Rb25det Stroker Question

[sammyp.]

Hi all,

So I'm looking at a r31 with an rb25 conversion that's for sale at the moment. The car's neat, good conversion etc.

However, the bloke who own's the car told me what I think to be conflicting information.

He reckons it's a r34 rb25 with rb26 pistons, rb20 crank and rb20 cams. He also said that this brings the compression ratio down to somewhere in the region of around 7.5/1.

Does this sound right to anybody? I've done a few google searches and it seems to be there's plenty of options out there to destroke a rb25 but this is not one of them.

Can anybody shed some light on this for me?

[Gerg_R31]

RB20 Main journal size 1.7699in / 44.956mm

RB25 Main journal size 1.888in / 47.956mm

3mm of clearence would rattle and vibrate into a big bang, still it wouldnt build up enough oil pressure to start

this guy has no idea what they are on about

how much are they asking?

[sammyp.]

Well that's definately not right then. Cheers for that info.

I can prob get it for around 5g's and the car itself is straight as, guy who owns it didn't build the motor so he's probably just being fed a load of horse shit.

I've seen it start up and drive etc and it sounds spot on even on a cold start, no misses, knocks etc.

He also said it's been bored out 1.5mm to suit the rb26 pistons but I thought they were the same bore as a rb25?

Could it be an rb20 block he's started with?

Also rb's are stamped on the block aren't they? Does anyone know where exactly they're stamped?

[Gerg_R31]

they are stamped near the gear box

25 26 and 30 run the same bore size

[sammyp.]

righto, cheers for the info I'll have to check it out and go from there