I was watching my freind install his new ctr pistons into his b16a2. Before he put the pistons in, I noticed he sprayed wd40 all over the cyclinder walls and the pistons. I dont have much knowledge on installing pistons, but is this okay?

 

it helps lubricate the cylinder walls and pistons, making them easier to slide in

 

It also helps the rings to seat.

 

I would've just used regular conventional oil. That's what you're suppose to use anyway when you prime the engine.

 

im with e30dood i would use assembly lube on the pistons and just some motor oil on the cylinder walls. you cant really put too much lube on before that first startup your car will have the most ware in the first 30 secs than in its lifetime if not properly lubricated. but anyway im not sure that WD40 is bad but im sure that there better ideas than that.

 

When I put my engine together I dunked the pistons top-first into 30W oil and worked it into the rings one at a time. I used tons of assembly lube putting the rods/crank together.

One important thing to remember when youre building an engine is, when it's ready to be started, crank the engine over for about 30 seconds with the spark plugs out. This primes the oil pump and gets the oil up into all the passages. Makes that first start up much more gentle.