Flat Top Pistons

[[email protected]]

I purchased an rb25det long block about six months ago, it had a rb20det head on it which i replaced with my rb25det head, during the swap i noticed that the pistons where flat topped and I the stock ones are domed, however I needed my car up and running so i proceededto put the engine in my r33.

Recently a friend of mine had some problems with his rb25det and we purchased a compression test tool.

Since we had the tool i decided to check my compression, all cylinders indicated 115 psi, can anyone give me some idea what the dynamic compression is.

[Adriano]

7.5:1 at a guess

[bnr#@]

115psi seems a bit low though... should be more arround 150-160psi...

My 26 is 175psi accross all 6...

Is yours even accross all the cylinders at 115psi?

[lachlanw]

is your engine in your car and running ? and are you doing the test while the engine is warm and holdingt the T/B wide open ?

[The Mafia]

how do you put a RB20 head on a RB25 block..?

[[email protected]]

as stated the block came with a rb20det head, i took off the head and repaced it with an rb25det from my orginal motor. it was then that i noticed the pistons where flat.

yes the car was warm and at wot, and yes the car ran fine up until yesterday when i noticed a knock