What Oil Weight?
Thread Starter
Drifting
Joined: May 2002
Posts: 1,546
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From: Back in Nebraska
What Oil Weight?
I just changed the oil and filter in my 350/300. I put 10w30 in cause I could not remember what I had in the last time. On my way home I could hear a slight knocking sound from the engine, not a octain knock but an enternal knock. What is the best weight oil for a 1970 350 with only about 3000 miles on the engine?
Le Mans Master
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From: Unreconstructed, South Carolina
Shell Rotella T 15W-40 ... NONsynthetic ... about $9 per gallon at most parts stores and walmart.
if everything is ok inside your 3000 mile sbc ... 10W-30 is NOT the cause of the noise
if everything is ok inside your 3000 mile sbc ... 10W-30 is NOT the cause of the noise
Last edited by jackson; Oct 6, 2007 at 09:39 AM.
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Burning Brakes
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From: Illinois
There was a long discussion sometime back on oil (Article "Oils ain"t Oils by Ben Nightingale at wwww.streetcommodore.com)--best oil is Royal Purple sunthetic $6.25/qt at autozone and Penrite synthetic--which I had never heard of at $75/5 liters. Most people on the discussion highly recommended royal purple for oil rear end, etc. I switched to RP. Hope this helps. 
Paul
Paul
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From: Sorrento Italy
...Of course light oil cannot be the cause of the knock.
a light oil like the 10/30 will give you a few extra ponies anyway (i know there will be some of you with the flame spitter already in hand to burn my *** for saying this
for it's the plain truth...
), a heavier one will give more protection, specially in heavy or racing use and with a high engine outputs.
a light oil like the 10/30 will give you a few extra ponies anyway (i know there will be some of you with the flame spitter already in hand to burn my *** for saying this
for it's the plain truth... ), a heavier one will give more protection, specially in heavy or racing use and with a high engine outputs.
Racer
Joined: Aug 2004
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From: Reinholds pa
...Of course light oil cannot be the cause of the knock.
a light oil like the 10/30 will give you a few extra ponies anyway (i know there will be some of you with the flame spitter already in hand to burn my *** for saying this for it's the plain truth... ), a heavier one will give more protection, specially in heavy or racing use and with a high engine outputs.
a light oil like the 10/30 will give you a few extra ponies anyway (i know there will be some of you with the flame spitter already in hand to burn my *** for saying this
for it's the plain truth... ), a heavier one will give more protection, specially in heavy or racing use and with a high engine outputs.
sorry to say this but i,d be looking some were else for your problem
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Race Director
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If you really have only 3000 miles on the engine, 10W30 or anything else reasonable would not cause it to knock. Don't go looking for miracles in a can.
Race Director
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From: Wellington, FL
St. Jude Donor '11 thru '25
Couldn't agree more.
Le Mans Master
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From: Tuttle OK
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Melting Slicks
Joined: Mar 2005
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From: Austin TX
10-30 is perfectly fine,..anything thicker will cost HP as described above. Also, thicker oils are hard on the distributor gear and cam since it also runs the oil pump. Even race cars with tolerences on the loose side are now running thinner oils.
Here's some good reading:
http://www.circletrack.com/techartic...il_change.html
If a thicker oil is masking a knock, you may have a developing problem.
Here's some good reading:
http://www.circletrack.com/techartic...il_change.html
If a thicker oil is masking a knock, you may have a developing problem.
Team Owner
Joined: Nov 2004
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From: Sorrento Italy
[QUOTE=73, Dark Blue 454;1562211086]10-30 is perfectly fine,..anything thicker will cost HP as described above.
Here's some good reading:
http://www.circletrack.com/techartic...il_change.html
interesting link, thanks for proposing it.
it prooves what i've always felt in my own engine without having a dino sheet, thin fully sint oils give a few ponies and allows also more free revving through the whole range, specially in the low end band to 4.000rpms.
it means my own power 'detectors' are still working well
Here's some good reading:
http://www.circletrack.com/techartic...il_change.html
interesting link, thanks for proposing it.
it prooves what i've always felt in my own engine without having a dino sheet, thin fully sint oils give a few ponies and allows also more free revving through the whole range, specially in the low end band to 4.000rpms.
it means my own power 'detectors' are still working well
Le Mans Master
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From: Tuttle OK
Cruise-In VIII Veteran
Originally Posted by circletrack
Now, of course, the question becomes, how thin can I go with my motor oil before it can no longer do its job? After all, making sure your engine is properly protected from friction must still be your first priority. The answer to that question depends a lot on your engine. Troutman says that blueprinting every bearing clearance to minimum tolerances dramatically improves oil control to the point that you can safely race ultra-thin performance oils where a stock motor would quickly damage itself. This also requires intelligently sizing and placing oil restrictors in the engine to reduce oil flow where less is needed while maximizing pressure at the rod and main bearings.
Team Owner
Joined: Nov 2004
Posts: 20,709
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From: Sorrento Italy
streight racing applications love monograde oils, i've always been using castrol high perf mineral monogrades 40 both on my racing mini and my abarth 695...but you'd also consider that rebuilds in a racing engine are much more frequent then on a street engine, so low end grades for cool protection are not a must. If you used monogrades on a street engine i bet it would not last more then a few thousand miles after each rebuild...
Pro
Joined: Apr 2005
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Oh, looks like we've re-opened the oil-can of worms
I'm running 10W-30 Valvoline in my '70 350/350hp right now, and it runs fine and doesn't knock. I've used 10w-40 and the 15W-40 Rotella (Shell) oils as well. I haven't noticed negative effects with any of them. I would think the 15W-40 might be a little thick in the wintertime, though.
If you didn't notice the knock before you went to 10W-30, then I would experiment and go back to 10W-40 or 15W-40 to see if there's a difference. Afterall, look at all of the varying opinions on this one thread!
I'm running 10W-30 Valvoline in my '70 350/350hp right now, and it runs fine and doesn't knock. I've used 10w-40 and the 15W-40 Rotella (Shell) oils as well. I haven't noticed negative effects with any of them. I would think the 15W-40 might be a little thick in the wintertime, though.
If you didn't notice the knock before you went to 10W-30, then I would experiment and go back to 10W-40 or 15W-40 to see if there's a difference. Afterall, look at all of the varying opinions on this one thread!