Painting LS motor

[Zedn]

Im getting a bit trigger happy and have decided now is the perfect opportunity to paint my engine before it goes in.

Just wondering if any one has painted their ls alloy block. And what type of paint you used. I have only painted a cast iron motor before and used regular 2 pack.

I am thinking I can just use 2k epoxy primer and then base and clear coats. Any advice?

I know I can use VHT or similar engine enamel, but I want to match the rest of the car.

Cheers.

[Rog246]

Zedn I think you will have to use an etch primer before you paint it.
You'll have to paint it GMH red of course, I mean it coming from a commonwhore and all. Should look great in there...................well.........maybe not so much

[Zedn]

I'm just not sure about how etch primer will handle the heat. I have been using upol acid 8 for other alloy which is good stuff but it doesn't specify heat.

I'm sure there is a simple answer, cause lots of people paint them.

Not red. Blue pearl and yes it will look good

[Rog246]

Zedn KBS Coatings do a high temp primer specifically for engines, here's the link Rust Stops Here - Paint - Tank Sealer - for rusty surfaces - KBS Coatings
Got to be worth having a look.
Rog

[Aussie Mike]

People have been painting aluminum motorcycle engines for years. Maybe check some of the bike forums or talk to a custom bike shop to see what they reckon.

Cheers

[Zedn]

Rog,
I had a look, but it only mentions steel and not alloy for that product.

Mike,
Good point, I hadn't thought about bikes. Will do some google.

I have sent an email to upol about the etch primer and they have forwarded to their technical dept.

[renovationinnov]

zedn just had a look a the por 15 cattle dog & they list a engine paint
might be a option to try
rob

[jcraigau]

Hey Liam,

Not sure POR is the way to go, it may just insulate the heat in the block.
How do you make it look good and practical?

--JC

PS My block's not in yet either so I'm keen to see what comes of this...

[Firefly9r68]

The LS motor actually needs to stay bare. that lest the heat out of it. if you paint it its like putting a blanket around the motor and the Alum wont breath well. I know im new on here so some may not think to listen to me :-) but i do have 23 LS motors sitting infront of me as we speak. :-). We are a shop that deals with just the LS motor on a daily basis. do yourself a favor and dont paint the block or heads, but you can paint the ACC and brackets if you would like. you can really make a LS motor look good. relocate the coil packs, nice valve covers. then the only wiring you see in injectors. you can make a nice clean looking LS that way

[sambo]

Firefly, my LS powered Cobra runs at 50 celsius in winter, which suggests the cooling system with alum radiator is doing a pretty good job. Are you really sure that a painted block would prevent that much heat from escaping? It's not like the paint would be cool to touch after a decent run - which suggests plenty of heat does get through.

[Zedn]

This seems to be a contriversial topic. Firefly is not the first to say this.

Im sure it is correct in that any motor that is painter would technically run hotter. But, as engines are water cooled and not air cooled i dont see this being a major issue for a weekend cruiser. Combined with bonnet scoop and side vents plus the design of the front of a cobra i dont think cooling is going to be a problem with the right radiator.

I plan to keep the paint thin with just enough to cover

[Paintwerks]

G'day all.

My name is Simon (people call me 'Sime'). Long time lurker, first time poster. I'm planning on buying a Pace 427 kit from Craig when they are released. Thought this as good a time as any to introduce myself.

I own Paintwerks, a SE Melbourne smash repair shop and we do quality, custom painting including fibreglass bodies, race cars and bikes. We paint aluminium all the time, including Brembo brake calipers.

When painting aluminium (or bare metal), we use a 2K etch primer....either PPG's D831 'Universel' or Metallux Direct to Metal etch primer. Both are WOW (wet on wet) systems that you can apply basecoat or direct gloss to (followed with clearcoat depending on what system you use). We haven't had a product failure yet using this method.....and that includes painted brake calipers.

I painted the Brembo's on my Subaru WRX STi back in December 2009 in candy orange using the above products. My car puts down over 300kw at all four wheels, gets driven hard and, over 2.5 years later, the calipers look as good as the day they were painted.

I can't comment on the VHT 1K aerosol products as we don't use them, but if you use professional 2K products and (importantly) follow the TDS' correctly, you shouldn't have an issue painting an alloy engine block.

Cheers,
Sime

[Rob. Smith]

I know a bloke that actually 'bogged' up a block and sanded it smooth to go into a "show-car" he then painted it the same colour as the car with the same paint..acrylic lacquer. I couldn't believe that the paint survived the heat like it did. It only discoloured near the headers. I haven't seen the car for ages but I bet the bog has fallen out by now.

[Tenrocca]

Just sand and polish it Liam. What better way to spend a couple of months of weekends.

[Zedn]

G'day Sime welcome to the forum. Great to have a paint person here. My next question is what primer for the plastic intake? Any recommendations?

Andrew I have thought about polishing and it's very tempting, but I would need to clear coat it and that would be harder to find the right product. Would look really nice for a week.

[Zedn]

Another question. What prep would you recommend for the rough casting? It's a brand new crate motor. I was thinking maybe a scourer disc on a drill or die grinder.

Should it be prepped within a certain amount of time of painting before it re oxidizes? I looked up the ppg product and it says to wipe down with 50/50 metho and water bofore coating. Is this to remove oxide or just clean oils.

Appreciate your help. My paint supplier has all the stuff but not the expertise. They sold me the wrong hardner with my clear and it gave me all sorts of solvent pop issues. They told me air was getting trapped and causing the pin holes.

[Paintwerks]

Originally Posted by Zedn

G'day Sime welcome to the forum. Great to have a paint person here.

Well thanks! Happy to be here!

Originally Posted by Zedn

My next question is what primer for the plastic intake? Any recommendations?

This depends on what type of plastic the intake is made out of. If it's PP, PPE, ABS or Fibreglass, you should use PPG's D820. However, if it's made out of PUR, then you need to use PPG D816. After D816 is applied, it needs to sit for a minimum of 40 minutes before applying topcoat/basecoat. The problem is that you need to do this in a spray booth where there is constant airflow over the part.

It's also quite possible that the intake is made out of polyethylene (PE). K&N intake kits are made using PE. And if that's the case, sorry......you're pretty much screwed as you generally can't paint PE without a lot of difficulty.

This is a US site which may help you (although they're US products which may not be available here), and the author does not specifically state that he's painting PE:

Dirt Bike or ATV Plastic Restoration via Painting By Edward Pinzel on 4Strokes.com

[Paintwerks]

Originally Posted by Zedn

Another question. What prep would you recommend for the rough casting? It's a brand new crate motor. I was thinking maybe a scourer disc on a drill or die grinder.

Should it be prepped within a certain amount of time of painting before it re oxidizes? I looked up the ppg product and it says to wipe down with 50/50 metho and water bofore coating. Is this to remove oxide or just clean oils.

Appreciate your help. My paint supplier has all the stuff but not the expertise. They sold me the wrong hardner with my clear and it gave me all sorts of solvent pop issues. They told me air was getting trapped and causing the pin holes.

Happy to help Zedn.

You need to prepare the casting by removing any burrs and dags. If you need to fill any imperfections, use JB Weld and allow it the full 24 hours to cure. Use the standard version, not the 'Kwik'. Standard JB Weld can withstand 500F temperatures and it does it really well.

You'll want to finish with a P180-240 dry paper. Yes, you then need to wipe the surface down using a 50/50 mix of metho and water. This cleans any oils out of the aluminium. Wear powder free latex gloves the whole time and don't touch/rub your face (and then the block) after you've cleaned the surface down.

You then apply your etch primer immediately and go on with your topcoating from there. It's worth mentioning too that given the pretty cold weather we're currently experiencing, you would should pre-heat your block to between 23-26 degrees celcius before applying any primers or topcoats. You'll also want to maintain this temperature throughout the entire dry process.

Even then, depending on what materials you used and how much material you applied, if cured at room temperature, the paint will still be relatively soft for approximately 1 week after painting (or about 48 hours if baked @ 60C for 30 min in a low bake spray oven).

Given this, you want to resist the urge to start bolting things back onto the motor for at least a week after painting!

Cheers,
Sime

[Paintwerks]

One more thing....I made a reply earlier re painting the intake, but it said a moderator needed to approve it before it would be live. I'm hoping ths occurs, but if not, I'll repost my reply later. I'm not sure how this reply made it to the forum then?????

[Zedn]

That's weird I dont know why a mod would have to approve.

When you say burrs and dags are you talking about the general casting roughness or just any ugly sharp bits, edges and joints? I was hoping not to have to sand the casting down. Was thinking the scourer because it would get in the low spots better than sanding which would just get the high spots.