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RB26 head oil drain solution


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One of the problems of the RB26 can be that at high performance levels they tend to flood the head with oil and starve the bottom end.

Some people fit oil restrictors in the galleries to stop too much oil getting up into the head but this can lead to inadequate oiling at low revs.

The best way is to fit an adequate drain to quickly get the oil back down into the sump.

This fitting is a simple,reliable method of achieving this that requires no machining.

It simply replaces the core plug at the rear of the head and allows either a -8 or -10 right angle fitting to screw on and drain the excess oil (via a flexible line) back down to the sump,either by another entry or T'd into the turbo drain.

If a few people want these I can get them machined up.

Let me know.

Can also get crank collars machined up out of 4140 high tensile steel and machined on a CNC for accuracy and high quality.These are mandatory for r32/RB26 and RB30 cranks which only have the narrow oil pump drives and are renowned for cracking the oil pump collar.







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i wouldn't have thought so,unless you were travelling vertically,but then i am not claiming to be an expert,but...

that's a big drain hose

G's can't be constant in direction unless it is oval track racing

the rocker covers would be full of oil first if there was that much lateral g force

for 99% of most applications i would say this is a better option than the restrictor method

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Don't forget, your not blocking off the regular way the oil drains out of the back of the head with this mod... your only adding another route to the pan.


When you put this fitting in the welch plug, you are not stopping the oil from draining out the factory drain area.


Its win win in my book!

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to those who expressed an interest in the oil drains they are US$40 each plus post

quality CNC diy part,easily fitted and removed if you ever choose to sell the head stock

PM me if you want any and specify -8 or -10 (by the way both sizes have been tested on an RB26 at revs and they flowed oil almost identically)

payal is available for payment

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guys initially i will get 10 oil drain fittings machined up in either -8 or -10 so let me know which most of you would prefer and i will do that batch

as i said there is no appreciable difference in oil flow at revs through the fitting/hose,there is a little more room when fitting the -8 as it is slightly smaller, however both sizes fit ok


for those that inquired about the crank collars,they are designed for the RB26(r32),RB25 and RB30 cranks that have the narrow snout oil pump drive which are renowned for causing oil pump failure if you are using the RB26 pump

they come with machining instructions/tolerances for a press fit and countersunk grub screws and are easily fitted to the crank by any competent machine shop

they are US$100+post (much cheaper than JUN) and will be the best $100 you will ever spend on an RB.....much cheaper than a new motor:?


don't forget your postal addresses

paypal probably the easiest method of payment

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Postage looks like US$7.50 (minimum charge for parcel shipping internationally)

This will cover up to a couple of fittings or a crank collar for example.

It looks like most guys wanted the smaller size fitting so I will get a batch of -8 fittings machined up to start with

So if you are interested PM me with your


Hybridz nickname



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guys i've had one confirmed and paid for order,i need to know who definitely wants the -8 fitting as i am sorting them out on monday

please post in this thread

1) how many of what you want

2) when you will pay by


if you commit to an order please don't back out down the track as i have no use for multiples of these fittings,i am only trying to help out Hybridz guys with a solution i have discovered for myself :icon14:

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