What oil do you use?

[Mex1man]

Just slapped in some Royal Purple 20W-50 and RP filter, no drips, feels like it runs smoother. Then again I just got it and P.O. had some cruddy black looking evil death juice running in it.

[gtdragon980]

you are correct, but the next question is which has adequate levels of ZDDP for an M20? the 5w and 0w oils tend to have under 900ppm which isn't enough. the 5w40 will definitely be better on cold starts but will be no good if it wears grooves in your cam.

I'd really like to try M1 5w40 turbo diesel truck in my M20 - pretty sure it's SM rated as well. it makes our POS Subaru not sound like a total POS Subaru - but it's difficult to find and almost 30% more expensive. Last time walmart had some, I bought 4 jugs, as half the time they don't have any at all. with other oils I've tried the Subaru is really, really loud when cold - closest thing I can find is a shell 10w40 but it's too thick for cold starts.

Hmm...then maybe I should keep the 5w-40 for the winter time and switch back to the 15-40 or 50 for summer...I'm no expert on this subject so I just want to run some good shit in my motor.

[Wanganstyle]

we all know 20w50 isn't going to destroy your engine or anything. but it's objectively worse by several measures. the main benefit it has is cost.

what's the ZDDP content of VR1? it's interesting they talk it up on their racing oil but they don't tell you what's in it so you can compare..

I hadn't seen the ZDDP of the turbo diesel truck 5w40 before. I'm definitely going to give it a go this winter - that is, if I still have any left. :p

also, you don't want to use a "race" oil on the street. those oils are not meant for long term use - maybe a day or two at an actual race. they don't have the extra additives that keep the oil from breaking down, for cold starts, etc. because race engines don't need them, and also because it waters down the base stock.

We use the Valvoline VR non street legal oil in the enduro e30 with both m20 and now m50 engine. Its grey compared to the blue street legal version.

The oil took a serious beating last event; blew a hg and raced cooking the oil for about 25 minutes. Bottom end and walls somehow are undamaged; head was warped bad and sent off to have full built.

Vr racing non street legal oil is good for racing. No idea about street use as we change it before each enduro event.

Sent from my GT-N7100 using Tapatalk 2

[jlevie]

I use Brad Penn 20w50 in both the race car and the street car. It and VR1 race oil are reportedly short on the additives that extend the oil's life (detergents I think). But since I change the oil and filter every 3k I doubt that matters. I'd rather have the high ZDDP levels that these engines were designed for.

[griffincox]

FYI. Mobil1 0W-40 and 10W-40 HM both have 1100 PPM zinc.

http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf

[digger]

a 0-50 with lotsa Z&P

http://www.penriteoil.com.au/pis_pdfs/1510%20TENTHS%20PREMIUM%200%20JUNE%202013.pdf

[nando]

sounds $$$

is 2200ppm really necessary on an M20? my cam looks pretty good with 80k miles on M1 15w50 at ~1200ppm.

[JinormusJ]

Honestly.. I have a feeling 1000+ ppm is relatively safe; I'd rather go for deisel oil because it had the highest ZDDP content (1700+ppm on most brands), but I'd steer clear of VR1: I've seen Bobtheoilguy articles where people treated their oil afterward and found traces of 500-800ppm of ZDDP additives in it.

I've heard pretty good things with M1, so I'd say its safe; i was running M1 high milage 15w50 synthetic (I know! dont spear me!) in my last e30, but I love the way my m20 likes the diesel oil; runs way smoother than the last one did. I would at minimum only run Dino oil though; steer clear of synthetic on our old engines.

[digger]

sounds $$$

is 2200ppm really necessary on an M20? my cam looks pretty good with 80k miles on M1 15w50 at ~1200ppm.

M1 has 1300ppm of zinc, 1200ppm phos
penrite 1690 zn 1530 P

neither Zn or P alone is ZDDP you need both to make the compound, but it is not just the sum of them either.

[LowR3V'in]

steer clear of synthetic on our old engines.

why?

[JinormusJ]

What oil do you use?

Synthetic oils have been known to have more detergent properties than regular dino oil, which would be good for a newer engine running synthetics from the beginning, but in an old M20 using flat-tappets and "out-dated" SOHC technology that has most likely ran its life with conventional oil, synthetic oil would clean the engine too well and eat away at gaskets that have already spent their life being heat-treated with conventional oil. This could lead to catastrophic failure of the seals and major leaks from FMS, RMS, and Oil-pan Gaskets if they are old and a possible decreased life of new seals. That, and the fact that many synthetics are produced year-by-year with decreasing levels of ZDDP in favor of cleaner emissions, would cause an increase in cam-wear and reduction in engine-life in a older engine that needs the anti-wear additive of ZDDP. An m20 simply cannot survive with lower viscosity oils because thinner oils would cause an increase in oil burn and high-rev starvation; most synthetics, due to the nature of how they are produced, have a "perfect"-molecular structure and lubricate differently, better, and most often times too well to be used in m20s. A 20w50 dino oil will lubricate slightly less well than a laboratory produced 20w50 synthetic due to fundamental molecular structure.

In a nutshell, M20s were not designed to run synthetics. Period.

M42s on the other hand, having a more modern timing-chain, DOHC, and updated seal compounds would more than happily chug Synthetics and thinner grade oils due to the nature of the engine internals.

[LowR3V'in]

So then you're saying mobil one is terrible for m20s and should
never be used because damage will happen?

Are you right, or the other guys saying to run mobil one?

[nando]

Synthetic oils have been known to have more detergent properties than regular dino oil, which would be good for a newer engine running synthetics from the beginning, but in an old M20 using flat-tappets and "out-dated" SOHC technology that has most likely ran its life with conventional oil, synthetic oil would clean the engine too well and eat away at gaskets that have already spent their life being heat-treated with conventional oil. This could lead to catastrophic failure of the seals and major leaks from FMS, RMS, and Oil-pan Gaskets if they are old and a possible decreased life of new seals. That, and the fact that many synthetics are produced year-by-year with decreasing levels of ZDDP in favor of cleaner emissions, would cause an increase in cam-wear and reduction in engine-life in a older engine that needs the anti-wear additive of ZDDP. An m20 simply cannot survive with lower viscosity oils because thinner oils would cause an increase in oil burn and high-rev starvation; most synthetics, due to the nature of how they are produced, have a "perfect"-molecular structure and lubricate differently, better, and most often times too well to be used in m20s. A 20w50 dino oil will lubricate slightly less well than a laboratory produced 20w50 synthetic due to fundamental molecular structure.

In a nutshell, M20s were not designed to run synthetics. Period.

M42s on the other hand, having a more modern timing-chain, DOHC, and updated seal compounds would more than happily chug Synthetics and thinner grade oils due to the nature of the engine internals.

another myth

if the only thing holding your motor together is 20 years of gunk buildup, it's fucked.

also, Mobil 1 has been around for a long ass time. in fact, their 1,000,000 mile demonstration motor was an M20B25.

updated seal compounds? huh? the engine internals of an M20 and M42 (bearings, seals) are the same.

the 15w50 was clearly designed for an engine like the M20. it also doesn't have flat tappets..

[JinormusJ]

What oil do you use?

Like I said before. I used Mobil 1 10w40 synthetic in my last e30 and had varying results; I had occasional bogging on hot days on long trips (only happened twice in the 8 months I owned it) that only happened after switching to Mobil 1. As also stated before Mobil 1 has a higher amount of ZDDP vs other synthetic oils which will help wear. (Which would explain people running it with good results). I didn't own it long enough or was running Mobil 1 long enough to know if any leaks formed

Switching to conventional Mobil Delvac 15w40, I've had no issues with bogging, enjoy the benefits of higher ZDDP levels, and have actually stopped a small leak (most likely switching to a thicker oil from the PO). I must admit, on 110*+ days, my engine was running sub-par, but not enough to bog or starve the engine. Not to mention that valve-train is much more quieter and seems "peppier", especially at higher revs..



Would I run Mobil 1 again? Probably, most likely on a newer engine, but on my current m20, no. The cheaper Mobil Delvac does its job just as well, if not better in my current engine.

[digger]

bogging is some other engine problem most likely a fuelling issue, normal engines don't do this and attributing this to the oil is silly IMO. different oils will cause slight differing levels of friction but its not going to be massive if you are using an oil in the ballpark of what you should be. the wear part (most important part) is alot harder to tell and you need alot of testing to see what works and what doesnt.