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Painting an alluminium engine
voucht - 16/8/19 at 08:23 PM

Hello everyone,

I am currently renovating an old Kawasaki GPZ 550 from 1984.

I’m almost finished dismantling the engine, and almost all the parts to be repainted (engine block, head, casings, lids and caps) have been already sandblasted and are ready to be prepared for painting. So I’m close to start the paint job.

First, do you think I should put the engine back together first, and paint it as on piece in one time when reassembled, or is it better to paint all parts separately, with the necessary maskings, and reassemble the engine afterwards?

Second, all these parts to be painted are in aluminium. For those of you who have repainted alloy engines in the past, what is the best paint and primer in your experience?

How did you prep the parts for painting?

I want to avoid powder coating and prefer spray paint as I’m well equipped for that.

Any input, tip, advice is welcome

Thank you very much.


40inches - 16/8/19 at 11:07 PM

I used Halfords spray Silver and brush on Black engine paint, no primer and 6 years on it still looks like new
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Should say that I assembled all the silver parts before painting, and the black before assembly.

[Edited on 16-8-19 by 40inches]


ianhurley20 - 17/8/19 at 07:40 AM

On my MX5 engine I used an etch primer on the aluminium parts followed by a silver spray paint followed by a couple of coats of clear laquer. The cast iron parts were done with the same primer, a black spray and then a clear coat. All done assembled except the cam cover. Looked a treat and no heat discolouring 12 months after. I didn't paint the exhaust manifold but wrapped it in black heat wrap, the black changed to white in the hottest areas but kept underbonnet temps down.


myke pocock - 17/8/19 at 05:19 PM

Hammerite do a paint suitable to prime difficult metals, alluminium, brass, copper etc. That can be brush or spray painted then overpainted after.


voucht - 18/8/19 at 08:46 AM

quote:
Originally posted by 40inches
I used Halfords spray Silver and brush on Black engine paint, no primer and 6 years on it still looks like new

Should say that I assembled all the silver parts before painting, and the black before assembly.

[Edited on 16-8-19 by 40inches]


Thank you. Do you remember which kind of/paint quality you used from Halfords please? Because their range is huge, and I want to make sure it is heat resistant. Thanks.

quote:
Originally posted by ianhurley20
On my MX5 engine I used an etch primer on the aluminium parts followed by a silver spray paint followed by a couple of coats of clear laquer. The cast iron parts were done with the same primer, a black spray and then a clear coat. All done assembled except the cam cover. Looked a treat and no heat discolouring 12 months after. I didn't paint the exhaust manifold but wrapped it in black heat wrap, the black changed to white in the hottest areas but kept underbonnet temps down.


Hi Ian,
Thank you for the reply. Do you remember what brand/quality you used please?
Thanks.

quote:
Originally posted by myke pocock
Hammerite do a paint suitable to prime difficult metals, alluminium, brass, copper etc. That can be brush or spray painted then overpainted after.


When I built my Haynes, I used Hammerite with their aluminium primer on my alloy steering rack, and it worked fine.
But I have had a totally different experience on my steel parts (uprights, steering rods and extensions, etc.). I used it without primmer, as it says, and it chipped very quickly. It looks like crap nowadays.
Also, I am not sure Hammerite (and their alluminium primmer) is suited for parts subjected to heat, is it? The engine of the GPZ is oil and air cooled, and I guess temperature can be pretty high.
Thank you.


40inches - 18/8/19 at 09:08 AM

quote:
Originally posted by voucht
quote:
Originally posted by 40inches
I used Halfords spray Silver and brush on Black engine paint, no primer and 6 years on it still looks like new

Should say that I assembled all the silver parts before painting, and the black before assembly.

[Edited on 16-8-19 by 40inches]


Thank you. Do you remember which kind of/paint quality you used from Halfords please? Because their range is huge, and I want to make sure it is heat resistant. Thanks.

Black LINK

No primer needed, goes on easily without brush marks and is a high temperature paint.

Silver https://www.halfords.com/motoring/paints-body-repair/specialist-decorative-paints/halfords-engine-enamel-aluminium

High temp and cover really well, no primer.
6 years on and still looks like it has just been painted


[Edited on 18-8-19 by 40inches]


nick205 - 19/8/19 at 09:25 AM

Painted my cast iron Pinto engine before re-assembling it. Make sure you mask off any mating faces/gasket areas prior to painting to keep them free from paint. I used Halfords high temp engine paint (red) after the engine parts were professionally cleaned for me. I didn't use a primer and after 3 years the parts still looked like they'd just been painted.


ianhurley20 - 20/8/19 at 07:11 AM

quote:
Originally posted by voucht


Hi Ian,
Thank you for the reply. Do you remember what brand/quality you used please?
Thanks.




Hi Sylvain - I've had a look and have disposed of the tins a long time ago - not at all sure what brands but they were nothing special just standard cans. The silver and clearcoat were probably from Aldi!! Etch primer from a local paint suppliers. This one was the third engine I've done in standard paints without issues due to heat so I usually do as a - if it works ok, if not I'll do it again with different paints - attitude.
Ian