Painting an Engine

[slow8]

This may seem like a basic question but its coming out of an abundance of caution on my part.

I am having a '51 Mercury flathead built and it is currently almost done.

Watching several videos on YouTube many folks recommend going over your block with a propane/MAP torch and heating it up enough to burn out any oils and moisture from the porous cast surface before applying paint.

Is this going to cause any issues on an assembled engine or on a flathead block?

Have you had success with this method? Any other tips or tricks?

I plan on brush painting it with some primer and then a layer of color.

[Ford Freak]

I've always just wiped it down w/lacquer thinner & let it air dry. Done it that way for over 53 yrs. now, & counting. Works for me!

[55blacktie]

I recently had my heads done. Although it looked like they had been thoroughly cleaned by the machine shop and were ready for paint, about 45 minutes to an hour after I primed them, the paint began to peel. Fortunately, the paint was easy to strip. I stripped them with Goof Off and a wire brush, and then thoroughly cleaned them with 90% isopropyl alcohol.
Don't judge parts by the way they look or feel. I, too, saw the article/video in which a propane torch was used to burn off any residue before painting. I've not tried it, but it's possible that the torch might leave some residue as well.

[Hot Rod Reverend]

I have painted many engines and never had any trouble with peeling.

Never use a torch - whatever it burns does not magically fall off the engine. I do not know why guys believe that. There would still be mechanical removal needed by a brush, etc.

I have always used lacquer thinner and/or isopropyl alcohol as stated above. Works like a charm. Eastwood sells a product call Pre-Painting Prep in an aerosol can. The stuff has gotten expensive though - it's almost insane to pay $18 for that can. But, the product has always done a tremendous job with any surface I have applied it to - engines, wheels, and espeically body panels.

[evintho]

I sandblasted my 5.0 block after filling all openings then wiped it with lacquer thinner and sprayed it with Duplicolor ceramic primer and Ford red. Got a feew hundred miles on it now with no peeling or problems.

https://www.fordbarn.com/forum/attac...1&d=1745024600

https://www.fordbarn.com/forum/attac...1&d=1745024600

https://www.fordbarn.com/forum/attac...1&d=1745024600

[Ford Freak]

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I agree w/evintho ^^^ I always use Duplicolor. Besides the Ford red, their Ford dark blue looks great also! Easy to obtain, as most of the chain auto parts stores carry/stock it.
On a side note: Like just about everything good, quality, spray can paint has gotten crazy expensive!!

[55blacktie]

There are a lot of places where sand can hide in an engine. After having my block cleaned and magged by a machine shop, I still found rust deposits and sand left over from the casting process. I pressure-washed the bare block at the local self-serve car wash until nothing but clear water was flushed out.

Years ago, a friend sandblasted and painted an intake manifold. Unfortunately, not all of the sand was removed, and it resulted in the engine having to be torn down after it was assembled and running.

The best rattle-can paint I've used is Seymour's. I used their PBE Primer, followed by their Ford/Chrysler Red. The same paint was recommended by Gil Baumgartner (CTCI Gil's Garage).

[ThirstyThirty]

After machine shop operations, following good tech and advice... I always gave the empty raw machined or departs'd block a boiling hot soapy water scrub down. bore brushes, etc... just for the job. cam holes brushes too, etc. Then out with the cold water hose and spray the block down with cool water, risen thoroughly. then with air compressor blow dry everything, every where... google required. then out with the oxy/actyl... and the rosebud. fire 'er up!... go over all with flame and warm everything to a nice happy clean happiness. then back into shop ready for assembly process... dry and clean!


my heads most often went to the head shop for specialty and rework, valves work, etc and came back clean!

[ThirstyThirty]

Originally Posted by evintho

I sandblasted my 5.0 block after filling all openings then wiped it with lacquer thinner and sprayed it with Duplicolor ceramic primer and Ford red. Got a feew hundred miles on it now with no peeling or problems.

https://www.fordbarn.com/forum/attac...1&d=1745024600

https://www.fordbarn.com/forum/attac...1&d=1745024600

https://www.fordbarn.com/forum/attac...1&d=1745024600

I have never used the sandblasting method to clean engine or engine parts. And I would not suggest it. But engine building is often part artwrok! and a good prep matters! from your pix, I would say you did a good job! engine looks great! and by looks of your shop, seems to me you know what you are doing!

My Dad was a master mechanic. Gunsmith, etc. Aviation A&P, etc... one thing he always told us boys was, when it comes to engine building "cleanliness is next to Godliness!" how clean should it all be?... clean enuff to eat off of!!, he would say. I have on more than one occasion... put my tongue to engine block, deck, head, intake etc... just to prove the point.. "Now that part is clean enuff!"

Good Luck with your fresh engine!

[Ford Freak]

Originally Posted by 55blacktie

There are a lot of places where sand can hide in an engine. After having my block cleaned and magged by a machine shop, I still found rust deposits and sand left over from the casting process. I pressure-washed the bare block at the local self-serve car wash until nothing but clear water was flushed out.

Years ago, a friend sandblasted and painted an intake manifold. Unfortunately, not all of the sand was removed, and it resulted in the engine having to be torn down after it was assembled and running.

The best rattle-can paint I've used is Seymour's. I used their PBE Primer, followed by their Ford/Chrysler Red. The same paint was recommended by Gil Baumgartner (CTCI Gil's Garage).

Yes, Seymour's is great paint too. I have used their Alumi-blast & Cast-blast for years. I was not aware they made engine paint. The stores around here only carry the Alumi & Cast blast lacquers. Do you order it online directly from Seymour's?

[55blacktie]

I have purchased Seymour's from Amazon and eBay. Their PBE primer dries very quickly and is the best I've ever used.

[Adriatic Machine]

I’ve seen Uncle Tony use a torch as paint prep to clean an engine. He makes a good point about pulling out the moisture from the iron. If you’re worried about damaging something internally then you might consider heating the whole engine with a shop heater while monitoring the temperature with one of those laser thermometers.

The last engine I painted did have some flaking afterwards. I also live very close to the ocean in a generally humid environment, not sure if that matters.

[Ford blue blood]

My engine paint prep has been clean with a degreaser followed by a spray down with brake cleaner followed by a hot water Dawn dish soap bath and a good rinse. After things are dried I put a coat of self-etching primer on followed by primer of choice.