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MG Midget and Sprite Technical - Which engine paint? POR15?

I've got my engine out for gearbox repairs, so I thought I'd spruce the engine up by repainting it.
I've stripped all the paint off it and it is now back to bare metal.

I was thinking about using POR15 engine laquer to re-paint it, using a light coat of etch primer first. But although I've never used POR15 before, I've heard stories of it reacting with other products.

Has anyone used POR15 for this purpose or should I just use a good 2K paint, which should be able to withstand engine temperatures, which is what was on it before I stripped it?
b higginson

Other than immediately around the exhaust ports (which aren't visible) if the engine gets hot enough to damage paint, the paint will be the least of your worries ...
Paul Walbran

Bernie

Why not keep it simple, just some regular brush on engine paint: http://minispares.com/product/Classic/engine/gap409.aspx

I have had many concerrn about assorted rusty things on BMC/BLMC/BL products, but engine blocks was not one of them (the paint stuck and the oil went over the top of it).

Cheers
Mike
M Wood

Do you need the old engine green, Bernie? Frogeye Spares have a tiny tin, enough for a couple of engines.
Nick and Cherry Scoop

Thanks Nick, but it was painted Toyota "Super Red" and I'd like to keep the colour close to that if I can. Not to everyone's taste I know, but as we all also know,a red engine produces more power.😆

I will probably use 2K again, but this time brush it on rather than spray it. I just wondered if POR15 would be better.
b higginson

Don't use a paint that requires the surface to be oil free. Oil will have impregnated the cast iron of the block and even if the surfaces seem clean, as the engine warms up this oil will come to the surface under the paint. For this reason an oil based paint works well.

This may not apply if you have been able to get the block steam cleaned thoroughly.
GuyW

The block had the original factory green engine paint from new. Then over the years has had three re-paints with various reds. So it was starting to lift because there was too much paint on it. It now has been stripped using professional paint stripper, thoroughly scrubbed and pressure washed, then cleaned down with brake cleaner.

I guess an oil based paint makes sense for the reasons Guy mentions, but will it stand up to engine temperatures?
b higginson

As mentioned, there are paints sold specifically as engine paint, in a variety of colours. That is what I used (and it was oil based) getting on for 20 years ago now. It has lasted well on the block; but the head has been replaced and repainted so I cannot confirm such a long life although so far it seems OK and sufficiently heatproof, as one would expect.

What about paint suitable for an exhaust manifold though?
GuyW


Thanks for that guy. Oil based could well be the best way to go.

I've used Sperex and other high temp paints on exhaust manifolds, which seem to work well except at the bottom of the manifold where it goes under the car. This bit is exposed to the wet and road muck and alway goes rusty, requiring re-treating.
My current manifold is a Maniflow, which has been on for about a year. I've not painted it at all and it's starting to rust in the same area.
b higginson

Thanks Bernie, and sorry for the deviaton!
I recently bought a new Maniflow, yet to be fitted so the ideal time to give it a coat or two of paint. Hence the question.

I once tried a Halfords VHT red spray paint. It was orange rather than my interpretation of red and very thin and runny despite lengthy arm -losening rattling of the can. The can ran out before I had enough thickness built up to hide the underlying metal. Not recommended!
GuyW

I've also used the Halfords one and I think I used a couple of cans, giving it light coats, but the manifold still,went rusty at the bottom.
I also tried using heat wrap at the bottom and the first bit under the car, but it still went rusty, probably because it gets wet and holds the moisture.
I don't think I'd go down the ceramic coating route though because of stories I've heard about heat retention in the head.
b higginson

I agree. Ceramic isn't what I want to try. There must be a better industrial quality high temperature paint than the Halford's offering.
GuyW

Hycote HT paint works well on an aircooled VW rear box which gets hotter than conventional silencers as it's located just aft of the exhaust manifolds - so more than likely good for LCBs etc.
Jeremy MkIII

I've used hammerite for the cam cover on the K series, it's survived great so far. Same on the Land Rover's block

for the exhaust manifold I can recommend stuff that's used to paint wood burning stoves with, I've got a little yellow and black pot from an ironmongers, says 600 degrees on the side.

It's the only thing that works on the K manifold - ragging it hard in the dark makes the manifold glow dull red....
Rob Armstrong

Smart move using wood stove paint, Rob. I've even got a tin of it in the garage. Why didn't I think of that !!
GuyW

I never thought of stove paint either, although I have used it on - er - stoves (and their flues).

I found PJ1 exhaust paint quite good on motorcycle exhausts and air-cooled cylinder heads, but you need to build up plenty of thin coats. I wasn't sure if it was still available so I had a look and it seems to be still going:

https://motorcycleparts-uk.co.uk/pj1-high-temperature-exhaust-paint-400ml?language=en¤cy=GBP&gclid=CjwKCAiAhMLSBRBJEiwAlFrsTg1_IjDYQbOzL8gLLj3fWKQ2bLS7iSQZ_xol-_wxOnqSOnhJf6YiPRoCAjgQAvD_BwE

(if the link works).
Greybeard

I seem to remember that I used stove paint on my previous manifold, and it says in the instructions that you have to at a certain point, fire up your stove to full heat, but that it has to be done within a certain time frame. Of course for us it means fire up and run your engine. I think the bottom bit still went rusty.😂
b higginson

This thread was discussed on 06/01/2018

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