Using Mobil 1 in 75 Twin Spark engine

[Brad M]

Have not seen Mobil 1 15-50 at my local Repco, looked up specs, seemed good for pushrod engines, but not recommended by as many car company's as Mobil 1 5-50, but it gets back to what i keep asking, how do you know what a good oil is, unless we are petroleum Scientists, Colin.

As Gary said earlier, everyone will always tell you what they are using is the best. I'm happy with Gary's recommendation.

For reference; I got my Mobil 1 15-50 from CostCo for under $60 for 5L. When I was at Auto Barn they checked the price for a special order it was king to be over $100 for 5L. I just hope Cost Co gets some more in soon, there hasn't been any there for a while now.

GioGTVTS, Apologies for your thread being hijacked.

[GioGTVTS]

I am following the thread with interest, Brad. Gary, thanks for your input. I have used M1 for a few of my cars & bike (ZZR1100) and found it really good. But every time I ask my mechanic, the answer is... no, the engine is not made to use synthetic oil. So my original question was, has any one used M1 in their 75 Twin Spark, and how did it go? Hope Costco re-stock the M1 15-50 again. Cheers, John

[colcol]

What does Mobil reccomend for a twin spark 75?, they say Mobil 1, 5-50 viscosity, even though Alfa say 10-60, for my 156 JTS, in the olden days when engines where 'looser' due to manufacturing tolerances, they used higher viscosity oils,  newer engines can get away with thinner oils, due to their tighter tolerances on manufacturing, Colin.

[Darryl]

Hi Darryl, the thing with oils is....everybody will have an opinion about the oil that they are using, and in the absence of problems they will all declare that their choice is the best.
Mobil 1 15w50 is a superior motor oil with very few peers. I don't support the argument that 'the engine was designed to use mineral oil' because if good quality synthetics were available 40 years ago we would have been using them then too. The 15w component will provide quicker oil delivery when cold and at operating temperatures the 50 will give serious protection at all speeds and temperatures with reduced friction. . (By way of comparison HPR30 is 20w60) In addition Mobil 1 is virtually impossible to breakdown under extreme temperatures and stress. Just ask Grant Tander. Another misconception often bandied around is the lack of zinc content in modern synthetic oils. In Mobil 1 there is no reduction in zinc with better than 1600 p/m. Use the Mobil 1.

Did you mean to reply to me? We seem to be in violent agreement +/- a choice of brand and that for a somewhat worn twinspark I (and the oil pressure gauge) are happier with a higher hot viscosity and a lower cold one than the old dino juice could manage. This is also (as the temps go up) higher than the Mobil product you suggest. As I'm sure you know the XwY pair of numbers doesn't tell the whole story, but fundamentally, the oil I suggested/have been using (Penrite SIN10) I use over HPR30 for similar reasons to those you cite - but with a bias towards being a bit thicker when hot without loss of protection on cold start.

Mobil 1 15W50:
SAE Grade   15W-50
Viscosity @ 100ºC, cSt (ASTM D445)    18
Viscosity, @ 40ºC, cSt  (ASTM D445)   125
Viscosity Index   160

Penrite SIN 10:
SAE Grade   10W-70
Viscosity @ 100ºC, cSt (ASTM D445)    28
Viscosity, @ 40ºC, cSt  (ASTM D445)   172
Viscosity Index   205
Zinc %  0.105
Phosphorus % 0.096

And compared to good ol HPR30 (which isn't good ol HPR30 - formula changed...):
Viscosity @ 100ºC, cSt (ASTM D445) 24.4
Viscosity, @ 40ºC, cSt  (ASTM D445) 216
Viscosity Index   141

[vin sharp]

NOTE; the Mobil1 15w50 is a racing oil as Gary says. If you check the Mobil info; "is recommended for older valve train designs that may benefit from higher level of anti wear normally not required for newer generation vehicles". e.i it has a good level of zinc in the racing grade oil, about 1600ppm. 
Other grades of Mobil 1 and all commercial oils specified for new vehicles are LEGISLATED down to less than 700ppm (to maitain life catalytic converters) and decreasing each year. Alfa engines up to certainly the 12 valve V6 engines were designed around the higher zinc parameters.
Oil company spin can go on all it likes about their lastest offerings of eternal and perfect protection for all parameters. but it just doesn't exist. They would not blend their current oils to what is offered off the shelf for mordern engines by choice; thet have to do it. And for the rest of us with older engines that cannot miraculously self-change the metallurgy of what the engine is made of, there are high-zinc content oils in both synthetic and mineral.
Do your homework and you will save yourself wear and oil use by NOT using the latest, modern-engine specified oils. Regardless of how "intelligent" the oil is, it is not what is required in our older design engines, nor the latest design  racing engines either for that
matter, which is why high-zinc alternatives ARE out there.
I often wonder and suspect that the valve-train  wear problem in the 156 JTS engines could be avoided by higher zinc oil. But the factory and dealers are NOT ALLOWED by law to specify it for a modern engine.......

[colcol]

Right on Vin!, the higher zinc oils would help the camshaft wear problems in the 156 JTS, but the zinc would cause havoc with the cat convertors, several thousand dollars worth$$$$, the oil contamination problems with the JTS, caused by fuel getting past the rings and the oil having fuel contaminating oil, this can be overcome by taking it along the freeway to burn out the rubbish from the oil OR changing your oil more regular, not the ridiculous 15,000-20,000 klms as recomended by some, Colin.

[Darryl]

NOTE; the Mobil1 15w50 is a racing oil as Gary says. If you check the Mobil info; "is recommended for older valve train designs that may benefit from higher level of anti wear normally not required for newer generation vehicles". e.i it has a good level of zinc in the racing grade oil, about 1600ppm. 
Other grades of Mobil 1 and all commercial oils specified for new vehicles are LEGISLATED down to less than 700ppm (to maitain life catalytic converters) and decreasing each year. Alfa engines up to certainly the 12 valve V6 engines were designed around the higher zinc parameters.
Oil company spin can go on all it likes about their lastest offerings of eternal and perfect protection for all parameters. but it just doesn't exist. They would not blend their current oils to what is offered off the shelf for mordern engines by choice; thet have to do it. And for the rest of us with older engines that cannot miraculously self-change the metallurgy of what the engine is made of, there are high-zinc content oils in both synthetic and mineral.

I'm probably sounding like some sort of Penrite fanboy. The only thing I'm a fan of is that they do put info out there so I can tell what I'm buying. You can find it for other mfgs to if you dig. I certainly agree with Vin that you should *not* put the heavily promoted product of the day in your engine without some evidence the *exact* oil you are buying is suitable for it and the way you use it. Like someones ad says, Oils ain't oils. One grade of the same "product" is quite different from another in more than those "headline" cold/hot viscosity numbers.

Just to fill in the blanks for those shopping for something at the local Repco or wherever, I did specifically check (and quoted above) the Zinc level for the Penrite SIN10 (about 1000ppm). As far as I'm aware this is as much as I/anyone would have been getting in typical road use non-synth blends in suitable grades for our engines for the last 10..15 years...  There is also what seems to me to be (for an oil co publication) quite a balanced "paper" on the whole Zinc issue on the Penrite website http://www.penriteoil.com.au/tech_pdfs/169%20ZINC%20MYTHS%20AND%20LEGENDS%202010%20UPDATE.pdf. Whatever you do, don't save the environment by putting one of their "enviro" oils in your alfa - unless you want to turn it into landfill.... It also appears all the Penrite HPR oils in appropriate grades for older Alfas (in particular the current version of HPR30) is still fine in this regard too.

[Darryl]

Penrite have changed their product lineup and split the sin x range into a premium 10 tenths and a racing 10 tenths range. The race products have a rather outrageous marketing sounding "shear free" added to the label. However, regardless of whether it is "shear free" or not, I can appreciate that an oil with better (less) shear will be better for high loads. And from my very limited knowledge of this area the main reason why the old mineral oils had shear issues was the use of viscosity improvers to get the viscosity vs temp more consistent to reduce cold wear, while a race oil didn't need this - but running a race mineral oil for your drive to the corner shop was not going to do your engine any favors.

But, given that the racing synth oil already has a perfectly acceptable cold crank viscosity I can't see a good reason *not* to use the "racing"  version regardless of race vs road use (price? haven't checked yet).

Is that sound? Under what circumstances would that be a bad thing to do? I know, I known buy mobil 15 race - which is fine - if it was easy to buy... If there is something else I can pick up at local repco or whatever I'll be happy to buy that instead.

[Steve S]

Interesting thread

M1 15w50 is a good oil but not strictly a "racing oil". You can use it in a road car just fine. Mobil 1 do make some proper racing oils. a 0-30 and a 0-50 both have far more anti wear than 15w50 (and I'm guessing less detergents etc)
M1 15w50 has around 1300ppm zinc which is similar the Penrite's "Full Zinc" oils. M1 5w50 and 0W40 still have 1000ppm. 40 and 50 grades are not going to meet the Ilsac specifications for fuel economy so they are in a different category, exempt from having to reduce zinc levels. It is the Low SAPS, Ilsac and ACEA A1/A5 specification oils that you really need to avoid in an old engine like these.

A good synthetic oil will always have a better viscosity index than the same grade mineral. M1 15w50 is going to flow better at start up than a basic mineral 15w50 and definitely a whole lot better than a mineral 20w60 (or even synthetic 10w60 for the record) and give far better protection when hot too.

[GTVeloce]

As a slight aside to the recent post, I have just changed my oil back to the usual oil I put in my TS engines, HPR10 (not the fully syn latest version). I had tried the HPR15 for the last 5000km which is a 15W60 oil to see if I could raise the oil pressure when fully hot as it drops very low at idle (quite normal I understand). It certainly worked from that point of view. My oil pressure never dropped below where I felt comfortable, however, I did start to get a little oil leakage through the oil sump gasket and the cam cover gasket plus the engine felt a little sluggish. I am guessing the leakage came from the increased pressure.

Needless to say, after changing back to HPR10 the engine is feeling much more lively and fun! Will have to wait and see if the leakage stops or not.