Exhaust rattle!

Just another data point. I have a '77 GTB without cats and no insulation on the headers for over 30 years. No heat issues.

 

I might be beating a dead horse here, but nevertheless...
Please keep in mind that exhausts of the two-valve cars cannot be fitted on the four-valve cars and vice-versa...
Exhaust tubes (those that go on the engine exhaust ports) of the two valve cars are rounded; exhaust tubes of the four valve cars are oval.
Those of the QVs and 328s are interchangeable.

Rgds

 

Sorry!
I thought that's common US-american wildlife

Best Regards from Germany (where we have vipers too, but rarely seen)

 

I'm no expert here but given the nature and function of the air injection system it is quite possible that the main purpose of the shrouds is to INCREASE the internal temperature of the headers to aid in the effeciency of the Cat(s) - especially immediately following cold starts when air is being injected into the headers.

In other words, they may not be there to prevent engine fires.

I know of at least one owner who has removed them and ceramic coated his headers with no apparent problems.

 

The whole point of my post was to say .. if you happen to drop one ignition bank on a US spec car it takes very little time for those headers to glow orange. Would rather have a sheet of aluminum between it and the rest of the components than nothing at all. My car is a euro spec. so not an issue for me anyway (no cats) just sayin.

 

The reason the exhaust is wrapped on emission equipped cars is to keep the heat inside and lite off the catalytic conver as fast as possible. This reduces emissions.

 

Has anyone tried to Jet Hot coat their headers/exhaust? Supposed to reduce heat tremendously from the outside.

 

Mike, that was my plan, until I ran across a local Chicago company displaying at World of Wheels (Autorama), called LoKo Coatings. They charge $300 for a set of headers ($350 for chrome finish), and use the EXACT same industrial process as JetHot, for about half the price. Wound up having them powedercoat or ceramic coat 28 parts during my restoration project. Highly recommended. There are some who say Zircotec uses a different process, but who knows.

 

Correct. They did also lower engine bay temps but that was just coincidental.

 

Oval ports. I think the 4 valvle engines are oval and 2 valve are round.

 

I have, but mine is a turbo. I do think it reduces heat.

 

I used the same thx to Justin

 

Haha

 

Perfect timing for this topic to come up... just spent an hour under my car trying to figure out what to do with my rattling heat shield.

I also got cold feet cutting it off due to the heat issues on the surrounding electrical parts and maybe even cabin heat.

Now I'm thinking the recommendations on here to coat the headers is probably the best bet.


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I, too, was a bit worried about radiant heat w/o shields, so I bought several lengths of 1800 degree heat shield hose wrap from Jegs and wrapped the 12v-starter and alternator wire bundle, then also put a velcro heat shield wrap around the starter (I actually purchased a Euro starter heat shield, but wouldn't fit around my gear reduction starter).

 

Yup.

Mine:
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Do you mean the "sniffer" tubes that go into the header ports, or the air injection rails that feed into the engine block? Either way, you can install plugs without pulling the headers (though you're gonna need some serious acrobatics for the front bank if the gas tanks are still in). Be very careful removing the sniffer tubes, as they rust into place and are easily damaged by turning a wrench on them. 12mm line wrench, and maybe a healthy pre-soak with PB blaster. I also used Deacon crow seal 2500 degree specilty threadlock for securing the plugs. It's pricey, but almost no other product out there has the heat tolerance for exhaust temps right when the gas exits the combustion chamber.

 

Here's the heat shield I added to the starter after removing the header shields (beefier solid euro shield wouldn't fit over my new starter). Who knows if it'll make a lick of difference, but I got a chance to feel creative for a couple bucks...
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I wanted to look as period correct as possible, so went with black instead of chrome finish. Fresh 12mm plugs also pictured.
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