To paint a case or not to paint a case?
I am seeing a lot of cases coming in our shop that are painted. Is this good or bad? Well I personally don’t like it. I think painting your block comes from the water cooled world. Cast iron blocks were painted and hey, it looks cool, right? Now keep in mind that motor has water in it. The water is what takes the heat away from the motor. We are aircooled and don’t have that system. If you live in a hot area, we can use all the cooling we can get. So what you’re saying is, “painting a block makes the engine run hotter”? In my opinion, yes. Think about it. Painting a case is like wrapping a jacket around the case. To prove my point, go stand outside with a shirt on. All the pores in your skin are shedding heat. Put a jacket on. Do you not retain the heat your body is giving off? Now the jacket on your body is a good thing as we might want to retain our body heat. On a motor that is making heat, don’t we want to shed that heat? All the pores in the casting of the case are just like the pores on your skin. Each little pour is shedding heat. Now is the paint enough to kill a motor? I doubt it, but it doesn’t help and I will take advantage of any type of cooling help I can for these engines. If we look at how the cases came from the factory none of them were painted. Hans and Franz must have done some homework there.
I think another reason people paint cases is it hides a lot of things that might not look so good. Example: I was working on my house and I had cut a piece of plywood for the roof at the peak. I laid the plywood down and saw that my cut was way crooked. Looked like shit. I started to take that piece off and cut a new one. The guy helping me said what are you doing? I told him I didn’t like the cut and it looked terrible. His reply was, no one will ever see that. “Trim and paint makes things what they ain’t”. Yeah.. I replaced the sheet plywood and took my time on the next cut.
Now don’t get me wrong here, on a show car or trailer queen a painted case looks good. Again, I don’t think just because your case is painted that it is going to overheat. My point in all this is we just aren’t taking advantage of some free cooling.
Ok, you sold me there. I think I will polish the case. NO. Don’t do that either. As I said earlier, all the pores of the case are what shed the heat. Polishing the case will get rid of those pours. Think about it. If you took all the minuet humps and bumps and laid it out flat you would have way more surface area then if you polished all those out. That surface area is what is shedding the heat. Look at an external oil cooler. The more surface area, the better the cooling. Making sense now?
Here is another way to look at it for you younger guys. The amp for your stereo is made out of aluminum. It has fins or lots of grooves in the housing. That is to get rid of heat that the amp is making. If you got rid of all that and had a smooth housing you can bet that the amp will run hotter. Too hot and guess what? No tunes.
So with all that said do you paint or polish your case? Hey, it’s up to you. Looks nice but are you hiding something? You might not be, but the guy standing there looking at your motor might think you are. Are you losing cooling? Yeah, you are. Not much, but every little bit counts in my book. If you’re thinking about polishing it, maybe just do the parts that can be seen. That’s all I got on this subject. All I ask is that you think about it while you’re shaking that paint can.