To wrap or to not exhaust wrap

[tomkidd]

Gents

As you some of you know I like things to look nice being a designer... I've always wrapped my exhaust manifolds more so for the visual appearance. Each time I have to do something on the car though it seems to get damaged and thus need replacing.

As I'm about to drop the engine back in I wondered if you thought I should just sack it off?

Do any of the top racers use it?

[mk1]

All top racers use it, it makes a massive difference to under bonnet temperatures in Minis.

[rich@minispares.com]

however, it can move the heat under the car, thin the exhaust manifolds, let the manifolds get too hot so they crack

its not the be all and end all

[tomkidd]

Cheers Gents

I think I'll stick with and buy some more.

[Pete]

Swifty uses special coatings now.

[Rubber Sprung]

Don't wrap the manifold ,it will overheat and start to collapse inside the wrapping .first thing you notice is a lack of power !we have seen this on quite a few race cars .

[mk1]

Swifty uses special coatings now.

Something like this;

http://www.performance1coatings.com/?gc ... Agrt8P8HAQ

Probably a better option than a wrap.

[tomkidd]

Don't wrap the manifold ,it will overheat and start to collapse inside the wrapping .first thing you notice is a lack of power !we have seen this on quite a few race cars .

I've examined the manifold and it looks in perfect condition after being wrapped before

[Vegard]

however, it can move the heat under the car, thin the exhaust manifolds, let the manifolds get too hot so they crack

its not the be all and end all

Yes it is. You just buy new manifolds with oil money...

[mk1]

[rich@minispares.com]

Yes it is. You just buy new manifolds with oil money...

trouble is, that in your case verg,

its snake oil..........................

[foxy52]

Gents

As you some of you know I like things to look nice being a designer... I've always wrapped my exhaust manifolds more so for the visual appearance. Each time I have to do something on the car though it seems to get damaged and thus need replacing.

As I'm about to drop the engine back in I wondered if you thought I should just sack it off?

Do any of the top racers use it?

...Well I have always used Thermotec wrap on my Maniflow manifold systems.. they have lasted so well and I have never had any problems at all.. and that with a car that I belt from time to time with 98bhp on tap !!!... only used 2 systems in 15 years !!!.. advantages outway the faff of having to replace.. my engineer reckons u can use the stuff twice if your carefull mummifiying !!lol.... just got back from having my S mot,d today.. I use the same garage year in year out.. the father of the brothers that run it had a Morris dealership from 29-68 !!!.. he sold 320 minis in North Norfolk as the records show !!! ..anyhows moral is stick with the same garage year in year out 10% disc on mot,s for regulars to ..as they know the car it makes for an easier appraisal/test.. mine passed hurrah !!!....foxy52.

[pad4]

General rule with wrapping is not to wrap the welds - this is what makes them crack , i dont wrap my 5 porter but i do wrap the 8 port as theres that much heat coming off it and radiating upwards warming the clutch master and slave cylinders and trying to melt the grp bonnet - but i only wrap the top part

on a 5 port i can see that wrapping would help possibly keep the carbs cooler but would only be of use on a full blown racer - that actually gets really hot

pad

[ianh1968]

My manifolds always crack anyway, even though I use the correct
brackets and have all the extra engine steadies. My exhaust is also
"hung", not fitted...

I've used the Thermotec 1" wrap and it does make a lot of difference
to the under-bonnet heat. The stainless ties are just plain evil, but
once you've got the stuff on, dried and sprayed with the correct
"paint", it's reasonably durable. It is a bit itchy when bashed about,
which is something to be wary of.

Most importantly, I no longer burn my hands when adjusting the carb
mixture on a hot engine. For that alone, I think it's worth doing...

Ian

[In the shed]

I'm just thinking chemistry here.....

You wrap your manifold and it attains a higher operating temperature. This presumably makes it more reactive....assuming it is the case that it falls to bits due to chemical degradation, rather than melty degradation!

So, what in the exhaust gas is causing this problem? An obvious culprit is O2. Why is there too much O2 in the exhaust gas? Is this a mixture thing, or an overrun thing? Are there any other components which could combine with iron? Partially burned carbony things? CO? Whilst Iron does form carbonyl compounds (with CO) it's not really something you'd expect.

Could it be that the O2 is percolating through the wrap and then reacting with the extra hot metal?

I wonder if it's an idea to polish the outside (reducing the surface area) before wrapping.....or whether you could coat the inside with something unreactive.....a bonded oxide layer, ceramic, etc.