Decking/shaving Rb Block

[nisskid]

hey guys, wondering if the following RB block can have a bit of deck shaved out of them, and if so how much? also factory block deck heights?

engines concerned that i need answers for are RB25/RB26/RB30, if u got the height for a 20 may as well chuck that up as well.

cheers

[GTRNUR]

Blocks can vary in deck height from one end to the other as much as 0.003". As for factory deck heights I cant say ive ever really bothered checking. Usually I only check the first cylinder, then install that rod and piston in the last cylinder and measure for the difference so the block can be leveled when decked.

As for deck height, there is no issue with going positive deck if you had to, or wanted to, in order to max out your CR. Just aim for a minimum of 0.037" piston - head clearance.

[blk94r33]

Also, things such as timing belt tension/er come into play at anything more than around 40 thou as a general rule?

[nisskid]

Blocks can vary in deck height from one end to the other as much as 0.003". As for factory deck heights I cant say ive ever really bothered checking. Usually I only check the first cylinder, then install that rod and piston in the last cylinder and measure for the difference so the block can be leveled when decked.

As for deck height, there is no issue with going positive deck if you had to, or wanted to, in order to max out your CR. Just aim for a minimum of 0.037" piston - head clearance.

yeh im just slightly weary of swaying away from the stock 0 deck height with quench pads. the idea is the build a budget reliable revver, i dont want to introduce any detonation issues.

[nisskid]

Also, things such as timing belt tension/er come into play at anything more than around 40 thou as a general rule?

yep, something ill definitely have to look into.

[Duncan]

I've run alightly decked block (20 thou) in the past. other than needing to run a thicker head gasket to keep the valves off the pistons it was fine