What motor oil do you guys run in your classic Buick?

[GS66]

Looks like the price changed now. Did you guys really order 5w-30 though?

[elagache]

Dear Walt, Chuck,

Edouard, does any of the shipping info you received show that it's a 19 pound case and not just a quart?

Well the box arrived this morning and inside was . . . . a single quart. 

So I'm returning it as the wrong item shipped.  Oh well, it was worth taking a chance.

I mulled over taking the chance it's a case and bought the last one last night! Due on Tuesday.

If you have any chance, you might want to cancel that order.

Looks like the price changed now.

Actually, not it hasn't.  Since they are out, Amazon isn't listed as the top supplier.  If you look on the side-bar, you'll find Amazon as a seller with the same price of $16.62.  So Amazon still hasn't straightened out this inventory error.

Oh well, I really didn't need the oil, but that would have been one amazing bargain!

Cheers, Edouard 

[WkillGS]

Drats.
Thanks for reporting back.
I submitted a cancellation request to Amazon but it failed, too late.
Oh well, it was worth the chance!

[elagache]

Hi Walt and mid-60s Buick bargain hunters,

Drats.
Thanks for reporting back.
I submitted a cancellation request to Amazon but it failed, too late.

I'm returning the quart for a full refund.  After all what I ordered was a case and that isn't what a received.  So I told Amazon they shipped the wrong item and they are giving me a full refund and free return shipping.  The product description is clearly for a case, so we should all do the same.  It's Amazon's mistake, we shouldn't pay a dime for their own folly.

Cheers, Edouard

[RVA65GS]

Getting back to the original question of which oil to use, I'd suggest researching Sequence IIIG engine testing or consult someone who is knowledgeable with this test.

The test looks at oil thickening (viscosity increase), piston deposits, oil consumption, and valve train wear.  The test engine is a flat tappet 3.8L GM v6.

Test parameters are 3600 rpm with a 250 nm load applied for 100 hours.  Oil temp is maintained at 150˚C, coolant at 115˚C, and afr is 15.0:1. 

My point is, don't look to much at claims in advertisements, you may not need to spend the additional cash paying for them. 

Off hand, I do not know the API rating of the reference oil for this test.  I'll try to get this information today as that rating may give you a good indication of what a flat tappet motor needs with regard to additive package (ZDDP content).

[elagache]

Dear RVA65GS and mid-60s Buick "gotta luv' d'em engines" caregivers,

Getting back to the original question of which oil to use, I'd suggest researching Sequence IIIG engine testing or consult someone who is knowledgeable with this test.

. . . .

I'll try to get this information today as that rating may give you a good indication of what a flat tappet motor needs with regard to additive package (ZDDP content).

Well the oil I'm using now was recommended by Mike Tomaszewski who owns TA-Performance and rebuilt this engine a second time after the real crankshaft bearing failed.  This engine is is modernized Buick big-block instead of a nailhead and it has hydraulic roller camshaft, roller rockers and quite a few modern features that in principle should allow it to work with modern oils.  Nonetheless, Mike recommends sticking with oils formulated for engines of the 1960s since not everything is modernized.

Also, the recommendation is err on the side of thin oils for the Buick big-block.  The oil passages are known to be too small for engines of this size.  There are a set of oil passage modifications that are normally applied to these engines and this engine was no exception.  Nonetheless given this weakness and the mild California climate, a thinner oil is a prudent choice.

Thanks for your offering your suggestions though! 

Cheers, Edouard