Shocked RE: 03 Explorer

[mikep]

quote:

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Originally posted by TallPaul:
I was a pump jockey (that is gas pumper, oil checker, etc. back when there was no self serve) for four years in the 70's. I never heard of 10w40 being for loose engines. Seems the routine back then was that everybody ran 10w40 in summer and 10w30 winter.

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Same with me. Did it for a couple years while in school but it was the early 80s for me. I remember even then people being skeptical about the "thin" 10w-30 stuff and still insisting on 10w-40. I'm guilty too as I ran GTX 20w-50 in my '69 Mach1 all year long!

Mikep

 

[Kompressor]

My opinion is that the oil has improved over the years and the car builders now recomending thinner oils because of fuel economy reasons, not because oil clearances have changed. I keep reading people state that the newer cars NEED thinner oil because of tighter oil clearances, I don't agree and would like to prove or disprove this as I think this is a widespread falsehood. Here is another such statement where I gave oil clearance examples of a newer and older 350 Chevs. Sorry for the rant

Originally posted by JohnnyO:
Yeah, but I bet that was on a dyno in a very controlled environment. Some car from the 60's would be okay on straight 30 weight but modern cars have a lot tighter clearances and run hotter, so I think you need a good multi-grade now.
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I've lost count of how many people have said this, but I think your dead wrong. True they are able to hold tighter tolorences these days, but that doesn't mean they are using tighter oil clearances. I dug thru some Chiltons manuals to compare the recomended rod and main oil clearances for a 1969 Chev 350 (truck) and a 1994 Chev 350 TBI (truck), the figures below. If anybody can prove or disprove any of this, please do.

1969 350
.0008-.0024 main
.0007-.0028 rod

1994 350 TBI
#1 .0008-.002 main
#2/3 .0011-.0023 main
#4 .0017-.0032 main
.0013-.0035 rod

 

[Terry]

If a motor needs a say 7 cSt wedge of Hydro Dynamic "cushion";

Which is preferable ?, a 10 cSt motor oil that thins to 6 cSt under pressure ( heating included).

Or a well additivized 8 cSt oil that looks like 7cSt to the bearing ?

The technology exists NOW to build oils that contain very little or 0 VII's but start relatively thin by the consumers viewpoint.

The oil is more stable and resists flow less so both heat and HP (MPG) are improved upon.

Thus the theoretical shift to thinner weight oils forced by the CAFE requirements and the ability of chemistries to be cheap enough for the API to bite into promoting them.

I've been experimenting with thin weights for 15 years and do not fear the 20w oils if well made.

Most of us have been running a 20w or thinner oil in our engines without even knowing it for years !

At least thats what your bearings and valvetrain would say if they could talk !!!

[ October 31, 2003, 02:23 PM: Message edited by: Terry ]

 

[geeeman]

Clearances for a 1993 Acura Integra: 1.8l I4

Main: 0.0009 - 0.0017 in. 0.0020 lmt
Rod: 0.0008 - 0.0015 in. 0.0020 lmt

The higher revving GSR engine actually has slightly larger clearances:

Main: Same as above
Rod: 0.0013 - 0.0020 in. 0.0024 lmt

And... the GSR specifies 10w30 instead of 5w30.

Not much difference from that old V8...!