wrapping the exhaust pipes

I seem to be having a heat problem when I shut down the car and then want to drive it later as when I gas up or go into a restruant. The engine is not overheating but the carbs are over heating after the car is shut down. I think the either the gas is evaporating out of the carbs or I'm getting a vapor lock in the fuel line. I intend to wrap the exhaust pipes and the fuel lines.

I'm wondering if those of you who already wrap your exhaust pipes are getting cracks at the end of the wrapping. How far does your wrapping go, all the way to the muffler or just as far as the end of the engine compartment.

I talked to Pierce Manifolds and they told me that the engine compartment gets to be about 300 degrees after the engine is shut down. That's almost hot enough to cook a good lasagna.

Thanks, in advance,

Bob Wassam

 

it really could be either one...

is your OEM cladding gone??

my cars don't boil fuel though...there are several dinky heat shield brackets that anyone in the right mind would throw away....but they are there for a reason....

 

if you run the pump the required 30 - 60 seconds and still hvae no fuel primed up you have another problem.....

vapor lock maybe.....fuel filter? failing pump not holding line pressure?

 

How original is the car? Thermonuclearreactor exhaust? Air pumps? You probably are familiar with carbs and all, but just in case, these modern fuels boil away a lot easier than back when the cars were made. And after a shut down, the heat always makes carbed cars hard to start as they want to flood. They already boiled a bunch of raw fuel down thier throats, and the hot rarified air dont help. Hot starting foot to the floor and hold it till they rev seems to always work well.. Wrapping the headers will just make them rot away faster, better would be to paint them with some 1500 degree VHT paint.

 

if yo uhave a carb car, you are experiencing vapor lock. i shielded my carbs from the intense heat with a hi tech thermal barrier placed under the carbs. i NO longer have vapor lock, and the carbs stay cool all the time - this was a si,ple install with the carbs off the car.....First piece I cut to fit on top of the engine below the coolant pipe, with a V opening to fit around the oil filter housing. laid it in nice and flat. The next 2 pieces I cut for each pair of carbs. Laid them in over the intake manifolds after I cut the openings from old gasket material as a template. The fuel bowls will be totally shielded from heat, while allowing air movement around carbs. Everything looks good, linkage is clearing nicely too
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Just another thought :
Shields made from metal would do the same thing as the mat material and it would look nicer. There was a thead with a article rebuilding carbs showing the metal shields.

Jim

 

I have metal shields under my intake manifold to shield it from the block's heat below it. It's good for 0.00978 extra horsepower.

Hey, the little things add up...

 

that was probably me with the metal shields. they never worked right - so hard to do with clearing linkages, getting the base gaskets to seal with metal shields attached, etc. i got rid of the metal shields and went with the thermal barrier - works 100% better than the metal shields. BTW, i am sure there is HP gain once the engine gets hot, my 308 used to run like crap when fully up to temp at altitude - definately noticeable. now it runs grreat all the time with cool carbs......and with the carbs on the car and air cleaner installed - you cannot even see the thermal barrier under the carbs...

 

I have used Exhaust Wrap on aircraft engines with great results.
Try http://www.aircraftspruce.com/menus/ep/exhaustcomponents.html

Help keep engine compartment temps down on fuel injected engines and reduces vaper lock. Anyone with a Beechcraft Bonanza knows what I mean.

I perfer the Thermo-TEC wrap. It can be applied on the header. I am thinking about using this on my 308. I dont have a vaper lock problem but the temps in the compartment are crazy after I shut down. Of course maybe if I kept the RPM's down and the car under 80 MPH that might help also but what fun is that?

Jeff

 

The car is not original. There's no cats, the air pump is gone, and the fuel pump has been replaced recently. I think I'll try the heat shield idea and wrap the exhaust pipes and also wrap the fuel lines.

Thanks for all the info. I appreciate it.

Bob Wassam

 

Hi Jeff,
As you know, aircraft exhaust systems are made of stainless steel, which holds up well when enshrouded. However, some of the wraps offered for automotive use reportedly 'contain' the heat too effectively, which can damage mild steel components ('though Thermo Tec claims their product won't "over-insulate"). I'm as interested as you are in re-directing exhaust heat, especially in our mid-engined cars. As an alternative to a full wrap, what do you think of the "Header Manifold Blanket" listed on page 2 of the Aircraft Spruce site?
http://www.aircraftspruce.com/menus/ep/exhaustcomponents.html?pg=2
Provided other protection (e.g. factory metal shields, selective use of wrap around 'collectors') is employed for starter, drive shafts, alternator, fuel tank connectors, this might be an option to consider. It appears that it would greatly reduce heat directed towards firewalls (fore & aft), fuel tanks/plumbing, and electrics...while allowing air to flow around the headers.
What d'ya think? Any other members want to roll in on this idea? If there are no concerns, I'll volunteer my Dino to be a test bed & see what happens.
Cheers,
Coop

 

Funny you should bring this up. I was thinking of using an insulator material on the firewall first. This would reduce the noise and vibration. Next I was going to wrap the headers down to the CATS ONLY. And last but not least, maybe rap the fuel tanks with insualtor padding also. This may sound like over kill but might keep things quiter and cooler in the engine bay area.

Never thought much about the material content of the headers. I just assumed they were stainless steal much like the over shrouds of the mufflers on a Bonanza which provide cabin heat to the cockpit.

I have never had any trouble with the exhaust wrap material on aircraft and the Thermo Tec material is rated to 2000°F. I just figured that if my exhaust ever reached that temp, I was done for anyway.

I will keep you posted on if I do this or not and tell you the results.

Jeff