Long branch HO manifolds: Has anyone ever used a wrap or heat shield on them?
 

I am thinking about either wrapping or using something like a flexible heat shield on my long branch manifolds on my GP. Has anyone done this on a B body car, Gen 1 Firebird, or '69-'72 GP that either came with or has been retrofitted with the long branch HO manifolds? Something kind of like this: https://www.heatshieldproducts.com/p...eat-shield.jpg

Ideas?

can i ask why? i have a set on my firebird with full size starter and have no heat soak issues...(knocks wood) lol but the manifolds them selves are beautiful. How about maybe ceramic coating to get the heat contained a little better and keep the looks?

I would be worried that condensation would build up under the wrap and severely rust the manifolds over time. Just paint them and leave them alone.

I am not overly concerned about heat soak, I am trying possibly improve scavenging and efficiency, keep the exhaust heat up for the O2 sensor, reduce underhood temperatures overall as well as protect my polyurethane engine mounts from the manifold heat. I had them on the engine for years without heat soak issues, and the car is now fuel injected, so it's even less of a concern. The heat shielding I am looking at is not a wrap and does not completely enclose the manifold (like a wrap would), most of the manifold facing the engine would be open to the air which should allow the manifolds to "breathe" and also not not encourage or hold in condensation on the manifold. I agree about the aesthetics, but it's a resto-mod and I am planning on trying some less conventional things to get the best performance, combined with passenger comfort possible. I am really trying to find someone who has tried some modern aftermarket heat shielding on a Poncho with HO manifolds - maybe I will be the 1st.https://www.heatshieldproducts.com/p...nifolds_01.jpg

I thought about that, that's why I am looking at a heat shield system which leaves most of the manifold facing the block open to the air, and that should reduce or eliminate condensation related corrosion to at least the bare manifold baseline. I have a number of goals with this project, and keeping the exhaust up to temp for as long as possible to get the right signal to the O2 sensor and help scavenging, while reducing underhood and passenger compartment temps is the goal.

I'd coat them for sure before even thinking about covering them with anything.

If ya don't want to pay expensive coating fees, look into Cerakote. They have thermal barrier coatings you can do at home, it's reasonably inexpensive, and if you don't have access to an oven, they have a system that doesn't require oven baking.

It's pretty widely used in the industry for a lot of different applications and becoming more common with powder coaters.

Wrapping them is probably the surest way to crack them.

Bead blast then prepare the surface with Metal Prep then brush off a couple of coats 24 hours apart of POR-15 factory manifold gray. Inexpensive and lasts a long time, best bang for the buck in manifold coatings.

The shelf life is easily decades as I’ve used an already opened can after sitting 20 years and only needed to thin it a little using mineral spirits, a pint of it goes a long way.

I recently did the log manifolds for my 421 HO and I’m trying it out in a VW merged competition header, I used just one coat on that.

Thanks B-man. These are not new manifolds, they have been through thousands of heat cycles, so cracking is far less likely as long as they don't approach the super hot - compromising integrity heat range. I was not realistically planning on wrapping them, just considering adding a heat shielding on about 1/2 of the manifold - allowing air to circulate on the portion facing the block - that should keep the temperatures fairly consistent, without overheating the manifolds, while lowering underhood temps and protecting the engine mounts, wiring, etc. . I am also using a multi step coating system (internal as well as external) to protect the manifolds. So far, everyone has just reacted without any real practical experience with this - just guesses. I have used wrapped headers on road race cars before, and I have melted headers, so I am pretty familiar with how things could go bad very quickly. That is not the path I am looking at with the HO manifolds. I am looking specifically at heatshield products heat shield armor, but I want to see if anyone has real experiences where they or someone with which they had first hand knowledge of using any number of available heat shield products as well as wrapping manifolds. This video shows the product I am interested in, and why. http://https://www.youtube.com/watch?v=wgtx89yYBLE

If you wrap them, they will get hotter than they ever have before. I dont see any benefit, they cost enough as it is. Airflow is what cools them, the O2 will get plenty hot enough.

Thanks Ted, but I'm not planning on wrapping the manifold.

I am looking at adding heat shielding over part of the manifold to reduce underhood temps as well as other reasons mentioned in the thread. Heatshield Products has some guidance for using their products under a variety of conditions, and they pretty clearly specify that using a complete wrap on a cast iron manifold might get it hot enough to melt - that's likely a bad idea. They also specified that using the heatshield armor properly is not likely to cause problems with cast iron manifolds or headers.

:eek:
I have apparently ventured into an untested concept within the Pontiac Hobby community. :noidea:

:idea:
I was mostly trying to to see if anyone had any real solid experience and/or data on what really happens if you use heat shielding (as I have described) or you wrap an HO (or similar) cast iron exhaust manifold. So far based on the responses, the answer seems to be that nobody has any real experience with either wrapping the manifolds or using heat shielding with Pontiac cast iron manifolds, and in this case it kind of makes sense because if you are doing a pure street duty car - you won't really care about such things that might push the limits :boom:, and if it's a race car you will use headers.

So I will likely be installing the heatshield armor in pursuit of cooler underhood temps, and reduced heat effects on the engine mounts, starter and wiring, and warmer, quicker exhaust flow, and when I have some experience and data I will post it. :horn:

I don't think you're going to find many, if any at all, that have wrapped exhaust manifolds or used anything other than stock shielding on pretty much any brand engine. I honestly don't see where it would even be necessary, with all the advanced coatings we have these days, it's pretty much made wrapping or concocting some sort of heat sheild obsolete.

As far as containing heat or creating a thermal barrier for any type of scavenging affect, the overwhelming choice among car hobbyists and racers is a simple ceramic based coating. Whether that be Jet Hot or Cerakote is really up to the end user. I've used them for years on Pontiacs, Chevrolets, Fords, etc... and it works as advertised, while also maintaining a nice appearance that isn't an eye sore. I highly doubt a loose fitting heat shield around just part of the exhaust manifold is going to create any type of scavenging affect or everyone would be doing it. That's where the coatings come into play.

When I had 1967 GTO HO reproduction RARE manifolds (POR-15 painted) on the 455 I used to daily drive in my ‘64 Tempest I used a reproduction starter solenoid heat shield. Also installed a Ford starter solenoid relay and huge 2/0 welding cables for sure starting.

Never had any heat related starting issues ever, I was using a stock starter.

I'm using coatings too. :) And I'm not looking at any of this specifically to address a starting issue that I have never had with the HO manifolds. Just looking to reduce thermal exposure to the engine mounts and manage exhaust heat in the engine compartment and keep it flowing in the exhaust system. Maybe it works, maybe it does not.

I've never had any heat related issues either using the RA manifolds. I've used the por15 as well and even though it doesn't necessarily have heat barrier properties it is a very nice product that is cheap and easy to apply and does last what seems like forever. I've had it on my RA manifolds for several years now, daily driven, and they still look like new.