Thread: whats the best weight oil for sbc &whats good oil presure

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just wondering what the best weight motor oil to use in sbc i just built a new 350 @450hp and need to decide what weight to go with ,also what is considered good oil presure on a warmed up motor at idle, thanks

im going to go buy the oil pump tomorrow and button up everything , so i need to decide whether to use a melling m55 or a m55hv , or a new style melling 10555 , these are whats in stock at the local part house ,anyone have a recomendation ,thanks for the quik response

I like 10w40, but I can't get any oil pressure with it so I'm stuck with 20w50.

Is it a Chevy roller lifter motor? They recommend a drastically different oil for some of the crate motors from GM. Did you buy the motor from a Chev dealer?

25/40 pounds at idle would be normal oil pressure in a run in motor.
If your running your motor in,,then your gonna want to change your oil and filter more frequently for a while,( i would change it first after 150 mile,,,and then again after 500 miles),,I stick with straight wieghts,,,non of this 10w or 20w crap,,,it's just a hold over for me from my day's as a diesel mechanic.
Typical big diesel engines will go over a million miles before rebuild if they are properly serviced.
I use straight 40wt oil in all my vehicles, and i have never had a failure due to insufficient lubrication.
But then i also use a cheap oil to flush my motor first( I change oil and filter the first time and put in cheap oil) then i change filters again and put in the good old 40wt.
also decide now whether your gonna use synthetic or standard.

Originally posted by techinspector1
I use Castrol GTX 10-W-30 year 'round in everything.

If I had 50 lbs at cruise and 30 lbs at idle, I'd be happy. You need minimum 10 lbs for each 1,000 rpm's.

The 10 lbs for every 1000 rpm's is an old tale. I'm sure you'd want more than 10 lbs at idle. At the same time, engines capable of 7000 rpm's do not need 70 psi.

Between 35 to 45 psi at idle and up to 55 lbs at speed would be sufficient. I run 5W30 Mobil 1 in my daily driver. As I'm sure you won't be doing any sub-zero driving. a synthetic 10W30 would be good for street use.

While breaking the engine in, use dino oil so the rings will seat. Sometimes synthetics work too well and the rings may no seat if used right away.

I'd run the engine to 300 miles, do an oil change, and then change to synthetic at 2000 to 3000 miles.

i use AMS oil 0W30, 15-20 at idle and 40 at cruise. ill change the filter around 12,000 miles and want live long enough to have to change the oil again.

All I ever used was 10w-40w and its worked fine for me in our cold winter and hot summers.

Originally posted by techinspector1
Tom, that 10/1000 rule of thumb came from Smokey Yunick, God rest his soul. I'm sure that by the time he passed, he'd forgotten more about internal combustion engines than you and I together will ever know.

I respect Smokey as much as the next guy (gotta love the 15/16ths Chevelle!), but more engineering went into the big threes cars than Smokey could ever have dreamed of. Watch the oil pressure guage on any car you are in. My Ranger, even at 90 MPH won't be less than 35 psi or more than 55 psi.

I can see upping the pressure on an engine built 'loose', but when running normal clearances this extra pressure is not needed. Check with NASCAR teams running engines at 9000 rpm's and I'll guarantee you they are not running 90 psi.

The LS1 style engine going in the Stude is being set up with the stock clearances as a guide, and I don't plan on raising the oil pressure any.

As far as the oil pump is concerned....what pan are you using?

If you are using the stock pan I would use the m55 pump....

If you use a deep sump pan you could opt for a m55hv but it's you decision...but I wouldn't.....

On a stock pan you would not want to use a hv pump on a new engine because with enough rpm's you can literally run the engine out of oil ( insuficient drain back time/ not enough reserve)

I really personally don't recomend using a hv pump unless needed because with a hv you can move the oil thru the engine too fast not giving the oil enough cool down time before being reused....thus ending up with oil being hotter than need be...just my 2 cents....

first i'd like to say im glad i found this place , ive looked around the net for a while trying to find a good place to exchange information on hot rod chevy motors ,and never really found a good home, ive been building this motor for a few months now and im just about ready to fire her up, built the whole thing from scratch,its been an expereance , and im sure my wife is about to divorce me ,
anyway i talked to melling tech today ,and read a bunch last nite and came to the conclusion that i can use the m55 or the newer
10552 w/10% more volume , my part houses only have the m55 in stock and at 13.00 im going to put that in and try it , if the oil presure is on the low side at idle i'lll switch over to the 10552 +10% unit, yes i have the stock oil pan

i realize the std 55 is suppost to be adequate in the envirment im going to use it in , my concern is pretty much soley based around having excellent warm ''idle'' presure , just in this thread alot of you guys are insinuating you wish you had better warm idle presure, w/a 10-30 wt
ive read quiteafew tech articals where they want you to fire a fresh motor up and take it right up to 1500-2000 rpms , because they thought the std oil pump may not supply enough oil at a regular
idle
thats why im thinking of using the 10552 pump , just 10% more volume, i dont think im going to have a chance to run the sucker dry, unless i was running 6000+ rpms across the mohave desert

am i wrong?

Originally posted by blewbyou2
i realize the std 55 is suppost to be adequate in the envirment im going to use it in , my concern is pretty much soley based around having excellent warm ''idle'' presure , just in this thread alot of you guys are insinuating you wish you had better warm idle presure, w/a 10-30 wt
ive read quiteafew tech articals where they want you to fire a fresh motor up and take it right up to 1500-2000 rpms , because they thought the std oil pump may not supply enough oil at a regular
idle
thats why im thinking of using the 10552 pump , just 10% more volume, i dont think im going to have a chance to run the sucker dry, unless i was running 6000+ rpms across the mohave desert

am i wrong?

either one will be fine normal driving or getting into it some times.

Originally posted by DennyW

PS, BTW your clearances determine what you have for pressure, reguardless of oil pump size at idle. [/B]

so your saying oil pressure at idle will be the same whether i use a
std 55 or say a 55hv ???????

then why have i read some put a hv pump in to compansate for low pressure do to worn bearings?
are you saying the presure would be the same at idle but higher at higher rpm's?

BTW that's great info on the different brands of oil , i think oil brands will always be a great source of debates, but one thing ive always noticed is no matter what type of engine application amsoil is alway rated at the top, notice how at the start of this thread i didnt ask what brand to use , but ,what wt to use , ive been on other sites where oil debates get a little crazy LOL