Exhaust Manifold Coating

[Maticuno]

While I was replacing the head gasket I saw that my exhaust manifold was cracked in the usual #4 spot. With a lot of patience with some nickle rod and a grinder I was able to completely seal the crack. Of course I know this probably won't last that long so I ordered a replacement (thanks Aaron!) so I can swap it out when the old one cracks again. In the meantime, I have read a few adds about high temp manifold coatings that are supposed to hold heat inside the manifold and keep the engine bay temps cooler. Are the claims accurate? Are there any down sides? I'd like to prevent this new manifold from cracking if I can.

[mr2tim]

Don't give up the OEM covers even if you go this route, engine bay fires are a frequent demise in this car.

I have used many coats of fire-proof paint and never ever noticed any heat reductions.

Have you considered "header wrapping" material? This material works, but on a different principle.

BTW the hotter the exhaust tubes the faster the air moves thru.

[Maticuno]

It's the rapid cool down of the manifold that causes the cracking isn't it? If so, header wrap might work. I'd just be afraid of moisture getting trapped inside and accelerating the rusting process. What about some kind of ceramic coating?

[eckoman_pdx]

Originally Posted by Maticuno

It's the rapid cool down of the manifold that causes the cracking isn't it? If so, header wrap might work. I'd just be afraid of moisture getting trapped inside and accelerating the rusting process. What about some kind of ceramic coating?

Cerma-Chrome or regular old Ceramic coating are great for this. They insulate the engine bay. I Cerma-Chrome a valve cover in my other car, and it helped cool the underhood temps quiet a bit. I'd ceramic coat or cerma-chrome the heated and manifold before I put wrap on it. It will help insulate the bay and keep heat down, while resisting water, rust, salt, corrosion, etc.

[Greengoose]

Jet Hot coating on the exhaust manifold and the manifold sheilds - that's what I did with mine and it works awesome - just check out my pics if you want to see close up shots - they also coat the inside of the manifold as well.
[url=http://www.jet-hot.com/]

[jus7o]

greengoose where are the pics man?!!!

[eckoman_pdx]

I've used this place for Cerma-Chrome before. Turned out good, great price and quick turn around.

Performance Coatings

[Maticuno]

^ Very useful link. I think I'll give them a try with my next paycheck (which hopefully won't be an IOU due to the state budget...)

[eckoman_pdx]

Originally Posted by Maticuno

^ Very useful link. I think I'll give them a try with my next paycheck (which hopefully won't be an IOU due to the state budget...)

You're very welcome. I'm always glad to help!! Keep us posted on what you do and how it works out for you

Wow...that would suck to get an IOU as a paycheck. Here's to hoping you don't end up with that.

[mr2tim]

The usual cracking of this manifold is the exhaust manifold bolts not staying torqued down.

Look at your exhaust manifold if you have all the OEM bolts intact your one lucky guy! (Can't see the inner bolts tho)

From my experience the end bolts on the exhaust manifold come loose first? Whaz up with this?

BTW forget rusting as a issue, this 3/16 wall clearance would take 50-100 years to rust thru. Being ugly is another issue.

19 year owner of 6 cars.

Originally Posted by Maticuno

It's the rapid cool down of the manifold that causes the cracking isn't it? If so, header wrap might work. I'd just be afraid of moisture getting trapped inside and accelerating the rusting process. What about some kind of ceramic coating?

[Maticuno]

Don't know if they were all OEM, but they were all there. They all came out fairly easily too. They weren't loose or anything, but they all came off without stripping or breaking.

[sccatech]

First- I was given a clapped out MR2 race car that had the TRD header wrapped. It was raced infrequently over several years. When I removed the wrap the header was quite rusted up. I would think that daily driving a car with header wrap would greatly accelerate the problem. Second - all the racer people I talked with say that ceramic coating is the best. Ceramic coating does eventually chip and crack and therefore will need to be redone or it will also allow the header to rust. Make sure that you verify that the coater can completely coat the inside. I will be having mine done by Jet Hot because the local coater cannot completely coat the inside of the manifold.