Backwards pistons?
 

ok so im pulling the head off of my 86 crx si with the d15A3 in and I noticed something a little odd. Well the D15A3 has a 12 valve head, meaning 2 intake valves and one larger exhaust.

Well on the pistons there are only the two notches for the intake side on one side of the piston.

the weird thing is that the notches are on the exhaust side of the block. so that the valves and notches dont wouldn't even line up.

Yet the engine runs fine and has for 213,000 miles (3,000 boosted :P)

I thought maybe i had a engine put toghter on friday, but i looked at another D15A3 in my shop and sure enough its the same way. And im about to pull the head off of another 86 crx si and i want to bet it'll be the same.

anybody have an answer for why the pistons are like this? or wether or not i should rotate them to match correctly?

Re: Backwards pistons?
 

It's mad jDm. Not only do they drive on the opposite site of the street they also in install pistons in backwards. lol. Naw thats just really odd. ???

Re: Backwards pistons?
 

I would guess that it was an assembly line glitch. if you know the VIN's I'd check those to see if they are close in numbers. I'm surprised it ran though. Your ever redline your's (valves get pretty close then).

Re: Backwards pistons?
 

take some pics, its probably normal.

Re: Backwards pistons?
 

ask on www.redpepperracing.com

Re: Backwards pistons?
 

yea, so i pulled a head off of the another 86 si and guess what, same thing.

can I just rotate them? the aroows on the pisotns would be poitning toward the front of the car if i fasted them correctly

Re: Backwards pistons?
 

Well since 3 motors are like that, I would leave them like that just to be safe. there might be a reason for it.. :8

Re: Backwards pistons?
 

maybe the valves actually cross each other> what size cam is the stock cam?

Re: Backwards pistons?
 

lol

warning this information is coming to you nearly three years too late

http://www.redpepperracing.com/techn...6285-3/aac.png

Re: Backwards pistons?
 

that cant be right, no D series rod is that big