INDYMAC

This is a good discussion that has gone on since I joined this website. Nobody really knows why Honda recommends 10W-30 or 5W-40. Maybe they never bothered to go back and evaluate the lower viscosity oils in the F20 and F22 engines (costs money).

Here is a UOA with 5W-20 dino that shows no real signs of significant wear problems, and it didn't appear to shear much on a very short OCI:

http://www.bobistheoilguy.com/forums/ubbth...=1149429&page=1

Although FRM liners might take a hit with lower viscosity oils, I think lower quality base oils might be a bigger contributor to glazing.

Will bearings take a hit with a 20W? Just keep an eye on the Pb numbers on your UOA's.

Will VTEC operation take a hit? Well, this system is very oil pressure dependent, and a 20W at high temps will result in less oil pressure that a 30 or 40 grade oil at high temps.

Will a 20W result in higher internal engine heat? I don't know for sure, but installing a temp gauge might help. Unfortunately, it won't tell you what's going on in the hottest parts of your engine. There are some in the know that suggest that a 20W might actually keep things cooler than higher viscosity oils due to their reduced resistance to flow (flow faster and dissipate heat quicker).

I like Spitfire's recommendation to try Redline first. Not neccessarily because of the specs, but because it contains at least some amount of group V ester based oils. 100% ester based oils are the only ones certified for aviation use (turbojet/fan/prop engines). Why? Because they are the only ones that can handle the heat. They are very low viscosity too.

As added insurance, you might want to pull the valvecover occasionally to look for varnishing. That might be an indication that the temps are getting too high for the oil you're using.

starchland

h22 used FRM

JackS

here's my thought. The lower viscosity oils are probably fine in the cooler climes or winter in the US but as weather temps rise, the low vis oils may be more prone to "drip away "'from bearing surfaces especially in lightly driven vehicles. If daily driven probably no problems. I can't state this phenom as an actual fact but it does seem reasonable.
It might be best for the average s2k'er to stay with their 10-30w rather than just accept that a weight other than this is okay.

starchland

IMO operating temp is more controlled temp and it's the starting temp which is more susceptible to change among users. IMO operating temp is where the motor could experience the greatest possibility of wear

SpitfireS

It's been well established that most wear occurs within 20 minutes after a cold start.
IOW, cold thick oil in a cold engine creates wear.
When the engine and oil are at operating temp there is almost no wear.

Its kinda still open for debate if thinner oil warms up quicker.

In the F20/F22 with the sandwich oil-to-coolant heat exchanger it IMO does make a difference, thinner oil gets the engine quicker to operating temp.
And thinner in this case means 0W and maybe 5W oils.
I say "maybe 5W" because some 5W oils are actually thicker than some 10W at higher temps, let's say 30 C.

Thinner oil at operating temp also - in the F20/F22 - gives more oil flow at higher revs because the oil pump bypass opens a little later, at higher engine & pump revs, so more oil goes into the engine.

The question is: How thin do you dare to go?
When it comes to cold oil: you can't go thin enough.
The catch: thinnest oil when cold is also thin when warm.
So when it comes to oil at operating temps one has to compromise a bit.

In this case with the Redline 5W-20 one almost gets the best of both worlds: a thin oil when cold, a thin oil when hot but not too thin and a "strong" HTHS.

Again: UOA's of dino oils have shown they get THINNER than this Redline after only 3000 miles and probably sooner.

I would not take the Redline 5W-20 to the track though.
For DD its probably fine.

But it is not officially recommended.

starchland

Is that the common consensus at Bitog? Do you believe that for people whReferring to the wear stastico track their cars? Referring to the statistic

jyeung528

is there a need for 20 weight? what's wrong with 30 weight?

is this just for shits n giggles?

Gernby

I thought I made it clear in the 1st post why I am considering it. If there's 1% to be gained in power and economy by using 5W-20, then I think it's worth considering.

jyeung528

no it wasn't clear.

your post stated that your LEXUS had benefits from it, after LEXUS issued a technical service bulletin.

i see no reason to think any benefits your LEXUS derived from their own technical service bulletin would be applicable to an S2000.

even if clearances are similar...they are still not the same.

jyeung528

using your logic, any and all cars that use 30 weight should stand to benefit from switching to 20 weight.

this just can't be true.

what if cars were originally spec'd to use 40 weight, but the manufacturer derived benefits from 30 weight so they spec'd 30 weight, and then you further thought it would benefit from 20 weight, so you use 20 weight in a car originally spec'd for 40 weight?

i believe lexus had a reason to issue a tsb to use 20 weight...and i'd leave them be. can't apply their tsb to any other car that is spec'd for 30 weight unless you know that the reason for the new spec is shared by the other car.