New Engine Build Questions
 

My car just died a couple nights ago and after some testing today I think i can confirm that the head gaskets have shat themselves. :-( So this unfortunate event has accelerated my plans on the new engine build my dad and I are doing.

The project consists of forged internals and an EJ22 and we have just a couple questions.

1. Because we are boring the EJ22 out to 97.5mm which is 0.020" overbore, will EJ22 metal head gaskets work or will we have to go with EJ25 metal head gaskets? I believe EJ25 gaskets are 101mm and i do not know how big EJ22 ones are. Can any one shed any light?

2. Is it worth making the engine semi closed deck?

In the end of this project the car will hopefully be my daily driver with some track racing whenever I get the chance.

Cheers all,
Geoff

Geoff,

why not get a ej20 block from a RS? closed deck from factory. bore that out to 2.2.

We already have 2 EJ22's. :-P How much would a RS EJ20 bottom end cost?

Why not grab AN EJ207, semi closed deck and get some forged internals for that or bore it out..

that 207 is gone already ;)

Cool.

The deck is the surface where the head is bolted too.

[IMG]http://i62.photobucket.com/albums/h90/Taktics/blockdesign.jpg[/IMG]

The open deck design is for ease of manufacturing and not good for high cylinder pressures. This cylinder wall design is supported in 2 places. Many people will say that these engines cannot be turboed effectively but that is not the case. There are a couple here in the club that have run low to medium boost without issue. The problem is where the top of the cylinder where it meets the head will distort from high cylinder pressure and damage the head gaskets ability to seal in the combustion gases.

A semi closed deck design is a little harder to manufacture, but supports the cylinder at the top, bottom and sides. (four places). This is stronger then the open deck design and therefore can take higher cylinder pressures.

The fully closed deck design uses a different casting process that takes longer to manufacture and weighs more. These blocks have the most support to the cylinders, which will enable you to run the highest cylinder pressure of the available choices.

Subaru introduced the closed deck block for homologation reasons to be able to run it in their rally cars. This engine was made famous when a very similar version to it was installed in the limited edition 22B. With the casting methods and alloys available at the time Subaru chose this route to ensure a strong motor. With todays “modern” casting methods and alloys even the semi closed deck designed motors are very strong.

As a guide I would say the following;

Open deck blocks will work for all NA or low to medium boost applications.

Semi closed deck blocks are better suited for boost applications that are not extremely high or prolonged.

Closed deck block are best suited for applications where there will be very high boost for extended periods of time.


Good read - understood abit more about this open-semi-closed deck business.

But I heard that semi/closed deck engines can have heating issues because there is no coolant around where the explosions in the engine are. But I will be making the new engine semi-closed by putting in some bits of magnesium or something between the cylinders, giving it the extra strength.

Also, in my opinion, boring the EJ207 or EJ20 will leave not enough of the cylinder left and will weaken the actual block. While boring the EJ22 to 97.5mm will only take 1mm from each side of the cylinder, hopefully keeping it strong. I guess if I wanted the strongest block possible I would sleeve it, but i'm still a uni student and do not have that much funds. :-D

So whats the purpose of building ??

No point doing all the above if is only for street/drags etc etc

207 that is all, simple bolt on cheap, and all the goodies you need.

ive seen the rs blocks go from $50 - $300.