Econoline":2m3a3085 said:
I'm paranoid so I run expensive oil. It's really not much more than any good oil. But honestly I think once it's run in good, like 5-10K+ you could probably put any quality oil in there, jmo. I think alot of it has to do with the conditions of work hardening and mating all the surfaces to one another. Imo, the time not to cheap out is right after spending $2K on an engine and firing it up and running it for the first while. I'm going to switch to synthetic after my next oil change, zddp enhanced joe gibbs synthetic.
ZDDP is required as the sacrificial wear surface to prevent metal-to-metal contact at startup (
boundary lubrication regime) and at very high loads (
oil film shearing). It's better to prevent metal-to-metal contact at high loads with an oil film than a ZDDP tribo-layer. See
Hydrodynamic Bearings.
Econoline":2m3a3085 said:
I've got almost 3500 miles now on mineral oil 10w30 joe gibbs 'hot rod' oil. Oil pressure runs 45-50 when it's hot, 60 when it's cold. I think I could go down in viscosity a bit. I'm thinking the synthetic at the 10w30 will drop the pressure a bit. I dunno, thoughts? Should I go 5w-xx?
The two components of a multigrade spec (eg, 10W-30) are the cold (10W, W is for "winter") and hot (30) viscosity grades. The hot viscosity spec of an engine oil is measured at 100°C (212°F). For it to be considered at 30 grade oil, an engine oil must have a viscosity that falls within 9.3 and <12.5 cSt at 100°C and have a minimum HTHS viscosity of 2.9 cP. See
SAE Viscosity Grades for Engine Oils.
Another thing to consider is the oil's
Viscosity Index (VI), which is a measure of how the oil's viscosity relates to temperature. The higher the VI, the more constant the viscosity with temperature. For a higher VI, you need better base stocks and/or better
Viscosity Index Improvers (VII). See
Understanding the Differences in Base Oil Groups. HTHS is a measure of an oil's film strength at high temperatures and high loads and indicates an oil's VII stability. Lower HTHS values generally mean better fuel economy.
Using Mobil oils as examples,
Mobil Super conventional 10W-30 has cold & hot viscosity ratings of 68.8 cSt and 10.5 cSt, with a VI of 140. 5W-30 has cold & hot viscosity ratings of 63.95 cSt and 10.7 cSt, with a VI of 158. For synthetics,
Mobil 1 synthetic 5W-30 has cold & hot viscosity ratings of 61.7 cSt and 11.0 cSt, with a VI of 172 while
Mobil Delvac Elite 222 0W-30 synthetic has cold & hot viscosity ratings of 69.0 cSt and 12.2 cSt, with a VI of 176. For a 40-grade oil,
Mobil Delvac 1300 15W-40 conventional has cold & hot viscosity ratings of 109 cSt and 14.1 cSt, with a VI of 130.
At an oil temperature of 100°C/212°F, the pressures of 30-grade oils would be similar. However, if your engine oil were to run hot at 135°C/275°F, the oils would become a lot thinner and we can
calculate the operating viscosity:
- Mobil Super 10W-30: 5.42 cSt
- Brad Penn PennGrade 1 10W-30: 5.61 cSt ... (3.54 cP HTHS)
- Mobil Super 5W-30: 5.65 cSt
- Brad Penn PennGrade 1 0W-30: 5.85 cSt ... (3.38 cP HTHS)
- Brad Penn PennGrade 1 5W-30: 5.87 cSt ... (3.185 cP HTHS)
- Mobil 1 5W-30: 5.89 cSt ... (3.1 cP HTHS)
- Duron SHP 10W-30: 6.13 cSt ... (3.5 cP HTHS)
- Mobil Delvac Elite 222 0W-30: 6.50 cSt ... (3.6 cP HTHS)
- Mobil Delvac 1300 15W-40: 6.90 cSt ... (4.1 cP HTHS)
At 275°F, I would say that
Brad Penn 5W-30 would have higher oil pressure than
Brad Penn 10W-30 but 10W-30 would provide better bearing protection (HTHS 3.54 vs 3.185 cP). The
Brad Penn PennGrade 1 High Performance partial synthetic multigrade oils all have 1400 ppm of phosphorus.
I couldn't find any published tech specs on Joe Gibbs or Shell Rotella oils.
Brad Penn or whoever. That's what they do and I'm happy to support them. I don't think the green 'penn crude' they sell today is the same as it used to be and probably there's a good reason people trusted pennsylvania oil over everything else for engines back in the day. There must have been something to it. It's all way beyond me. But I have faith in those that make a living off of experience and results. I'm happy to support them. It was Quaker State I was always warned against b/c of it's waxy nature. I used it and never had a car long enough to know one way or another 