Open vs closed deck block

[DamirGTI 364]

I did not realize this till was metioned here , theres more to the XU10 iron block difference than i thought .

 

Digging through my stash of iron blocks , pulled out 2.0 T and S16/M16 block to compare the two .. the deck is indeed different - coolant galleries more open on 2.0 T block , and semi closed on S16 block ...

 

Im building 2.0 T engine thus need to pick the block for it and the bores on S16 are in much better condition than the ones on the 2.0 T .

Just unsure if it theres any downside using S16 block instead 2.0 T , would one block cool better than the other ?! 

 

S16 certainly has more deck surface area , which is a bonus for the head gasket clamping/stability , but is it worth opening up the water galleries im not sure , guess not as they'll be closed by the head gasket anyways ..

 

 

[DamirGTI 364]

Breather also , bigger on 2.0 T block , smaller on S16

[petert 639]

I assume you'll use Ø86.50 aftermarked forged pistons. So isn't the bore irrelevant? And then what rods?

 

The turbo block has the turbo oil drain in the back, although you can obviously use the oil level hole in the S16 block.

Edited December 19, 2025 by petert

[DamirGTI 364]

Peter , im going with stock 2.0 T pistons and rods ..

I've two variants though , dished pistons which are flush with the deck and flat top which sit around 4mm down the bore .

 

I picked dished as they improve squish seems better choice me thinks , but on the other hand the flat top ones looks stronger .. 22mm guid pin for dished , 24mm for flat top .

 

Oh crap ! I forgot about the oil drain hole !!

[SRDT 252]

The older diesel-like design was also used on the 405 T16 so there is probably some provision for a oil drain hole if needed.

There is also a middle rear coolant passage on the closed deck that is matched by a corresponding hole on the XU9/10J4 head design that has 8 exhaust ports.

Not a problem for you with a 8v head but if you have future plans for a 16v turbo with the S16 head why not pick the block with extra cooling on the exhaust. On the same note you should check if the 8v block is machined for the 16v oil jets rear mounting points just in case.

[DamirGTI 364]

Indeed , oil drain point is present on the 16v block just needs drilling ..

 

Oil jets yes , i need to check if i can swap 16v with 8v .. i hope so

 

Deck too , i can drill out the front side to open up the galleries kinda like on the 8v block but unsure if it's needed aka if it does make sense for the cylinder top cooling , i do not see it making that much difference but might be wrong 

[SRDT 252]

The rear coolant passage on the deck is mostly inherited from the diesel block, for years many hybrid T16 had a XU10J2TE block with a S16 head and ran just fine.

[welshpug 1,736]

oil jets are easy enough for a competent machinist to retrofit into a block even if they had none at all, the oil gallery is the same,  a spot face with an end mill and a few holes drilled and tapped.

 

someone familiar with cosworth YB engines will know this task as it was one of the small detail differences between a 2wd and 4x4 spec engines in the Ford Sierra cosworth.

[petert 639]

11 hours ago, DamirGTI said:

 

Oil jets yes , i need to check if i can swap 16v with 8v .. i hope so

Why do you need to swap? It appears both blocks have jets.

[SRDT 252]

Yes but they are not the same, he has the correct 8v ones at hand so it's better to use them if they just fit on the 16v block.

[petert 639]

How do they differ? 

[SRDT 252]

The 8v ones are diesel-like and the 16v ones goes from one side to the other in order to spray the exhaust side of the 16v piston. You can see them on the firs post.

[DamirGTI 364]

17 hours ago, petert said:

How do they differ? 

 

Few pics of the 2.0 T jets : 

[DamirGTI 364]

... direct swap , no messing about needed ! 

 

D

[petert 639]

Thanks. A great explanation. I have an 8v block here that I stored away but never gave it a 2nd thought.