M20: Switching to Liqui Moly 10w-40

[Zambuzan]

NOTES: This is not meant to be a product review, but maybe it'll turn into one . Rather, this is meant to be about the reaction from my stock 220k-mile engine to this new oil.

I am making this thread because I'm a noob when it comes to oil, I tried out this new oil in my engine, and would like some input. So my car has an m20b25 and all of its life it has been running off of good 'ol conventional 20w-50. Me, in my infinite wisdom and cheapskatery, decided to try this LM semi-synthetic oil mainly because FCP Euro recommends it on their website (also because of the warranty ), and because I hear that LM is overall good German stuff. This oil is meant for high mileage engines.

First reaction: ITS GREY!! (later I learned that this was the MoS2 additive).

Since doing the oil change, I have put ~350 miles into it and I feel that literally nothing has changed in comparison to using 20w-50... except for one thing: every single cold start consists of the engine idling at 2k rpms, and after 5 mins it smoothens out to 750 rpm.

This is honestly the only difference that I can distinguish (some claim quieter lifters, but I can't tell due to my ebay exhaust ;) ), but it's really consistent! I even put timers on the cold start and it always idles like that for a solid 5 minutes before quieting down. And when the engine gets warm, it feels perfectly normal. The engine overall is in really good shape and well-maintained, mind you.

So can somebody chime in and explain this phenomenon? Is it because I went from 20w-50 to 10w-40 (Florida btw), or because I went from conventional to semi? Should I not worry about, or should I start parting my car out?

For my next oil change, I'll definitely take an oil sample and see what comes up.

I know some are going to say "stick with what works, you damn novice," and you're probably right lol.

[e30davie]

I cannot see how your cold start routine has anything to do with the oil.

[Zambuzan]

I cannot see how your cold start routine has anything to do with the oil.

Well it's the only immediate change that I've noticed, and it's consistent! At first I thought it was just old gas, but new gas didn't make a difference.

[ForcedFirebird]

We have been running the LM 10w-60 in all the m20's lately. Really good stuff. One of the guys said his mileage increased, but I take that with a grain of salt....however, the cars with oil pressure gauges do show an increase in hot idle pressure - specially the turbo ones.

[digger]

thinner oil affects how much ICV pw you need because it requires less power to idle when cold as the oil is thinner, but its a small change and usually the idle speed doesn't change because its in a closed loop system. could be a coincidence, maybe some old deposits got dislodged somewhere IDK.

[digger]

We have been running the LM 10w-60 in all the m20's lately. Really good stuff. One of the guys said his mileage increased, but I take that with a grain of salt....however, the cars with oil pressure gauges do show an increase in hot idle pressure - specially the turbo ones.

of course a thicker oil will have more idle pressure, but does it need more pressure and is it actually better. gotta love oil threads...

[Zambuzan]

thinner oil affects how much ICV pw you need because it requires less power to idle when cold as the oil is thinner, but its a small change and usually the idle speed doesn't change because its in a closed loop system. could be a coincidence, maybe some old deposits got dislodged somewhere IDK.

Interesting... So should I be fine? No inherent damage done by switching from 20w50 to 10w40, or conventional to semi?

Thanks! :)

[ForcedFirebird]

of course a thicker oil will have more idle pressure, but does it need more pressure and is it actually better. gotta love oil threads...

HOT idle pressure. We run endurance cars that see 12-14hr of straight track use. One hot summer day in 2015 or so, everyone was complaining about oil pressure (one Mustang lost a bearing). We were running 20-50 conventional and ours dipped below 5psi at idle after 1hr of beating on it. Next day we swapped out the LM 10-60 and the idle pressure was 16psi after the same abuse.


If you check out the specs on oil viscosity, a conv oil will start to break down at about 250°f (ie, cook), and the LM 10w-60 is advertised to be at 30w at 250°. I don't normally endorse products, but the LiquiMoly has proven to me time and time again - even in turbo cars - that it is a superior product to anything else we have run over the years.

[digger]

to play the devils advocate i guess what i am getting at is what does the higher oil pressure mean? other than its thicker at that point in time in which case there are alot of 20W-70 oils sold around these parts that will be thicker again than a 10W-60 and would probably have more pressure but it doesnt mean its better.

120C is nothing for a modern half decent synthetic oil there are plenty of similar oils that will happily operate at those temps any of the well known brands have something. there is so much more to what makes an oil good than what the hot oil pressure is on a racecar

[ForcedFirebird]

I agree on your points, but also put these engines through the wringer. When I see the oil on a dipstick that's black after 2-3hr of straight racing time vs another oil that still looks like honey with the same abuse, it is fairly obvious - even with the pressure reading aside.

A couple locals drift/race their turbo m20's and even the turbo journal bearings show wear when they swore by the Rotella branded "turbo" oils. Perhaps I can get them to post as they are members, but the way I see it is, you will spend the same $$ per mile if you use good oil and change it less vs a cheap oil and change it often, but the wear indicators are obvious when breaking them for routine maintenance season after season.

[ForcedFirebird]

..to add. The dyno will show an increase in power with thinner oils. Not much more than say removing the mechanical fan, or keeping the coolant temps lower, but there is an increase in power with less sheer weight. The racing we do is geared toward reliability, so we often run a little thicker oil, and even adjust the AFR's a little richer than peak power. My "argument" may be biased, but I tend to stick with what works in real life.

[digger]

I agree on your points, but also put these engines through the wringer. When I see the oil on a dipstick that's black after 2-3hr of straight racing time vs another oil that still looks like honey with the same abuse, it is fairly obvious - even with the pressure reading aside.

the colour is kinda misleading it doesn't necessarily mean what people think as the oil goes black from the crap within the engine getting suspended within the oil

[ForcedFirebird]

the colour is kinda misleading it doesn't necessarily mean what people think as the oil goes black from the crap within the engine getting suspended within the oil

Perhaps when the said engine was already used for miles on the street, but a shiny one that's all new and fresh-looking at the start is another story.

For instance, we had to shove a truck lm7 in a Mercedes swapped race car to replace an ls1 when we were in a pinch. The truck engine was black inside, carbon build up to the max. Quite gross to be honest, appeared it was very neglected over it's 200k mile service life, but the bearings we're in surprisingly good shape, so we ran with it. After just one 12hr race, one could practically eat off it. The inside was a nice silver color with a hint of gold. Even the bottoms of the pistons were nearly silver. Everything was steam cleaned and looked like it had 10k on it. Oil that came out was black as midnight.

When we start with a fresh engine, color has a lot to do with oil condition.

Again, take my word with a grain of salt, only can say what I have seen. YMMV.