RB26

Hello

I read somewhere on this form that you have experience building RB26’s and it was said that there are some quirks while building this block. I’m trying to build my first rb26 and was hoping you could explain some of the more important parts to remember and the tricky parts I may I counter while building the block.

Thank you

Leighton McColl

What you will need to do is going to depend on the model of RB26 you're building and what sort of power and rpm level you're planning. The early R32 RB26 has an issue with the width of the oil pump drive on the crankshaft. You can rectify this by fitting a crankshaft collar kit or use a later model R33-R34 crankshaft which had a wider drive face from the factory. The stock oil pump is also prone to fail if you rev above 8000 rpm so it's common to fit a high volume pump from the likes of Greddy/HKS etc. There are also significant issues with oil drain back from the cylinder head so an oil restrictor is normally fitted in the main oil gallery that feeds into the head and often this will be coupled with an external oil drain back from the head.

If you're dealing with a high mileage block it's also common for the block to crack around the head bolt holes and into the water jacket so you need to very carefully inspect the deck surface to ensure the block is worth machining in the first place. Lastly the factory cast guides are prone to failing which can result in expensive damage. If you're doing any work on the head I'd recommend fitting a set of bronze valve guides. You'll also need to have the head clearanced around the bucket bores if you're going to fit cams with decent lift otherwise the lobes won't clear the head.

For an high power rb26 street engine with the hopes of putting a lot of boost to it what sort of oil clearances should I be looking for? Also would it be a good idea to upgrade the oil pump drive of the late model crank to a spline drive set up and run a N1 oil pump with a higher flow rate then OEM?

It really depends what your definition of high power is. For an RB26 running around 600-700 hp I'd be sticking to the stock recommendations. If anything I'd aim for the loose side of the factory tolerances. For power levels above this I would aim for around 2 thou on the big ends and around 2.25-2.5 thou on the mains. The N1 oil pump is a common upgrade and definitely not a bad idea and the spline drive is superior to the Nissan flat drive system but certainly not essential provided you're not using the early crank with the narrow drive flange.