The cast-iron exhaust manifold on my car has developed a large crack (see photo). It's a log-style collector manifold which came bundled with my AVO turbo system and is about eight years old, but has seen less thank 40K miles driven. I've reached out to AVO to see if a replacement is still available, and if so what it costs, but am waiting for an answer.

After searching the forums, it seems these components are prone to cracking - so I'm also trying to figure out what my other options are. I've looked at turbo manifolds from Flyin Miata, BEGI and on eBay, but it doesn't appear that any of them would be a direct plug-and-play replacement for the AVO piece I have now.

I've been told that a cast-iron part like this can be welded, but it takes a fair amount of skill and patience, and that the repaired manifold would remain prone to cracking. I'd like to get a repair estimate from a local welder, but have no idea who to reach out to.

Do you guys have any recommendations?

 

FWIW, begi makes a great manifold, i have their manifold on my car and it looks great with ceramic coating.

 

nothing is going to be a direct replacement.

You can either take it off, get it welded, and make relief cuts and try again, or it's time to source a new manifold and DP.

 

Is it just the angle, or are you missing the center stud/nut in the center?

Vash-

 

It is hard to tell you where to go when you don't have your location listed in your profile.
Just get it welded and move on, if it cracks again, which it will, and I predict it will crack exactly next to the weld, weld it again.

 

Make sure its done properly.

Mainly that a hole is drilled past the cracks end to terminate it. Otherwise it will continue on outside the weld.

If I were in your shoes. I'd let someone clean it/drill it/grind down into the crack and then toss a big fat hot mig bead on it.

 

Well damn. I've never noticed that before. I took a look at the high-rez photo and sure enough, there's no stud there.

Thanks for the reminder, I've updated my profile. I live in Atlanta, in case any of you guys can recommend a skilled welder in this area.

 

from what i've heard a lot of welders won't touch cast. I've heard though if you pre-heat, it'll weld and hold no problem

 

corky will make that thing brand new for you.

 

AVO quoted me $690-750 for the part, depending on the method of shipping from Australia. Ouch. The local Mazda tuning shop quoted me $300-350 to install the part, if I wasn't to do the work myself. Needless to say, I'm going to keep searching for a skilled welder.

 

Some peoples needz to put da crack pipe down son!!!

Just go to any machine shop that's been in business for a long time and hand them the manifold and ask them to weld it. That's what I would do if I knew no welders.

 

Did we mention "RELIEF CUTS"?
Maybe a set of new studs, nuts, washers and bolts (grade #8 or higher)

 

if it is ductile cast iron it should be easy to weld.

 

I had my Greddy manifold welded recently. It had the usual cracks as the prev owner did not make enough relief cuts. I'll let you know how mine works out over time.

To repair it I took it to an exhaust shop and asked the guy if he could fix it. He seemed confident he could. At least that was what he said. When I got it back it was painted black. Presumably because he filled in the crack with a golden colored substance. The paint was to hide the repair. I'm not a welding expert so I can't tell you what it was he used to fill it. Cost was $70. He did mention that since it was cast he would need to braise (sp?) the new metal in to fix it.

 

I had my FM mani repaired a while ago, and it failed again a few months later.

Yours is pretty easy to reach, grinding the hell out of it and filling it all back in is a plus. Definately a place with an oven, etc, not just some guy who 'can weld anything'.

It's worth a shot, but I'd start saving for a new mani/DP combo. Good time to upgrade turbos, while you're at it. And with the new IC piping, maybe a bigger IC. All that flow, and it'd be a shame not to put in bigger valves. More power means bent rods, so toss in some carillos....

Wait a minute, I thought this was supposed to be cheap. :-)

Anyway, it won't hurt to try.

 

Who's that?

 

that is the EXACT same manifold i am using. you are missing the center stud which could have contributed on why it cracked right down the middle. that middle bolt is a bitch to get on, but it sure is necessary.

 

holy **** I need a career change.

 

I had the same AVO which lasted 8 years and 40k miles - I had the center stud, but I had a 1/8" NPT hole and an EGT probe, in the collector where the crack is, and it cracked there. It also cracked a few days after I lost an exhaust support donut and was too damn lazy to check the noise out. :(

I ended up getting a BEGI manifold and downpipe, but lost spoolup. I then got an ETD shorty tubey mani and a custom downpipe, which is now waiting to be installed.

 

Take that sucker off and drill out the ends of the cracks, stop it in its tracks. Use a good cutting wheel on a grinder and V out the crack all the way into the manifold, but don't make it huge. Bake it at 450 degrees for around 30 minutes then use a nickel welding filler and close it up. Do it clean but quick, don't clean the weld.. Drop it into a bucket of powdered Lime and leave it overnight.

Did that to a cracked E6 Ford 2.3 turbo manifold almost ten years ago, still rock solid to this day.