Cracked manifolds

[supersix]

The recent increase in fumes in the cabin of my 4.5 made me suspicious, and sure enough when I took the airboxes off I've got a small crack about an inch long on both manifolds just next to the weld where the pipe from the front cylinder joins a little further back.

It looks to me like a good cleanup and a simple run with the MIG will suffice. Bearing in mind I'm new to Cerb ownership but certainly not working on cars, how hard is it to get the manifolds off the Cerb? Presumably you disconnect the cats, unbolt the manifolds and lift. Is there much else needs to come off? I'll admit to not having been underneath the Cerb yet - need to get some decent ramps for it, but time's been at a real premium these last N months....

Does this explain the fumes? Anyone else notice this before finding their cracked manifolds?

Andy.

[Gray_101]

It's a common fault, but you will have to un bolt the engine mounts, remove the drives side manifold first, then move the engine over to get the passenger side manifold out.

Your water rails above the manifolds may also need removing

I think your better off getting them Tig welded, I'm not sure why, but that's what Raceproved are doing to mine along with port matching and ceramic coating

Edited by Gray_101 on Tuesday 17th May 11:59

[supersix]

Gray_101 said:

It's a common fault, but you will have to un bolt the engine mounts, remove the drives side manifold first, then move the engine over to get the passenger side manifold out.

Your water rails above the manifolds may also need removing

Ta for that, sounds feasible.

Gray_101 said:

I think your better off getting them Tig welded, I'm not sure why, but that's what Raceproved are doing to mine along with port matching and ceramic coating

TIG is generally easier to control how much heat you're putting in, which can result in a better joint. MIG's still pretty good though, when carefully applied. When I've got them off I'll make a choice whether to MIG it or take it to my pet welding outfit for a good TIGging.

[pmessling]

MIG you'll have to be careful not to start blowing holes into the metal, how thick is the metal on the pipes? although chain welding would work,

Best bet would be drill the ends of the crack then to Vee the crack slightly and shallow, purge the manifold with argon then tig weld, should give a smoother finish on the inside of the pipe

[jammy_basturd]

I'm MIG welded a set of manifolds, the end result didn't look amazingly pretty, but it did the job. I'm sure a more experienced welder could have done a better job still.

[supersix]

Thanks for the input. I'm pretty practiced (and qualified) with MIG and TIG, but only have MIG at home. Either will work, TIG will look better (but then, the original welds don't look brilliant...)

Sounds like I'll be able to get them off with some effort. Anyone got any thoughts on whether it's the source of my fumes?

[Gazzab]

Are you decatted? Decatted cerbs always have a fumey smell

[supersix]

Gazzab said:

Are you decatted? Decatted cerbs always have a fumey smell

Yep, but seems worse lately. Cats are going back on soon, when I get a chance to have the map checked over at the same since, since it was mapped on the decat pipes. Guess I'll find out then...