Oil Recommendation for '66 Cadillac 7.0L

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Originally Posted by aquariuscsm
Do they still make Pennzoil GT 25W50?
Unnecessarily thick for a lightly-loaded big-cube cruiser. Unless he's using a 7-liter Cad v8 in a road-race or Pikes Peak climb car and not telling us... :-p
 
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Any of these will be fine. Harvest king all fleet 5W40, 10W30, 15W40 CK4 Rotella T4,T5,T6 5W40, 10W30, 10W40, 15W40 CK4 Supertech 15W40 CK4 Traveller 15W40 CK4 Valvoline VR1 SAE 30, 40, 10W30, 20W50.
 
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What this Texas stuff? This is a water cooled engine with a radiator the size of my bed, It's not an H-D V-twin Rule use the LIGHTEST oil you can get by not the most viscous!
 
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Originally Posted by ARCOgraphite
What this Texas stuff? This is a water cooled engine with a radiator the size of my bed, It's not an H-D V-twin Rule use the LIGHTEST oil you can get by not the most viscous!
So why don't we just use 0W-20 in everything, in the Death Valley heat also...
 
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You Cadillac engine does NOT need any type of "exotic oils" - suggesting VR1 other race oils is completely laughable. C'mon you people!
Originally Posted by clinebarger
Stock Cadillac 429/500 engines are almost immune to flat cam lobes. The machining & metallurgy of these engines was some of the best in the world at the time.
100% correct. Any basic 10W-30 (I'd prefer any basic 15W-40, myself) and that engine will probably outlast you.
 
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Originally Posted by tundraotto
Originally Posted by ARCOgraphite
What this Texas stuff? This is a water cooled engine with a radiator the size of my bed, It's not an H-D V-twin Rule use the LIGHTEST oil you can get by not the most viscous!
So why don't we just use 0W-20 in everything, in the Death Valley heat also...
BC in "everything" the journals and pump and drainback were not designed for 20 grade low HTHS oil. The car is not a human its a machine. It's water cooled. to a nice 95 deg C. Monitor oil pressure and oil temp and adjust accordingly. Been this way for decades.
 
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The owners manual recommends straight 30W oil for the vehicle at above 40F degree temperatures.
 
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Originally Posted by tundraotto
The owners manual recommends straight 30W oil for the vehicle at above 40F degree temperatures.
You know why, right?
 
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Originally Posted by kschachn
Originally Posted by tundraotto
The owners manual recommends straight 30W oil for the vehicle at above 40F degree temperatures.
You know why, right?
I think so - they did not have available a 15W-40 HDEO to put in there that is perfectly suited for it - especially in the TEXAS climate.
 
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Back in the sixties there wasn't a whole lot of oil choices. This engine probably ran just fine on SAE30 or 10w30. No need for fancy or exotic oils here.
 

Jackson_Slugger

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Originally Posted by tundraotto
The owners manual recommends straight 30W oil for the vehicle at above 40F degree temperatures.
Em, if we're talking about a 429 cu. inch 7.0L, the manual recommends nothing heavier than 10W-30 or "SAE20" above freezing (32F, 0C). Below 0F, they recommended 5W-20 (or 5W)... The interval was 60 days, but not to exceed 6,000 miles... I would use Rotella T5 10W-30 or Mobil 1 HM in the same weight...
 
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Originally Posted by Jackson_Slugger
Originally Posted by tundraotto
The owners manual recommends straight 30W oil for the vehicle at above 40F degree temperatures.
Em, if we're talking about a 429 cu. inch 7.0L, the manual recommends nothing heavier than 10W-30 or "SAE20" above freezing (32F, 0C). Below 0F, they recommended 5W-20 (or 5W)... The interval was 60 days, but not to exceed 6,000 miles... I would use Rotella T5 10W-30 or Mobil 1 HM in the same weight...
In 1966 the 429/7L V8 - the The owners manual recommends straight "30W oil for the vehicle at above 40F degree temperatures." I wouldn't be surprised if a 1966 429 V8 went through 10W-30 oil like a sieve, but that's just guess.
 
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Originally Posted by tundraotto
In 1966 the 429/7L V8 - the The owners manual recommends straight "30W oil for the vehicle at above 40F degree temperatures." I wouldn't be surprised if a 1966 429 V8 went through 10W-30 oil like a sieve, but that's just guess.
Not sure. My 67 Camaro (admittedly only 250 CID but similar era design) doesn't appear to use any 5W30 Pennzoil Platinum between changes. Very similar lack of consumption to the ancient 262 CID V6 in my Sonoma. But the "modern" DOHC 3.6 High Feature V6 drinks it right up about a quart per thousand.
 
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Originally Posted by tundraotto
In 1966 the 429/7L V8 - the The owners manual recommends straight "30W oil for the vehicle at above 40F degree temperatures." I wouldn't be surprised if a 1966 429 V8 went through 10W-30 oil like a sieve, but that's just guess.
I don't understand that, aren't the two grades similar in viscosity above freezing? I know there is a difference, but "like a sieve"? Even if there is a difference are you saying the consumption occurs at startup rather than operation?
 
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In an old large engine such as this 429 cid V8 the size (= area) of the oil control rings is much larger than on a small engine of today. Also unless the engine has been rebuilt with new pistons & rings & sleeves....it would be even more likely. Oil consumption was part of the game in the late 60's - even in new cars. What I am trying to say that if, and when this 429 cid uses oil - it will use more of it when 10W-30 is used as opposed to 15W-40 or straight 30 weight. - At startups AND operation.
 
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