20W40 vs 20W50 (77 280z @ 75K)

[MH77280Z]

Guys, I am debating between 20W-40 and 20W-50. The weather in CA does get in the 90s in Summer but in colder winter it does come down in the 40-50 range.

Right now I am at 20W-40. Let me know what you guys use.

Also any good brand in the 20W-40 range with good dose of ZDDP?

[Patcon]

Are your oil pressures good?

Do you have any excessive engine noise?

[dutchzcarguy]

In my L24 and L28 i use 10w40. (even in my 300zx Vg30dett i use 10w40.. as it was recommended for the z32.)

The L series engines are in medium to colder temps on 10w40 or 10w50.. i can imagine to use 20w50 but that's a heavy oil more used on engines that have many miles on it..

(It is possible that in the 280 engined cars the oilpressure light go's on when idling on 600rpm or so..  thats normal.. always check the oil on your camshaft when this is the case you'll see that it is oiled well and then that's OK!  Also putting the idle rpm on 650-700 as is standard, solves this problem most of the time.)

[MH77280Z]

7 hours ago, Patcon said:

Are your oil pressures good?

Do you have any excessive engine noise?

The oil pressure is good. It drops below 1/3 at idle but then climbs up while running. I do expect some oil burn though as i do need a engine rebuild. But for now I want to run the car for sometime to get everything else figured out. 10W-40 is also a good option.

What were u thinking?

[MH77280Z]

2 hours ago, dutchzcarguy said:

In my L24 and L28 i use 10w40. (even in my 300zx Vg30dett i use 10w40.. as it was recommended for the z32.)

The L series engines are in medium to colder temps on 10w40 or 10w50.. i can imagine to use 20w50 but that's a heavy oil more used on engines that have many miles on it..

(It is possible that in the 280 engined cars the oilpressure light go's on when idling on 600rpm or so..  thats normal.. always check the oil on your camshaft when this is the case you'll see that it is oiled well and then that's OK!  Also putting the idle rpm on 650-700 as is standard, solves this problem most of the time.)

10W-40 is good choice too. I was just going by what was listed in the manual attached. Temp in CA varies quite a lot Winter below 50 and Summer 75+

I have not come across anyone who uses 10W-50 or 20W-50 though as mentioned here in the manual.

[Patcon]

I used really heavy oils in motors that were noisy or had excessive bearing clearances. I'm unsure sure whether 20wXX oils are the right choice or not. I wouldn't run a 50 weight oil unless I had an engine issue that convinced me otherwise. You oil pressure sounds very normal. so I would run the 10w40 probably. It's more flowable when cold but still on the heavier side. Running a 20w oil when its really cold can cause other issues

[siteunseen]

I've used Valvoline max life 10w30 for 5 plus years and the cam lobes look nice and shiny. Oil never gets really dark like Castrol 20/50 I ran in my '89 BMW 325is. Good pressure on the gauge too but I use turbo oil pumps.

[MH77280Z]

I have decided to go with 10W-40. I have used it in my 69 Cadillac with a 472 block and flat cams and it has given me great results last 7 years.

https://drivenracingoil.com/i-30497806-hr5-10w-40-conventional-hot-rod-oil.html

[dutchzcarguy]

You could buy it in bulk, then it's much cheaper then in 1 ltr (or qrt) bottles.. oil does not get old very fast..

[Dave WM]

that looks like a good oil to use. I have used Valvoline VR1 20/50 and or Rotella T4 (diesel) 15/40. It rarely gets below 60's here (colder than that I generally stay indoors 🙂  )

Edited January 26, 2022 by Dave WM

[Galaxybj]

I have used Valvoline 20/50 racing oil/VR1 in my 5/71 240Z since 1972.  All temp ranges (Eastern Wa, Montana, Florida, and New Mexico) with no issues.  Of course no winter time driving.   Amsoil has Z-Rod which is high-zinc formula.

[w3wilkes]

On 1/25/2022 at 8:16 PM, MH77280Z said:

I have decided to go with 10W-40. I have used it in my 69 Cadillac with a 472 block and flat cams and it has given me great results last 7 years.

https://drivenracingoil.com/i-30497806-hr5-10w-40-conventional-hot-rod-oil.html

I also have been using this "joe Gibbs" racing oil since 2017 and am quite pleased with it.