Switch from M1 15w50 to a 5w30

[RooflessVW]

But which one? I have been using M1's 15w50 because my 280zxt has an oil cooled turbo, and my Schneider camshaft is known to possibly have wear issues with some low ZDDP modern oils. To my knowledge, M1 15w50 is a high ZDDP oil, and I have had no issues with abnormal wear thus far.

My engine has about 5,000 miles on it since the rebuild, and I'd like to switch to a 5w30 for better fuel consumption and honestly, lower oil pressure. My oil pressure gauge seems constantly pegged once I am off-idle. Original spec for the engine is 10w30, 10w40, or 20w50, but that was in 1982 and I know oils have come a long way.

So, I'm going 5w30. My choices are between PU and M1, and I know they're both fine oils. I'm leaning more towards the PU, but I've read that switching between brands can cause some wear. Something about the oil film being removed when you switch brands.

What do you guys think? Stick with M1, or switch to PU? I plan on using 5w30 year round from now on, and for the life of the vehicle.

 

[Donald]

Look at Amsoil ZROD oil.

 

[aquariuscsm]

Don't go 5w30 in your Z. Try 10w40 if you want to go thinner. I had a 77 280Z and I ran 10w40 or 20w50 gtx.

 

[daman]

Either M1 5w30 or 10w30HM oil will fit the bill both have a API SL additive package that will help with your worries of engine wear and i believe are on the upper limits of there viscosity grades.

 

[CATERHAM]

rooflessVW, welcome to BITOG.

I'm glad to hear someone in Europe has come to there senses that running rediculously heavy oil is counter-productive.

Since I run light energy conserving oils which have low phosphorus levels, I just add a ZDDP suppliment to raise the level to whatever oil I want. I use Red Line Break-In Additive and it only takes a couple of ounces to raise 4L of 600 ppm of P to 900 ppm. So one 16 oz bottle can last a long time.
There are other ZDDP products out there.
Another option is to just run Red Line oil such as their 0W-30 which actually has about 1200 ppm of P; more than you'd ever need. You could even blend the RL oil 50/50 with something else less expensive. Just a couple of ideas.

 

[CATERHAM]

Originally Posted By: aquariuscsm
Don't go 5w30 in your Z. Try 10w40 if you want to go thinner. I had a 77 280Z and I ran 10w40 or 20w50 gtx.

But you don't make your oil choice based on oil pressure; you're not on the same page figuratively speaking.

 

[HerrStig]

I'd be looking at the pressure regulator on the oil pump. This happen "since the rebuild"? And, perish the thought, what's the book say about oil pressure? Senders have been known to go bad.

 

[aquariuscsm]

Originally Posted By: CATERHAM
Originally Posted By: aquariuscsm
Don't go 5w30 in your Z. Try 10w40 if you want to go thinner. I had a 77 280Z and I ran 10w40 or 20w50 gtx.

But you don't make your oil choice based on oil pressure; you're not on the same page figuratively speaking.


Depends on how it's driven. If it's driven the way a turbo Z is meant to be driven,you'll blow the motor on a gas mileage oil. If you're just granny driving to the grocery store and back,gas mileage oils will be fine.

 

[LeakySeals]

Don't forget Rotella T6 5w40. It has the extra ZZDP your looking for. +- 1200ppm according to VOA's

 

[RooflessVW]

Yeah, the turbo oil pump moves oil. A lot of oil. So much that with 15w50, my oil pump bypass is opening at around 2000 rpm to keep the pressure reasonable, even when hot as all [censored]. It's a new, tight motor. Idle pressure is better, but only when hot. Cold pressure is stupid high too.

I would run M1 0w40 if I could find it at a reasonable price.

 

[RooflessVW]

How will I blow my engine if the original spec for all temperatures is 10w30. What makes the 5w30 so drastically different?

 

[CATERHAM]

Yes M1 0W-40 is not a bad compromise due to it's relatively high 185 VI, and it has 900 ppm of P. It's too bad it's expensive in Germany.

To minimize OP on start-up and during warm-up you'll want a 180 or higher VI oil and their are some, like Total Quartz 9000 0W-30 and Liqui Moly Energy 0W-30 but I'm sure their P levels aren't particularly high.

What you could do is try M1 0W-40, despite the cost for one oil change to see how you like it and whether it is actually light enough. With a HTHSV of 3.8cP it may still be heavier than necessary when the oil is fully hot, and go from there.

 

[aquariuscsm]

Originally Posted By: rooflessVW
How will I blow my engine if the original spec for all temperatures is 10w30. What makes the 5w30 so drastically different?


Having owned three Z's and being around Nissan trained Z owners/mechanics,you want to run a minimum 40wt. For instance,in my fsm it says to use 10w30 for fuel economy *only* and to bump up to a 40-50 weight if the car is going to be raced and/or driven at sustained high speeds. Nissan knew these cars were going to be driven fast and hard,that's what they're made for. I'd use a good 40 weight if I owned your car.

 

[CATERHAM]

Originally Posted By: rooflessVW
How will I blow my engine if the original spec for all temperatures is 10w30. What makes the 5w30 so drastically different?

Of course you won't.
Remember the 10W-30 dino of 20 years was lighter than an A3 0W/5W-30 syn' oil of today.

 

[RooflessVW]

Originally Posted By: aquariuscsm
Originally Posted By: rooflessVW
How will I blow my engine if the original spec for all temperatures is 10w30. What makes the 5w30 so drastically different?


Having owned three Z's and being around Nissan trained Z owners/mechanics,you want to run a minimum 40wt. For instance,in my fsm it says to use 10w30 for fuel economy *only* and to bump up to a 40-50 weight if the car is going to be raced and/or driven at sustained high speeds. Nissan knew these cars were going to be driven fast and hard,that's what they're made for. I'd use a good 40 weight if I owned your car.


Your FSM is not for a 280zx turbo. And the FSM, with regards to oil, is outdated. Right?

 

[bigjl]

Originally Posted By: CATERHAM
Yes M1 0W-40 is not a bad compromise due to it's relatively high 185 VI, and it has 900 ppm of P. It's too bad it's expensive in Germany.

To minimize OP on start-up and during warm-up you'll want a 180 or higher VI oil and their are some, like Total Quartz 9000 0W-30 and Liqui Moly Energy 0W-30 but I'm sure their P levels aren't particularly high.

What you could do is try M1 0W-40, despite the cost for one oil change to see how you like it and whether it is actually light enough. With a HTHSV of 3.8cP it may still be heavier than necessary when the oil is fully hot, and go from there.


I would probably go for M1 0w40 aswell, though there is a caveat with that. Possible increased oil use. I have previously gone for Mobil 1 0w40 in an Omega turbo diesel and oil use increased dramatically, a switch to 5w40 Millers Syner D and back to normal. A friend had the same happen with a '95 BMW 520i, though I don't know what he put in afterwards.

It is all very well saying European's use overly thick oils.

But not everyone wants to have to change oil before going on a long run as they are running 5w20. Or drive along keeping an eye on the oil pressure gauge all the time.

And the recomendations of the manufacturer need to be considered also.

Another concern is why the thinnest manufacturer recommended winter rating is 10w--.


It is true that oil technology has improved since the car was built, but it is still an old car with old technology in it.

I had an '66 Austin A40 years ago and it was given the same viscosity oil as it was in '66.

I think it is great that people are happy to experiment with their own cars, my knowledge is not in depth enough to be prepared to consider these experiments.

I wonder if a 5w40 or 10w40 would be less of a risk.

Also not sure that Mobil 1 is that expensive in Europe, but I think Skyskip has said that LiquiMoly oils are well priced.

Perhaps the OP could consider their products.

 

[RooflessVW]

Went with M1 5w30HM. We'll see if it blows.

What Do you guys think, send a sample off at 5000kms?

Edit: The'82 FSM recommends 5w30 for all temps up to 60f, and 10w30 for all temps above 10f. I personally see no reason not to use 5w30 year 'round, or to run it in the winter, switching to 10w40 or 15w50 in the summer.

 

[zoli]

Hi rooflessVW,
Try 5W50 all-year-round oil: M1 Peak Life 5W50 works well at all operating temperature.
But no experince with the oil pressure...

 

[aquariuscsm]

Originally Posted By: rooflessVW
Originally Posted By: aquariuscsm
Originally Posted By: rooflessVW
How will I blow my engine if the original spec for all temperatures is 10w30. What makes the 5w30 so drastically different?


Having owned three Z's and being around Nissan trained Z owners/mechanics,you want to run a minimum 40wt. For instance,in my fsm it says to use 10w30 for fuel economy *only* and to bump up to a 40-50 weight if the car is going to be raced and/or driven at sustained high speeds. Nissan knew these cars were going to be driven fast and hard,that's what they're made for. I'd use a good 40 weight if I owned your car.


Your FSM is not for a 280zx turbo. And the FSM, with regards to oil, is outdated. Right?



My advice,either spend some time on a Z forum or sell your Z.

 

[CATERHAM]

Originally Posted By: rooflessVW
Went with M1 5w30HM. We'll see if it blows.

What Do you guys think, send a sample off at 5000kms?

Edit: The'82 FSM recommends 5w30 for all temps up to 60f, and 10w30 for all temps above 10f. I personally see no reason not to use 5w30 year 'round, or to run it in the winter, switching to 10w40 or 15w50 in the summer.

Not a bad choice in a fairly heavy 30wt oil.
As you probabily know the factory test OP spec' is 54-62 psi @3,000 rpm. I have no doubt you will be still well above that with the oil as hot as it gets especially in the winter months.
At the very least you'll have the cool winter months to get fully familiar with the OP characteristics of your engine before the warmer summers months arrive.
Let us know (or PM me) with your actual OP figures on this oil.