How much longer do our engines last with modern oils?

[Colin]

So I'm one of the odd balls that daily drives my 2002 and have been doing so for almost exactly a decade now.  When I bought the car, the previous owner had the engine rebuilt to what looks to be a pretty good standard.  I'm always running AMS Oil or VR1 synthetic racing oil and for fun, I've sort of wondered how much longer the stout old m10 can last.  Anyone have any anecdotes or insights?  Mine seems to be doing pretty well as I don't have any excessive blow by, smoking etc.

[Conserv]

Good question.  I certainly have no idea.  Does synthetic oil really extend the life of a ca. 1970 engine?  Or is the extended life of modern engines more a function of design, engineering, materials, and the manufacturing process, operating within a synthetic oil environment?  I hope the answer is “Yes, modern lubricants extend the lives of vintage engines”.  But I, personally, have never assumed my ‘76’s engine — despite being balanced, “blueprinted”, and lightened at it’s 100,000-mile overhaul — would last any longer than....100,000 miles.

 

Eager to hear informed viewpoints and actual experience — which would distinguish those posts from mine! ?

 

Regards,

 

Steve

 

 

[Colin]

 

[Colin]

This is a nice demonstration of the advantages of modern oils. Seeing this, one can't help but think that they can't be shortening the life...

[robspeed]

Beware that modern oils can actually be harmful to older engines. 

https://www.hemmings.com/blog/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines/

[Preyupy]

I have seen back to back engine dyno runs between Dino and Synthetic oils that show both an increase in Torque and HP as well as a drop in oil temp while holding the same water temperature.  The life expectancy of any engine is much more dependent on the materials used (piston rings, bearings, pistons, valve seals etc) and the machining tolerances AND the kind of driving you do.  If you start and run your car for less than 30 min and drive around town on the AVERAGE for 100,000 miles, that works out to around 20-30 miles each time you drive it you will never get the oil warm enough to evaporate the moisture out of the oil.  If you don't drive it often you will find some amount of surface rust on some internal engine parts just because of the before mentioned moisture in the oil/crankcase.  If you get a small amount if surface rust on the cylinder bores when you start it up you won't be doing your piston rings any favors. 

 

If however you drive it 100+ miles on AVERAGE every time you start it your engine life measured in miles will probably be quite a bit longer compared to short trips. 

 

Without doing a direct comparison between 2 engines that are driven exactly the same way and are put together with the same parts and care there is no way to quantify the advantage of one oil over another. 

 

If you are talking about a track toy or race engine and are talking about the ability to lubricate properly in a high temp and load environment there is no question that the synthetic oils have shown an advantage over many years.  For street cars I'm not sure if you will see a significant increase in engine life but the fact that the dyno shows a reduction in internal friction and heat would lead me to believe it can't hurt.  I have been running synthetic oil in everything for over 30 years because no one has proven to me it is worse than Dino oil. 

Edited January 15, 2018 by Preyupy

[Mike Self]

Long-term experience with two daily drivers:

1969 2002, 224k miles--always used conventional oil (Pennzoil).  Valves ground at 157k, pan never off, original timing chain etc. Still has good compression, burns about a qt every 500 or so miles of highway use.  60+ psi oil pressure at highway speeds.  Oil change & filter every 4 k miles.

 

1973 2002, 261k miles.  Used conventional oil (Pennzoil) until 204k miles (changed w/ filter every 4k miles)--rebuild due to 3 cyls with blown head gasket.  Upon teardown, crank journals and cylinder bores were within standard specs, oil pump showed no wear.  Rebuilt, running synthetic oil since break-in.  Slightly lower oil pressure with the same weight synthetic.  After 56k miles on the rebuild, uses no oil between 8k changes.

 

Draw your own conclusions.  Will most likely switch to synthetic when I rebuild the 69's engine.

 

mike

[jp5Touring]

https://bobistheoilguy.com/forums/ubbthreads.php/forum_summary

 

So much info it will make your brain hurt 

[jimk]

3 hours ago, mike said:

1969 2002, 224k miles--

Mike,

When your do your rebuild, please take note of the oil return holes behind the oil wiper ring (lowest ring) that return oil wiped to the sump.  Bet they will be quite closed and it's my opinion that is a big contributor to the oil usage.

One of the major advantages of a good synthetic (they are not all alike) is the lack of residue,

Other shops that have access to used pistons, your observations are solicited also.

I know of a product that I used on a used car with M20 engine i bought that had 100K miles and had quite heavy residue caked in the valve cover area.  After two oil changes with this product added, most of the residue was gone and bright aluminum showing in some places.  It had been running for some unknown time with a thermostat stuck open that I immediately changed when I bought the car.

[jrhone]

On 1/15/2018 at 12:55 PM, robspeed said:

Beware that modern oils can actually be harmful to older engines. 

https://www.hemmings.com/blog/2012/10/18/tech-101-zinc-in-oil-and-its-effects-on-older-engines/

 

 

There are modern synthetics WITH zinc in them like synthetic Valvoline VR1. So you can get modern synthetic oil with good old fashioned zddp. I was reading the Mobil 1 synthetic bottle and it kept saying it had zinc in it as well. I wonder if it’s similar to the levels in VR1. Walmart sometimes has the 5 quart jug for under $20 for 15w-50 full synthetic. 

[bento]

2 hours ago, jrhone said:

 

 

There are modern synthetics WITH zinc in them like synthetic Valvoline VR1. So you can get modern synthetic oil with good old fashioned zddp. I was reading the Mobil 1 synthetic bottle and it kept saying it had zinc in it as well. I wonder if it’s similar to the levels in VR1. Walmart sometimes has the 5 quart jug for under $20 for 15w-50 full synthetic. 

 

Mobil 1 publishes their zinc content.

 

 

Have not looked around to see if Valvoline offers similar data.

[Simeon]

Biggest improvement to engine longevity? Electronic Fuel Injection. 

 

EFI is more accurate at providing  well atomized fuel under all driving conditions and engine temperatures. They will also continue to work pretty much as designed as the mileage gets up.

 

Carbed cars tend to give a mixture that’s wrong as often as it is right. Rich mixture washes the bores clean of oil, this wears the bores, increases blow by and decreases compression. Yes, modern oils are great but they won’t do miracles. 

[AustrianVespaGuy]

Anecdotally, regardless of oil,I've made a few observations on general M10 longevity, including:

 - I don't think valve stems seal all that long, regardless of quality of rebuild, parts, or oil used.  They all seem to start sucking a little oil on overrun before long no matter what.

 - I think the cranks are basically bulletproof. Mine with unknown (but certainly high) mileage needed nothing more than some light polishing and was well within tolerance, which I think is a quite normal story around here.

 - Oil pumps seem to hold up pretty well too, but I think most still replace them due to the criticality of the part.

 - Valve dings in the tops of cylinders seems pretty common also, and while I think this tends to lead to increased oil consumption past the valve stem, it rarely seems to be catastrophic to either the piston or the valves.

 

Feel free to corroborate or refute any of this, just my personal observations from my cars and the forums.

[jrhone]

11 hours ago, bento said:

 

Mobil 1 publishes their zinc content.

 

 

 

Have not looked around to see if Valvoline offers similar data.

 

Thanks!  After I posted I went to both sites...after a little math Mobil1 15w-50 has the identical amount of zinc in it as Valvoline VR-1 20w-50 both Dino and Synthetic variants.  Those are the street versions.  Valvoline makes a "For Race Only" version that has slightly more.  Mobil1 also makes a 0w-50 "Race Only" synthetic that has ALOT more zinc in it.  Almost double than VR-1 and the 15w-50.  The FAQ on Mobil's website states the "Race Only" oil should be changed at 500 mile intervals.  I'm wondering if its very high in zinc, yet low in some other additives that are good for a street driven car.  I'll probably be switching to Mobil1 15w-50 from Dino VR-1.  Cheaper, full synthetic and the same amount of zinc.  After a bit of reading the VR-1 oils and the Mobil1 "Racing" oils have less detergents in them.  Another plus for Mobil1 15w-50. 

Edited January 17, 2018 by jrhone

[TobyB]

To add to AVG's anecdotes,  with which I agree,

I find that the valve guides are not durable, by modern standards.

They are side loaded by the rockers, and don't really get lubrication

(until the stem seals wear out!)

 

So while they may last 150k on a sympathetically driven engine,

they're usually out of spec by 50k.

 

Likewise, the original piston metallurgy wears at the ring lands.

The bottom end will go 200k, but the pistons are beyond spec well before that.

Good air filtration, oil change intervals, and EFI go a LONG way towards extending this.

I think modern pistons last much longer than vintage, but I don't have

much empirical data to prove this.

 

So use a good air filter, change your oil regularly,

and your coolant and brake fluid every two years

and be happy.

 

t