Cylinder head paint options

[ZGjethro]

I had the engine head recently milled down a bit, and it looks like the machinist may have bead or sand blasted the top and sides to clean it up. I would like to paint it before I install it and I was wondering what to use. I have read about Eastwood paints, but I would have to order that and I was hoping to use something I can buy locally. Are there any paints from a hardware or auto store which would work well? I have had the head off since April, so a week longer is not a big wait if Eastwood paint is recommended highly over other paint

[Zeke]

I had an old Willys flathead 6 that I painted with XO Rust primer and paint that I bought at a True Value hardware store. It is very similar to Rustoleum. I degreased the engine with solvent and hit it with a wire brush wheel in a drill to clean it up. I put on 1 coat of primer and 2 coats of gray paint with a brush and it looked good even after driving it almost every day for 4 years. If your cooling system is working right, the engine won't get hot enough to burn the paint off.
Zeke

[ZGjethro]

Thanks Zeke.. I have been reading a little on engine painting, and one site recommended paint to metal, with no primer. I also found duplicolor makes engine paints which are another option. I am leaning towards a silver color, since I think the block might be that color under the grease and oil.

[w30bob]

ZG,

Almost any automotive engine paint will work well, the key is in the application. A few light coats will produce much better lasting results than heavy coats. VHT makes the best engine paints, but I've used Dupli-color successfully. Engine paints typically need to heat cure, so follow the directions on the can to the letter. I've tried painting engine parts and letting them sit for a few months before installing them on the engine and then curing....doesn't work. Also, make sure the head surface to be painted is really, really clean. Really.

regards,
bob

[ZGjethro]

Bob, any opinion on primer use? I have to say I have not been really impressed with typical spray can primer on metal

[w30bob]

ZG,

I've never primed on engines. I've got a 1939 Farmall A and a 1959 Farmall Cub that have their original paint. They were not primed at the factory and the paint is still on there today. It's gotten thin and faded over the years, but hasn't peeled or flaked or come off in any way on the engines, even around the manifolds. I think they knew what they were doing back then.

Maybe others have had good experience priming before engine paint.....but I haven't. It might be that the primer, being of higher solid content, can't expand and contract as much as needed, or just the added thickness of the primer combined with the topcoat makes the paint layer too thick and non-flexible.

Again, there should be lots of opinions on this subject......this is just mine.

regards,
bob

[refit1701]

I believe I used a light grey color in the Duplicolor engine paint line. No primer. So far so good, but I haven't left the yard with it yet.....

[ZGjethro]

I went to the VHT website and looked at their engine enamel, which was 550 degrees rated. The spray can said the engine enamel was not for use on cylinder heads (?) so I bought a can of silver flame proof header paint (2000 degree), which they also say is good for radiator and cooling systems. The paint does not become chemically resistant (according to instructions) until it is heat cured. That is done by baking it at 200, then 400, then 600 degrees with cooling between cycles. The paint can also be cured on the vehicle by running the engine and doing heat cycles. I am going to do the latter as I do not want to warp my freshly milled head by oven curing it.

Thanks for the advice given in this thread

John

[LickskilletM37]

I could be wrong, but I wouldn't expect the outside of the cylinder head to get too much hotter than the coolant temperature. It's not like an OHV head that gets very hot around the exhaust passages. It looks like most of the original military trucks just have OD green on the motor which probably isn't special paint either.

Chuck

[ZGjethro]

I thought the part about the paint not being for cylinder heads was suspect also. The other paint was pretty much the same price and higher temp so I bought it.

[w30bob]

Hi Lick,

The outside temp of a cylinder head can get much hotter than the coolant temp, but that would take prolonged engine use at high power........think of those header ads where the pipes are glowing cherry red. That high temp exhaust gas is coming from the cylinder heads and is HOT. But in normal driving the outside of the cylinder head won't get that hot.....just as hot as the exhaust manifold. Thats's why on a freshly painted engine you always see the paint burned off the heads in that location even after a few runs.

I looked on the VHT website and didn't see where it said not to use on cylinder heads, but EVERYONE does. If it were only good for block paint no one would buy it.....because you'd have to find a match for it for from another vendor for the cylinder heads. Unless they're talking about aluminum heads....which are very hard to paint due to the thermal contraction/expansion. Nothing sticks to those for long.

regards,
bob

[ZGjethro]

Bob, I went to the VHT site and could not find it either. I do know that I read it when I was reading the product specs when I was trying to buy it online from an auto parts store.