heat shield or insulate exhaust downpipes?

[RichC]

having replaced the the original two piece manifold & (rotten) 2 into 1 downpipe with a nice 4 into 1 mild steel set from Jono I am struck by how much extra heat there is in close proximity to control box and clutch slave cylinder & piping . I can reroute the clutch pipe .
it would be possible to jig up a heat shield to protect the clutch slave cylinder , but for the passenger footwell I see some nice blingy gold stick on heat shield .....
Found this on ebay & it seems a neater solution to the containment of exhaust heat .
http://cgi.ebay.co.uk/50mm-heat-protect ... 286.c0.m14

what's the downside ? I've already painted the downpipes so there's no exposed steel to attract condensation .

if anyone has done this before perhaps they can tell me how far 10 metres goes when wound round . if i am taking it from the exhaust ports all the way down to the y piece would it be enough?
RichC

[Old English White]

having replaced the the original two piece manifold & (rotten) 2 into 1 downpipe with a nice 4 into 1 mild steel set from Jono I am struck by how much extra heat there is in close proximity to control box and clutch slave cylinder & piping . I can reroute the clutch pipe .
it would be possible to jig up a heat shield to protect the clutch slave cylinder , but for the passenger footwell I see some nice blingy gold stick on heat shield .....
Found this on ebay & it seems a neater solution to the containment of exhaust heat .
http://cgi.ebay.co.uk/50mm-heat-protect ... 286.c0.m14

what's the downside ? I've already painted the downpipes so there's no exposed steel to attract condensation .

if anyone has done this before perhaps they can tell me how far 10 metres goes when wound round . if i am taking it from the exhaust ports all the way down to the y piece would it be enough?
RichC

Richard(?),
Have a quick look to twincams pictures on the net , you ll made your own answer . Nobody use other solution than heat shield ...
That Ebee solution if effective will made your manifold just bigger and more difficult to bolt on.
Personnally I used a piece like this :

Christian.

[Tonyw]

Rich,

I am in the process of rebuilding my 67 DHC and have a set of mild steel headers similar to yours, they were chromed but have surface rust so i have had the chrome removed, like you I am concerned about the amount of heat transfered to the body.

I have read some good things about ceramic coating with many people saying that this reduces heat significantly...i do not understand how it works or even if is dose in fact work but I am proposing to do mine however as my car will not be completed for at least 18 months I will be unable to let you know the outcome.

Has anyone on this forum actually had their pipes ceramic coated and if so is the heat reduced??

Tony Warner

[Tonyw]

All,

OK so I was a tad lazy, just looked at the archives and it seems that quite a few Loti owners have used ceramics with apparent success, can any of you report on how the longevity of this coating is holding up?? and do any of you have any detailed results on tempreture reduction??

Tony W

[rdssdi]

http://www.designengineering.com/produc ... =sp&pid=27

I used DEI heat barrier. I was told it could be used "outside" exposed to water etc.

I shielded all body tunnel areas and engine compartment in proximity of exhaust headers.

Self adhesive. Easy to use but requires care when cutting as metal "skin" is tough.

I also had my headers Jet Ht coated.

They still throw off a lot of heat but the fiberglass has bee well protected with the heat shielding.

Bob
1969 Elan 2
1968 TVR Vixen

[prezoom]

I have been using ceramic coatings on exhaust headers on my race car for severa years. At the first opportunity, I had the pipes coated on my S2. in both cases, it has reduced the termperatures surounding the exhaust a measurable amount. Though I have not actually measured the temps on the Elan, I have on the race car and it amounted to several hundred degrees. I have the coating applied to both the inside and the outside of the pipes. In addition to the coatings, I fabricated a stainless steel heat shield that stands off the foot box for air circulation and protects the clutch pipe as well.

On the gold stick on insulation material, recently I was at Pratt Miller in Michigan looking at the class winning Corvette from LeMans and talking to its crew chief. At the time he was showing us the new GT2 cars and I noticed a significant amount of the gold insulation in the cockpit area. When asked about its usefulness, he replied it wasn't that good. They have used a spray on insulation that works magic in insulating the cockpit, but it is not water proof and must be applied only on interior panels.

Rob Walker
26-4889

[RichC]

thanks Rob,
i guessed maybe the gold stuff was for show rather than anything else.
As my downpipes are already in situ ( & i spent hours fiddling around trying to get them into position....had to remove LH engine mount, jack the engine up a bit , remove servo, servo bracket , control box ) I'm opting for the ceramic wrap lagging. I'm used to taping racing bike handlebars & have opted for the narrow stuff . i know it's gonna be awkward, but i hope it will be a relatively simple & neat solution . upstairs in the loft i have a reel of brass piano wire left over from restringing my old square piano years ago.. i'm nothing if not resourceful.
RichC

[freddy22112211]

A piece of alu plate in the centre of the air gap keeps the fibreglass at the foot well at normal temperatures, ie no hotter than anywhere else in the engine area - probably a lot cooler than the bonnet (hood) even.
Gordon

[prezoom]

Hi RichC,

Prior to resorting to ceramic coatings, I wrapped the headers on my race car with an insulating tape. I believe because of the sustained high temperatures during races, the headers/down pipes, being wrapped tight and holding in the heat, soon developed cracks. However, in normal day to day driving, I would think the wrapped pipes would not reach the sustained high temps and may last forever.

So far, I have had good luck with the ceramic coatings. The replacement headers on the race car were new when coated. The ones on the Elan were well used and required internal, as well as external sand blasting to present a clean surface. The only problem encountered with this process, was there was some warping of the headers, cylinders 1 and 4, after the coating process. It took some time to tweak the headers back into alignment to fit the head. That was a bit of a hassle. I don't think this would have been a problem if the headers were unused.

Be sure to let us know how the project works out

Cheers and good luck,

Rob Walker
26-4889

[bcmc33]

I simply glued HeatMat to the passenger side wall. I also glued and dangled a piece of HeatMat to the bulkhead (firewall) to protect some cables.

I bought HeatMat from CBC

http://www.cbsonline.co.uk/heatmat-htmat-1567-p.asp

[rocket]

Do you think that helps keep the heat out of the car Brian?


Ian.

[jkolb]

I have an Elan, but it is still under construction so I will comment on my experience with my Exige S. The Toyota manifold that is standard on the engine used in the Elise/Exige i made up of a cast header flange and tubular pipes in a 4-1 configuration. These pipes are within 3-4 inches of the fiberglas of the boot, and have a metal heatshield that stands off the pipes by about a half an inch. Looks ugly and, well, you know the Lotus owner thing about weight, I wanted to throw it away. Anyway, I took the header off and did some mild cleanup work inside, then took it to my local powdercoater. He recommended coating the inside with the same barrier coat ceramic that they use on the tops of racing pistons, with a cosmetic ceramic on the outside. I chose an aluminum looking finish for the outside.

In any event, the coating, including sandblasting the header inside and out, cost $120 US. The results were amazing. I can run the car hard, open the engine lid and put my hand within an inch of the header tubes without discomfort. The boot surface is merely warm.

I strongly recommend this approach. You can choose a wide range of colors for the outside. I am going to use a satin black for my Elan header.

Jerry

[bcmc33]

Do you think that helps keep the heat out of the car Brian?

I'm sure it does, but the real reason I did it was to protect the fibre glass from the direct heat of the exhaust.
As you can see from the picture, I've removed the lump from the bottom of the vertical face that I always thought was too close to one of the downpipes. When removing the lump it was evident that the heat had seriously affected the integrity of the fibre glass that made the lump. On removing the lump I made good the resultant hole with resin and f/g and added a couple of layers on the inside surface.

After a short run-out, and the engine ticking-over for 15 minutes playing with the idle bye-pass, I was not able to feel any 'hot spots' on the footwell surface. Only then did I glue the carpet back into place.

[freddy22112211]

As I said once before the heat had, over the years, made (burnt?) a hole in the fibreglass next to my header! So it seemed like a good idea to do something about it!
Gordon

[Lincoln62]

I had the exhaust manifolds on my Lincoln ceramic coated and it makes a big difference to the engine bay temp. When I get new headers for the Elan I will have them coated for sure. I am a fan.

Pete
66S2