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Exhaust Heat Issues


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Okay, so I'm new to the world of small-block V8s, so I had someone build and install the motor for me. Now that I have it running and I'm doing the break-in, I notice that the headers I have radiate lots of heat (no duh, right?).

 

I am using a some steel block-hugger shorties that have the black header paint on them, it finally stopped "curing" about a week ago. That smell is awful. The problem with the heat is that I'd rather not boil my fuel on its way to the carburetor (which I think I've alleviated that issue by rerouting the fuel lines) or melt wires that run near the headers/engine block (ignition stuff, starter relay circuit, etc.).

 

There are a lot of guys on this board running these types of headers, so I'm wondering if I could get some input. I realize regular steel is bottom of the barrel material, but to go stainless looks like it's way out of my price range, does stainless cut down on heat? I know SS is generally more conductive and would conduct heat away from the head faster, but I'd also think it'd radiate more in that case? Are there any other options, ceramic coatings, etc?

 

I have a buddy that has been helping me work through some of the issues on my swap, but we seem to butt heads when it comes to certain things.

 

I am of the opinion that header-wrap might be in order, but he swears up and down that it will disintegrate my headers after like a few weeks of driving (like 500 miles or so), I have never had cause to wrap my headers before, is this really an issue?

 

If I can't wrap them, does anyone make good heat shields that might fit?

 

Any other suggestions? I'm kind of at my wit's end with this car, should've just stuck with the L6, looking back, lol. It is ridiculously fast, though.

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What is Jet-Coating? Where would I take it to have it done?

 

I need more information than "just do this."

 

And, at $100 per header, I might as well get different headers while I'm at it.

 

Go to Ebay. Look for Stainless Steel SBC Block Hugger Headers form KMJ. Order same, install and heat wrap. Done.

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http://lmgtfy.com/?q=jet+coating

 

Jet coating is basically a ceramic thermal coating that keeps heat from penetrating into the metal. It is on the outside and inside, which is the important part. Wrapping any set of headers will "trap" heat within the wrapping, which could lead to cracking if you buy some crappy made headers. I was quoted by a local muffler/welder shop that coating my 6-1 headers was $100. Since I got them with my car it would be cheaper than buying MSA's coated headers at $250. I didn't know that a pair of headers for a V8 is that cheap.

 

In my opinion jet coating would be a more permanent solution, if you plan on keeping the car for a long time. You can polish the coating and make them look better and I don't like getting fiberglass all over me (wear protective gear if you wrap headers) because it itches like hell

Edited by BluDestiny
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Normal JetHot Sterling does next to nothing for heat reduction. JetHot 2000 actually works at heat reduction. Swain has the most functional heat reducing coating although its not as pretty as Jet Hot's products.

 

http://forums.nasioc.com/forums/showthread.php?t=273930

 

FYI... for my own cars I've always run Swain's coatings.

 

For any of those companies, just call their 800 number to get the proces started.

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Yeah, I am looking for a somewhat permanent solution, but if I have to redo the wrap every so often, that wouldn't be terrible as long as it doesn't damage the headers.

 

I don't really care what it looks like as long as it works. The black headers I have now are probably next to worthless as far as sealing to the heads, they have a flimsy looking flange and it looks like it is already warped/warping. They are also nothing that fantastic to look at, they're flat black and kind of don't fit my orange/brushed aluminum/chrome theme, anyway.

 

I'll look into Swain coatings. I'd prefer something that doesn't cost like $500, but if I can order it and get it ready to bolt on, that would be ideal. Just looking to lower the temps in my engine bay to avoid potential failures in the future. I plan on getting some heat shielding for my battery and starter, as it is.

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Yeah, I am looking for a somewhat permanent solution, but if I have to redo the wrap every so often, that wouldn't be terrible as long as it doesn't damage the headers.

 

I don't really care what it looks like as long as it works. The black headers I have now are probably next to worthless as far as sealing to the heads, they have a flimsy looking flange and it looks like it is already warped/warping. They are also nothing that fantastic to look at, they're flat black and kind of don't fit my orange/brushed aluminum/chrome theme, anyway.

 

I'll look into Swain coatings. I'd prefer something that doesn't cost like $500, but if I can order it and get it ready to bolt on, that would be ideal. Just looking to lower the temps in my engine bay to avoid potential failures in the future. I plan on getting some heat shielding for my battery and starter, as it is.

 

The most cost effective solution is to purchase the Stainless Steel KMJ Block Hugger Headers and wrap them with a good heat wrap. This is a VERY EFFECTIVE method of reducing under-hood heat. I have purchase the KMJ Block Hugger Headers and they fit just fine as they have clearance between the steering shaft and the headers. I plan on using plenty of exhaust wrap not only on the headers but also further back to reduce heat migration into the transmission and differential as they will be generating their own heat. If necessary may circulate T56 trans fluid through the cooler built into the radiator.

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I second RSICARD's comments on the KMJ block huggers. I bought their ceramic coated headers a year ago for $164 shipped, and they've been great. Good fit, good quality ceramic coating, and strong thick flanges. No problems with leakages, warping, etc. Check 'em out.

 

KMJ block huggers

 

There's also several products out there to insulate your fuel lines...they work really well to keep the heat out.

Edited by jhm
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Just want to point out that stainless steel doesn't conduct heat anywhere near as well as plain steel.

 

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

 

I would also warn that this may be a matter of perspective. You are gathering different opinions, what is good to one guy may still be unacceptable to you.

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Another vote for the cast iron manifolds. I put a 383 with comp eng. headers (I painted them with VHT) in my 67 Camaro and wished I had just installed the exhaust manifolds. In my humble opinion, some of their disadvantages have been already mentioned:

- heat

- hard to reach/replace spark plugs

- special routing of the spark plug wires to protect them from getting melted

- whole bulkiness of the headers filling up the engine bay interfering with the power steering unit

- requirement to have special header lock bolts to prevent them from getting loose

 

My headers were painted, after 5 years they finally started to show the signs of internal rust. 350/383 engines have plenty of torque for a small car like 240/280z. The additional headers' 20-30 hp won't do you much good unless you are into racing and every millisecond counts.

 

Regards!

 

PS Forgot to add - the exhaust manifolds are dirt cheap! You probably can find some for $15-20 on craigslist.

Edited by darom
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Yeah, I had asked the guy who built the motor why he didn't just use the original manifolds. At this point, I have the rest of the exhaust tailored to block huggers, unless the collectors/flanges are analogous on the stock manifolds?

 

I am ordering a set of KMJ headers this weekend (gotta wait for some extra cash), still haven't decided whether or not to spend $250 on getting them coated (That's what swain said it would cost + shipping) or just wrap them. The "titanium" vulcan wrap is cheap and is advertised to like 2000 degrees direct heat.

 

I like the sound that headers produce, even though I have my exhaust muffled and baffled so much you can't tell there's a v8 in it (it sounds like a VW bug, lol).

 

I am also looking at spark plug boots, starter shield and some heat reflective tubing for the fuel lines. This might be overkill once the headers are wrapped, but I like being able to take the car on long road trips. I've never had heat issues before in a car like this, even with some of the crazy turbo applications I've built.

 

Does anyone know if someone sells 1/4" phenolic carburetor-to-intake manifold gaskets? All I can seem to find is 1" or larger.

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I got paid, so I ordered some DEI "titanium" wrap about 100 ft. of it, so maybe I'll have some extra to do some other things with it and a set of those KMJ SS headers.

 

Looking into those phenolic spacers and spark plug boots.

 

I appreciate everyone's feedback. Ultimately, I decided against the jet-hot/swain option just because I'm going to end up getting new headers, wrap and heat shielding for everything else for the price of the cost of just the coating.

 

If I melt or blow a weld on these headers I might look into getting a set of stock manifolds, polishing and radiusing them myself and send them off to get some kind of heat treating. Although, with cast-iron I imagine it'd be less of an issue to begin with. :/

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I got paid, so I ordered some DEI "titanium" wrap about 100 ft. of it, so maybe I'll have some extra to do some other things with it and a set of those KMJ SS headers.

 

Looking into those phenolic spacers and spark plug boots.

 

I appreciate everyone's feedback. Ultimately, I decided against the jet-hot/swain option just because I'm going to end up getting new headers, wrap and heat shielding for everything else for the price of the cost of just the coating.

 

If I melt or blow a weld on these headers I might look into getting a set of stock manifolds, polishing and radiusing them myself and send them off to get some kind of heat treating. Although, with cast-iron I imagine it'd be less of an issue to begin with. :/

 

Let us know how the titanium wrap works out. Also order ARP stainless steel 3/4" header bolts with drilled holes for safety wire. Safety Wire has been used in Aviation for MANY years. If done properly the header bolts will not back out. Also use anti-seize on bolts going into the heads as it will be much easier if they have to be removed.

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Yeah, I always use anti-seize. It's a habit I got into working on my launchers (which were always exposed to weather) while I was in the Navy.

 

I already have ARP exhaust bolts. I've never had a problem with my exhaust bolts loosening themselves. It's usually the opposite problem, they won't come loose when you need them to.

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these work well on a Z V8 conversion.

 

http://www.thezstore.com/page/TZS/PROD/7BSA03/30-7090

 

but point the opening forward, not to the rear as in the photo.

 

The forward opening blows cool air down on the headers and really makes a difference with the under hood temps and the firewall temps. (I have tried it both ways and forward works much better).

 

Header wrap works well also.

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