How choose a good oil for an M30 engine.

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Brucey
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How choose a good oil for an M30 engine.

Post by Brucey »

I've read widely on the subject of oils, including the LN engineering web pages. From this I've compiled some brief notes on oils for M30s. Mostly this is a 'precis' of information from elsewhere but where I've expressed my own opinion I have indicated it as best I can.

1. M30 has a two-valve head with strong springs and a high rocker ratio. This means that cam follower loadings are very high, much higher than those seen in many modern oil performance tests which tend to simulate modern 4V valvetrain loadings. Some older valvetrain wear test sequences (VE, VD) which simulated the M30 more closely are now thought less relevant to new oil testing.

2. ZDP (AKA ZDDP) is required to prevent 2V valvetrain wear, and some detergentcy is required to deal with ZDP breakdown products. However the required amount of ZDP increases with yet higher levels of detergent. High detergent oils (e.g. for extended drain intervals, especially Calcium based detergents) cause more wear at the same ZDP levels than lower detergent oils.

3. API SE, SF, SG, SH, SJ rated oils (from a time now passed when 'newer spec = better oil' was the rule) typically have good levels of ZDP and moderate detergent levels. However API SL oils may have much lower ZDP levels (unless other specifications are also met). Valvetrain wear problems apparently increased suddenly with the introduction of API SL. API SM or higher rated oils will almost certainly have ZDP levels that are too low for an M30. (ZDP is not used in these oils in part because of newer emissions/catalyst requirements. Very high ZDP levels can kill catalysts.)

4. API CF rated oils will also have high ZDP levels and moderate detergent levels (lower detergent than, say, CI rated oils) so should make the best of the ZDP present.

5. ACEA A3/B3 rating is overall a good thing. Valvetrain scuffing wear limits are typically ~1/5th of those allowed in (say) API SM testing. Also many other properties of the oil when hot are tested more stringently than API-only rated oils. However there is a catch; ACEA A3/B3 rating implicitly limits P to 0.1-0.12 maximum; this may be sufficient in an M30 only if the oil meets some other specifications as well.

6. LN engineering recommend 0.12-0.14 Zn and P for air-cooled Porsche engines (higher valvetrain loadings and oil temperatures than the M30 as I understand it). They suggest one route is to use STP to slightly boost Zn and P levels in a good quality ACEA A3/B3 oil.

7. My M30 suggestion is to find an oil which meets no more than API SL (or preferably SJ or lower), API CF ( but not higher) and ACEA A3/B3. The API SL and the ACEA specifications confer many good things in the oil, but do not guarantee very high Zn and P levels (although they may cap them). However the API CF rating ensures fairly high Zn/P levels and a moderate (but not excessive) detergentcy.

8. Oils meeting the specifications above should be OK in a 6er for the standard drain interval, provided filtration is OK, oil pump/pressure is good, and blowby etc is not excessive. I would not recommend extended drain intervals or indeed many of the oils that give extended drain intervals in other engines. Remember that generally the more miles the engine has on it, the more likely it is that the oil will slip out of grade earlier rather than later.

9. In my view there is nothing wrong with changing the oil more often than normal. There are loads of healthy high mileage engines out there which have had the oil changed once every four thousand miles or so. You may read that wear particles in the oil may increase immediately after an oil change; I believe that this may be the cleaning action of new oil (with fresh detergent action) releasing bits of trapped crud from various nooks and crannies in the engine. This sort of thing is very much more likely in an air-cooled engine IMOE. Unless you plan to never change the oil again this cleaning action is inevitable, so it is a question of choice here; a little and often or infrequently but a lot more. Fitting a magnet to catch all this crud seems like a very good idea.

10. The saving grace in the M30 may be oil temperature. I would be surprised if the oil was routinely in excess of 120C in the rocker box, where with (say) air-cooled Porsche engines it could be much higher than this. Higher oil temperatures of course lead to greater emphasis on the requirement for anti-scuffing additives.

11. To date all cam wear problems in M30s that I have seen personally are likely attributable to a simple oil supply problem of some kind, not to the finer points of lubricant selection. Having said this, why take a risk? In fact some of the oils that will work in an M30 are cheaper than supposedly 'better' oils that are in fact less suitable.

12. My daily driver's handbook (for turbocharged DI diesel) explicitly prohibits the use of API CG or higher rated oils; API CF is what is required, presumably for reasons related to the ZDP issue. I have recently rationalised my oil selection; I have just bought a large container of a Comma 15W-40 API SL/CF, ACEA A3/B3 rated oil from my local auto parts shop. This will go in my daily driver, my land-rover, and of course my 6er. Previously I had different oils for each which was a bit of a logistical nightmare.

13. Fully synthetic, semi-synthetic or mineral? For reasonable drain intervals in an M30 used on the road, really I don't care which just as long as it meets the correct specifications. Many of the alleged 'benefits' of fully synthetic oils relate to extended drain intervals, or are assured by the correct specification (especially the ACEA A3/B3 tests) anyway. However for tuned/turbo engines or hard track use there is a good argument for a different oil to be used. There are some good suggestions on the LN engineering webpages.

14. Which viscosity should I use? An easy one this; just follow the guidance in the owner's handbook depending on the climate. Having said this 15W-40 will be fine nearly everywhere in fact; it'd have to be really cold or unbelieveably hot before BMW would prefer that you don't use it.

I hope you find all this useful; all comments welcome.

cheers
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Oil

Post by 603racing »

Great information Brucey!

So I pose this question. My '83 635 Euro is an enduro racer. It is a track only car and all of the races are between 14 hours and 25 hours. The motor is completely stock and only the exhaust has been upgraded. Based on your research what type/weight oil would you recommend? I have previously run BMW/Castrol TWS 10w-60, but now I am second guessing that.

Looking forward to your thoughts! And once again, great info!
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euro24

Post by euro24 »

I usually run 5w-50. Sometimes I run 20w-50 (mostly in the summer). Thanks for the writeup! :D
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Re: Oil

Post by Brucey »

603racing wrote:Great information Brucey!

So I pose this question. My '83 635 Euro is an enduro racer. It is a track only car and all of the races are between 14 hours and 25 hours. The motor is completely stock and only the exhaust has been upgraded. Based on your research what type/weight oil would you recommend? I have previously run BMW/Castrol TWS 10w-60, but now I am second guessing that.

Looking forward to your thoughts! And once again, great info!
Take a look at the LN engineering pages; they have some good recommendations for oils to go in engines that see the very hardest use. Something to think of is using an oil primarily recommended for motorcycle engines; some of these are really good quality.

I would say that changing the oil after 1500 miles or less of hard track work is about right. The 10W-60 grade is OK but a 20W-50 would be fine too provided the oil temperature stays fairly low (you have a gauge, right?).

cheers
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Oil

Post by 603racing »

I do not have an oil temp gauge. The car runs pretty cool as I have modified the cooling system. We change the oil and filter after every race. If the race has a "half time" or break in the middle we change the oil then as well.

I will check out LN, thanks again for the info!
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Re: Oil

Post by Chris Wright »

Brucey wrote:
603racing wrote:Great information Brucey!

So I pose this question. My '83 635 Euro is an enduro racer. It is a track only car and all of the races are between 14 hours and 25 hours. The motor is completely stock and only the exhaust has been upgraded. Based on your research what type/weight oil would you recommend? I have previously run BMW/Castrol TWS 10w-60, but now I am second guessing that.

Looking forward to your thoughts! And once again, great info!
Take a look at the LN engineering pages; they have some good recommendations for oils to go in engines that see the very hardest use. Something to think of is using an oil primarily recommended for motorcycle engines; some of these are really good quality.

I would say that changing the oil after 1500 miles or less of hard track work is about right. The 10W-60 grade is OK but a 20W-50 would be fine too provided the oil temperature stays fairly low (you have a gauge, right?).

cheers
Here is the LN engineering page:
http://www.lnengineering.com/oil.html

Here is another discussion on ZDDP and a list of oils:
download.php?id=9567

Brad Penn is the old Kendall GT "green" oil that all of the old racers swore by. The name Kendell was sold, but the original refinery is still making it from the same crude.

Here is a quote form LN:
  • "The Brad Penn Penn Grade 1 Racing oil is the same "green" oil everyone was familiar with back when Kendall GT was the best motor oil money can buy, as both the original and this newer product both come from the same facility using genuine Pennsylvania crude. These oils are proven to protect cams, rockers, lifters, and all valve train components as well as provide superior rod bearing life because of their very high HTHS viscosities AND low levels of individual detergents to net a high level of detergency with the use of Ca, Mg, and Na synergistically. Just ask anyone about the "green" Kendall oil from decades past and you'll know why we like it so much."
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Post by GripGreg »

I didn't understand much of what Brucey or Chris wrote, and I'm sure it's valid but, I use Castrol 20/50 year round. But, I live in Long Beach, Cal., where the weather is sorta mild year round. Fifty degrees is damn cold.
Where are you located? East coast wintertime oil should be a lil lighter than 20/50 me thinks. Summertime, 20/50 Castrol might be fine & dandy.
But, the multi-grades have a lil more detergent & you need that.
I advise an oil & filter change every 3,000-4,000 miles.
Another way is if you can't see the dipstick when checking, it's past time.
If you don't drive it too much, then change the oil every quarter, no matter how many miles you put on it.
You do check the dipstick in between oil changes, I hope? These wonderful cars tend to absorb oil through the metal. It's in their DNA. Keep your baby well lubricated & she'll show you love.
If you drive her every day, check the oil and all levels once a week.
Get a book, do some research & stay close to this website.
Hit the apex
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Post by BORN2RUN »

I change oil every 4 months. I'ts become an internal calendar, and I make sure my son changes his in his '03 Neon at the same time. I live in SoCal, and while it's mild year 'round, I sometimes drive up in the mountains where it's in the teens and of course it easily reaches over 100 in the summer months.

I use Mobil 1 5/40 or 5/50. Previously I've used this in my old TR6, a Boxster, several Mercedes, and an old Jag XJ6. My 6er, despite over 190,000 miles still runs strong and its rare when I have to add even a few drops of oil between changes.

WARNING - I BLEW OUT AN OIL SEAL BECAUSE I CHECKED THE OIL IN THE DARK AND THOUGHT IT WAS A QUART LOW. I WASTED MONEY THAT COULD HAVE BEEN OTHERWISE SPENT ON AN UPGRADED EXHAUST SYSTEM. SO DON'T DO THIS!!!
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Post by GripGreg »

Born2run
I use to live in Altadena, now in Long Beach. Maybe we can hook up at Barney's Beanery? (just a thought) I use to enjoy Stottlemeyer's too.
I have two E12's, one is a very nice '80 & a good strong '75 back-up, & now a nice '82 Euro 6.
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Post by chicane »

I use Mobile One 0w-40 in the crankcase, Royal Purple Synchromax in the manual tranny and, Royal Purple MaxGear in the diff.
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BORN2RUN

Post by BORN2RUN »

Sounds like a great combo to me. I've also used Amsoil on occasion.
horsetan

Post by horsetan »

Over here, 'tis Castrol Magnatec 10w-40 semi-synth. Change every 3,500 to 4,000 miles.
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Post by tschultz »

horsetan wrote:Over here, 'tis Castrol Magnatec 10w-40 semi-synth. Change every 3,500 to 4,000 miles.
Also have this, just went with a sllightly different weight. Glad to see somebody else uses it!
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Post by horsetan »

tschultz wrote:
horsetan wrote:Over here, 'tis Castrol Magnatec 10w-40 semi-synth. Change every 3,500 to 4,000 miles.
Also have this, just went with a sllightly different weight. Glad to see somebody else uses it!
It used to be available in 15w-40, but that was withdrawn from the UK market about two years ago.
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Post by Brucey »

many of the oils mentioned are fine oils.

For modern 16v engines.

Unless specifically formulated to do so, they probably will not have sufficient amounts of friction modifiers such as ZDDP to give acceptably low levels of valvetrain wear in older 2V motors.

If they did, they wouldn't meet the latest specifications, which effectively prohibit certain oil additives by type and quantity.

cheers
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Post by TN_M6 »

The large volume of the oil industry has passed us all by you know. It's only the specialty formulations like Brad Penn that are right for our cars these days. I'm a huge Brad Penn fan and fortunate to have a distributor that will deliver to my workplace in middle TN. I get 2-3 cases of Penn Grade 1 20w-50 at a time and it gets used in the M6, 535, e30's and also my Mercruiser sterndrive instead of marine oil. I spoke personally to Frank Fahey some time back and he is a fan of it.

Here's an example why I like it... We bought an e30 thinking we would use it for parts. It had a rather noisy engine with a low oil press light that came on when it warmed up and the auto trans was DOA. We pulled the valve cover and it was full of sludge like the Ford commercial and the cam was pretty worn and I don't think it was the 285k miles but the use of wrong oil formulation and weight. After adjusting the valves running some seafoam through the engine and then switching to BP it quieted down a lot and the OP light has never come back on. My daughter is using this car daily (replaced trans) and we hope to get a year or two out of it while she finishes grad school. It's been running like a champ and burning little to no oil. Is it the oil? can't hurt.

My 535 has been much better maintained (by me for the last 6-7 years)and running BP most of that time and is now ready to break 250k miles. It runs great and pulls strong to red line and needs no oil between changes.

The M6 gets BP and I hope it last another 20 years since it has barely over 50k miles. Twice as many cam lobes to worry about wear you know but I basically drive it daily. It uses just a little oil but that's an M thing.

Personally, I would NOT use Mobil 1 and I would NOT use anything lower than 15w-?? unless it was really cold. Mobil 1 5w-20 runs out of my wife's pilot like water. Not engineered for an M30.

Sorry to sound like a commercial but really just want to reinforce that we should all use an older formulation oil on these engines. The mye28 guys like Valvoline non-synthetic VR1 racing 20w-50 because it's easier to find so there's another recommendation.
Chris Wright

Post by Chris Wright »

I have to say I cringe a bit when I hear of people using "0" or "5" (0w40 or 5w40) weight oil in these older cars. I suspect some people may be getting the weight number backwards. I know I used to, thinking that a 5w40 oil is a "40" weigh oil with additives added to make it pour like a "5" weight oil when it is cold, but that is actually backwards,

In a 5w40, the base oil stock is a "5" weight oil to which additives in the form of long, curled up molecules are added, that uncurl when hot to make the oil act like a "40" weight. The problem is that in use these long molecules are sheared and can no longer make the oil act like a "40" weight, so the oil is only a "40" weight when it comes out of the can is constantly degrading toward the "5" weight.
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Post by bpoliakoff »

I personally suggest Brad Penn Racing Oil. This is one of the few oils with high ZDDP ( zinc) content which is highly recommended for over head cam engines. I spoke with the factory rep while at the Barrett Jackson auction, who recommended 10-40 or 10-50 depending on the climate you are in. In Phoenix, I will run the 10-50 due to the extreme heat of our summers. I also have an oil cooler on my Euro. They also make a break in oil which I will use when I light up my fresh engine.
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Post by challenger »

Thanks for good consideration about oil viscosity. I've been running synthetic 5W40 by different wellknown brands, same as other car's I own. Now I've been recommended a thinner oil for my V8 car, I'll go for 5W30 for that engine. So then I decided to read about BMW M30 oil too and perhaps go for something else. 10W40 sound like a good choice for my car and driving habits. Now I had a good offer on Mobil 2000 semi-synthetic 10W40 API-CF and bought enough for two changes.

Reasons I discarded synthetic and chose this:
No racing.
Car is not driven in winter (only a few startups, but I do make use of the electric block heater installed).
Temperatures in summer aren't that high around here.
Oil change intervals usually between 8-11.000 km, or at least once a year.
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Re: How choose a good oil for an M30 engine.

Post by dwcains »

Bumping an old thread, but is anyone using the LiquiMoly 10W-40 with MoS2? Along with the Moly additive, it's got a high ZDDP content.

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https://www.ecstuning.com/b-liqui_moly- ... gQodkO0CtQ
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Re: How choose a good oil for an M30 engine.

Post by sansouci »

Dean & Brucey,
Even though New York State doesn't check emissions on 25yo cars, I still have cats on my car. So the question is: will this oil (Liqui-moly) damage mine?
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Re: How choose a good oil for an M30 engine.

Post by dwcains »

I don't know for certain, but there are plenty of other oils with high ZDDP content (e.g. Brad Penn, Valvoline VR1 20w/50, Mobil 1 15w/50), if that's your reason for asking. I've heard that if the engine is an oil burner the cat can be contaminated, but otherwise, you should be OK. A quick Google search doesn't seem to yield too much more conclusive information.

My car is cat-free, and I should mention the LiquiMoly came with the car, as the PO had been using it for several years before I bought it almost 3 years ago. 200K+ miles on the original engine, with a rebuilt top end, and it neither burns, nor leaks, a single drop between changes. It's time for an oil and filter change, and I'm hesitant to change what's been working, even though all my other cars have had Mobil 1 since the late 1970's. Neither the M1 15w/50 nor the LiquiMoly 10w/40 are that easy to source locally, as the former is now only stocked at WalMart and the latter at some NAPA stores, so I'm going to order 8 liters from ECS (need >$49 for free shipping), which is $54.

I'm also going to install one of Bert's spin-on oil filter adapters so I can use a big Mobil 1 M1-301 filter, and I'll document that with lots of pictures.
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Re: How choose a good oil for an M30 engine.

Post by bpoliakoff »

Shell Rotella
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Re: How choose a good oil for an M30 engine.

Post by TN_M6 »

I'm not a big fan of Rotella after seeing recommendations my son put it in his Subaru LGT Turbo but the stuff just disappears. No leaks because we fixed all that and relatively new turbocharger. He switched to Mobil 1 and now it uses very little oil. But...

I said years ago in this post and still stand by the need for a 15 or 20w in these cars with higher ZDDP. My 535, M6 and e30 project car are still all in great condition running on Brad Penn. The other e30 M20 I tried to save eventually needed new cam & rockers. PO had been running 5w-30 from the chain oil change places. Low additive 5w-30 brings wear to these old engines IMO.
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Re: How choose a good oil for an M30 engine.

Post by tschultz »

Lately I have started using NAPA 15W50 synthetic as it is stocked locally and cost is low. As I understand NAPA version oil is rebranded valvoline so it has the higher ZDDP that you want.

I also switch to the higher weight after realizing that 5W30 caused more oil leaks and wasn't as originally specified. Also it isn't designed to give protection at the higher air temps of summer/spring.

I like an oil that I can use year round and change based on mileage.
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