Holden Engines

[ratm]

I was reading a Australian magazine and i read this quote "As the VL (Holden Commodore) came out standard with the RB30 engine it's an absolute snack to install the RB20 turbo engine." Does anyone know why they have the same engine code? Did Holden use Nissan engines? Or is it just a coincedence that Holden and Nissan have the same engine code system?

[UncleBen]

thats strange. i have no idea.

[themadscientist]

They are RBs, they share the same bore with the RB25 and 26 (86mm) but have a taller deck and longer stroke. They only come SOHC though. With some slight modification an RB25DE head will drop onto the 30.

[ratm]

So the block is the only thing that is the same? Also do you know how long they used these engines? I'm guessing they stopped some time before GM took control.

[themadscientist]

They are the same family of engines yes but the deck on the 30 is taller than the 20,25,26 ones. I think they stopped making them in the late eighties, ask Meggla.

[ratm]

Thanks for the information.

[Sopdadope]

The RB30E is an SOHC manufactured by Nissan for Holden.

The RB25 head is "almost" a direct-fit because the oil galleys have to be a machined and another drilled for the valve cam timing of the RB25 head. The flow of the RB26 head is superior to the RB25 but a lot more machining is needed for it to fit the 3.0 block.

Also from what I hear, the RB30 block can't handle high revs like the RB26DETT. The crank and bottom end need major work to handle high-boost, high-rpm stresses.

Casting flash is more of an issue with this block as well, as opposed to the it's lower displacement kin.

[Sopdadope]

Also, the RB25/RB26 pent-roofs have a larger combustion chamber area than the RB30 single cam head. The final compression ratio of an RB26/RB30 hybrid would be barely 8:1. Maybe a combination of domed pistons and shaving either the gasket or the head itself will be the perfect remedy.

[Sopdadope]

Hood clearance will be a big problem as themadscientist mentioned. Not only is the RB30 block 35mm taller than the RB26DETT block, but the RB26 head is about 11mm taller than the SOHC head.

[pistolero]

"So the block is the only thing that is the same? Also do you know how long they used these engines? I'm guessing they stopped some time before GM took control."

1986-1988. GM has owned Holden for a long time (possibly since the 50s when Holden started). It is actualy called GMH and GMH sourced the engine from nissan because the local engines were too crap to comply with new emissions laws introduced in 1986. After two years of running the rb30 the engines were replaced with the buick 3.8- god knows why.

I am new to this forum but will some one tell me why some smart australian doesn't ship 500 rb30 blocks to the US for you guys. Is there a problem your end because they are dime a dozen here?

[krazy skwerel]

my assumption would be that not many people know of the block and or they simply don't feel they beneft enough from it.