Cracked Exaust Manifold

nello

nello

Active member
Anyone here ever had a small crack on one exhaust manifold before? I think I found a crack but of course it's in the most difficult of all places to see, drivers side.

My truck's symtoms are: the first boost launch seems decent, 14.5 psi but then it doesn't hold solid...a bit of flutter on the boost guage needle (autometer). When the truck becomes hot it can't seem to hold the psi at all. Launch and the needle goes to about 10 or 12psi then promptly drops to about 5psi and holds, again with a bit of flutter.

I think whats happening is when the truck becomes hotter, the crack gets wider :lol: and my exaust gasses are leaking out instead of spinning my turbo. How can I fix this? I don't want to buy headers or a new old manifold. I'd like to know any other solutions for a fix and if this CRACK could be the cause of what I tried to explain.

Thanks fellas.
 
M

MikeRenz

not stock
Re: Cracked Exaust Manifold

it's common for the stock manifolds to crack, especially on the turbo side. Often they crack from being forced on. You should bolt the center port on first (you'll notice this port's bolt holes do not have an elongated hole). You should never have to use a manifold seperator brute force method to install these manifolds.

You can stick weld a cast manifold like this. JB weld isn't going to do squat for you.
 
Norm

Norm

Donating Member
Re: Cracked Exaust Manifold

jb weld is a 2 part epoxy. It works for some things really well, just not well enuff on a minfold. Cast welding can be done. Just take the maniofld off,take it to a good welding shop. Or try find one for sale on the site( or e-bay).
 
Loeryder

Loeryder

New member
Re: Cracked Exaust Manifold

I guess I am lucky that mine didn't crack using the spreader to line the holes up.

I started in the middle like Renz said but the holes were still slightly mismatched on the ends.

I was putting L35s off a NA and re-using my SyTy manifolds.

and they can be welded on.
Just need to heat the entire manifold since its cast.
 
4C FED

4C FED

Absolutum Dominium
Re: Cracked Exaust Manifold

MikeRenz said:
You should never have to use a manifold seperator brute force method to install these manifolds.
Click to expand...

Never say never.
Mine are so far off it's ridiculous. The first time I tried heating them up in the oven (500 deg.) then trying to put them on. Yeah, that was a fantastic idea.:rant:
 
attackdog

attackdog

New member
Re: Cracked Exaust Manifold

AJ has a nice set of manifolds if you want to replace them. He is SY1219 on the forums. Hope that helps.
-Dean
 
JSM

JSM

Active member
Re: Cracked Exaust Manifold

If the drivers side is cracked, find someone that has an extra as they rarely crack.

Pass sides now crack often with the weight of turbo on them. I have welded them before, takes a technique and crossed fingers but it can be done. Don't think you can just throw some weld on them though, takes some special prep work before welding and after.
 
JSM

JSM

Active member
Re: Cracked Exaust Manifold

V-ing the crack is part of what i do, everybody has a different style.

You may also need to drill holes at the ends of the crack to get them to stop.

Preheat the manifold, weld with nickel rod, and cool it down as slow as possible.
 
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