My Rb30/25

[megzz]

Hey Guys,

I brought a running Rb30/25 in an r31 last year and i just did a waterpump + timing belt kit on it and I noticed that it is running a standard 147tooth RB25 belt. In all my research online i have never heard of anyone being able to run an rb25 belt.

The block is stamped RB30 so I know i didn't get ripped. But though the car was running fine I am wondering if will cause any log term issues like this? Both idler and tensioner sit below the waterpump.

[JonnoHR31]

Are you certain it's a 25 belt? The block is 38mm taller and it looks like you have a standard position idler and tensioner, which isn't possible.

[megzz]

Yep. because that's what came off so I purchased another genuine Nissan RB25 belt and replaced it

[megzz]

its got me stumbled - as in it might not be a 30 bottom end. but engine numbers don't lie.

[JonnoHR31]

Take a picture of the front of the motor around the tensioners and post it up.

[megzz]

Here you go, now the engine is out

[urtwhistle]

thats a 25, a 30 block would have 30mm gap between the top of the water pump and the head.

[JonnoHR31]

thats a 25, a 30 block would have 30mm gap between the top of the water pump and the head.

Yep, definitely not a RB30.

[megzz]

hmmm. but have a look at this 30\25

http://www.lewisengines.com.au/prod58.htm

unless they just used a photo of a 25

[urtwhistle]

very possible because its not common to use the standard lower idler points. esp when you notice that 1 is an idler and 1 is a tensioner. On my 3025 I had to use 2 tensioners. 1 above the water pump.

[r32-25t]

I'd like to see a photo of where it's stamped rb30, cause its starting to sound like a number job

[megzz]

Now that you mention it I can see some machine marks on the right on the edge of stamp plate

Isn't there an oil gallary difference between the 2 blocks as well

Do these numbers mean anything

[XKLABA]

that is not a 30, on the 30 there will be a gap between the water pump and head as mentioned and the water feed on the side of the block steps down at the front

and I'm sorry to say but that engine number is not genuine Nissan lettering, it has been restamped

[JonnoHR31]

Now that you mention it I can see some machine marks on the right on the edge of stamp plate

Isn't there an oil gallary difference between the 2 blocks as well

Do these numbers mean anything

That's a standard 25 block, sounds like you got ripped off unfortunately.

[megzz]

we'll I'm up for a rebuild any way so if I went for a 30L, judging by the photo do you think I would get away with the current piping with the extra height of the 30?

[luke gtr]

very possible because its not common to use the standard lower idler points. esp when you notice that 1 is an idler and 1 is a tensioner. On my 3025 I had to use 2 tensioners. 1 above the water pump.

my 30 block came with the idler and tensioner already done from factory.

have used the pullies off the 26.

and yes, its definitely a 30, extra deck height, all the 30 castings, etc....