Jaguar exhaust manifolds, why?

[3.8 MOD]

I'm thinking about pre 70s straight sixes, (maybe they had them after but I'm not familiar with that era).
Why were they enamelled?
Even new ones last only a short time.
Obviously they looked really good when new but the enamel would start cracking and flaking within a couple of years yet they continued the practice.
Any ideas anyone?

[neutral 3]

From owning many E Types etc in the past, i think that the exhaust manifolds were vitreous enamelled. But they were all laughably heavy !

[lowdrag]

Which is why, four years ago when we found that my manifolds (which had lost all their enamel 20 years before) were cracked, I replaced them but not enamelled. I used BBQ paint which cost £10 a tin and which is still as new. Plus I have a load left over if I need to repaint. That's 7,000 miles by the way

Edited by lowdrag on Thursday 13th December 11:28

[//j17]

And yet, ceramic coating exhausts is one of the new "big things".

Maybe Jaguar were just ahead of the curve - and being the 70s in the UK using 40s technology applied between strike votes.

[a8hex]

3.8 MOD said:

Why were they enamelled?
Even new ones last only a short time.

I think they lasted much longer when they were originally done. They just haven't lasted 60+years.
When I bought my XK150 it 47 years old and the enamel wasn't in bad condition.
I remember a discussion on Jag-Lover's XK forum about this topic, I suspect it comes up regularly. The process they used at the time wouldn't be allowed now, all sorts of noxious chemicals were involved. Re-coating them can't reproduce the original conditions, over the years of use containments seep into the metal. I can't remember what was said about the new replacement manifolds, but I think someone pointed out the composition isn't the same as was available in the 50s.
There are alternative treatments, as Lowdrag says, he's just used a suitable paint. One person on the XK forum just seasoned the ones on her XK120 in the same way she did with the cast iron range and fire back. The photos looked great.

[droopsnoot]

lowdrag said:

Which is why, four years ago when we found that my manifolds (which had lost all their enamel 20 years before) were cracked, I replaced them but not enamelled. I used BBQ paint which cost £10 a tin and which is still as new. Plus I have a load left over if I need to repaint. That's 7,000 miles by the way

I keep meaning to get some of this, I think you've mentioned it before. I've done my restoration with VHT exhaust manifold paint, and it didn't last as long as it took to get it from installing the engine to getting its first MOT since 1988, so I'm unimpressed.

[EXKAY120]

Would probably work on my log burner also ??? does it come in black tony ?

[lowdrag]

On enameled manifolds, it was well known that if you exceeded 60 mph it would start to crack with the heat, so if you ever see an E-type with perfect manifolds you know why. The new method of treating them seems to have a marmite finish, some staying beautiful and others not, but again, that could be because the car isn't driven as Sir William intended. Maybe someone will give us chapter and verse on the subject. That is black BBQ on my exhausts by the way and I think we got it from B&Q. Last of the big spenders me. You can find it here:-

https://www.amazon.co.uk/dp/B073RMCBWP/ref=sspa_dk...

800C should be enough!

Edited by lowdrag on Wednesday 12th December 12:57

[3.8 MOD]

lowdrag said:

On enameled manifolds, it was well known that if you exceeded 60 mph it would start to crack with the heat, so if you ever see an E-type with perfect manifolds you know why. The new method of treating them seems to have a marmite finish, some staying beautiful and others not, but again, that could be because the car isn't driven as Sir William intended. Maybe someone will give us chapter and verse on the subject. That is black BBQ on my exhausts by the way and I think we got it from B&Q. Last of the big spenders me. You can find it here:-

https://www.amazon.co.uk/dp/B073RMCBWP/ref=sspa_dk...

800C should be enough!

I think that black finish looks really good.
I replaced one manifold on my series 2, I think I bought it from SC spares. The enamel didn't even last two years!
I see your coil is mounted in the correct place, no problems with it cooking itself?
I had that problem on two occasions until I mounted it away from the engine.

Edited by lowdrag on Wednesday 12th December 12:57

[lowdrag]

I've had one coil fail in over 30 years, but always carry a spare just in case. The coil has always been in the correct place from day one. Maybe you just were unlucky?