Visual Difference Between 20 And 25 Heads

[GOLD_JET]

hey guys looking at a new car. guy said it has an rb25 in it but im not to sure. what are the visual differences between an rb20 and rb25. it has no coil pack cover and the timing cover dosnt say anything? any help would be great. cheers

[Cubes]

If its the R32 RB25DE then there's no way you can tell the difference without pulling the motor apart.

They look 'identical'.

[blind_elk]

Turbo or N/A?

[funkymonkey]

reach down the side with a flashlight and read the engine block number? should tell you if its a 20 or a 25.

[blind_elk]

On a RB25DET, the hose joining the 2 rocker covers points forwards. Also, the hose to the PCV valve is smaller, and comes out the side of the driver's side rocker cover.

On a RB20DET, the hose joining the 2 rocker covers points backwards. And the hose to the PCV valve is larger, and comes off the top of the driver's side rocker cover.

And, yes, the engine number should have the engine designation (RB20, RB25) as the first characters.

[MZTRBO]

A rb20det and a rb25det have different plenums...The rb20 is much rounder and longer, where as the rb25det is much shorter.

Cheers

[Cubes]

Unless its an R32 Rb25 then it looks identical to the rb20.

[MZTRBO]

Oh my bad, just took rb25 engine as rb25det.

So how does the N/A plenum look on a rb25de (r32 series), Im taking its identical to the rb20det plenum.

Cheers