CarsandWomen

iTrader: (19)

309 was designed as a filler to weld together dissimilar steels like stainless to carbon.

madmax4499

iTrader: (3)

well i did it, ended up using 309 rod and mild flange. used my oven for pre and post heat. V notched the manifold and flange. did a root pass then an over pass. welded like butter! the manifolds act like cast steel, i could not find any one with the equipment to test it's properties, its not like a manifold from 20 years ago. also i cant find any info on this type of manifold/flange set-up cracking or failing. bottom line, tig, mig, pre heat or not, just do it and post your results as to how it is holding up.

kmracer

iTrader: (1)

the first go i didnt pre heat or post heat, and actually just cut a bit out of the manifold and welded the stock flange back on so it would clear the low mount alt. welded it on 19v or so (the hottest my welder would weld) and dunked it in fine sand right after. i could immediately hear it cracking. sure enough i had it media blasted and there was fine cracks everywhere...

went back and did it all over, this time with mild steel v bands, pre heated and post heated, worked like a CHAMP. i was very very particular about it. i pre heated it to 500* and welded it up. for post heat i kept both the flange and the manifold within 25* of each other. i checked temps every 30 seconds or so,warmed the areas that needed to be warmed, then turn the torch off. every time i lit the torch i made the flame smaller. its pretty simple, just try to keep em within 25-50* of eachother til it gets to around 160 or so...

if you have access to a torch or oven i highly recommend it....

Silverback

Cast iron and mild steel should have very close expansion rates, most grades of stainless will have roughly 50% greater expansion rates, so mild steel should last longer.

I'm not sure what this stuff is made of or about the distinctions that people have made (cast iron and steel are just iron with other materials alloyed with them, the statement "more steel in it" doesn't make any sense when talking about cast iron, maybe something like "closer to cast steel," would be more accurate), but manifolds welding like this is not unusual. I welded some steel flanges, a section of steel pipe and even a steel plate to some cut up/modified early 70's Cadillac manifolds roughly 8years ago (that have been on a daily driver since then with no problems) and they welded just like what was described here, though I was pretty careful with controlling their cooling rates to prevent cracking (buried them in kitty litter wrapped in a pair of welding gloves).

I do wonder why a few people list problems with cracking even if they were relatively careful where most have no problems even if they just grab a MIG and weld it with no special prep.

celicaxx

iTrader: (2)

The metal of these manifolds are of great quality compared to most cast manifolds. They are definitely cast steel with little to no porosity. They tig'd well to the v-bands with no contamination.

LanceL

Mad max, what do you mean by V-notch the manifold and flange?

Johnmaster

iTrader: (3)

He is saying to make a bevel on each so you have something to fill instead of a smooth butt joint that would result in a big hump of filler metal.

tomz28

iTrader: (20)

STICKY!!! Love this thread

Geezer's Garage

Found an article in the Canadian Welding Association Journal pointing out that a certain version of ductile iron has become popular for exhaust manifolds because it pours well and highly weldable. It contains higher levels of silicon and molybdenum than plain old gray iron. The article goes into detail about spheroidal graphite inclusions, ferritic matrices and a bunch of other techie stuff. Also shows a picture of an silicon/molybdenum exhaust manifold from a 2004 Cadillac XLR that has a stainless steel cat welded directly to it at the factory.

Main learning for me is that all cast iron is not the same and what we're working with today are not our fathers' exhaust manifolds.

Experimented over the weekend cutting off the EGR boss from a truck manifold. Made a mild steel patch, pre-heated to 400 degrees and welded half with plain old mig wire and the other half with a spray torch with a powder that is high in nickel. Stuck in back in the oven and did a gradual cool down. No cracks and looks good. Will post pics later.

Old Geezer

iTrader: (3)

Just got a pair of 2.5" flanges off the Bag, from E-Motors, in Indy.

NICE pieces! Weld area of the flange is 3/16" thick...Should weld well.
Weld pieces are 409 and the clamp is 304.
$38.00 including the ride... Ordered the 12th... arrived via Fed-X at noon today.

Now, the real fun begins!

In the "FWIW" dept:
I'm also working on a set of Moosetang tubular headers.
I bought 3/8" x1 5/8" flanges on the Bag.. $40pr/laser cut, NICE!
http://stores.ebay.com/LASER-ART-WORLD?_rdc=1

Slowhawk

iTrader: (12)

We weld the flanges on the truck manifolds with our regular 140 mig. We just clean them up good, heat the manifold with a torch. Weld while keeping most of the heat on the manifold and pulling the weld to the flange. After done about 5 minutes later we heat them with a torch again and let them air cool. No cracks.

Big thing is to support the turbo weight from the engine or frame to take stress off the pipes/flanges.

tomz28

iTrader: (20)

Don did you use mild or stainless?

silver_82

heres mine. triple pass. single root. then a double weave top pass. **** welds easy.

[IMG][/IMG]

Hotrod406

iTrader: (6)

I welded flanges on Caddy STS manifolds cold, tig, 309 rod. Welded just like steel. No cracks or problems. Been on the car all summer with a 6766 hanging right off the end of one of them. The manifolds had cats welded to them like the XLR units do.

SSZ

I think i am convinced. Gonna have to give this a shot. Just looks very doable. Will a Lincoln Mig-Pak 15 with .030 mild steel wire and argon gas be good enough?

miatainthe10s

Has anyone welded on the new hooker swept manifolds yet? They are a lot tighter to the motor witch is ideal for my app. But $300 is wasted if it doesn't weld well.

9sectruck

iTrader: (9)

5.3/6.0 manifolds, what do I need to buy 2.5 v bands or 2.25 v bands?
my build is a pt88 370
great thread

LS1NOVA

iTrader: (12)

The 2.5 fits the manifold better and you have a pretty stout setup so you might as well use 2.5.

Danny

iTrader: (16)

I want to do the same thing with my truck manifolds on my twin turbo build. I'm going to preheat them in the oven for 1hr after they've been cleaned up to make sure I get a clean weld. My question is can my welder and wire handle the task. I'm running a MIG welder on 110V w/ 75% argon/25% carbon. Wire is 0.23 non-shielding wire.

Let me know what you guys think...

LS1NOVA

iTrader: (12)

You will be fine. I just welded two sets, same setup but .030 wire. Preheated in oven for 30 minutes, welded, put back in the oven for 30 minutes at 250, then turned the oven off and took them out the next day.

I also put the other end of the v band on it after welding so it doesnt warp. Id like to leave it on while welding but the bulky clamp gets in the way.