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mattbibbey

Which OIL is Best?

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Hello everyone, we all know that the most expensive oil isn't always the best and especially not for classic cars. So, just which oil is the most suitable for the older Z cars. I know there was an article in a recent/current Practical Classics issue but was interested in what everyone was using and if anyone had any horror stories with "the wrong oil"

I'll start with a story, in the army we use an engine oil called OMD90. It is a good oil and it contains a small amount of some sort of detergent. My friend at work has a triumph TR4a on its second engine now because of "the wrong oil".

So from this I am keen to use the most suitable oil for the 70's mechanics in the old Z.

Any help and fact and opinions are welcomed!!

Thanks for everyones time.

Matt

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Please don't take it the wrong way, but...........this should be good!!ROFL !I did a search a few months ago and read so much I got tired of reading:stupid:and still could not find an answer to the original question - I guess it is kinda like describing the perfect women................

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I posted this topic on a UK Z site and have had a few suggestions already. Namely Millers 20/50 classic and Valvoline 20W-50 racing synthetic oil so far. Anyone use either of these?

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There are lots of discussion of this on many of the Z car forums, like Travel'n Man I also get tired of reading after awhile. Oil is kind of a personnel thing. Find one that works for you and go with, comes down to cost, previous experience, research and peace of mind.

I use Valvoline Vr-1 for the engine, after reading a few things I picked this and have stayed with it. Is it better? Who knows, but I feel comfortable running it and I am happy to pay the price.

You really did open a can of worms, you will never get 'the best oil' you will only get the best oil for that person that replies. You can also use UOA (Used Oil Analysis) and see which one is working better for your engine after a few changes, too much hassle and dollars for me.

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Thanks for that. Like you say, I am after an oil that's suitable rather than the best as "best" is as you say a personal preference. I read in this magazine article about the frothing of modern oils and how that can adversly affect the take up in a classic engines sump and oil pump. As long as someone else is running an oil without any dramas then i suppose it's suitable. It's a shame Nissan are trying to sweep the old days of datsun under the rug, otherwise they might be giving us the manufacturers recommended oils and lubricants like MG did.

Have you ever picked the wrong oil and had problems with your car?

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The debate on which oil is best will always rage on. What is more important to realize is the older engines weren't designed to run some of the lighter weight oils on the market today, so would never run anything lighter than a 10W weight oil in our engines.

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I'll offer the "nutshell" explanation I was given, not to start a war, but to offer a point of view by someone who did a lot of research on it:

Newer cars have a catalytic converter in the exhaust system which can get plugged up with the casual blow-by combustion of older oils, which contain Zinc. Older engines, due to the nature of their design, benefit from the added Zinc in the oil on those polished surfaces that are in constant rub/wear with other metal pieces (cam, crank, valve lifters, etc.). Newer engines have newer bearings, surface treatments and linkages in these areas that reduce the requirement for Zinc, and as such do not need Zinc in the oil. Oil manufacturers were pressured to remove the zinc from their motor oils.

Now, our cars without a catalytic converter and an older engine can use the Zinc in the oil.

From what I've been told, the oils to use (and this is not an all-inclusive list):

1) Valvoline Racing 10-30 in the Grey bottle

2) Shell Rotella Non-Emissions

3) Standard Dello Non-Emissions

All of these are a bit pricier than the standard convenience store quart, but they're "worth it".

I won't quibble the details, if your mileage on this issue differs, enjoy.

FWIW

E

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yeah cool, that's kind of what I thought but just wanted confirmation. I know here in the UK and probably in the States as well, we have Castrol Classic, don't know how much it is but thought i might give it a go. I'll post the findings of 'Practical Classics magazine' here as well if anyone is interested. They tested a whole load of different oils in a load of scientific ways, which is probably why I switched off reading it in full haha. I'll read, digest and summarise it next week.

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I likewise just recently read a lot of threads on oils until I got tired of it. I settled on Napa premium performance universal fleet plus 15w-40, it is also what my machinist recommended. This is Napa's best conventional oil and it cost $2.99, made by Valvoline for Napa. I started the engine on Joe Gibbs BR oil for the first 20 minutes. Then replaced this breakin oil with the Napa 15w-40 provided by the machinist. I have a Comp Cam street cam and I am using their additive to protect the cam.

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My opinion is that the BEST oil has three primary characteristics:

1. It is clean

2. It has been in your car's engine less than six months

3. It is the appropriate viscosity for the current outside temperature.

(e.g. no 20W50 below 10 deg. C and no 5W30 above 40 deg. C)

Secondary characteristics, including ZDDP content are important, but less so that the three listed above.

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I'll offer the "nutshell" explanation I was given, not to start a war, but to offer a point of view by someone who did a lot of research on it:

Newer cars have a catalytic converter in the exhaust system which can get plugged up with the casual blow-by combustion of older oils, which contain Zinc. Older engines, due to the nature of their design, benefit from the added Zinc in the oil on those polished surfaces that are in constant rub/wear with other metal pieces (cam, crank, valve lifters, etc.). Newer engines have newer bearings, surface treatments and linkages in these areas that reduce the requirement for Zinc, and as such do not need Zinc in the oil. Oil manufacturers were pressured to remove the zinc from their motor oils.

Now, our cars without a catalytic converter and an older engine can use the Zinc in the oil.

From what I've been told, the oils to use (and this is not an all-inclusive list):

1) Valvoline Racing 10-30 in the Grey bottle

2) Shell Rotella Non-Emissions

3) Standard Dello Non-Emissions

All of these are a bit pricier than the standard convenience store quart, but they're "worth it".

I won't quibble the details, if your mileage on this issue differs, enjoy.

FWIW

E

I second this explanation and reasoning. I live in Arizona so I use VR1 20W50 as it gets rather hot here in the summer. My only advise to you is once you choose an oil stick with it. Don't switch back and forth.

Jan

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I am no expert and still unsure about the best oil to use, but I stay away from synthetic in my car. I have heard that synthetics are a bad idea in older high mileage autos.

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My opinion is that the BEST oil has three primary characteristics:

1. It is clean

2. It has been in your car's engine less than six months

3. It is the appropriate viscosity for the current outside temperature.

(e.g. no 20W50 below 10 deg. C and no 5W30 above 40 deg. C)

WM beat me to my post!

One Caveat from me and YMMV, I put that new-to-the-market, hyped Mobile 1 in my 260Z back in late 1976 - the car had maybe 25K on it. That stuff disappeared in my car! I always went with 10-40 dinosaur goo after that!

My oil gauge sender broke at the same time - coincidence? Never had a problem with burning or disappearing oil or pressure after I switched back.

A lot of guys that run the old SOHC4 750 Honda's run Rotella for the very reasons that Escalon posted. And they also have the yearly oil wars. Interesting tidbit: that motorcycle came out at nearly the same time as the original 240Z!

Since we bought our Dodge trucks new in 1996, I have been running a blend in my V10 and a full synthetic in my wife's 360. When changing oil, mine comes out a little dirtier than hers. A couple of times I ran pure dinosaur goo and my oil was black and thin. I have nearly double the mileage. I hear that the synthetic stuff is not as sensitive to AGE, which seems to be true. Some years, my wife's truck does not even do 2k miles. So, it might be 2 years before I change her truck's oil! It still comes out pretty clean. But I could be dumb on this truck deal. :stupid:

Edited by oldhemi

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I am no expert and still unsure about the best oil to use, but I stay away from synthetic in my car. I have heard that synthetics are a bad idea in older high mileage autos.

I have never had a problem with synthetic oil in any car, regardless of the mileage, PROVIDED it met with the three requirements in my earlier post.

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I ran nothing but synthetics in my old E21 323i, which had over 330,000 km on it when I sold it. No issues with oil over the 5 years I had it. If your car's gasket or seals are marginal, you could see increased leakage. But on a well-maintained engine you should minimal issues, if any.

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Loads of good advice here guys thanks. Some amusement too LOL. It' seems to be a purely personal choice but there is quite a lot to think about. I am rebuilding 2 engines at the moment so I suppose I'll know which oils are best for those when they're apart?! I think I will put Castrol Classic in my current engine for the next oil change and see how it goes.

Cheers again everyone who offered help etc here.

Matt

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Just an observation from the forgoing posts but I'm under the impression that Nissan originally built their engines with "wider" tolerances to accomodate the then available oils, ie 20/40 or similar. Rebuilt engines might be different tho.

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I second this explanation and reasoning. I live in Arizona so I use VR1 20W50 as it gets rather hot here in the summer. My only advise to you is once you choose an oil stick with it. Don't switch back and forth.

Jan

And i third this, i went with a oil made for diesel engines when i broke in my re build engine, it contains ZDDP, can't remember the viscosity, but i have no preassure issues and no leaks.

Chris

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The viscosity would be important. Especially in the case of a rebuilt engine as Nigel mentioned in post 18. Diesel engine oil has more polymers and detergent additives allowing it to keep more combustion residue in suspension for a longer period before being changed. Seems to me that would create a sludge problem especially if your engine is rebuilt with tighter than stock tolerances. It's been debated many times but in my opinion, I'd stay away for diesel oil in a gasoline engine.

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Pick a brand of fully synthetic oil and a quality filter. I use Amsoil, but Mobil and some others are good too. Don't go out and buy a synth oil and cheap Fram filter or something.

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The diesel oils that are rated oil for "fleet service" will have an SM or SL rating as well as the C ratings. It is a HDEO designed for both diesel and gasoline engines. The Napa 15W-40 fleet service oil is SL rated which means it has zinc and phosphorus additives. A gallon cost me $10.99.

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Horrors!

I'm certain that the individual who suggested synthetic oil probably uses Crisco as after-shave! I can't believe all you guys (and there are some experts here) are making suggestions without ANY reference to what the manufacturer recommends. Whoa!

It is with distinct pleasure that Her Majesty the 26th offers this information from the engine service manual. This, of course, is from the 1970 service manual. Later issues may differ.

post-4148-14150810526148_thumb.jpg

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Chris;

The reference you present is informative and compelling.

Does this mean we should also be on the look for 95 octane gas? After all, that IS what that sheet recommends. Last I checked, 92 octane IS considered Premium, unlike the 100+ I used to pump into my motorbike in the 70's.

Don't get me wrong, it is an excellent reference and should help a lot. However, I'm just wondering how many of the oils specified are still being offered in their original specifications. That is, the ORIGINAL formula as specified by the Nissan Engineering team when that sheet was printed.

Many expendable items for our cars have changed in the 35+ years since they were new (and 40 for the dates of this specific spec sheet).

You really would have a hard time finding 175HR-14 tires at your local tire store, and if you DID find a set... would you really buy them and not Radials? Then again, would you rotate them as the original manual shows? The manual does warn about mixing the THREE different types of tires, but does NOT give a recommendation on size / type of the other two types. Does that mean we are limited to only ONE type of tire? Or that the engineers felt that you would make an educated or informed choice?

Oil also changes formulations as time goes on.

One spec sheet from my manual for the 72 Z shows that the Monograde oils from Shell and Esso listed on the sheet you provide were "Not Available" at the time of printing, and that's just 2 years AFTER your sheet. Additionally, Caltex, Castrol and BP are NOT listed, and in their place we have Sunoco alone. Not to mention that Shell's X100 oil on your sheet is now Super Motor Oil on mine (and only in Multi-Grade), and Chevron dropped the RPM in their oil name, and Texaco went to the Havoline Super Premium name.

Yet the Mil-Spec (MIL-L-2104B) remains the same for all those oils.

Hopefully that Mil-Spec is still the one that the cans you buy today, but last time I checked (about 2 minutes ago), the Mil-Spec doesn't appear on the cans...oops, plastic bottles I have.

I think part of the point of all this is, that things do in fact, CHANGE! This is what this thread is all about.

Your reference is good.... for a starting point. But as far as to what to use today... well that's what everyone is asking.

Tire sizes, types and construction.... not the same as when the car rolled off the assembly line. Same with oils, DEQ, Gasoline and so many of the other consumable items on the car. That is the nature of progress in the automotive world.

To service an older car, you ask around, from reputable sources, and from the manufacturer and even then, sometimes it boils down to a discussion of what IS available and not what you'd like it to be.

2¢

E

Edited by EScanlon

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Enrique,

Enjoy your comments as always, however it is the "reputable sources" that has me concerned. How on earth could this conversation be considered "reputable" without any reference (or worse, discarded reference) to what was originally specified? Your octane rating and tire size examples reference original specification. Why not oil? Throughout this thread there is mention of temperature and operating conditions. What is the reader left with, though? Some vague idea that this might be important, perhaps, but nothing specific enough to warrant further thought? Perhaps the answer to this poor fellow's question is; "go ask a reputable source because you won't find it here"!

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