RB25DET Wiseco and compression questions

[DETurbine]

Hey all... I am trying to get some more information of the RB25DET. I am trying to figure out what my compression is going to be at once everything is all built. In order to find out my compression, this is what my machine shop will need to know (so if anyone could help me out that would be great):

1. RB26 rod length?

2. Compression heigth of Wiseco 86.5mm pistons?

3. Combustion camber?

4. cc of Wiseco piston and if it is a dish or dome piston?

I am worried, becuase I have heard when people do the Wiseco's 87mm and a 1.2mm head gasket they get a compression ratio of around 7.9:1 and that is of course way to low for my blood. I atleast want to get around 8.6:1 or so, and if this is true I will probably end up milling the head down and decking the block also.

Thanks,

Zach

[Cubes]

I wouldn't worry too much.

The machine shop should be able to measure everything up and select a piston to suit.

If not well.. erm.. that means there will be problems.

[DETurbine]

I am getting the Wiseco's, becuase they are the cheapest and are pretty well made pistons, so I have to go with what they give me which is just the 86.5 or 87mm piston. The only way of me correcting my compression is by decking the block and milling the head down, but I need to know what the compression is going to be at before I decide, hence the reason why I am asking.

Could use the help,

Thanks,

Zach

[Bobjones]

The compression should be 8.5 as far as I am aware. That is with standard deck height, standard Nissan head gasket and the 86.5 pistons that are 20 though over.

That is what I was told by the people that rebuilt my engine, I believe that the compression is slightly less than standard...

[_Ryan_]

I am getting the Wiseco's, becuase they are the cheapest and are pretty well made pistons, so I have to go with what they give me which is just the 86.5 or 87mm piston. The only way of me correcting my compression is by decking the block and milling the head down, but I need to know what the compression is going to be at before I decide, hence the reason why I am asking.

Could use the help,

Thanks,

Zach

couldnt you use a thinner head gasket to raise the compression?

-Ryan

[muaythailuke]

Hey all... I am trying to get some more information of the RB25DET. I am trying to figure out what my compression is going to be at once everything is all built. In order to find out my compression, this is what my machine shop will need to know (so if anyone could help me out that would be great):

1. RB26 rod length?

2. Compression heigth of Wiseco 86.5mm pistons?

3. Combustion camber?

4. cc of Wiseco piston and if it is a dish or dome piston?

I am worried, becuase I have heard when people do the Wiseco's 87mm and a 1.2mm head gasket they get a compression ratio of around 7.9:1 and that is of course way to low for my blood. I atleast want to get around 8.6:1 or so, and if this is true I will probably end up milling the head down and decking the block also.  

Thanks,

Zach

1. pretty sure RB26 rod is same length as RB25

2. Im getting Wiseco piston also, 86.5mm pistons give a about a 8.0-8.4/1 c/r depend on if you have had the block decked or not, and thats with a 1mm head gasket

3. what about it?

4. RB25 wiseco pistons are a flat top piston without vale pockets

the info i have given you is from the wiseco web site, hopefully ive read it correctly

so using a 87mm piston and a 1.2mm head gaket without getting the block decked 7.9/1 c/r sounds about right according to that info