Exhaust manifold

H

hughc

Forum User
Hi all,

Just wanted a bit of advice re. changing an exhaust manifold on my 280zx. When I bought it, it had a manifold gasket leak which I got replaced (plus a lot of glue apparently). Running beautifully for a few weeks, otherwise in really good condition and now it's started leaking again. My mechanic thought this might happen and tells me the original leak had damaged the manifold. He reckons it might be a nightmare job to replace the manifold and can't venture an estimate, but is confident that would solve the problem. Can anyone give me any advice on whether it really is as difficult a job as he tells me and how much labour might cost?

My options are either go for it and have it replaced or sell it on for someone with a bit more time and experience.

Thanks,

Hugh
 
P

pmac

Well-Known Forum User
hughc said:
Hi all,

Just wanted a bit of advice re. changing an exhaust manifold on my 280zx. When I bought it, it had a manifold gasket leak which I got replaced (plus a lot of glue apparently). Running beautifully for a few weeks, otherwise in really good condition and now it's started leaking again. My mechanic thought this might happen and tells me the original leak had damaged the manifold. He reckons it might be a nightmare job to replace the manifold and can't venture an estimate, but is confident that would solve the problem. Can anyone give me any advice on whether it really is as difficult a job as he tells me and how much labour might cost?

My options are either go for it and have it replaced or sell it on for someone with a bit more time and experience.

Thanks,

Hugh
Click to expand...

Is it a stock cast manifold or aftermarket header/tubular??
where is it damaged/leaking????
 
SeanDezart

SeanDezart

Well-Known Forum User
"He reckons it might be a nightmare job to replace the manifold"

For what reasons given - lots of people replace their stock manifolds with after market ones and I can't see how a leak can damage the metal.....!
 
H

hughc

Forum User
It's a stock manifold. Not sure exactly where the damage is but I was told the previous leak was major and had been going on a while and the hot gases had corroded the metal. He said the difficulty of replacing it would be because a lot of other parts need to come out to remove the old manifold and he can't guarantee it will come apart easily/without further damage on an old car.
 
R

rallymanDP

Well-Known Forum User
The original cast Iron Exhaust Manifold can corrode away to leak just about anywhere, but is more common at the joints or at the interface with the Cylinder Head.
It can often 'warp' at the Head to blow with the same result.

Yes, it is complicated to remove it as it comes with the Inlet manifold sitting on top and has heat shields to remove beforehand and all sorts of hoses, etc. to disconnnect.

It can be repaired by the Arc Welded method, but can then blow again somewhere else. So, better to replace it with another from a breaker 280ZX, and it will still take a decent mechanic at least 4-5 hours to do it properly.
 
zpuppy

zpuppy

Well-Known Forum User
You beat me to it rallyman,, cast exhausts can and do warp and corosion is often a problem as well. It's not a huge job for DIY, just lots of stuff to come off. Repair with weld and machine the faces on a known good turret mill ,and use a GOOD gasket set and all should be well . Machine shop work wont be cheap, but if done properly should last ages. :driving:
 
SeanDezart

SeanDezart

Well-Known Forum User
Why not merely fit a goof second-hand one (there must be some out there hanging around in peoples' garages after all the ZXs broken for parts) or an after-market one from MJP ?
 
H

hughc

Forum User
Yeah I was planning on getting one from a breaker. Sounds like its not the end of the world, thanks for the advice!
 
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