Exhaust manifolds / headers.

[Hugo]

That's nice - what is it? Did you smooth the cast surface down first?

[Heuer]

Huh? VHT is $9.49 at my FLAPS. How much is a can of BBQ paint? Do they give it away for free?

VHT is £9.99, B&Q Stove and BBQ paint is £6.93. Rustoleum BBQ paint is £7.50. Blackfriar BKFHRB250 250ml Heat Resistant Paint is £7.90 with the added benefit is comes in a conventional tin for application by brush so you can touch up the manifolds every year without having to remove them. All these are rated to 600°C.

Oh I dunno - it makes sense to me - the thing about the Jet-hot process is that they coat the inside as well as the outside; if you use a reflective silver coating it will work like a Thermos flask & the heat will go out the taipipes. Black would of course be less effective, but they claim it still makes a significant difference.

Well they are not going to say "it makes no difference whatsoever"

[64etype]

I've used the ceramic coating process on three previous engine exhaust systems. On the Bitter SC (3.8 Opel six) I had to stand back when I opened the hood after a drive on a hot Texas day (100* F). No way I could place my hand in the engine compartment. After the conversion to a 5.7 GM V8 with ceramic exhaust I could place my hand next to the header under the same conditions. Ceramic is used extensively by the racing community, presumably for a performance reason. Piston tops are coated with ceramic...presumably for a reason. But aside from the thermal properties, it looks better than rust and it stays put without periodic touchups.

[64etype]

That's nice - what is it? Did you smooth the cast surface down first?

Ceramic. Not my car.

[Hugo]

Well they are not going to say "it makes no difference whatsoever"

True enough, but their claim is based on the fact that they apply the coating inside as well as outside, unlike other companies (they claim!).

[jag68]

I do a lot of auto crossing in my E Type with a big valve head. When I installed a set of headers from XK's Unlimited (not long branch) I noticed an immediate drop in low to mid range torque. It was readily noticeable so it was significant enough. High end power was improved - the car wanted to rev. If you only drive on the street I think a header system is a waste of money.
I used to live in Calgary which is a major oil town and has many industries that "coat" things to protect them. I had several companies "porcelain" my manifolds in gloss black. None ever lasted beyond what the factory did. I think it's a hopeless project to try. One solution is to have your cast manifolds polished, or do it your self, its not a difficult job (dirty though), and them apply one of the flat black high temp paints, following the instructions. After it's baked on take a soft rag and polish them. They should come up to a very nice soft shine that's close to porcelain, but lasts. With the manifolds smoothed it looks great.
I had ceramic coating done, inside and out, on my exhaust system on my race car ('65 coupe). The headers stopped peeling the paint off the frame tube that ran by them so I know it works, at least at very high temps. Your idea of having the inside of the manifold coated to protect the porcelain may have some merit but....... the issue with the porcelain detaching seems to have to do with different rates of expansion and contraction loosening the bond, so...? Worth a try I think.

Terry Sturgeon

[Hugo]

Thanks - I spoke to a metal polisher yesterday about smoothing them & he said no problem, so that's a start.
One question - do RHD cars have a heatshield between the headers and the frame like the LHD cars do? I don't recall seeing them but I think it would be a good idea, with the battery & wiring loom in close proximity.

[cactusman]

Painted my standard exhaust manifolds with sperex....brilliant...the rhd cars have no heat shield...really the wiring is far enough away...mostly

[mgcjag]

My RHD S2 2+2 has a heatshield between the headers and the frame, protecting the servo..dont know when Jaguar started fitting them...... Fossways do a nice one http://www.fossewayperformance.co.uk/servo-heat-shield/

[mark10337]

also look at zircotec
https://www.zircotec.com/exhaust-coatings/

They have done eType mainfolds before, although I've not been able to find the owners who had them done or if the cars are "drivers" to test the durability of the coating.

[Heuer]

My FHC had gloss black Zircotec on the cast manifolds. Turned to dust in the first 500 miles of my ownership! The PO had also had the entire exhaust system treated in silver which was supposed to reduce noise and temperatures. Seemed to make no difference in either respect and I quickly replaced the entire system with a mild steel one, which sounds glorious and does not produce excessive heat.

The coatings are a waste of time and money in my view! Jaguar only coated the cast manifolds so the cars looked good in the showroom and they knew it would fall of very quickly although I am not sure if it was covered under warranty.

[Hugo]

I seem to recall way back in the last century when I used to work in a garage, the manifolds on the few Jags that came our way (not E Types unfortunately) held up reasonably well. Mind you, the more 'gentlemanly' saloons we saw were probably driven more gently than yer average E Type.

[AshM]

I use a stove enamelling paint from ‘Stationery Engines’ here in the UK. They look good for a couple of years.

So every other winter remove them, have them fully cleaned off at local blasters, single coat and 20 minutes in the oven at 140.

Works a treat and they retain the black gloss well.

Cheers
Ash