Cast iron exhaust manifold repair

Anyone have success stories? Tim?

I've found "muggyweld.com" and they seem to have some interesting looking electrodes to use. I have a 1-1.5" long crack in my exhaust manifold (the typical between 2-3 runner corolla crack). I'd like to fix it.

Any thoughts?

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Welcome to the cult of JVL drink the koolaid or be banned.

Lots and lots of juice, and let it cool off nice and gradual like. Like maybe with a little help from a propane torch.

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Jay Woodward
Snohomish, WA
'90 Mazdog Frankenprotege
Chronologically, 46...

I might have a guy that welds cast iron, let me check. As Jay said, pre-heat, and cool slowly

Awesome thanks guys. I also forgot to mention, I'd been seeing "hi nickel content" filler rods and something called "super missile rod?"

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Welcome to the cult of JVL drink the koolaid or be banned.

His name is Larry, super cool old guy. He is in Redmond and works out o f his house. He does cast iron.
425-885-3757

Cool, thanks Sean!

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Welcome to the cult of JVL drink the koolaid or be banned.

Pre-heat and some sort of thermal blanket that you can wrap it up in so it will cool slowly. As with any crack, drill out the ends, grind a "V" along the crack and weld.

If it's a non-turbo car, I have used brazing many times with great success. It involves fire and smoke, two great things! If you are TIG welding, I believe the rod you need is MG200. TIG welding works some of the time. Cooling it down slowly is the biggest thing. Also, listen to it when it cools down, you can tell if it has cracked.
Also, DO NOT get manganese confused with magnesium. I grabbed some cast iron filler the other day instead of magnesium and had one heck of a time cleaning that mess up!

Can't find a tube header??

Too bad the manifold isn't the same as the fwd Corollas. Last year we tossed 3 or 4 of them in garbage.

-Jon

I can't believe you aren't MAKING a tube header with all the other stuff you've done.

With your standalone, why are you staying stock? The stock setup is not bad,but I talked to a guy named Bob (who I really trust with knowledge about the 4AGE) and he told me that pretty much any 4-1 header would improve the engine for what I was using it for (mostly AutoX, with occasional HPDEs). Most 4-2-1s, he said, ended up actually killing the mid and upper-end power, but a 4-1 wouldn't necessarily kill my low-end torque, with the engine setup that I had.

I don't remember if you went oversize on the bore, piston compression, or what you had done to the head/valves/cams, But I really think that a header that fits would probably help out your power delivery in the RPM range where the engine will live.

I went from 108/98 hp/tq to 133/105-ish (or 122/91 on a different Dyno) with just a header, fpr, and a set of cams. The header and fpr I put on first, and there was a noticeable difference, then the cams got put on six-ish months later, another huge difference.

"Driveability" really increased, according to my butt dyno. The low end was definitely better than it had been, but the mid and top end just keep going. I'm 90% sure that I could get another useable 1k-1400rpm out of the engine if I were to move off of the stock ECU.

Are you staying with the stock cast-iron stuff just for durability and ease of replacement, or is it because it's hard to find a "nice" header at a reasonable price? With all of the other really good work in this car, I'm suprised that this isn't part of it. Or, is this just for testing/break-in? Weren't you looking into a Martelius or something at one point?

--Jorden

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---** To be in compliance with the Anarchy **---
Jorden R. Kleier
Baraboo, Wisconsin, USA
1990 Mazdog Protege 4WD
1973

I'm getting the martelius header, but I need something until then. TRD Group A used the stock exhaust manifolds, at roughly the same power my engine should be making. Plus, as far as stock cast manifolds go, the 4ag's isnt HORRIBLE. It's just heavy and cracked lol.

I was going to get a cheap OBX trd knock off or something, but that was before... now they're apparently 2.5-3x the price they used to be. I refuse to spend that much just to replace it again.


Al, I can't tell if that was a joke, an insult, or actual shock lol

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Welcome to the cult of JVL drink the koolaid or be banned.

Timm do you know Jesse Fairbank? Not a member of this forum but is heavily envolved on some of the other ae86, Toyota forums. He is currently wrapping up his very serious street hatch build and is fanatical about details like flow, balance, maps etc. he spent tons of time figuring out his final choice of header for his build and I am sure he would be happy to pass along his findings to you for your build. He like jorden found that an ill advised header was actually killing some low and midrange power. Not what you want for rally.

Sorry I can't speak to your original question about cast but if you do go to a tube style header I thought you might find this helpful.

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Zap zap my ass...



Edited 1 time(s). Last edit at 07/20/2012 02:13PM by slidewayswrx.

FWIW I ran a cracked manifold the entire time in the Merkur. Then again, it's a turbo car...

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Grant Hughes

$200 for an ebay header. I'd bet William could cut you a flange and I can get you a deal on mandrel bends from my warehouse up there. Couple evenings and you're set.

Toyota didn't use the stock manifold for GpA because it was awesome, they had to by the rules. Plus you don't know they weren't getting creative with the manifolds either. Chrysler, Nissan and Toyota have all produced non-stock stock parts for their race efforts, and probably every other manufacture. Any reasonable 4 into1 header will be a benefit to power as well as cooling. Prolly a 10-15 hp gain with most any header.