Engine Paint

[treue]

Hi Guys,

My shop and I are about to start putting the engine (330 2+2 No. 9129) back together. Before we do, I want to paint the major parts with aluminum-color engine paint. My shop says the heads and block are NOT painted but the oil pan is. I know the main front cover is primered inside and aluminum painted outside, like the oil pan. The cam cover and the small cam sprocket covers are black crinkle-paint.

My questions: What parts of the engine are painted aluminum-color? Is there primer underneath the aluminum paint? What parts are primered inside (besides the oil pan)? Is the edge of the gaskets painted aluminum, too? Any thoughts on a good-quality paint? Bob Smith says VHT from an auto parts place. Griot's has a pricey (and presumeably good-quality) aluminum-color paint.

Thanks,
Tom

[Chris Coios]

Tom,

I shall disagree here with your shop. Typically, observation is that all of the aluminum engine castings are painted on early V-12's. It is possible that the paint, in your case, was removed from the block and heads by an earlier rebuilder. For V-12's of the late 50's and 60's 250/275/330, the color is silver, and a little bright, but not so bright like radiator paint. Harley-Davidson high heat silver is a fair - though not perfect - match. VHT tends to be a bit too gray. I do not know how the Harley paint holds up long term. The primer was typically zinc chromate and there is an old thread about this. You will find that the Factory painted the inside of many of the castings with zinc chromate also to seal the pores. Over time, the exposure to oil turns the color brown. It may be that the castings were primed before they were machined, because the mating surfaces are clean and it is doubtful that they masked every casting. My guess is that they primed the castings, machined them, loose assembled the motor without gaskets (self-masking approach), masked the exposed essentials and painted the lot. Then they disassembled for final fiiting up of the engine. I speculate on this process, because you will not see the gasket edges painted on an original, and often the ends of the studs have silver paint on them, but never the nuts. There is a good close-up picture of an inside plug 250 freshly completed at the Factory in Karl Ludvigsen's recent softback book of Factory photos - you can see clearly the paint on the ends of the studs. This photo, taken and lighted from a low vantage, also shows very nicely the texture of black wrinkle finish of the era.

Chris

[tyang]

Hi Tom,



Here's picture of my car during assembly. Most of it was painted with Krylon dull aluminum paint, which has just the right finish.

Tom

[fest]

I believe the Block and the Sump were painted by the Factory
but NOT the Heads

the Heads appear to be a different Alloy
or at least have a much better finish
compared to the rough(er) cast Block and Sump, etc.

Painted area appears to be primed with Zinc Chromate (Acid Etching?) Primer

I chose Eastwood's 'Aluma Blast' Paint
and I am very pleased with the results
low Gloss, but Smudge-Free finish

[fest]

sorry
puter troubles

the Timing Case is also painted
which I re-painted with Aluma-Blast
along with the Block and Sump

[fest]

booted off AGAIN...

I chose Aluma-Blast
because the Eastwood and POR Engine Enamels
in Aluminum both seemed moch too glossy-
but Aluma Blast has the right look

my only concern with Aluma Blast
is that it is not a high-temperature paint
but as I am NOT painting the Heads
(that is where the paint gets really hot
especially near the Exhaust Ports)
I think the paint will stay on OK

I DID paint lower Flywheel Cover
but did NOT paint Water / Oil Pump Housing
BTW

[matt]

I spoke to a shop last week about rebuilding my V12 engine. They use a paint called emron.

[Chris Coios]

When in doubt, some research again into the painting of castings. Checking various books with Factory photographs of engines in assembly or promotional photos, I remain convinced that all the engine castings are painted on early V-12's, including the block and heads. As I mentioned, page 33 of Karl Ludvigsen's Factory photo book has an ideall reference photo of an inside plug 250 motor just finished. The cylinder heads are clearly painted - paint on the exhaust manifold studs. Factory photos of the 275 GTB/4 engine show the heads brightly painted with finish matching the block, the sump, timing case, bell housing, small castings, etc. Graham Gauld's "Modena Memories" book shows a 250 engine on a stand, heads clearly painted. On the best restorations, the heads are painted along with all the other exposed casting surfaces. Some accessory items are not painted. For example, the bodies of Marelli distributors are natural aluminum. Most Webers are natural, but the bodies of 36DCL and 40DCL Webers of 250's are painted black. (The GTE carbs, the number of which I forget, are also black?). I agree with Fest that the head castings tend to be very smooth, but still, I believe they were painted, as many heads of the day were. (Fest, this comment is not meant to challenge your points, just highlighting what I think is an important restoration detail, if that is one's objective.)

Chris

[JimB]

I used aluminum paint from Bill Hirsch. He sells it in quart cans. It brushes on very easily with a sponge brush and leaves no brush marks.
It is very durable and looks great. I bought many cans of spray aluminum and did tests on the engine. This paint has by far the nicest finish. It cleans up easily if the engine should get dirty(God forbid).
Bill Hirsch advertises in Hemmings.

Jim Burnett

[fest]

Chris-
no offense taken
the decision to not paint the heads
is a personal one-
(wether or not they were painted originally)
they just looked too pretty to paint,
that, and as I stated, I was afraid the paint would burn off
around the Exhaust Ports

I am NOT removing Heads on this job
nor doing the bottom end
if that was the case, I would do it right
i.e. Hot Tank and Bead Blast all the Castings
and then Prime with Acid Etching Primer]
and Paint the whole darn thing

in this instance, the Timing Case looked like crap
as the paint had worn off in spots, exposing Primer
so I wanted to 'freshen it up' a bit;
the Block looked kinda beat as well
(and would really look like crap
aginst the freshly painted Timing Case)

so I decided to paint just those parts
that really needed it...
this is 'just' a Timing Chain Job
not a complete re-do

[fest]

while we are on the subject of Paint-
what is the correct paint for the A/C Compressor
(Aspara late 70's vintage)

it looks to be a Silver Hammertone finish?