Open Deck, Closed Deck, Semi Closed Deck

[TTT]

I have 2 questions and I will start a seperate thread for the other one which will probably get a one sided response... anyway.. for this topic..

Closed deck and so forth are frequently spoken about in Subawho circles in regards to the engine.

apparently the RS turbo Liberty's were the only ones with a closed deck and all the WRX ej20's after that have been semi closed deck.. and the NA ej engines are all open deck.

so that's all lovely, but what is it in reference to?

why is closed deck better?

is this "DECK" type something in all engines or just the boxer motors?

if in all engines, what are the RB range of engines?

cheers..

[rev210]

reffering to the heads, open/closed chamber?

Edited November 6, 2006 by rev210

[TTT]

what chamber?

[r33_racer]

I think hes referring to the combustion chamber in the head the recessed part where the in/out valves are and the spark plug.

Im guessing one type is where its recessed like in rbs..and another type is where maybe its flush or closer to the actual bore/piston?

That would be my interpretation.

[T04GTR]

ummm, all wrong

[T04GTR]

"deck" refers to the block

open deck blocks have the cylinder liner un suported by the block up top.

honda and subaru, (except rs-turbo)

semi closed is where the liner is partialy suported up the top. ie youve got the bore with suport bits stoping the liner moving around.

ie:sr20,some hondas.

(open and semi open deck are mostly alloy block engines)

closed deck is where the only gap around the liner is small holes for the water galleries. ie:pretty much all iron block motors.

[T04GTR]

closed deck is strongest, the bores dont move. which can lead to broken rods,pistons and blown head gaskets

[T04GTR]

open deck:

closed deck:

[r33_racer]

ahh...im more the wiser now...cheers for the info:)

So rbs are closed deck.

[rev210]

..

Edited November 6, 2006 by rev210

[rev210]

..

Edited November 6, 2006 by rev210

[MattSR]

Deck isnt Subaru slang... it simply refers to the top flat surface of the block that mates to the head gasket and cylinder head...

T04gtr,

If the open deck is inferior, then why did OS Giken choose it for their all-conquering RB30?

[N I B]

Theres some nice kits for the open deck Honda engines(steel inserts) and i spose there is for Subs but thank god Nissan never did this with RBs etc.

[rob82]

Only guys with small decks say that size doesn't matter!!!

[MattSR]

NIB,

Block guard kits (such as the Nuformz) for Hondas are not as good as you would think... People simply look at it and assume its stronger without considering what they really do...

If OS can build an open deck engine that revs to 13k and makes over 1200hp without a problem then maybe there's something in that. maybe..

[N I B]

Because the support is only 30mm belowthe new deck but Hondas etc the deck is open all way to the base of the block.

[Abo Bob]

Just some info I had lying around. Can't find CA.

R = 6 cylinder, closed deck.

B = Gasoline application using cast iron/nickle based block.

S = 4 cylinder, closed deck.

R= Gasoline application using sand-cast alloy based block.

K = 4 cylinder, closed deck.

A = Gaslone application using sand-cast iron based block.

Q = 4 cylinder, open deck.

R = Gaslone applcation using die-cast alloy based block.

[Sydneykid]

Deck isnt Subaru slang... it simply refers to the top flat surface of the block that mates to the head gasket and cylinder head...

T04gtr,

If the open deck is inferior, then why did OS Giken choose it for their all-conquering RB30?

That's a spacer, the deck (top of the block) is still "closed" where the liner is inserted.

cheers

[T04GTR]

Deck isnt Subaru slang... it simply refers to the top flat surface of the block that mates to the head gasket and cylinder head...

T04gtr,

If the open deck is inferior, then why did OS Giken choose it for their all-conquering RB30?

because the "open" part is only very short and made of high quality ductile iron so it doesnt flex silly,not run of the muck cast iron.

besides its abit harder to make a fancy sleeve spacer on a 20k bottom end.lol.

who knows. perhaps they know its bolted/pressed onto a rigid iron block

(couldent find any decant pics of the same motor with a closed vs open deck kthanks subbie)

[T04GTR]

i hope you not running the factory oil cooler/filter block on that!!!!!!

have fun keeping it coool.

ie: 2 seperate 25 row serk coolers in -10 cant do it, it all bypasses inside the factory oil filter block, 4 valves 2 for the filter 2 for the coolant/oil cooler

in mine anyway, perhaps im special