Best Oil for a Big Old Engine ?

[fun71-454vette]

I've owned my '71 Corvette for 3 years. It has an original 454/365bhp engine. Since something generally goes wrong with her every 6 months or so, I usually have my mechanic "change the oil" while it's at his shop. I've never asked what he puts in it -- frankly just never gave it much thought. Today I brought the car in to a different garage just to have the oil changed. The mechanic recommended Mobil-1 15W50 due to the age & size of the engine. I felt like a moron for having no basis to agree or disagree with him. I'm an oil ignoramus. Did I make the right call? Is it OK to jump to a synthetic oil after an engine has spent 33 years using conventional oil? The engine runs really hot as all older big blocks do. Help! Any info or recommendations would be greatly appreciated! Joe

 

[Jason8691]

That oil should do that old big block just fine. There was a topic on here about a Toyota of Honda (cant remember which) that has over 600k on a 4cyl running 15W50.

 

[KW]

I would possibly use one of the 15W40 oils like Delvac 1300 or Rotella T. A syntetic may not be the best answer at this point in the game.

 

[JohnnyO]

Old engines like that frankly aren't very picky about oil. As long as it doesn't cause a leak the Mobil 1 is a good choice, or also a quality 10w-30. A full syn like M1 will hold up better (I'm told) in storage. [ May 17, 2004, 09:12 PM: Message edited by: JohnnyO ]

 

[fun71-454vette]

OK -- why might the move to a synthetic not be the best idea? and what exactly is the difference between a "40" and a "50" in the viscosity ratings? Remember -- I'm an oil ignoramus!

 

[Jason8691]

KW made a good point. I know its the original engine, but has it ever been rebuilt or overhauled?

 

[Bdiddy]

I use Pennzoil Longlife 15w40 in all my older cars (mostly 70s vintage) and they seem to love it. I don't run the oil in any of the cars long enough to warrant synthetic, and I'm sure Longlife keeps my engines pretty clean. I convinced my brother to try it out in his Nova with a built 350 and he's now a Longlife convert.

 

[fun71-454vette]

I do not have a complete 33 year history of the engine as I'm the 4th or 5th owner of the car. It is all original based on casting numbers, but whether it was ever rebuilt say 15 years ago ... I have no idea. It does go through oil almost a quart every 1000 miles -- although it does not leak it on my garage floor. (This was also using unknown weight oil.)

 

[Calvin]

I have a 69 Chevy with a solid lifter Rat motor in it and I'm running 7 qts Delo 15W-40 in it... Since it gets it's oil changed friequently I dont bother with synthetics.The Delo is inexpensive , readilly available and the consensus seem to hold that it's a darn fine oil. How many miles do you tend to put on your oil before it gets changed ?

 

[fun71-454vette]

I'm thinking not nearly enough to warrant putting the higher-cost synthetic in! Last year I put 3-4,000 miles on her total. She is a "weekend & sunny day driver."

 

[bigbassfisher]

I'd go with Delvac 1300, Delo, or Penz. Long Life.( All 15w-40) You can get any of these at Wall Mart.

 

[JustinH]

I couldn't agree more. I would go with a diesel oil in that vette. Delo is an excellent recommendation.

 

[sbc350gearhead]

It has been my experience, that BBC's like 40 weights.

 

[427Z06]

If the M1 15w50 is already in it, and doesn't develop any leaks, and I don't have any reason to believe it will, I'd keep using it. 19 bucks and some change for the M1 15w50 at Walmart. If your penny pinching, the 15w40 oils listed above are another great recommendation. By the way, many years ago I owned a '70 SS Chevelle 454/450hp, and it did run hot, but it also blew the doors of many Fords and Chrylers.

 

[427Z06]

quote:

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Originally posted by 427Z06: If the M1 15w50 is already in it, and doesn't develop any leaks, and I don't have any reason to believe it will, I'd keep using it. 19 bucks and some change for the M1 15w50 at Walmart. If your penny pinching, the 15w40 oils listed above are another great recommendation. By the way, many years ago I owned a '70 SS Chevelle 454/450hp, and it did run hot, but it also blew the doors off a many Fords and Chryslers.

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[fun71-454vette]

Thank you all for your input!

 

[davefr]

I have a '76 Trans Am with a 455. It's also a "garage queen" that only get's driven <1k/yr. M1 10W-30 works great. I've also considered dropping down to dino to save a few bucks but I'm not willing to take the risk. The M1 protects it well and it doesn't leak or burn any oil.

 

[G-MAN]

quote:

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Originally posted by fun71-454vette: Thank you all for your input!

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As old as this engine is, you're probably going to develop some pretty good leaks with Mobil 1. I'd get it out of there and go with a good HDEO 15w40 like Rotell T, Pennzoil LongLife, Delo 400, or Delvac 1300.

 

[Bror Jace]

Fun71, most of the big pushrod fans here believe these motors are happiest with a XW40 weight oil ... and I've seen nothing which would dissuade me from that belief. Going with a $5 per quart synthetic is going to be a waste for you as it sounds like this thing doesn't go past 3,000 miles without a change. They only come into their own under the extremes ... heat, cold and duration. If they made a 15W40 high-performance (extra barrier anti-wear additives) for gas engines only, that might be ideal ... but you're mostly limited to the HDEOs for both gas and diesel. Any of them will be good choices. I like Pennzoil Long Life 15W40 (has moly) and Chevron Delo400 15W40 as their base oils are probably the best going over-the-counter HDEOs. Others are probably fine too but I have my preferences. Schaeffer 15W40 synthetic blend might be the best of the bunch ... and at $3 per quart will save you money over any of the full synthetics. I don't think you'll find a stronger additive package anywhere short of Red Line Oil ($8 per quart). Wear protection should be the best you'll get from any oil for short periods of time. And the Schaeffer 15W40 additive package is very strong ... important for a vehicle being stored for months at a stretch. The various 0W40s and 5W40s would work but most aren't terribly shear stable and are synthetics ... with synthetic price tags. When companies make 10W40, they don't seem to be putting their best stuff in them. Most Chevron oils are Group II+ base but I believe their 10W40 is "only" a Group II ... and has not proven very shear stable here. I suppose a marine 20W40 would be another good choice (should be even more stable than 15W40) ... but with other excellent choices, who would bother with the expense and hassle of procuring this stuff? I wouldn't resort to a XW50 weight (5W50, 15W50 or 20W50) unless I was somehow dissatisfied with the performance of the XW40 weights. The extra drag is gonna rob you of a tiny bit of power. I also don't think straight weight oils are gonna help you. Harder to crank over on cool mornings and since you're not racing, that last tiny bit of shear stability won't be a factor. Straight 40s and 50s are available but I don't think I'd use them unless I found nothing which would last 6 months/3,000 miles in that Rat motor. Modern multi-viscosity oils are just too good these days. As for cooling help, ever try Red Line Water Wetter or the comparable Schaeffer product ("Clean 'n Cool"?) in your cooling system? You might want to do a forum search on these names in the "Additives" subsection. Gonna report back to us with a UOA at the end of the summer? --- Bror Jace

 

[Motorbike]

Motorcraft 15w-40 .....$1.42 a quart at Walmart . The marketers have the 5 quart jugs and the 10w-30 version in quarts . Blackstone Labs, 5-10-04 Update, Motorcraft 15W40 CI-4 Iron-1 Boron-321 Silicon-5 Sodium-1 Calcium-2909 Magnesium-258 Phos-1138 Zinc-1388 Vi[email protected] Flashpoint-420F I added this Sulphated Ash .09 [ May 18, 2004, 02:00 PM: Message edited by: Motorbike ]