Classic cars forum & vehicle restoration.

[Ronniej]

Participant


I have fitted a military engine to my 1938 Morris 8.
(For the benefit of persons unfamiliar with Morris 8s I should explain that Morris Motors made the auxiliary engine for Centurion tanks and these were very similar to the one fitted to the car.)
This engine was new when I fitted it and was still in its MoD crate.
It was painted in a most unattractive duck egg blue.
Although it had not been used I cleaned it thoroughly and painted it black using proper engine paint. It looked great at first but over time the black paint has bubbled and come off in patches. It looks like the new paint has reacted with the original paint. This spoils the under-bonnet appearance which is otherwise quite presentable.
I have a number of jobs planned over the coming winter and one of them is re-painting the engine. I think that to be certain of a lasting finish I will need to remove the original paint. Does anyone have any advice to offer on how to go about this?
Any hints or tips on the subject of painting the engine will be most welcome.

Ronnie Johnston
Glasgow,
Scotland.

[ukdave2002]

Hi Ronnie

I would have though the engines would have been painted in cellulose, I doubt Morris motors would have used anything special ?

Using cellulose over acrylic generally results in the paint blistering, the other way round is supposed to be ok but I have had problems when using acrylic aerosols, I suspected due to the high solvent content.

However in both cases the blistering was within hours, so I am wondering if your problem may not be a paint reaction? was the engine degreased prior to painting, did you use primer? if so how long before the top coat went on as primer can absorb moisture, this can lead to micro blistering months later...

Any pictures?

Cheers

Dave

[Old Wrench]

The basic rule of automotive painting is one can put Cellulose over Synthetic: however never ever put Synthetic Over Cellulose.

It will pull and partially solve the preceding undercoat.

Cast Iron (Blocks, Gearboxes, Axles, Machine Tools etc) were always treated with synthetic paints. These tended to be "Flat"; i.e. non-gloss.

For a superior glossy finish, all our racing engines and cylinder heads were finish painted in a light blue (Team Colours) Polyurethane Paint then marketed as Kingslac.

Heat and oil, petrol resistant and gave an excellent finish.

In those halcyon days I always used Valentine paint systems (Valentine Paint and Lacquer Company) and they enjoyed a very full range of simple paints for such varied items as combine harvesters, tractors, lorries, coaches, piers, engines, chassis, etc.

In the workshop and bodyshop, everything was painted with a light blue "flat" machinery paint; benches, equipment etc.

Same was used in the precision machine shop, as I reconditioned each and every machine, myself, and went back to bare cast iron, prior to repainting.

Core secrets: if you want "Show" finish: back to bare metal, thorough de-grease, then red oxide primer. Then topcoat.

That said, show finish does not replicate original manufacturer's finish on engine blocks, heads, gearboxes and axles; this must be "Flat": i.e. non-gloss.
_________________
Well, apart from that, did you enjoy the play, Mrs Lincoln?

[bob2]

I know a lot of people over here do not like it but I have used hammerite (smooth finish) on many engines on many cars, even friends' cars and always found it very good, good coverage with 2 coats and lasted many years!
Infact I have done my green mini's engine block in hammerite black and its been like that since around 2000, never ever touched it and the under bonnet area in a mini especially a tuned one can get pretty hot quite quickly.

Same goes for my hunter, the cooper I used to own before, a lot of other minis belonging to friends, my cousin's 124 and maybe even others I can't remember right now!!
The first time I used an engine enamel was last year when I did my blue mini's engine in mowog green and that was because I could not find a match for it so ordered some via ebay!

[Ronniej]

Thanks to all. The help is much appreciated.
It is a pity I had not sought advice about this before painting the engine.
I did not think of using a primer and that may be where I went wrong.
This forum is indeed a fund of good advice based on long experience!
My car is very presentable but not a show car. ( I like to use it!).
I will go for the flat finish that would have been there originally.

Thanks again,

Ronnie Johnston.