hey man, I am just curious as to what u know about the closed and open block design of the prelude H22a's, I am going turbo on my lude and its a 4th gen so therefore a h22a with a closed deck from what Iread in uur other posts...

I know that under Forced induction closed is better so I am happy about that but u wanna explain the difference man?

 

Well I'm not JG, but I'll give you a little explination.

On an open deck motor the water jacket that surrounds the piston sleeves is open to the head. In other words there is a gap between the piston cylinder walls and the rest of the block on open deck motors that coolant flows through.


A closed deck motor does not have those openings around the cylinders.

Gabe


[Modified by Gabe, 6:54 AM 8/16/2001]

 

BINGO! The man gets a prize.

Yeah, open deck can allow the cylinder "walls" or sleeves to flex at high rpm. But, it's easier to cool. The closed deck won't flex. Much stronger.

The closed deck looks more like what you would expect, a traditional block so to speak.

 

How deep are those coolant channels around the sleeves?
I guess the H22A1s don't have cooling aound the cylinder sleeves?

 

they do, but they're channels.

 

how big or deep are those channels? Under FI I think that the flexing of the those blocks could lead to some serious damage... But is there much difference in strength from teh closed to open deck? like would the maximum boost taht these blocks can hold change by more than 2 psi?

 

If you're going to boost the hell outta it... you want the H22A1. The A4 is fine for a turbo, but if you plan on going super psi, then yes, there is a chance the cylinder walls/sleeves could walk. I've seen it on a well built b18c still flex under boost conditions even AFTER having benson's sleeves.

 

A blockguard is not the answer if you have the choice of finding a closed deck block. So many people have overheated with drop-in blockguards. I understand there are newer designs that allow coolant to flow, but I would not risk it if I could find a spare block.

 

exactly.