P38A Exhaust headers looking a bit yikes

enjoi · Feb 19, 2022

I’ve been enquiring with an exhaust place near me about options for my P38. I’ve noticed the headers/flange look quite rusted.

do you think I should go for an engine back system rather than cat back given the state of it? Or am I overreacting

I’ve attached some snaps

thanks!

Grrrrrr · Feb 19, 2022

I think when you see the price you'll leave it until the head gasket goes and you have to move it.

tomcat59alan · Feb 19, 2022

Look ok to me, heat shields starting to go but as said leave them until you have to.

Marshall8hp · Feb 19, 2022

Nothing wrong with those.

kermit_rr · Feb 19, 2022

Looks healthy to me

Ratae · Feb 19, 2022

Look fine to me too. Bit of surface rust.
As long as the mating surfaces are good then carry on with them.

brianp38dse · Feb 19, 2022

Unless you fit stainless headers all the steel ones will look like that after awhile, look like normal 20year old headers to me.

Rubberknees · Feb 19, 2022

As an old boss of mine used to say If it ain't broken don't mend it. Look OK to me

Datatek · Feb 19, 2022

Looks fine to me,

Ratae · Feb 20, 2022

brianp38dse said:
Unless you fit stainless headers all the steel ones will look like that after awhile, look like normal 20year old headers to me.

Be careful with stainless systems.
Got a sports system with tubular stainless headers on my classic. Fitted around 20 years ago.
Surface rust on the header flanges & all tubing - the boxes are still shiny so I suspect more than one grade of stainless used.
Did a top end rebuild about 3 years ago & the state of the gasket faces on the headers was absolutely shocking. Rusted & badly pitted & needed refacing to get a decent mating surface. The cylinder head faces were fine.

DanClarke · Feb 20, 2022

Those exhaust manifolds withthe concertina expanders are about £450 each I think. Leave well alone until you have to touch them.

Grrrrrr · Feb 20, 2022

Ratae said:
Be careful with stainless systems.
Got a sports system with tubular stainless headers on my classic. Fitted around 20 years ago.
Surface rust on the header flanges & all tubing - the boxes are still shiny so I suspect more than one grade of stainless used.
Did a top end rebuild about 3 years ago & the state of the gasket faces on the headers was absolutely shocking. Rusted & badly pitted & needed refacing to get a decent mating surface. The cylinder head faces were fine.

Definitely check the grade of stainless used and that it isn't just the boxes but the whole system.

RangeRoller dt · Feb 20, 2022

Seem very clean in the photo if they were problematic everything around there would be stinking dirty
If you take the cat-back part off I would start her up, then block the exhaust with my hand (wearing heatproof glove) if it cuts out it’s fine if there’s issue you will see it leaking.

Ratae · Feb 20, 2022

Grrrrrr said:
Definitely check the grade of stainless used and that it isn't just the boxes but the whole system.

I did when I got it.
The boxes are not magnetic but the rest of the system is.
Bit of a rough & ready test I suppose, but the fixings on the boat aren't magnetic either & I've never had any issues with those.

To be fair, the pipes have surface rust but that's as bad as they've ever got.

The visible parts of the header flanges - one for each cylinder - are surface rusted but I was

&

when I saw the faces that contact the gaskets!

Rubberknees · Feb 21, 2022

Ratae said:
I did when I got it.
The boxes are not magnetic but the rest of the system is.
Bit of a rough & ready test I suppose, but the fixings on the boat aren't magnetic either & I've never had any issues with those.

To be fair, the pipes have surface rust but that's as bad as they've ever got.

The visible parts of the header flanges - one for each cylinder - are surface rusted but I was & when I saw the faces that contact the gaskets!

If magnetic more than likely galvanized

Ratae · Feb 21, 2022

Mine are definitely not galvanised mild steel.
There are a large number of grades of stainless that are magnetic.
My boat ones - fixings & a few plates - are A4 (aka 316) and not magnetic.
No doubt down to cost, as austenitic s/s is more expensive then ferritic or martensitic.

As not immersed in water it can't be galvanic corrosion.

Datatek · Feb 21, 2022

Rubberknees said:
If magnetic more than likely galvanized

Not so, low grade stainless is magnetic. All stainless corrodes to some degree look at 5 year old mast stays on a sea going yacht under a microscope and they are full of little corrosion holes.

Datatek · Feb 21, 2022

Ratae said:
Mine are definitely not galvanised mild steel.
There are a large number of grades of stainless that are magnetic.
My boat ones are A4 (aka 316).
No doubt down to cost, as austenitic s/s is more expensive then ferritic or martensitic.

As not immersed in water it can't be galvanic corrosion.

Beat me too it and with more detail

P38A Exhaust headers looking a bit yikes

enjoi

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Grrrrrr

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