which oil weight with these clearances

hey what weight oil is best to run with these clearances
Main clearance is .0032 rod cl .0024

598 cu in
My pressure at start up is 72
When hot its 25

should I be running a 10W30 or a 20w50

nothing LESS than a 25w/50 , even with your close bearing clearances, check some other recent posts for other comments

what oil are you running now?

GIJoe wrote:hey what weight oil is best to run with these clearances
Main clearance is .0032 rod cl .0024

598 cu in
My pressure at start up is 72
When hot its 25

should I be running a 10W30 or a 20w50

my 598 oil pressure is the same. I was advised to use 20:50 by Phillip

Phillip has my engine using 20/50w also

I use 20/50 but psi never gets under 75# ....so far

Hell I would go to town and buy some 90 weight gear grease if you want to run 20/50 that is all so old school why not set it up and run a deacent oil like 10/30? ask the pros what they run it is 5/20 or 0/20 I know some prostockers are running 0/10 all you are doing is giving up Hp cuz you are trying to turn grease........

the Coug wrote:Hell I would go to town and buy some 90 weight gear grease if you want to run 20/50 that is all so old school why not set it up and run a deacent oil like 10/30? ask the pros what they run it is 5/20 or 0/20 I know some prostockers are running 0/10 all you are doing is giving up Hp cuz you are trying to turn grease........

I guess Oakley has no clue then ??

Royal Purple syn 20/50 here too per Mr Oakley..

must be the way he set it up then cuz I see no need to use a thick oil when you can use lesser weight oil and keep the same oil PSI.... I just think there is a loss of HP to turn thicker oils....... whem thinner will do the same with less tension on the pumps

ive used 20-50 forever, it has 5-50 in it now.


oh, and the oil is green also.......

Good for all you old school Ballers go ahead and put 90 weight in it your the ones loosing HP so be it........ I am just happier than a Pig in slop for Ya'll





One of these day I wish someone would do a real world test to see how much difference in hp they are loosing running 50wt vs good Visc oil on the dyno

the Coug wrote:Good for all you old school Ballers go ahead and put 90 weight in it your the ones loosing HP so be it........ I am just happier than a Pig in slop for Ya'll





One of these day I wish someone would do a real world test to see how much difference in hp they are loosing running 50wt vs good Visc oil on the dyno

With over 1100...I have a few horses to spare..
I'd rather make sure I have no bottom end issues..
You should get a copy of this years Winter Tech seminar, where Lake Speed Jr talked about this very subject..
What he had to say would surprise you..

As per Adney at the last couple of tech seminars, the oil weight you use is determined by the operating temperature of the oil. The higher the oil temp, the higher the oil viscosity needs to be to keep it from breaking down. IIRC under 180* oil temp, you can use 30w oil, the 40w takes over then up to like 200*, and after that you need the 50w. There is a shear factor to take into consideration too, and it is better to err on the safe side and run too high of an oil wt than to run too small. I run a synthetic 50 in mine, and always will. The synthetic stuff is more forgiving to temp than the straight petroleum oil.

I guess it all depends on the application, bearing loading, & bearing clearances.

The high winding 500" NHRA Pro Stock stuff might be using real thin oil. But a number of the Pro Mod guys around here are using straight 70W oil because of their applications looser clearances & higher bearing loading vs what the high RPM 500" Pro Stock stuff sees.

the Coug wrote:Good for all you old school Ballers go ahead and put 90 weight in it your the ones loosing HP so be it........ I am just happier than a Pig in slop for Ya'll





One of these day I wish someone would do a real world test to see how much difference in hp they are loosing running 50wt vs good Visc oil on the dyno

hell i got too much power as it is now lol, im in need some throttle stop oil anyway, maybe strap a case to the front bumper......

richter69 wrote:

the Coug wrote:Good for all you old school Ballers go ahead and put 90 weight in it your the ones loosing HP so be it........ I am just happier than a Pig in slop for Ya'll





One of these day I wish someone would do a real world test to see how much difference in hp they are loosing running 50wt vs good Visc oil on the dyno

hell i got too much power as it is now lol, im in need some throttle stop oil anyway, maybe strap a case to the front bumper......

i would'nt use the green oil! if you come off a 6' wheelie and bust a can they'll never get that shit cleaned up.

I had def decided on the green oil...maybe I'll bump it to 40W and see if I see a difference at temp. The 20 cold is what kinda scares me...

by green Im talkin Schaeffer's......

DILLIGASDAVE wrote:I guess it all depends on the application, bearing loading, & bearing clearances.

The high winding 500" NHRA Pro Stock stuff might be using real thin oil. But a number of the Pro Mod guys around here are using straight 70W oil because of their applications looser clearances & higher bearing loading vs what the high RPM 500" Pro Stock stuff sees.

500" Prostock stuff is not a good example for the average bracket racer. They push the cars to the line, fire them up and go for it with cold oil thats looks like 0 weight vegtable cooking oil and get rebuild about every 30 runs.........

IMO If your clearance are set-up right 30, 40 or 50 weight are acceptable. 20/50 works fine, 10/40 works fine, 15/40 works fine and IMO always use synthetic oil, it is much better. The thinner stuff is worth a little power with a proper oiling system, but sometimes its not worth the small gain.

pro stock , lots of spares lots of money, anything for the last 5 hp. i prefer a bit of insurance as i want this engine to last, with big bearing clearances and high rpm if i lose 5hp while the oil system keeps the engine alive i do'nt mind

On my 509 cube wet sump truck pull engine Im running 3.5 on mains 3.2 on rods 9500 rpm , found 11 HP on the dyno switching from 20-50 VR1 to 10-40 royal purple XPR...... After an entire season, the oil filters have all been cut open every other run and havbe yet to find anything between the pleats.

Just sayin.....

hookin78 wrote:On my 509 cube wet sump truck pull engine Im running 3.5 on mains 3.2 on rods 9500 rpm , found 11 HP on the dyno switching from 20-50 VR1 to 10-40 royal purple XPR...... After an entire season, the oil filters have all been cut open every other run and havbe yet to find anything between the pleats.

Just sayin.....

Exacary !! Synthetic is definetly a better product.

I run 20-50 in my 598. I don't think you'll find many builders that argue with that oil, at those clearances.

Brad Penn Grade 1 straight 50wt here.

P.S. Its the other Green oil