Topic: Engine Powder Coat or Paint?

[theoctopus]

Well, I'm about to pull the engine on my bike and begin the process of rebuilding it from the ground up.  I've never worked on engine internals before, so this is going to be a slow (and admittedly painful, at some points) process.  I'm excited though.  That was the plan with this bike from the start: learn by doing.  I'm going to be installing a big bore kit (836 forged pistons, cam, etc. etc.), and probably getting some head work.  It still is yet to be determined if I will do more than this.

My question is this.  I would like to have the entire engine assembly be black.  I know a lot of people go the cheap route and spray bed-liner or textured hi-temp paint on the engine, but I'm a little wary of this.  How would people suggest I achieve the intended effect?  Powder coat?  Paint?  Either way, I know it'll take some serious cleaning to get the engine prepared for either, and I'm ready for that. 

If I did end up powder coating the engine, what sort of prep work aside from deep cleaning/de-greasing would I have to do?  Can a shop spray/baked the whole engine assembly as an entire unit assuming all holes were plugged/masked?  Or would I have to break it down into smaller parts, remove all engine internals, and powder coat that way?

[Toxic]

If you are going to go to the expense of powder coating you can get a heat dispersing ceramic coating for the same money.

Nothing wrong with engine paint if applied properly.  It's all in the prep work and following the makers directions to the letter.

[theoctopus]

I'm tending toward high-temp ceramic coatings, to be sure.  There's a local shop here that specializes in them.

I guess what I'm really interested in is what sort of prep work I will have to do.  Will I have to pull out all engine internals in order to coat each part individually?  I tend not to trust someone else to do my work for me, so I'm interested in knowing how much I'll have to put in before I can send it off to the shop for coating.

[kghost]

I've done one.

I'll never do another.

It takes Hrs of work.

[theoctopus]

I've done one.

I'll never do another.

It takes Hrs of work.

That's the answer I was looking for.  I was fearing that would be the case.

So I guess the alternative is to polish the engine, because it is a sight for sore eyes right now.

[kghost]

I've done one.

I'll never do another.

It takes Hrs of work.

That's the answer I was looking for.  I was fearing that would be the case.

So I guess the alternative is to polish the engine, because it is a sight for sore eyes right now.

Polishing won't come out super pretty on the cases as thier pressure cast.

[theoctopus]

Damn.  So what's the best option?  It's really ugly as is.

[kghost]

Damn.  So what's the best option?  It's really ugly as is.

Depends how much work you wish to do.

Simplest and easiest to touch up is paint.

[faux fiddy]

That coating on the 350f rocker cover is 95% pretty amazing except fot the small spot where it failed. I thought mask mine  off and touch it up.

[SOHC Digger]

You can buy the black wrinkle paint that Harley uses on their motors if that's the look you are going for.  It's actually not terribly expensive from them either.  Make sure you clean everything REAL WELL first.

[Toxic]

You are doing a 836 kit so the top is going to be off anyway.

Remove all the side covers and take your time.
-clean
-degrease
-scuff up the surface
-clean and degrease again.

Then follow the paint instructions.

The barrels and head are going to be easier to clean as they will be disassembled.

[MattFreeman]

I've been debating this same question. I'm leaning towards paint for ease and cost.

Octo, great avatar. I like it almost as much as the guy with the zipper booby girl. Makes me want to pick up a bottle of gin and dig out the ol'baseball bat.

[theoctopus]

I've been debating this same question. I'm leaning towards paint for ease and cost.

Octo, great avatar. I like it almost as much as the guy with the zipper booby girl. Makes me want to pick up a bottle of gin and dig out the ol'baseball bat.

Thanks Matt.  It's from a comic book called "Milk and Cheese" by Evan Dorkin.  Really wild stuff.

So which paint does everyone use?  The Duplicolor High-Temp paint looks promising.

[Hannibal Smith]

IMO-

I have full bead blast and oxide blasting capability at my shop, and I don't use it on CB engine cases.

It can be done, and it's done all the time, but you run a pretty serious risk. No matter how well you degrease and mask ALL holes/orifices/internal surfaces etc. you will have glass beads that sneak in.

You have to clean, clean, scrub, clean, inspect, clean....................and do it again or run the risk of errant glass beads (invisible to the naked eye) destroying your fresh motor within a week.

Cabinet contamination is also an issue, most folks use one cabinet for oxide and bead blasting, so you have a mix.

PSI- for glass beads you must not exceed 45 PSI at the gun, or else the glass beads WILL fracture (now jagged little meteorites) and embed themselves into the surface of your aluminum, and no solvent will remove them, it is a mechanical bond.

Best bet IMO is to degrease the crap out of the cases with "MarHyde Tal Strip" (aircraft coating remover), then degrease the hell out of them with your favorite stuff. Take a stainless steel brush that is virgin or has only touched aluminum alloys, and spend 20 minutes lightly scuffing the case halves.

Paint- Get some 2 stage stuff (like Eastwood Engine Paint) and shoot the cases, no rattlecan action if you want true durability IMO. Let the cases sit for a week, then reassmble the motor.

Just my opinion, but I bead blast stuff everyday for Military applications, and I have made every mistake in the book!

[bistromath]

IMO-

I have full bead blast and oxide blasting capability at my shop, and I don't use it on CB engine cases.

It can be done, and it's done all the time, but you run a pretty serious risk. No matter how well you degrease and mask ALL holes/orifices/internal surfaces etc. you will have glass beads that sneak in.

You have to clean, clean, scrub, clean, inspect, clean....................and do it again or run the risk of errant glass beads (invisible to the naked eye) destroying your fresh motor within a week.

Cabinet contamination is also an issue, most folks use one cabinet for oxide and bead blasting, so you have a mix.

PSI- for glass beads you must not exceed 45 PSI at the gun, or else the glass beads WILL fracture (now jagged little meteorites) and embed themselves into the surface of your aluminum, and no solvent will remove them, it is a mechanical bond.

Best bet IMO is to degrease the crap out of the cases with "MarHyde Tal Strip" (aircraft coating remover), then degrease the hell out of them with your favorite stuff. Take a stainless steel brush that is virgin or has only touched aluminum alloys, and spend 20 minutes lightly scuffing the case halves.

Paint- Get some 2 stage stuff (like Eastwood Engine Paint) and shoot the cases, no rattlecan action if you want true durability IMO. Let the cases sit for a week, then reassmble the motor.

Just my opinion, but I bead blast stuff everyday for Military applications, and I have made every mistake in the book!

This might be TMI, but I spent a quality afternoon in the bathtub with my 550 cases (no, really) after having them blasted. It took, all told, about four hours of scrubbing, washing, and rinsing before I was confident that the beads were gone. I had also masked off every large hole with a glue gun, and every threaded hole with old bolts.

Be sure to put a mat down so you don't scuff the hell out of the tub... I managed to scrub the scuffs out with Comet before the wife found out.

[rebabal]

I painted mine with rattle cans.  Turned out pretty good, prep work was wiping it over and over with mineral spirits to clear off all the dirt/oil.  Looks good.

Took about a day or two to do all of it.

[the-chauffeur]

Next time (!?!) I do anything paint-wise with the engine, I'm gonna use petrol resistant lacquer on the painted areas of the engine cases - but not the head 'n' barrels.  The H 'n' B get hot enough to keep the paint cured to the point where it stays impervious to almost everything. No matter what paints I've tried on the cases themselves (clue - loads; and all properly heat treated after painting) they don't seem to be able to withstand petrol spills from the carbs.

Just a thought . . .

[greasy j]

if you really want to paint it a few hours of prep work is necessary at the least. I wouldn't let that throw you off, though. anything worth doing takes a bit of time and the better the prep the better the paint looks. if you do it right and spend the time it will last for years, and you will have a great looking engine.

rattle cans can do as good a job as spray guns if you do it right. prep is everything!

don't let the laggards influence you, do what it takes, you'll be happy you did in the longrun. (no offense laggards)

[campbmic]

I don't know if anyone else had this problem. I painted my engine with Dupla-color high temp engine paint. One drop of gas ruined a huge area. Then lots of drops of gas out a stuck float ruined the rest. Now I have the engine in the bike and I'm having to sand and polish all the #$%*ty crumbling paint.

If I had to do it again I would sand until you get to 2000 grit. Then steel wool, then scotch brite pads.

[greasy j]

I'd like to hear someone's recommendation for a gasoline resistant case paint, also. does the ceramic paint work in this regard?

and as far as dupli-color, for their primer at least, they have more than one grade. there is the stuff at the auto parts store and the stuff at the paint store. the normal stuff is kind of crappy, the pro stuff is actually pretty good. I usually only use rattle cans for primer, but I'm thinking maybe the engine paint is the same story? next time I'm at the paint store I'll ask my local guru.