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Anyone using Exhaust Manifold Heat Shield or Wraps ??


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Hello again,

 

My initial thoughts are that the car would run much better if it were breathing cold air, basic engineering. But having the air intakes directly above the manifold must cause a few issues on this front no? So I am thinking maybe the fitment of a heat shield below the air filters / above the xhuast manifold. Or using exhaust heat wrap to keep external temps down and an gas exhaust efficiency increase.

 

My plan is to fist fit a tubualr manifold by the way.

 

Also of course I would look to include some descreet cold air ducting to the filters.

 

What do you folks think on this subject and what options have you chose??

 

Cheers

Dave...

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Hello again,

 

My initial thoughts are that the car would run much better if it were breathing cold air, basic engineering. But having the air intakes directly above the manifold must cause a few issues on this front no? So I am thinking maybe the fitment of a heat shield below the air filters / above the xhuast manifold. Or using exhaust heat wrap to keep external temps down and an gas exhaust efficiency increase.

 

My plan is to fist fit a tubualr manifold by the way.

 

Also of course I would look to include some descreet cold air ducting to the filters.

 

What do you folks think on this subject and what options have you chose??

 

Cheers

Dave...

Dave there is usually a couple of stainless heat shields on ebay and likewise for manifold wrap which is definitely necessary if you fit a four branch.

Stuart.

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We have a Stage 2 engine with SAH/TriumphTune 4-branch on my TR3A, and standard engine and cast iron manifold on Lynda's TR4A. Heat doesn't seem to be a problem with either, but both cars still use a dynamo. I would definitely fit a heat shield if I swapped the dynamo for alternator to avoid cooking its delicate little elecronics, but I'm not convinced about wrapping the manifold.

 

Having said that, if someone can convince me that cooling the air to the carbs has a significant performance improvement, then I may change my mind.

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I wa sjust thinking along the lines of "every little helps". Its common knowledge and basic physics that an engine runs better on cold air so the reverse is also true. A tubualr manifold will most certainly give off more heat that a cast example of the same, so wrapping that would be a must for me, well having inlet on the same side anyway. Also just about every tuning company in the world sells air ducting and vents to aid cooling and fresh air into your engine. So why not on a TR? For the small cost involved I reckon its got to be worth it?

 

As a little extra thought, have you felt the diffence on a forced induction car when you fit a large intercooler? Also water sprays are used to bring IAT down further. They dont do that for nowt!

 

I have seen the heat shields on EBay actually, but maybe a bit too bling fo rme? I reckon good old fashinied exhaust wrap is the future!

 

Cheers all

 

Dave...

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Its a long way into the future but when I get to that stage on my TR3a I was going to wrap the exhaust and fabricate a plenum chamber out of aluminium with a duct to just behind the grill - unless I can find someone who sells a ready made item that is.

 

Basic reasoning is that cool air is denser than warm air and as you've already said engines run better on cold air. Many years ago I had an Alfa with twin Webers and that was so much smoother on cool damp mornings that I installed a similar ducting arrangement with noticeable improvement. (It already had a plenum chamber as standard but the inlet wasn't very clever.)

 

Rgds Ian

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Ian and Dave,

 

Revington TR sell aluminium plenum chambers. You can easily fit a duct to behind the grill where it will draw cold air.

 

They certainly fit Webers as I have one of these plenum chambers on both my TR3a and my TR4. They may do something for SU carbs but you would have to call and ask.

 

In terms of insulating manifolds and exhausts, you may wish to consider ceramic coating such as what Zircotec are able to do.

 

It is more expensive than wrapping an exhaust but possibly easier and better. There have been stories of oil soaked heat wrap going up in flames with the inevitable result. In my opinion, ceramic coating is worthy of consideration as an option.

 

Regards

 

David

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Ceramic coating is very nice yes, and quite expensive as you say! Modern heat wrap is flame resistant but I suppose if soaked in oil then the oil could ignite. It would have to be pretty well lashed on and bloody hot though, but still possible. Petrol from the carbs is more of a worry, but I wont go down that route! It woul dhave to be a pretty well soaked bit of insualtion to catch light though, I would be more worried about the oil loss. If its petrol then it will be there anyway and drip straight onto a bare manifold and so burn either way.

 

Wrapping an exhaust is dead easy by the way. Especially if its a new manifold and off the car. Just be sure to use some steel fasteners at the start and end of the wraps so trhey dont get loose and flap about. I like stainless steel cable ties for this job!

 

Ther are heaps of air boxes on the market for twin webbers, all the main names make some kind of air plenum with cone filter end kind of affair. But I must admit to never seeing them for SU carbs, but they must be out there. I will go look see...

 

Just been thinking there, I have seen air boxes with blank backing plates to suit different applications. I bet one of these could be modified to suit?

 

I will see what I can find out and report back.

 

Cheers

Dave...

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Just a quick one, from Zircotec...

 

"Classic and sports cars

Heat soak and the temperature-related degradation of component finish can be greatly reduced by a plasma-sprayed ceramic coating already relied on by five Formula One teams.

 

Desmond J. Smail, one of Europe's leading specialists in exceptional classic Aston Martins, is already using the technique. "Most classic cars have very poor thermal management from new," explains Desmond Smail. "Our customers today don't want to be cooked by exhaust manifolds close to the scuttle or have the finish of their rebuilt engine ruined by heat within a few thousand miles. They also expect reliability equivalent to modern vehicles, so components and fuel systems have to be protected from the heat of the engine. Zircotec's high temperature coatings have proved extremely effective at addressing all of these issues."

 

Smail also points out that the plasma sprayed ceramic coating is often chosen just for its aesthetic qualities. "In its natural state it looks like period asbestos paint, but of course it lasts many times longer making it ideal for competition cars. For road cars, we usually specify a silver finish that matches the engineering quality of the DB series," he says. "We have found Zircotec to be a very professional business, managed by people who genuinely care about quality and service. They are a great supplier for a specialist in high quality, high performance restorations."

 

Manifolds are one of several components that can have these kinds of ceramic coatings applied, helping to protect classic cars from the effects of excessive heat.

 

The Zircotec coating process

The zirconia-based ceramic coatings have a thermal conductivity of less than 1.7 W/m K, so provide an excellent thermal barrier. When applied to an exhaust manifold system the Zircotec coating inhibits the radiation of heat from the surface of the material, holding the heat inside. The coating can also be applied to other components including heat shields and carbon composites."

 

They have it sold to me. I will find out how much it costs and get back...

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How about one of these air boxes...

 

http://www.pipercross.net/competition/prod..._600_airbox.asp

 

Then either get the Blank Baseplate. Or ask for the base plate from this range...

 

http://www.pipercross.net/competition/prod....asp#baseplates

 

Sorted!

 

I have seen many more applications from other companies in the past, but have only ever looked at twin DCOE carbs prior to now. Oh its just like starting off all over again!

 

Cheers

 

Dave

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See TR Tonys comments under this form thread - > alternator heat shield, best supplied item or own design?

 

Tony "uses" his rally car and so it would run quite hot. I was with a guy at the weekend who uses a phoenix extractor manifold and dynamo and hi torque starter - no shielding and he has had no problems. If you really use the car hard all the time e.g. rallying, I guess that is different.

Having looked at the layout, I agree with his comment about getting enough air to the right hand side of the car. this can be ducted from the radiator shroud if you wish.

 

Mal

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Dynamo, starter, alternator, etc will always be fine. I never had concern for them.

 

I am just thinking that every little helps. Yes the car will run with no major issues and will do so for many more years. But helping it along by feeding cool air can only be a good thing. ie.. Will be even better than running "fine".

 

Cheers

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I have seen many more applications from other companies in the past, but have only ever looked at twin DCOE carbs prior to now. Oh its just like starting off all over again!

 

 

Dave,

 

Surely, you have a pair of DCOEs you can fit, then it will be worth getting some cool air in there. ;)

 

I have also been looking for a way of getting cool air in, but I am not convinced with this manifold wrapping. I work on industrial gas turbines and the only fire we have not been able to put out quickly, is when oil soaked insulation kept re-igniting, and this with sophisticated fire extinguishing systems installed.

 

Whilst I appreciate it would be difficult to ignite initially, the fact that it is not easily extinguished worries me, with all that petrol and flammable brake fluid in the same area.

 

Cheers

Graeme

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Never mind yet again, this buyer is certainly very aware!

 

Also wont see what?

 

Can you tell me the number of cases you have personally either seen or experienced yourself with a wrapped exhaust manifold catching fire? (on a car of course) For one, its an exhaust, where would the oil come from to soak it? If I had that much oil in my engine bay I would be more worried about the mechanics than the exhaust catching light? I simply am far too aware (maybe more than many folks that only ever open their bonnets at shows) of my cars mechanics to let it get that far?? Also as Graeme points out, how would it ignite?? There is nothing in an engine bay externally hot enough to light up a fire proof material soaked in a fluid with a flash point greater than the minimum 400 degrees?

 

I can appriciate where Graeme is coming from with the petrol side of things, this could actually happen if a carb decides to leak over night and soak the wrap. So I will accept that one. (Not brake fluid though) But I reckon the smell would give it away pretty quick when you walked into your garage? Probably evaporate under heat before it ignited anyway?

 

Wrapping an exhaust is a common practive in all forms of motorsport (ie sports cars) and has been for many years. It is there for the reason of keeping exhaust temperature contained aiding gas exhaust and minimising engine bay temperatures.

 

Like I keep saying "Every little helps".

 

Ever wished you had just kept your own thoughts and questions to yourself!

 

Graeme, even with SU's they will go better with fresh air mate. I only have one set of DCOE's at the moment. They are 48 SP's and so way over the top for a little standard Trumpet engine. They are currently also on the BDA but I am thinking of converting that to throttle boddies so they may soon be spare?? ;)

 

Also working in the Oil and Gas industry, within the plant integrity side of things I am very familiar with industrial applications such as gas turbines. They are a tad larger scale and do tend to get a fraction warmer than your average TR4. :D

 

I will get off my soap box now. That will be tuppence please?

 

Cheers

 

Dave...

 

PS> I am going to ceramic coat mine anyway. So ner, ner!!

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Hi Dave,

as for prices of ceramic coating 'CamCoat' oop north (Wigan I think) charge apprx £120 (last time I looked) for triple coating of a 4 branch manifold (one internal coat, external under coat plus external finish coat, various colours). I'm surprised how thin the coating is (apprx 0.001" per coat) yet it still keeps the temp down better than the fabric wrap.

 

Roger

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Roger,

 

I hear that the standard ceramic coating if just sprayed on in a normal fashion can break down quiet easily. They are also prone to chips and scrapes and so will rust through (unless you have stainless tubes of course) easily. I read one report from a chap that had his manifold coated and after a short period it failed to an extent that he had to remove it and start again. In his write up he recomended Zircotec, independantly. This method uses a plasma spray which bonds much better, I am told anyway.

 

I actually got this reply from Peter at Zircotec by email...

 

Quote...

 

"Zircotec coatings are proven for application to a variety of substrates including cast iron, providing a high performance ceramic thermal barrier coating, which improves the efficiency of exhausts and prevents local component and chassis damage from radiated heat. In recent independent testing surface temperatures where reduced by up to 173oC when comparing coated with uncoated manifolds, with subsequent under bonnet temperature reductions of typically 30oC.

 

The full process consists of: de-greasing, masking where the coating is not required, grit-blasting, spraying of nickel base coat and finally spraying of ceramic thermal barrier coat. As we use gas plasma spraying process the coating is to the external surfaces only. No preparatory work is required by you. The natural colour of the coating is white/cream, however, we are often asked to over spray with a top finish; routinely we supply silver or black, both in a matt finish for an extra 15% charge. This topcoat is for aesthetics only and has no affect on the thermal barrier properties.

 

Regarding pricing; for the tubular manifolds it will depend upon size but as a guide a compact four cylinder manifold is £228; the four cylinder cast iron is £120 and the downpipe is £135. All pricing is for our standard white/cream finish and exclude shipping and VAT. Turnaround time is a maximum of 10 working days with payment accepted via cheque, credit card or bank transfer. Should you wish to send us the items we will provide a no-obligation quotation for your authorisation."

 

These prices were for me just getting a new tube manifold coated, then the old cast one when removed and a Turbo down pipe for my Tarmac car. The 10 day turn arrond would be a problem for folks during summer unless like me you are fitting a new manifold and so can get it done prior to fitting.

 

I am going to ask for club bulk discount if anyone is interested? Now I know single prices I can work on from there. ANyone else please feel free to drop me a line??

 

Cheers

Dave...

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  • 7 years later...

 

 

I coated the inside of my s/s extractor manifold with special coating from Frost's.

I sprayed the outside with quite a few coats of Sperex VHT paint.

I wrapped the manifold with heat resisting tape and sprayed that with VHT paint.

 

I fitted a s/s heatshield from Revington's to further protect the alternator.

I applied some heat resisting tape to the underside of the heatshield.

 

Tom.

Edited by Fireman049
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Interesting topic. I have a cast iron manifold and I seem to recall reading that only tubular ones should be wrapped. Can anyone confirm and if so, why?

Norman

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attachicon.gifIMG_1091.JPG

 

I coated the inside of my s/s extractor manifold with special coating from Frost's.

I sprayed the outside with quite a few coats of Sperex VHT paint.

I wrapped the manifold with heat resisting tape and sprayed that with VHT paint.

 

I fitted a s/s heatshield from Revington's to further protect the alternator.

I applied some heat resisting tape to the underside of the heatshield.

 

Tom.

 

Is your engine running yet, Tom?

 

How is the wrap attached to your exhaust manifold? One can't be sure from the photo, but it looks kinda like nylon zip-ties. That's surely not right, is it?

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Hi Don ~

 

No, my new engine is not running yet. Perhaps it never will after my recent sad events!

The exhaust system worked perfectly with my old engine ~ quite a heat reduction believe me.

 

The exhaust wrap is secured with stainless steel zip-ties.

 

Regards ~

Tom.

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Hi Don ~

 

No, my new engine is not running yet. Perhaps it never will after my recent sad events!

The exhaust system worked perfectly with my old engine ~ quite a heat reduction believe me.

 

The exhaust wrap is secured with stainless steel zip-ties.

 

Regards ~

Tom.

 

Thanks, Tom -- that makes a LOT more sense. The zip-ties looked surprisingly "white" in your photo, and not silvery.

 

You'll get there with your car. Not today, and not tomorrow, but with time. Hang in there. Like many on here, I wish you peace and strength.

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Hi Don ~

 

Very many thanks for your kind thoughts.

 

The s/s zip ties look 'white' because they've been sprayed with VHT paint.

I gave the manifold a final overall coat of VHT paint prior to refitting it.

 

Incidentally, I double wrapped the No.1 branch pipe nearest the alternator

and double wrapped the pipes running next to the starter motor.

 

Best regards ~

Tom.

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Hello again,

 

My initial thoughts are that the car would run much better if it were breathing cold air, basic engineering. But having the air intakes directly above the manifold must cause a few issues on this front no? So I am thinking maybe the fitment of a heat shield below the air filters / above the xhuast manifold. Or using exhaust heat wrap to keep external temps down and an gas exhaust efficiency increase.

 

My plan is to fist fit a tubualr manifold by the way.

 

Also of course I would look to include some descreet cold air ducting to the filters.

 

What do you folks think on this subject and what options have you chose??

 

Cheers

Dave...

I have a Phoenix manifold that's wrapped and I've used lock wire to keep it tight. I've just fitted the Revington alternator shield too so it's all groovy.

 

My air box is to be welded now it's cut to suit the Webers and will be fed with fresh air via an air filter sitting inside the rad cowl and duct to the air box. Fresh air is as you say a good thing to the carbs.

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