Engine painting

Ken Tidswell

Well Known and Active Forum User
VOC Member
If the cases are bare, then you need to get them chemically clean for painting. This is not easy , since bead blasting , aquablasting means that all the bearing surfaces need to be protected and oilwayd plugged to prevent the ingress of the glass beads in to the oilways of the cases and covers. i speak from the experience of spending hours getting beads out of the internal oilways of a pair of shadow cases. The problem is not finished then, because a cover in particular the primary chaincase cover may be porous. My is. If you can find someone in your local section via this facilty, who has experience of this problem , and knows a painter you can trust to do the job. then good. This may be obvious to you already. Acid etch prime , Zinc Chromate is no longer available, there are other acid etch primers. Then a coating of methacrylic two pack should do it. My two pennorth.
But seek out a painter and ask to look at his work
Ken
 

Tom Gaynor

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VOC Member
A friend did what looks a super job, using Simonize Engine Enamel, on his Shadow covers. He used about 6 tins. Slowly does it... It has the advantage that if the motor is clean, it can be done without insinuating crunchy little bits of silica into your engine's sensitive little crevices. I should have asked him if he prepped it, normally by using an acid-etch medium, but I didn't. He may not have. I can't remember if he did the heads and barrels, I think not.
I used Polycote gloss as advised by "well known experts" on my Shadow covers. The finish is best described as "dull" although I may be guilty of exaggeration. It might be worth using a metal prep spray, often phosphoric acid, like the ones supplied by Frost / Eastwood / Restom.
This response is governed by my aversion to stripping the castings to the bare bones, screwing them all together, blasting them with a medium always erroneously described as "non-invasive", and either spraying them or dipping them in the heated 20 gallon drum of Pinchin and Johnson stove enamel that I don't have.
If life is too short to stuff a mushroom (Shirley Conran) it certainly isn't long enough to go through the procedure above. So I would go for Simonize.
 

Ken Tidswell

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VOC Member
What i should have said and it was implied from the length of preparation / cleaning up
was, don't do it this way. The cases can be got very clean using brake cleaner fluid , bought in aerosols, do not smoke, inhale or use in a confined space it says on the tin.
I have just cleaned out a very contaminated timing cover, full of what must be very fine polishing debris. The pressure relief plug was stuck in i eventually got it out with a length
of welding rod pushed up the drill way from the oil filter chamber. Took out the slotted grub screw and squirted brake cleaner down the hole the filth which comes out from all the various holes was amazing . It is a good idea in my opinion to do this when reassembling any motor. Ken
 

Len Matthews

Well Known and Active Forum User
VOC Member
I attempted to paint the crankcase and covers of a Twin engine using International Paints High Temperature Black Gloss by spraying. The result looked very good until the front carb flooded and washed the paint off proving that it was not fuel proof. I had a word with the local car paints specialist; he said I should have used Two-Pack which he could supply in aerosol form but would have to strip off what was already on the surface. Time didn't allow for this so I had to touch in the affected area with Humbrol Gloss Black and do something about that front carb!
I've often wondered how the Factory enamelled Twin engines. Did they assemble an empty shell, masked off where necessary or was each component enamelled individually?
 

Tom Gaynor

Well Known and Active Forum User
VOC Member
Good question! Known knowns: 1) They dipped them after phosphating (in Pinchin and Johnson's finest...) 2) Engine covers were matched to their cases.
Which would suggest that they sent built, empty, motors to be dipped? Which doesn't sound all THAT likely, but would require less masking than doing covers individually. Maybe crankcases and covers were assembled and dipped, and barrels and heads done individually? But Shadow heads had polished ports, and I would do that before painting.
Someone must know. I am not that person.
(The Big Sid method is to build the motor empty, then spray it with Polykote. I did not get a good finish, but since all my gloss painting seems to turn out matt, it could easily have been me.)
All that said, the original finish on my motor, which still largely exists, is completely eclipsed by "restored" Shadow motors I've seen, which have engine cases that look like Sunbeam tanks. (Ordinary production Sunbeam tanks were dipped in P and J and rubbed down FIVE times (Vin tanks were done once) and show bike Sunbeam tanks were done SEVEN times...)
 

Little Honda

Well Known and Active Forum User
Non-VOC Member
Note b/4 Painting

I want to paint my Vincent twin engine black, what does this invol;ve and where can i get it done?
When Brian Dees did my Shadow engine 6 or 7 yrs ago, it came back with very poor surface here and there, which he explained to me like this: "On older crankcases, the oil has penetrated the metalurgic structure during thousands of heat-up and cool-down-processes. It may now happen, after surface cleaning and building up a professional cover,
starting with primer, filler and several final covers of gloss black, that, if you heat-harden
the final cover, some of these oil particles are evaporating under your new cover, so destroying its shine.
So, as a consequence from this, I wld recommend to heat up yr engine parts, b/4 starting
the colour job and wiping them clean with brake cleaner and kitchen paper. I would observe the hot surface through a lens, to detect any evaporation. Good method for
heating crankcases and covers are kitchen induction heaters. No risk to overheat.
Do not use Supermarket-Colour-Stuff! The right materials, matching to each other, are
most important! The correct handling of these materials require some experience, like choosing the right viscosity and operating pressure of the spraygun. Most demanding:
Cyl.-heads plus cylinders. Good luck!
 

Tom Gaynor

Well Known and Active Forum User
VOC Member
Anyone else feeling a sudden, previously non-existent, tolerance for restoring Black Shadows as White Shadows? Amazing how a heinous crime suddenly begins to seem like perfectly sensible behaviour...
 
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Howard

Well Known and Active Forum User
VOC Member
A friend did what looks a super job, using Simonize Engine Enamel, on his Shadow covers. He used about 6 tins. Slowly does it... It has the advantage that if the motor is clean, it can be done without insinuating crunchy little bits of silica into your engine's sensitive little crevices. I should have asked him if he prepped it, normally by using an acid-etch medium, but I didn't. He may not have. I can't remember if he did the heads and barrels, I think not.
I used Polycote gloss as advised by "well known experts" on my Shadow covers. The finish is best described as "dull" although I may be guilty of exaggeration. It might be worth using a metal prep spray, often phosphoric acid, like the ones supplied by Frost / Eastwood / Restom.
This response is governed by my aversion to stripping the castings to the bare bones, screwing them all together, blasting them with a medium always erroneously described as "non-invasive", and either spraying them or dipping them in the heated 20 gallon drum of Pinchin and Johnson stove enamel that I don't have.
If life is too short to stuff a mushroom (Shirley Conran) it certainly isn't long enough to go through the procedure above. So I would go for Simonize.

I've used Simonize. Use an etch primer first and take your time. The only problem is petrol, the odd drip or two doesn't seem to harm it, but one of my taps recently developed a leak and a constant drip managed to bubble the paint down to the metal.

I've also had some success with stove enamel and the oven (best when the wife's out or the fumes cause severe ear ache).

H
 
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