Mobil 1 0w40 - shearing and HTHS

[vinu_neuro]

Mobil 1 0w40 is well known to shear down to lower viscosities by varying degrees. At what rate does this happen assuming average fuel dilution (ie. it's not used in a NYC cab).

When will HTHS fall below 3.5? It's an A3/B3 oil and meets all the OEM certs when new, but at some point in it's life based on this characteristic I'd think it doesn't.

 

[chubbs1]

There are so many variables involved. I don't think a geophysicist could answer that question with any certainty. But you never know on BITOG...what kind of engine is it going in?

 

[d00df00d]

Originally Posted By: vinu_neuro
Mobil 1 0w40 is well known to shear down to lower viscosities by varying degrees. At what rate does this happen assuming average fuel dilution (ie. it's not used in a NYC cab).

When will HTHS fall below 3.5? It's an A3/B3 oil and meets all the OEM certs when new, but at some point in its life based on this characteristic I'd think it doesn't.

ACEA A3 and "all the OEM certs" (or at least most of them) require the oil to stay in-grade after a long testing sequence that simulates thousands and thousands of miles of harsh usage. Unless you don't trust the ACEA and all those OEMs, I'd say you can trust the oil to perform as advertised.

 

[vinu_neuro]

I'm not concerned about it shearing out of grade; in fact I don't mind it shearing some in the interest of fuel economy. What I'm after is for the HTHS viscosity and film strength to be adequate even after it's used for a few thousand miles (I'm planning 10k mi oci).

It's going in a Honda Prelude. In the last 5-6 years there have been some H22a4's with serious camshaft gouging. The original engine I pulled out of my car was showing some initial signs of wear as well. Rocker pad hardness is known to be down in the H22 compared to B-series, but some have attributed reduced phosphorous levels in recent years to pushing the problem over the top. This only happens on the exhaust side.

I'm also considering Mobil 1 Turbo Diesel Truck and Rotella T6 for ~100ppm boost in phosphorous over Mobil 1 0W-40 (1200 vs 1100).

Example 1, unknown oil:

Same engine, intake side, no stains:

Exmaple 2, Mobil 1 5W/10W-30 for the life of the engine:

 

[TFB1]

Slider cam + reduced zinc level = bad news... This is exactly the type problem that was predicted when the zinc level was reduced in oils... Is this stock or are you using a aftermarket cam with increased spring pressure???

No matter what the case, I'd either use a ZDDP additive or maybe run the M1 racing oil with 1850ppm of zinc...

 

[d00df00d]

Originally Posted By: vinu_neuro
I'm not concerned about it shearing out of grade; in fact I don't mind it shearing some in the interest of fuel economy. What I'm after is for the HTHS viscosity and film strength to be adequate even after it's used for a few thousand miles (I'm planning 10k mi oci).

Well, HTHS viscosity has a much bigger effect on fuel economy than kinematic viscosity.

But again, if it's protection you're after, the specs on the bottle attest to the oil's ability to continue to perform after a grueling sequence of tests. I don't think you have anything to worry about.


Originally Posted By: vinu_neuro
I'm also considering Mobil 1 Turbo Diesel Truck and Rotella T6 for ~100ppm boost in phosphorous over Mobil 1 0W-40 (1200 vs 1100).

I strongly doubt 100 ppm of phosphorus is meaningful when comparing entirely different formulas.

There are a few oils that I can imagine picking over Mobil 1 0w-40, but those aren't among them.


Originally Posted By: vinu_neuro
Exmaple 2, Mobil 1 5W/10W-30 for the life of the engine:

The 0w-40 is on a different level from those oils.

 

[bullwinkle]

Time to start looking for German Castrol? Unusual to see cam wear like that outside of a SB Chevy or PD TDI!

 

[NismoMax80]

Originally Posted By: bullwinkle
Time to start looking for German Castrol? Unusual to see cam wear like that outside of a SB Chevy or PD TDI!


what do those pictures have to do with Mobil 1 0W40? if that's why you stated that.

 

[Audi Junkie]

I believe if the +100c visc is reduced by X%, the +150c visc will be reduced by a similar amount. The trick with Mobil 1 0w-40 is that it will re-thicken from oxydization for the end of the test spec sequence.

 

[Mau]

I'm running PP in my h22, 213K on it and still running strong.

But I cannot say what condition my cam shaft is in as the last time the cover was removed for timing belt change and I had it done at my mechanic (also got him to do a valve adjustment). He didn't say anything at that time so I'm assuming its fine.

When I got the car with close to 100k on it the previous owner was running Castrol Semi Synth, I switched to GC for a couple runs, then Amsoil ASL for a couple runs and finally switched to PP the last 2 years.