As part of an engine rebuild project, I'll be repainting (Chevy orange) the engine and bell housing on my ’70. My objective is to stay as close to stock as possible. From the research I've done thus far, GM assembled the engines (minus the carb, distributor, and alternator), taped off the valve covers (L46) and sprayed away. Although the exhaust manifolds were also painted orange, the paint quickly burnt off.

Here are my questions:

1) Did GM paint the water pump orange?
2) Should I primer (GM didn't) the engine before painting?
3) How many cans of paint does it take to cover the engine & bell housing (assuming two coats?)
4) What color should I paint the exhaust manifolds?
5) What's the best (quality, durability, and ease of use) paint to use?

Any "tips" you all can give me will be appreciated.

 

I've used a couple of different brands of "engine enamel" spray can paint that I get at Pep Boys or Autozone. I think one is called PLASTICOAT and the other one is DUPLI-COLOR, but they both work equally well. Just use what you find, as long as it says "engine enamel" on it. I also ALWAYS use the "engine enamel primer" that they sell right along with the paint. I've always had very good luck doing this, with no issues at all. Just remember to clean the parts very well before spraying the primer, so that everything sticks well. Any paint job is only as good as the prep work. I'd guess maybe getting 2 cans of primer and 4 cans of color, would be in the ballpark. You'll probably have some left over, but its not going to break the bank.

Eastwood sells a very high temp brush-on (use a foam brush so that there are no brush strokes) coating that is sort of a bare cast iron color, that works extremely well on exhaust manifolds. I have it on an old 283 in a '57, and it still looks perfect after many years.

 

Yes, water pump was painted orange (and timing chain cover). Since you have the engine out and you want to do a good clean-up, take the headers off and have them sand/shot blasted to get them clean. Then you can use a good quality high temperature header paint (cast iron color) or have them coated (more $$$). OR, you can buy some Calyx header coating. This is a metalic "paste" substance that you put on the [freshly shot] headers to give it the cast iron finish. It's best that you do this just before you install the engine, as the exhaust heat causes the Calyx to "bake on" to the surface. Since they are off the engine anyway, I guess you could put the Calyx on them and bake them in an oven (not you wife's oven, of course).

 

I haven't researched it, but every waterpump I've seen on a chevy (Corvette or otherwise) SB was painted. I didn't prime my engine, just made sure it was clean and dry. Paints been there for several years with no problem. I don't recall how many cans I used. One is probably not enough, but two would leave you some extra if you wanted to go back and touch it up. I used a product from Eastwood, High Temperature Coating, silver/grey to coat the ram horns. I just recently recoated them, but they were also coated several years ago before they were on the car. I don't really have an opinion on which brand paint to use, I used Dupli-color on my waterpump when I recently replaced it. Just be sure to use the high temperature ceramic paint. Good luck!!

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If you are going for NCRS judging than you should paint the motor with the exhaust manifolds on as they were at the factory and got some overspray on them. If you are not going for judging that I personally prefer to paint the block without the exhaust manifolds on since I prefer to not have the overspray.

As for your questions:

1. The water pump was on and painted at the same time, along with the timing cover and balancer. Other items that may or may not get painted are the intake and valve covers depending on the motor. Iron intakes and steel valve covers were also painted at the same time. Aluminum intakes and aluminum finned valve covers were not painted

2, 3, & 5. depends on the paint whether or not to prime the block first. I painted both my '65 and my '78 motors using paint from Hirsch Automotive http://www.hirschauto.com/ (1-800-828-2061) and was very pleased on the paint both times.
Hirsch uses a high-temp enamel paint for motors that goes on easiely and dries down great. They recommend NOT priming the iron block as they claim their paint sticks better to the bare metal rather than primer. The steel oil pan needs to get primed first though.
My '78 took 3 spray cans of their paint and that was spraying five light coats on. In my case I didn't spray the bellhousing since it stayed with the tranny in the car nut if you are thinking about only two coats than one or two cans should be fine. I just prefer to do multiple light coats rather than fewer heavy coats.
The '65 motor was painted almost two years ago and the '78 motor was painted a little over a year ago and so far the paint has held up extremely well. Based on my experience with it I'd use it again and have no problem recommending you consider trying it.
Of course the overall quality and longevity of the motor paint is the same as any other paint and that is determined a lot by the prep work done before hand.
Before painting the block I stripped the old paint off the best i could using paint stripper I got from Pep Boys. I also followed up the paint stripper with spray can carb cleaner as carb cleaner is also good at removing paint and it got into a lot of the nooks and crannies I couldn't get with the paint stripper. With both products I applied it, let it sit and let the chemicals do their work softening the old paint and than scrapped it off with plastic scrappers and in tough areas used wire bristle brushes to help get the paint off. After stripping the old paint the best you can use lacquer thinner or Prep Sol or another similar "Ppre-Paint Cleaner" and thoughly wipe down the entire surface. This will remove any remmants of the paint stripper and carb cleaner that if left would bubble up your new paint. The lacquer thinner and/or pre-paint cleaners will dry quickly and not leave any residue. To be doubly safe I used both the lacquer thinner than followed up with the Prep Sol although it may have been a bit of overkill but i figured better safe than sorry.

if it helps here are pics from the cleaning and painting of the '78 motor - the stripping and painting is about halfway down the page:
http://lbfun.com/Corvette/78Vette/mcu/parts.html

 

If you are a fanatic about originality the timing cover will not have paint behind the water pump as the pump was in the way when it was sprayed. A cardboard mask was over the pump snout I believe. The balancer was at TDC and the timing indicator tab would prevent any paint from getting to the part of the balancer that was under the tab. Aluminum intakes and finned valve covers had a mask dropped over them before the paint went on. I like originality more than most people here but no way would I duplicate these quicky factory spray paint jobs during a resto. Kind of sloppy IMHO. Paint them off the engine first.

-Mark.

 

Everybody.........Thanks for your replies. There's some very good information here.

Although I will not submit the car for NCRS judging, I do want it to look much like it did when it came off the assembly line in July of '70.

The engine comes out on Monday - wish me luck!!