I noticed there has been mention on here before
is there a thread that discusses the differences??
Is the closed deck really that much better or is it a little hype
regards in advance

 

For high boost pressures the closed deck block is best as there is more metal holding the cylinder blocks in place. I have heard of open deck blocks collapsing in on each other, plus you are more likely to blow head gaskets with the open deck blocks. I have some stuff on my site about this

http://www.geocities.com/subman2001nz/

 

From a open deck to a closed deck

 

Nyer nyer nyer!

I've got a closed decked block.

 

How do you know if you've got one as opposed to the other?

Cheers

Rich

 

I presume you have rebored and had new pistons fitted?

How far down did you weld??

David

 

I've got a first generation WRX. Thats how I know. :P

The only way to really find out if you've got one is to open it up and look at it.

 

katana, unless you have seen it, its no guarantee!

what exactly do you mean by first generation wrx? if you mean of the same era as the first sti, then you are more likely to, but not guaranteed.

Only model which has one in all known reported cases and all advertising literature is the 22B.

 

93 WRX. I've been told somewhere around here that its all up to the 94 WRX model or something.

 

My car has now 315 hp and 420 Nm
it is a uk my98 whit a DTA ecu and a vf23 turbo and a front mounted intercooler.

I am now looking for pistons and rods for my new project
I want now 370 hp.

Is it posible to put 22b pistons in it
And the crank can it hold 370 hp

 

The only scoob i know of that had a full closed deck block was the STI version 3, dunno about any others

Tony

 

Did you weld rods in, or just bridge the gap and then skim the face?

David

 

doesnt it cause cooling problems.... with the lack of water galley ways..????

Dan

 

Open deck




Closed deck



What I am lead to believe is that a closed deck block will make the biggest difference in the reliability of the engine under high boost.

[Edited by ChristianR - 6/6/2002 12:15:56 AM]

 

If you're getting the blocks closed, apart from stress issues from heating up small sections of the block only, you need to compare the holes in the head gasket, to those in the block, and it would be worth die grinding the holes back to match.

FYI, Cobb Tuning in the US, heat the whole block up in an oven, before the welding work ia carried out. It is then left to cool, and then re-heated for stress relief.

Christian, it looks like the pic's you posted are of a reworked block to. Seem to be a few about these days

Mark.

 

tony,

the sti 3 is by no means guaranteed to have a closed deck block.

ask moray if his sti 3 is closed!

all stis had the option of a closed deck block, the only one that came with it as standard and therefore will always have and has always so far of those that have been opened as I said is the 22B.

Katana,

I had been told that with that age of car, you are likely to have one. no guarantee, but more likely than not!

 

Do not ruin my fragile fantasy of having a closed deck block.....especially since my boost is going back up to 18 psi or probably even to 20 psi!

I'm sooooo going to be friendly with the breakers ain't I.

 

I think Mark has just p1ssed on my bonfire about making my own.... Who knows... I might see if I can get my hands on a knackered block and get it welded up and then machine it for some different pistons

My budget modding has gone out of the window

David

 

But of course - instead of closed deck - you could wire ring it and use high tensile head studs - or am I wrong?

Trout

 

Are the studs not high tensile allready?

What does wire ringing involve, as I have never seen it done or explained???

David

 

I used to run around 20PSI of boost in my old UK94. I had the head gaskets changed for "Group A" ones I think. They were certainly VERY expensive and were complelely metal if I remember correctly.

Apart from blowing a piston when it was used in competition on *REALLY** high boost I had no problems with the open deck block. Ran with Cosworth pistons as a replacement and they were fantastic apart from the oil usage increased as they have VERY short skirts ..oooh eerrr misses.....

 

Are the group A the same as STi as I heard that these are all Metal..

David

 

STi head gaskets are all metal.

 

Trout you are right, the head bolts are not strong enough for ultra high boost levels.

You can also drill out the spigots holes and replace with longer spigots, stops the head moving on the block.

Wire ringing stops you blowing head gaskets. If you look at a head gasket the have metal rings around the material, well what they do it slot the head so these fit into the slot and make a cooper ring to also fit in this gap. This stop the gakset from moving.

[Edited by submannz - 6/7/2002 1:28:22 AM]