Oil

[goldengarat]

Almost a year ago I switched from Reg Oil to Synthetic, currently using 5W30. Would Synthetic be ok? What type of Synthetic should I use?

[datzenmike]

I tried it years ago in my 620 and wouldn't use it. You can safely use synthetic if you want but...

 

1/ It provides insane protection that you will never ever use.

2/ Tends to seep out past old seals and gaskets where thicker conventional oil will not.

3/ Way too expensive.

4/ NEVER use a 5 weight oil!!!

 

Today's oils have reduced their zinc anti scuff additive ZDDP by about half what was in the oil when your Datsun was new. Oil makers claim it is reverse compatible and that the previous higher levels were excessive. I do not believe them when it comes to my precious (basically irreplaceable) Datsun valve train. Most engines today are roller cam and both don't need it, and it fucks up the new catalytic converters. So my advice it to not use today's oils but instead switch to a diesel oil like Shell Rotella T4 or Chevron Delo 400. Diesel oils are exempt from the lower levels of ZDDP and need it for protection of their flat tappet cams. Some after market racing oils are also OK. These all have ZDDP levels similar to 40 years ago. I only drive my Datsun in the summer heat and just last summer switched from Rotella T4 15w40 to 10w30. Cost's about the same and is available everywhere.    

[goldengarat]

Thank you very much! I will keep that in mind.

[datzenmike]

To be clear synthetic is fine to use. I use synthetic gear oil and the rear seal in the transmission, the pinion seal in the rear end and the seals in the transfer case became wet. For those, I put new seals in and it was fine after that. For the leaking timing cover seal it was too much bother to change and the oil was too expensive to ever pay for itself.

[Charlie69]

I run the Shell Rotella T4 15 40 here in the Phoenix area.  I have a fresh rebuilt Z20 and a L20B that will be broke in with Shell Rotella T4 30w and then after the first 500 miles I will switch both engines to the Shell Rotella T4 15 40.  Both of these engines have new cams in them.

 

 

Edited May 13, 2021 by Charlie69

[Lockleaf]

I run some form of Diesel oil in all my Datsun engines.   Rotella mostly, but sometimes just whatever I find.

[Diesel Dentures]

I use Delo 400SDE 15w 40 in my sd22. Seems to be good so far!

[datzenmike]

Even WallMart 'Jug-O-Oil' has to meet a minimum specification for quality. More expensive brand names just have a superior additive package. I think they still make non detergent oil. In a pinch you can use it but don't run it regularly. All other gas engine oils today are low ZDDP so again ok in a pinch to top up, but I wouldn't run it regularly. In diesels run only a diesel oil they are still high in ZDDP because they run valve lifters and push rods. Any gas engine running lifters and push rods and are known as flat tappet engines. The L series runs the cam directly on the rocker arm and needs anti scuff protection. Newer gas engines are mostly lifters with rollers on the ends and don't need as much ZDDP.