Exhaust manifold wraps
 

To assist in protecting my distributor from the heat of the adjacent exhaust manifold, I am considering insulating tape wrap or perhaps high temp thermal paint for the exhaust pipes. But some of these products claim HP gains due to hotter exhaust gasses that therefore exit faster and create better scavenging effects. I'm skeptical. Looking for responses on the heat reduction claims as well as the HP claims. If the heat-reductions are real, this seems like a good mod to pair with grill blocks.

HP gains will be there but we're talking a fraction of a HP would be my guess. I'd go with a wrap, not a coating. Before I did either of those I'd try to bend up a piece of scrap metal to go between the two to make a metal heat shield. Its cheaper, easier and will probably even work better.

Wraps are known to rot out exhaust components in a hurry. I'd go with a shield.

Thanks guys. I'll paint if I do anything to the pipes at all. Here's an odd-ball idea too: a small pipe running from the upper grill directly to the distributor to blow ram air onto the distributor during driving. More directed and smaller than a grill opening and therefore maybe more effective in cooling the distributor and less likely to reduce the WAI's effects. Not worth it?

Wrapping does work in the short term. It can even work in the medium-term on stainless steel components. But even those will eventually start to corrode when wrapped.

I am told that ceramic coating makes a very noticeable difference for temperatures, making a header pipe that was formerly second-degree-burn temperature into one that is merely too-hot-to-hold. Coatings on brand-new parts that have been properly prepared can last a long time, but I don't have first-hand experience.

A heat shield can be made from sheet aluminum. Stock ones frequently are, in fact, and they work reasonably well and cheaply. Even when there is a stock shield there, another one can still have some effect.

-soD

Definatly use a heat shield. I have an SS header that is wraped and you can actually grab it and not get burned, however you must release it very quickly because it will be too hot to hold. The wrap definatly works to reduce underhood temps. Will it give you more mpg? probably not. Being winter time, I like the idea of having more underhood heat :) I don't mind runing my underhood temps as high as possible, with out causing damage.

The problem when people wrap pipes they skip a step.
Almost no one seals the wrap. There are silicone sparys that seal oil and water out of the wrap.
I have seen properly wraped piping fail at the flange, where its not coved at all after years of service. The sealed sections on the pipes looked good.

Sealing exhaust wrap/pipes against water
 

I read online one argument that the paint is inferior, claiming that the paint can't contain the heat as well. I have seen folks who polish them up, the paint them with high-heat paint to protect against corrosion, then wrap them. When in such a process would you apply sealant? Only at the end, I guess?

@ Tygen: I painted my heat shield with flat black 1200 degree paint and reinstalled it. Looks nice.

Is the dizzy really getting that hot?

dizzy hot
 

It was, and I made it worse by removing the heat shield thinking I would eventually clean and reinstall it. It being "winter" in California, I think I underestimated the dangers. I developed ignition coil problems that may or may not have been related. The dizzy is right next to the head and above, left of the exhaust manifold. In summer I get too high numbers on the WAI and my grill blocks of course mean more heat in the engine bay. Seems some sort of heat reduction is prudent.

But hey, I just realized I posted in the unicorn corral because of the FE and HP claims associated with the wraps. Maybe those claims are unicorn material, but the heat reduction seems worth while, no?