Fully Open, Semi Closed or Fully Closed

[WR1 Bro]

Can someone explain the difference between the Fully Open, Semi Closed or Fully Closed deck?

Pics would be great too

[marky mark]

It's to do with the support from the crankcase castings around the liner tops.

The higher the combustion pressures, the more tendancy for the tops of the liners to walk and distort. This will give you head gasket problems. The new age 2.0 Semi closed deck blocks are good for at least 500 BHP with no issues.


Open deck, as found on pretty much all classics (this is my blown P1). The liners bores are not supported in any way.



Semi closed deck as found in new age STI’s (this is the Spec C block I put in my P1). Note the 4 ribs supporting the liner area through the water jacket




Closed deck, as in some early version RA’s and legacys (although this as an EJ257 modified to make it closed) Liners are fully supported, there are just a few holes through the block for water flow, oil return, and cylinder head studs

[The Swede]

So I understand the closed deck is stronger than the open deck ?

What's the inconvenient of having closed deck then ?

[marky mark]

So I understand the closed deck is stronger than the open deck ?

What's the inconvenient of having closed deck then ?

Closed deck is stronger yes, but is pretty pointless unless you want 550 BHP + at which point it may be wise.

No inconvenience, other than the fact they are becoming a bit rarer now (as they have not been made for a few years) but they are still avaliable if you know where to get them.

[Gee Wr1]

Nice post Mark i always new the closed decks were stronger but didn't know what it was that made them stronger the three pictures show the differance between the three types of blocks perfectly & i now fully understand.
Cheers bloke another lesson learnt from your knowledge

[WR1 Bro]

Nice post Mark i always new the closed decks were stronger but didn't know what it was that made them stronger the three pictures show the differance between the three types of blocks perfectly & i now fully understand.
Cheers bloke another lesson learnt from your knowledge

You can thank me too for asking the questions that you are scared to ask!

[Gee Wr1]

Nice post Mark i always new the closed decks were stronger but didn't know what it was that made them stronger the three pictures show the differance between the three types of blocks perfectly & i now fully understand.
Cheers bloke another lesson learnt from your knowledge

You can thank me too for asking the questions that you are scared to ask!

PMSL at to scared to ask! As usual your to full of your own self importance Bro, yes you did ask the question but it was Mark who provided the answers. Are we supposed to give you praise just because you asked the question??? Na i don't think so

[marky mark]

As usual your to full of your own self importance Bro,

QUALITY!

Take that Bro - Goodbye, you are the weakest link!

[WR1 Bro]

My self importance is too full to let that bother me

[jd]

My self impotence is too full to let that bother me

not seen the doctor yet?

[WR1 Bro]

My self impotance is too full to let that bother me

not seen the doctor yet?

No mate. But I think you meant "impotence"

[jd]

well spotted, you know the affliction well

[WR1 Bro]

Yes mate. Please don't mock though as when my self esteem is low.... so is my ability to perform!

[jd]