20w50 too much?

[gearhed1971]

My gut tells me that 20/50 oil is too heavy for my engine. Its got about 50 miles on it, in the span of about 1 year. My builder says - "no problem,we use it in all our own stuff". I'm not aware of the bearing clearance, but still, is it too soon to run that kind of oil? Its cen-pe-co 20 /50 in a med built 289 w/.465 lift crane, moroso windage tray, edelbrock carb and shorties. Just for clarification, this is not the break in oil, I am going to change it out. It was originally run on Brad Penn break in oil.

[Caveman Tony]

What's your oil pressure at idle?

at 2k rpm?

3000?

4000?

I don't think it'll hurt anything, just sap some power trying to move all that molasses around.

[Stich496]

depends , in the summer months it be fine..
I've always ran 20-50 in the summer on my older stuff.. the grand mark was at 460k when I sold it.
my 302 powered 88 150 was 350k+
the stuff isn't all that thick once warm..
in the winter I'd never use it.. only in the delivery car that ran 10 hours straight..
but that had an oil heater on the pan,
you didn't say what type cam.. but I know bronze dissy gears don't like that type load at cold start up..

[SpiderGearsMan]

costs power ..I use low tension oil rings ..30w in the summer

[CDMBill]

289's have decent oiling and unless there are some other factors beyond what is presented, ie solid roller or something 10-30 should be fine. Given you don't know much about the engine in terms of clearances, if the current working pressures seem normal, 40-65 cold, 30 -50 hot the lower weight oil will be fine. Realistically you won't notice a difference with 15-50 or 20-50 until winter anyway.

Lucas told me I should stick with 15-50, but this is .800 lift, 7000 RPM big block. You've done the right thing with break in oil, and that makes me think you have a flat tappet cam so I'd stay with the higher zinc, phosphate oils or an additive for the first 3-10K miles.

[TC]

Ya I run 10-30 in everything........But then I use Royal Purple too.............

[bnjny]

Royal Purple... Yuck...

With a flat tappet cam and being unsure of clearance, etc. I would stick with a 50 weight oil. There are some very good 5 and 10 w 50 oils that work well. From what I have seen (I have been looking at a variety of 50 weights) most have a good amount of the ZDDP pack as these oils are marketed for older cars. If you are that worried and you want to use a lower viscosity oil, do some oil analysis... Cost is only a few dollars and is worth the piece of mind for some...

I use ELF (Total) 5 w 50 in my Porsche with great results. However, I use Amsoil 5 w 30 in my Suburban and the wife's DD

The previous owner of the burb used 10 w 40.... After analysis, I was comfortable with the 5 w 30... Same for the other cars... The Porsche was running Mobil 20 w 50....

I would also pay a visit to www.bobistheoilguy.com

Get some real world data versus opinions.

[Beagle]

I put 20-50 year round in the ratty ass daily Vega I used to have - it didn't drip out as fast. I never really noticed the pressure change that much over 10-40 which was the "go to" at the time. Using the 5-20 they recommend for my new car scares the crap out of me, but it's quiet and I'm guessing the tolerances on everything are tight? I beat the poo out of it too.

There are several real world "opinions" in here already that bear consideration. Modern builds often have pistons that use smaller / lighter / lower tension ring packages and still seal pretty good. Unless I were running it WFO constantly under load and the bearings were a loose fit, I'm not sure I'd sweat it. I've been running 5-30 in the Lightning for years with no issues and it has definitely been rode hard and put up wet for the last 40k or so of it's 140k pulling trailers. I ran the same in my '88 F150's 302 and when I pulled it down at just over 250k, there was negligible wear. Hatch all the way up and down the cylinder and a tiny barely feel it with your nail top ring ridge.

CC just did an article on this too in the August 2011 edition , but it dealt mostly with breakin oils. I'd probably consider another oil change with break in oils if it's only got 50 miles on it.. just thinking out loud.

[SpiderGearsMan]

a sams club sized can of stp or mac's motor honey

[TC]

Thicker oils put more strain on the oil pump, think of it like trying to suck Ice Cream through a straw. Saying that I only run oils like 20-50w on old worn out high mileage vehicles......

[Chad's Dad]

I used Chevron Delo 400 30wt for about 30 years untill last year when I started using Valvoline Synthetic Racing oil "not for street use".It is 10-30. Oil pressure is good. I am still using the original high volume 1969 oil pump in my 302!

[Scott Liggett]

I used Chevron Delo 400 30wt for about 30 years untill last year when I started using Valvoline Synthetic Racing oil "not for street use".It is 10-30. Oil pressure is good. I am still using the original high volume 1969 oil pump in my 302!

You still running the factory solid lifter cam?

[Chad's Dad]

Basically yes. I have been running a Lunati RL302 Stock eliminator cam that is solid lifter with 485 lift and a hell of a lot of duration.

[Scott Liggett]

Basically yes. I have been running a Lunati RL302 Stock eliminator cam that is solid lifter with 485 lift and a hell of a lot of duration.

You racers and your cam secrets. haha.

[SpiderGearsMan]

square cam