TedH

I run 20W50 in my C3 after having been accustomed to using in my engines in the 70's/80's. I'm thinking that is overkill and will probably switch to a lighter 10W30. Is there a big difference in power loss between the two weights? Should I gain much power 'back'?

mrvette

Here in Florida, I"d stick with the heavier weights....better lubrication...and the oil stays hotter for the lack of pan cooling.....up north, hell, with 20-50 in it you can't even turn the engine over, starter takes one look and tosses in the towel....;-(((......

I have run heavier weights in summer than winter for decades.....now if you have a full race clearanced engine, bearing set looser...you may want to run heavier oils......but a totally stock tight new engine....you may not need to run anything over say 30 weight or so.....

GENE

page62

Overkill. 20w50 should only be used for old, tired oil burners. I use 10w30 in winter and straight 30w in summer. My oil pressure is comfortably high (as it should be; the engine only has 60k on it).

The advantage of 30w is that the actual viscosity of the base oil is 30-weight -- it's not a 10-weight oil with viscosity modifiers, like a multigrade oil would be.

redvetracr

TedH,
You might see a HP loss on a dyno but in the real world I doubt you (or I) could feel a difference. ...redvetracr

mvftw

I run 20w-50 all year round, up north. I don't start it under 40*, but the pressure is good all year. I have 3:70's so I'm driving around 3500-4500

Tom73

With the modern oils out there the major wear is at start up while the friction parts are waiting for the oil to arrive. The thicker the oil the longer it takes to get there. With the engine in good shape and warmed up, there is almost no wear when cruising the highway. So you want the oil to get to the parts as quickly as possible, then an average thickness for normal running. So a 5w30 or 10w30 is all that is needed. The 5 (or 10) will get the oil through the engine very quickly and then the 30 will take care of the engine during normal use. You only need the thick stuff if you have very large clearance in the bearings so that it will fill the extra space :)

tom...


[Modified by Tom73, 6:28 PM 4/28/2003]

Matt Gruber

20w50 in my vettes i run 3 to 3.5 qts in the pan with a scraper for more power(see jamie below)
10w30 in my 67 ford


[Modified by Matt Gruber, 7:29 AM 4/29/2003]

killain

My 79 calls for 10-40 and I stick to it, I do sometimes put some Lucas oil stabilizer. But you want to have a good quality oil and it doesn't have to be gear oil. :yesnod:

Black Snowman

:iagree:

I run full synthetic Shell Rotella T 5W40 all year round in all my motors, including my motorcycle and my lawn mower. I now have an exception though. My tired old Olds 350R which gets 20W50 since it ran down to no oil and munched some bearing. Oops.

Of course right after than my Oil pressure guage died. And just to add to the fun the dipstick hits a starter wire that burned through the tube so in order to check my oil I have to disconnect the battery. But this thread isn't about my T/A so I'll shut up now :cheers:

jamiejamison

I'm running mobil 1 syn 20/50 in my ZZ4 engine but going to switch to something lighter. Don't have any dyno test but evey time I change oil, I add at least a tenth to my quarter mile et. I'll be doing 12.90s ang change oil, I start running 13s. Some of it might be the level also. Before the change I'll be a quart low and only a 1/2 low after the change. I'm usally running in hot weather (south Florida). Good to Go, Jamie j.