off the first time.

 

x2

 

As was mentioned, just use as is or replace. I wouldn't bother welding those areas then machining.

 

I'd toss it and get another. Why mess with it?

 

No. Its not that easy. Successful cast welding can only be performed by someone who knows how to do this. Not all welders know these secrets and you cant simply take the MIG to it without the right prep. Is it worth welding is the bigger question?

 

The only successful cast iron welding I 've seen is when the item is baked to 400* and then welded using cast iron rod with a stick welder type machine.

 

Thanks guys for all the good answers. And so fast. This site is really the best I have been a part of. I just wish I had more to give back.

I like that a couple of you are okay with using it as is. I'd heard that one has to make sure the manifold has no cracks (which I didn't do carefully enough) and I can barely imagine that this massive manifold could have cracks much bigger than mine because it doesn't seem like they could open up much, sitting mounted on the engine. Have you see manifolds that have much bigger cracks? I think I will go with using as is and using sealant to seal it off from the inside. Maybe some super glu in the cracks first?...

I'm surprised that you all can find these so easily. I've been looking around for a year and I felt lucky to find this one and paid $75 locally so that I wouldn't have to pay that much for buying one for between $100 and $200 somewhere else.

Thanks!
Tom

I let you all know how it works out, but it will be a few weeks because I'm working hard on getting my 3.0 CSi ready for the 100 year BMW celebration at Laguna Seca...

 

Quote:
dave b.
former olds employee in lansing 1968-73 bldg. 70

Dave. Did you put together my 1972 Vista Cruiser?! :-)
That's very cool...

P.S. I also heard that cast iron pieces need to be pre-heated and welded with special welding rods, but I was still hoping it might work just to seal up these cracks where strength is not so important.

 

Eric, why is this an EGR manifold? My 1972 VC doesn't have anything smog related that I can see, except that I heard the engine has lower compression?...

 

I wouldn't weld that. Temperature is low enough you could even epoxy the outer cracks if it's a leak, but I doubt that it is.

 

google cast iron welding with a flux core mig...i troll thru some welding forums with regularity..just to see whats new..

they are doing amazing things with cast iron and flux core wire welding...inexperienced people are stumbling onto things by trial and error...they are migging the crap out of exhaust manifolds for turbo applications building logs (good to 1200 HP)...ive been amazed at what some "kids" are doing..its funny when lifer welders say no way and a guy with a $199 mig welder is building stuff because he has no funds or options but to do it himself...

 

If the only crack is between the barrels it won't matter even if it leaks slightly which I doubt it will. If the crack was larger I'd suggest veeing it out slightly with a Dremel and using JB weld.

 

I could be mistaken, because the perspective is hard to fully grasp, but it seems like I see an EGR port in the background in this picture.

I suppose it could be the choke stove port - I just can't tell.






Interesting point.

I welded some cast iron manifolds when I was a kid with a wire-fed MIG and had no problems with them over the few years that I daily-drove them.

It was NOT a pretty job, but it DID hold together, and hold the exhaust pipes on.

- Eric

 

Why all the negative on welding this intake just plain unfounded. I suspect it is because there is some rumor that it doesn't work. The answer as suggested is use a mig welder. One a side note metal when hot expands and cold contracts. The cracks will grow some when hot. How much when hot i dunno.

 

I wouldn't bother laying down a couple beads of weld on the thin ear of that intake myself. Why... well try it and see, but look for another intake prior to attempting.

 

Not much thinner than a divider on heads. The crack in the divider to me isn't even a problem. Now the other crack could cause a air vacuum leak. Key word here is {could} not saying it would.

 

That's the choke stove. The EGR is angled more vertically and has two holes, one smaller one larger.

 

Ah. Okay.

So it's a non-EGR, non-Toro cast iron 4bbl intake.

Still highly available for the (not inconsiderable) cost of shipping, or just a bit more.
People take these off, throw them out, and replace them with aftermarket intakes all the time.

I would be very surprised if there was nobody near you with one of these somewhere in his garage, that he'd be glad not to have to trip over anymore.

- Eric

 

My only concern is the cracks will keep propagating unless you stop them at the root. The way to do that is to drill through the casting at the end point stopping the crack from continuing. At that point I don't see why an epoxy wouldn't work although I'd be more happy with it welded. As stated above cast should be heated up, welded and then slowly cooled for the best results. That's not to say it won't hold otherwise but it is the best way.

 

Maybe epoxy!BTR Migwelds cast with out heating. Joe Mondello in his book has done Mig welding on head dividers intake not much different. I have Mig welded dividers on a set of E heads. I talked to a head restore company who repairs heads they said no problem welding cast as long as it isn't thick material. They told me for thick material you need it heated up and they do this in a special oven to weld cracks.

 

[QUOTE=TripDeuces;942010]My only concern is the cracks will keep propagating unless you stop them at the root.

That is why I said I wouldn't lay a couple of beads along the thin ear wall of that intake. But try it.. and have another on hand.

 

Wow! This is the thread that keeps on giving :-) Now, I might change my mind again and try laying a bead from the inside after all. I already have the welder out for the roof rust on the Vista Cruiser anyway :-(


You could be right Eric, but they aren't advertising on Craigslist or Ebay. I guess, I could have advertised on CL's wanted...

 

I tried it and I think it worked out ok. Starting the weld was a little tricky, but after that I got a good weld pool and penetration and it's definitely enough to prevent leaks from getting any worse and probably good to add some strength back to the cracked areas and stop them from getting worse. Thanks for all the good suggestions.

 

tcolt You know you need to check clearance for carb throttle blades.

 

Thanks. No, I didn't know, but I'll check. It seems like they come close at full throttle. I might grind just a little.

My carb. rebuild kit came with a spacer. Was that used originally and what is it for?

Tom

 

Originally, there was a gasket, but no spacer.

As for grinding, remember that the condition that you want to avoid is one where the throttle plates can be opened with foot pressure, but will not close with spring pressure.

- Eric

 

Thanks Eric

I just checked and I also noticed that the primary and secondary shaft of the carburetor that I "rebuilt" have about 20 thou. play. Is that considered par or do I have to re-bush those too? It's hard for me to guess whether that much "false" air leaking into the carb. would throw things off a lot?...

 

if it idles well..leave it alone...the only real time it would be an issue is when the throttle blades are closed...if it surges and stumbles off the line..well..it needs repaired..just my opinion...im no carb guy

 

Sorry I couldn't respond right away, things got a bit busy at work.

I agree with Mark- install it and see how it works. Personally, I don't think 0.020" is too much most of the time - see how it works and if it's bad, then decide what to do. It's not hard to remove if you need to.

You could make it perfect, but you may not notice any improvement if you do.

- Eric

 

I figured it would have opened up the crack from the other side plus pressure crack it further. I'm surprised really. Wicked job!!!

Put-r-ther !!
Eric

 

Exactly....Then wrapped in several layers of heat blankets and allowed to come down to ambient temp REAL slow 24 hrs slow. I did the ears on the WX exh mainfolds on my 68 in 1986 this way. 30 years later they are still good.

 

Good for you. I don't think this apply's to a intake period. I also think welding on head dividers with a mig welder is the best way to go BTR is a very well known person in the Oldsmobile hobby. If Bill Travato says that the way to go i am on board. I already did this welding on dividers on a set of BBO E heads with no problems. JMO

 

Yes, good for me, thanks. Yes, it applies to intakes in my world....Will a MIG plug up a hole...yep. There is no one blanket way to weld cast. Im aware of 3-4. I have not had good success with the "cool method" which is one of the 3-4 and the one OP is referring to here. Guess you have to ask your self.... do you want to just get it out the door or do you not want to see it come back in through that same door.

 

What ever i guess you didn't read the part of i ask a cylinder head repair business about mig welding. Maybe they didn't prep well enough. Intakes don't get as much heat as a exhaust manifold. So regard my post with a gain of salt. My mig welded exhaust dividers in my E heads never crack since 2001 till present. Now this set of heads were not welded by me but never the less are working just fine. I was assured i could do the same on a different set of E heads and have done that welding myself as well as welding the heat riser hole shut with a custom plug. Not just putting it out the door. Proven method.