17 replies to this topic

[leepol83]

As title what oil do I stick in my mpi ?
Thank you all ??

[Quinlan minor]

I use Millers Classic Mini Oil in mine.

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[leepol83]

I use Millers Classic Mini Oil in mine.

Thanks is that an mpi ?

[nicklouse]

Is it manual or Auto transmission?

[Quinlan minor]

 

I use Millers Classic Mini Oil in mine.

Thanks is that an mpi ?

 

Yes, a '98.

[leepol83]

I use Millers Classic Mini Oil in mine.

Thanks is that an mpi ?

Yes, a '98.

Brilliant thank you mate ??

[Twincam]

Is it manual or Auto transmission?

Going on from what Nick asked, autos like a different oil compared to manuals so it's worth thinking about if you have one.

[nicklouse]

 

 

 

I use Millers Classic Mini Oil in mine.

Thanks is that an mpi ?

Yes, a '98.

Brilliant thank you mate

 

Your Kat will not like it.

[jamesmpi]

I’ve always use this Millers Oil
https://www.opieoils...engine-oil.aspx

Edited by jamesmpi, 20 January 2020 - 06:26 PM.

[leepol83]

I use Millers Classic Mini Oil in mine.

Thanks is that an mpi ?

Yes, a '98.

Brilliant thank you mate

Your Kat will not like it.

My Kat will not like it ? What do you recommend ?

[Quinlan minor]

No reason it should affect the catalytic converter, if that’s what you mean.

[g0myw]

Millers or MiniSpares own brand.

[leepol83]

What about the Halfords one (green tin)

Why won’t my Kat like it nicklouse ?

[bluedragon]

I suspect the comment about the catalytic converter is related to zinc levels. The so-called "classic" oils boast higher levels of zinc diphosphate (ZDDP), which serves as an anti-wear additive to motor oil. This additive can "poison" catalytic converters, rendering them less effective over long periods of time.

 

My own personal opinion is that the issue of ZDDP is vastly overrated. The issue first came up in the mid-2000's as claims of excessive wear on flat tappet cams cam up. This was blamed on reduced ZDDP levels.

 

I'm not convinced this was ever the case - I suspect deficient metallurgy from cheapened production sources as the true culprit. Here's why:

 

1) Massive levels of ZDDP don't equate to greater protection. Only so much ZDDP binds to metal surface at any given time. It doesn't keep plating itself on thicker and thicker. High levels can be useful for break-in because there is no protective layer of ZDDP on fresh metal. ZDDP bonds as a result of high pressures and temperatures - so racing engines may deplete this faster. 

 

2) It is akin to vitamins in the human body - taking 10,000x the daily recommended dose of vitamins does little if any good. If your body can't use it, it just makes you see funny colors when you visit the restroom after a night at the pub. Your body gets rid of what it can't use. ZDDP just stays in the oil unused.

 

If you did an oil test after a change, and found that the levels were very low compared to what you had when the oil was fresh, then that could justify using a oil with a higher level of ZDDP.

 

But also note that oil companies aren't stupid - they've long since found alternatives to ZDDP for high-load wear protection, and the current oils meet all the national standards for oil wear and protection (which apply to all cars, not just the latest models.) Especially consider that modern engines have higher tolerances than many classic cars, so if they wear out faster, it seems they would be affected sooner.

 

Flat tappet cams are hardly the only area subject to high temperatures and friction. So why aren't the rings and bearings wearing out faster because of lack of ZDDP? It's not like modern engines have all switched to roller-bearing crankshafts or anything like that.

 

And in fact, if you want to get nitpicky, ZDDP actually increases friction in the motor (though it decreases wear, because it's sacrificing itself in the process instead of the base metal surface.) Probably immeasurably low on a engine dyno, but some racers think it's worth avoiding and use oils with other anti-wear additives.

 

After all these years I've yet to come across a scientific study showing that flat-tappet cams are being killed through lack of ZDDP. It's anecdotal testimony - builder X says this, builder Y says that. That isn't worthless, but it's not scientific.

 

They don't know for sure it's the lack of ZDDP that did it. They don't have a control set and an test set to compare against. It's why so many of them rail against synthetic oil - same deal. They see a failure and say the oil is the cause. But how do they really know without a metallurgic analysis at least?

 

 

 

Dave

[Quinlan minor]

Fair comment, Dave.
But is there any “scientific study showing that... ZDDP additive” does "poison" catalytic converters, rendering them less effective over long periods of time”, in normal use, on a well maintained engine?