Hydraulic lifters -- viscosity extra-important?

[mattd]

Yep. adjustments are easy, at least on the 4cyl. But according to my honda maintenance schedule, first valve clearance inspection is at 105,000 miles IIRC.

 

[dparm]

Fine, fair enough, what I meant was, "periodic valve lash inspection".

 

[Rickey]

Hydraulic lifters Vs: Viscosity.

Consider this:

How thick is 5W30 at 0 F? A hydraulic lifter has to work under those conditions. 5w30 at 230 F? A hydraulic lifter has to work under that condition, and worse for that matter.
My opinion is that a properly functioning hydraulic lifter is relatively insensitive to viscosity.

Rickey.

 

[CATERHAM]

Originally Posted By: Rickey
Hydraulic lifters Vs: Viscosity.

Consider this:

How thick is 5W30 at 0 F? A hydraulic lifter has to work under those conditions. 5w30 at 230 F? A hydraulic lifter has to work under that condition, and worse for that matter.
My opinion is that a properly functioning hydraulic lifter is relatively insensitive to viscosity.

+1

Higher viscosity oils require more energy to entrain air but take more time to release it. A lower viscosity oil will typically entrain oil more easily but also release it more readily. Some oils tend to aerate more easily depending on the oil's anti-foam qualities.
Different engines, different hydraulic lifter designs

Rickey.

 

[CATERHAM]

Sorry didn't finish my post, to continue:

Different engines, different hydraulic lifter designs and adjustment, can also affect hydraulic lifter bleed down, so numerous factors come into play.

If one is experiencing noisy lifters, try a higher quality oil with known high anti-foam qualities. In my experience, I have found GC 0W-30 and Toyota (Nippon Oil-Eneos) 0W-20 to have exceptional anti-foam qualities.

 

[Bruce T]

I agree, oil aeration can be an overlooked factor in the valvetrain, which can froth the oil like a kitchen mixer. Not that other factors can't contribute to aeration: low oil level (air sucked into oil pump), high oil level (crankshaft), high oil pressure, low sump capacity, bad oil pan design, high engine rpm, combustion gases, oil particles, etc.