Should i primer the engine block before i paint it with hi temp paint.
what kind of primer is best.
I will be painting over some of the old paint

 

I've had good luck using a high temp engine primer from dupli-color. I also have used cast iron grey color as a primer on the block. Good success both ways.

I have even used high temp paint straight onto the block, but usually have to use a can or more extra to get it to look right.

The biggest thing is getting it clean. If its really oily I like to use brake cleaner on the bad spots. Before I paint, I usually use a tire brush with dish soap to give the block a good scrubbing, hose it off and repeat as needed, followed by air to dry it.

sb

 

Do whatever the instructions on the paint tells you.
If it recommends priming then do it. (use the same brand primer as paint.)
The main thing I find is whatever you use, don't lay it on too thick.
Like 80 cutlass said, get it clean first.

 

blocks aren't primed from the factory. I've seen a lot more problems with top coat not adhering to primer than straight paint adhering to a block. I've painted a bunch of engines not using primer and never had a problem, providing the surface is good and clean.