exhaust Exhaust Header/Manifold Wrap

[oldtuckunder]

Hi All

 

Got all the induction and exhaust removed today, bit painful as it was this time last year I was loving assembling it, but I need the new AFR bosses welded in, so off it all comes.

 

When I was lifting off the 6 branch I noticed that the heatwrap lovingly applied last year was crumbling away in my hands!

 

Now in itself not a problem, as it all has to come off and be re-done after the welding. But in principal its a problem, here we have an engine that by my guestimate from rebuild has run for about 12-20 hours.

 

Its a shame Standard didn't think to incorporate the hour meter from the Tractor Speedo when building the cars:-)

 

 

But anyway this exhaust wrap is "Toast" literally, its all in place and looks perfect but I'm sure if I had put a pressure washer in the engine bay it would have just blasted it all away. As it is just prodding with anything and it just breaks and shreds.

 

So did I just buy some cheap exhaust wrap? Well I thought not at time, and it came from a reputable performance house which I won't name as some further research suggests that they didn't sell **** deliberately.

 

So from a few hours Googling it appears that the majority of exhaust wrap is all the same, doesn't matter what it's called who it's made by, or what special magical treatment they claim to have applied to it.

 

They are virtually all manufactured from E grade Fibreglass yarn that has a base maximum operating temperature of 1000°F. or around 550°C.

 

Note that is maximum and there appears to be a lot of evidence around that continuous temperatures a fair bit below that the fibreglass yarns just bake and go brittle.

 

Now in the upper header region on a normally aspirated petrol engine running hard I would be expecting somewhere in the region of 800-850°F, which if true and the state of my exhaust wrap after not that much running concurs that Fibreglass yarn bakes and goes brittle fairly quickly in that temperature range or below.

 

OK so is there anything better?

 

There are a couple of products around that "claim" that their fibreglass yarn based product is better because it has had thing like Titanium added to make the weave stronger, or Graphite to increase its abrasion resistance, or its fibreglass is made from Lava, or it has been treated with some potion to make the fibreglass handle higher temperatures.

 

But I'm a bit suspicious, some of it sounds a bit like snake oil, and I can't get it out of my head that if fibreglass yarn cooks at/below 1000F, then it will cook at that temperature what ever you treat it with.

 

Anyone been through this issue and found a better wrap?

 

I have found one product from Heat Shield Products that they call "Inferno wrap" which they claim:

 

"When you want all the benefits from exhaust wrap, but require a higher temperature for your manifold or turbo application then Inferno wrap will do the job.
Unlike other forms of Silica wraps made from leached fibreglass, Inferno wrap is manufactured from texturized amorphous silica filament yarn.
It is strong and flexible while operating at its designed service temperature of 1093.3°C (2000°F) continuous and 1648.8°C (3000°F) intermittent."

 

Now I'm no chemist but I thought plain fibreglass was made from silica filament yarn, so I'm not sure what adding "texturized amorphous" actually does. Anyone know?

 

Now I don't mind giving it a go, but it is double the price of the expensive Snake Oil fibreglass versions, so I don't want to waste my money.

 

Otherwise my research seems to say buy the cheapest you can find of a given thickness, as its all much of a muchness if its made from fibreglass yarn.

 

Thoughts anyone?

 

 

Alan

[graeme]

Alan,

 

My thoughts are, don't bother!! More trouble than its worth.

 

If you do need something, then ceramic coating is the way to go. http://www.zircotec.com/

 

Cheers

 

Graeme

[Dave Larnder]

Alan

 

On my TR3A I wrapped with the stuff that Moss sells and it has been on now for 12000 miles with no degrading so far,I wrapped the four branches separately at first, then into pairs where they met and finally into one which I continued through to almost the cruciform as that was the end of the second roll.

I find that it improves the gas and heat flow as I don´t get any heat in the cab BUT I do get a slight discolourisation of the left side rear over-rider which indicates that there is a lot of heat coming out of the tailpipe, which has to be a good sign as heat is being blown out the back away from the engine and car.

 

Dave

[oldtuckunder]

Alan

 

On my TR3A I wrapped with the stuff that Moss sells and it has been on now for 12000 miles with no degrading so far,

Hi Dave

I carefully spent half an hour responding to this, but as too frequently happens this crappy forum software crashed between the review and post and has lost it all!

 

Who ever writes this stuff should be shot it spends most of its time trying to make links to third party web sites like twitter, google+, facebook, you name it, and if they fail what your doing gets trashed!

 

has anyone ever "liked" or +1'd a thread in this forum?

 

Anyway I'll hopefully find the will power to recreate tomorrow

 

Alan

[BrianC]

Alan,

 

I learned long ago that when writing anything more than a few lines in reply to an email or post on any forum, that it is far safer to write offline in a text or word processor and then copy and paste into the online application. If it fails, then you can simply try posting again later and at least you avoid having to repeat the thought process and retyping. Also useful if your post gets deleted, individually or along with an entire thread.

[McMuttley]

I would have thought the Motorsport guys would know what the best heat control treatments were - the various providers tend to 'haunt' the paddocks

[Davidw]

Just adding a plus 1 for Zircotec. Best money I have ever spent on the TR!

[oldtuckunder]

Hi All

Sorry for the delayed follow up, but it took a few weeks to get the heat wrap from the states, and been busy since trying to get the winter rebuild bits back together so that I'm reeady for Gurston at the end of the month. Engine ran again for the first time today and I don't seem to have broken anything. Anyway the new heat wrap was way stiffer than the normal fibreglass wrap, and on first run smoked a fair bit less. So I guess I'll report back at the end of the season to say how it holds up.

The old fibreglass wrap that came off was brittle down all the header pipes and collectors until the bottom bends from where it still retained its structure, its probably at that point where its in the air flow that it is kept a bit cooler.

It was interesting that Heat Shield Products do three grades of wrap, normal fibreglass wrap (which they claim in only good for about 2/3rd's of the temp that other suppliers claim) a Premium which they claim is good for a constant 1300F and an Inferno wrap which they claim is good for 2000F.

 

I went for the Premium wrap as a normally aspirated engine should only see 800-850F anything above that and your running so lean that you are burning away the pistons! anyway we will see how it goes.

 

Alan

[oldtuckunder]

So I guess I'll report back at the end of the season to say how it holds up.

 

Hi Just a quick update, removed the manifolds a couple of weeks back for the engine rebuild, and prompted by another thread I thought I'd just update this issue for future reference.

 

The Premium Inferno wrap is still as solid as the day I fitted it from the collection pipes right up to the head, so I'm pleased that the extra money paid off, don't know if anyone in the UK sells it though.

[Peter Cobbold]

To me, its all a fad. Wrapping or insulating came in with turbos where a hot and hence pressurised exhaust flow is useful, promotes performance. I dont see it improving perfomance in a naturally aspirated engine.

As long as the intake has cold air, has a reflector to deflect radiant exhaust heat, and the underbonnet isnt cooking with exhaust heat - I would not bother.

Peter

[oldtuckunder]

As long as the intake has cold air, has a reflector to deflect radiant exhaust heat, and the underbonnet isnt cooking with exhaust heat - I would not bother.

Peter

 

I can heat shield the carbs and do, and I can and do duct cold air to the carbs, but the inlet manifold on my MK1 is very close to all the header pipes and gets "quite" hot without the wrapping, six steel pipes throw out a lot more heat than the cast iron lump did and over a much bigger area, I want the inlet tracts as cool as possible, where cool means warm not hot! It also saves cooking the starter motor and the odd burn to the hands!

 

I also buy into the concept that hot gasses travel quicker than cooler ones, and I'd like the hot ones away as fast as possible and into the main pipe before they start cooling. But yes I may have been baffled by bullshit

[Willie Felger]

Greetings Old Tuck,

 

I don't know if your petrol is as volatile as our unleaded. My TR3A was a pain in the butt as fuel was forever evaporating in the pipes to the carbs. I used braided steel hose as it looked pretty. I have heat shields on the carbs but it didn't help. I replaced the pipes with thick wall rubber and wrapped the manifold. Result? no more problems even in high summer in France.

 

Keep TRucking,

 

Willie

[Dave Ashworth]

Hi All,

 

For what it's worth,

 

the subject of heat wrap was discussed at length some time ago on the forum and the conclusion that I took away from that series of conversations was don't bother unless you go for the ceramic coating.

 

All the best.

 

Dave.