The what oil do you use thread [RB20DET/RB25DET/RB26DETT/RB30DET]

[DatsunZ31]

I'm not sure if this forum has one yet but there are a few places i visit that have a thread like this.

What brand oil do you use?

I personally use penzoil/valvoline but lately I've been wanthing to switch to something a little bit better don't know what to yet. Synthetic? non-synth?

What weight do you use?

I personally run 10W30 valvoline non-synth for my VG30ET but I'm going to run 10W40 for the RB20DET I have, not sure what exactly i want to run with a engine as unique as this. Does oil make a difference with the RB's? I've read RB's are very very picky with the oil and gas put in them and can act up. So is there a brand everyone recommends?

Lets not make this a flame war thread debates are good and healthy as it excercites your brain but please be rational if you cannot come to an agreement with someone on oil simply agree to disagree.

[den80]

i use Motul 5w40.

[Nismo_line]

i run royal purple 5w30

[gtrjon]

Rotella t6 15w40

[nimblestix]

Rotella t. Its amazing.

Sent from a galaxy far, far, away.

[Black BNR32]

I just search the forums, pick one I like, and don't bother making a thread to see what all the cool kids are using.

[Skym]

Stock is 7.5w30 (what works with the stock clearances), which is a 5w30 off the shelf (have a sticker on side of centre console that mentions to run 5w30 oil). If you know basic engineering, clearances take into account oil thickness.

The key is getting the correct cst rating (oil thickness) at the oil temps engine reaches.

To work this out you need a oil pressure gauge (match to factory oil pressure figures if using stock oil pump), oil temp gauge (to see how hot oil is getting).

Thicker oil than what's needed can make engine feel very sluggish and can cause excessive bearing wear.

This PDF mentions the cst rating at 100 degrees C for W30, W40, W50, W60 oils (note the cst rating of w30 oil which is for factory clearances) -

http://www.opieoils.co.uk/pdfs/tech-articles/10w-60-oil.pdf

As engine ages the clearances widen, so would run a thicker oil to suit (maybe a w40 that's good to around 120 degrees C).

On road a lightly modded RB20DET can reach 90 degrees C, so getting close to the limit of the stock W30 oil before it breaks down.

If thrashing car on racetrack and oil temps excede 120 degrees C, a W50 oil is used.

RB20DET doesn't run a stock coolant to oil oilcooler (as found on stock RB25DET, RB26DETT). An engine oilcooler is a must have mod if engine is not factory and car is thrashed (high oil temps).

The brands of oil that these people suggest is a good brand of oil to use (they are the experts) -

http://www.opieoils.co.uk/c-1445-motorsport-car-engine-oils.aspx

There's a tech section if you want to learn about what oils are best -

http://www.opieoils.co.uk/t-technical-info.aspx

Best oil for E85 fuel is said to be Motul brand.

[MarusGTR]

^How come you say 90°C is the limit for breakdown when 85°C is the FSM running temp and the CST certification is made at 100°C? I'd say worry past 100°C; get your oil around 110 on stock clearances, move up 10 points, e.g. from 30 to 40.

But that's my mildly uneducated opinion.

[Skym]

I said "getting close to the limit" (100 degrees C). I assume the factory doesn't expect people to thrash the car. If they do thrash car the oil temps probably don't get that high due to running engine rich (into 10's with A/F ratio) at factory which keeps cylinder temps down that affect's coolant, oil temps spark plug heatrange, etc. A proper oilcooler setup can keep oil temps to around 80-90, so the 5w30 oil should work.