Rebore

[paulrandy]

Just had the block rebored +4thou and noticed the the top of the liner ends about 6 or 7thou short of the top of the block, from there up is just alluminium. I assume this is normal yeah??

 

[sypher]

i dont think so, i think this will cause PROBLEMS with the sealing of combustion chamber. i thought the block should have been decked afterwards some one else will give an opinion

 

[ashills]

pretty sure its how they all are (maybe wrong lol)
the liners are encased in alli

 

[sypher]

just thought.. on the deck of the block is it all in line or is it new liners pressed in from the top which have gone in a little too far. coz if its this i thought that would cause gasket sealing probs

 

[paulrandy]

No, they're the original liners, they look like they were cast into the block in the factory, I would imagine it should all seal fine but my machinist was a bit worried.

 

[sypher]

in metric how much was taken off cos i'm gonna have to go +1mm on mine

 

[paulrandy]

Yeah the rebore was +1mm upto 87mm so it's a common enough rebore.

 

[ashills]

yeah the liners are cast into the block not pressed as far as i know

 

[Sirnixalot]

the block is aluminium the cylinder sleaves are steel/iron, they are pressed in from factory.

 

[ashills]

wrong as usual lol

 

[Nad]

Just had a quick chat with Nikko.

From what I know the block is cast round the liners hence why the aluminium laps over the top. The block is then bored to align the bores to each other, which is why in my block the liner is thicker one side than the other as it was cast in wonky.

Nikko says that they are pressed in and that the aluminium lapping over the top of the liners is done by "magic" :lol:

Nad

 

[Sirnixalot]

foot in mouth again...gotta recheck my sources

 

[sypher]

DOHHHH !!!!

 

[paulrandy]

Thanx guys, so i take it the general consensus is it's normal and it'll be fine?

 

[Websnowbo]

They don't cast aluminium block's around liners, the liners are shrunk with NO2 then fitted.

 

[Nad]

They don't cast aluminium block's around liners, the liners are shrunk with NO2 then fitted.

Why are the liners wonky then in the block? If the liners were put in afterwards why arent they straight, and how does the aluminum then cover the top of the liner? We are on about mass production here, not aftermarket engineering. Ur telling me they are gonna sit there and cool down and fit 4 liners to every SR20 block Nissan have ever made. That would cost way too much.

Nad

 

[Sirnixalot]

new liners are pressed in this way but they sure dont use nitrous oxide.....liquid Nitrogen is alot cheaper.

I am not sure on this one, i am still going to research it a bit more to be sure.