crainholio

iTrader: (2)

Check the Mobil-1 High Mileage oil specs:

http://www.mobil.com/USA-English/Lub...leage_Oil.aspx

always faster

iTrader: (6)

Pretty good stats here
So the 10w30 in the high mileage is a little better (1 full point at 100 degree) and the 10w40 seems to be really good (3.71 point at 100 degree).

My main concern is how much is too much ???I want to get better oil pressure at idle without putting a oil that is too much tick.I mean would the 10w30 in the high mileage would be enough to get like 30 psi or more with oil temp in the high 220 low 230(right now im at 24 psi).Or should i just jump to the 10w40 and call it a day ?

I dont see the amount of zinc/phosphorus/hppd in this oil ????

Thanks a lot by the way those are really helpfull specs.I dont do auto-x or autocross session but i do beat the crap out of this car and really like spirited driving

crainholio

iTrader: (2)

Zinc, phosphorous, and other specs for all Mobil-1 oils:

http://www.mobil.com/USA-English/Mot...duct_Guide.pdf

always faster

iTrader: (6)

For the info:

Mobil 1 5w30 High Mileage: zinc 1100 ppm, phorphorus 1000 ppm

So the high mileage M1 would be better than the standard M1.It doesnt meet the gm dexos mark because GM doesnt want more than 800ppm of zinc in there oil mainly because it could decrease the life of the cats.Do we even care

Mobil 1 High mileage is just like the normal M1 but with a better additive package.The only drawback with this oil is a slightly higher shear point.

Now 10w30 or 10w40 ???

crainholio

iTrader: (2)

The "thicker" the oil, the longer it will take to get up into the valvetrain during startup. Thicker oil will also generally flow less volume through the bearing clearances, limiting it's usefulness in carrying heat away from the bearings.

Everything is a compromise. Every book I've read on the subject concludes that the thinnest oil that will maintain a hydrodynamic wedge between the bearing and crank surface under the conditions the engine sees is the best one to use.

I'd go with 10W-30, test it, and see what you get. The 30psi @ idle target you've set is not a magic number and doesn't indicate how good a job the oil is doing...used oil analysis after you've put hard use on the engine is more accurate.

The only time I jump to a -40 or -50 oil is during road course events where I'm running 30+ minutes at a time beating the daylights out of the engine.

Wound-for-Sound

What are your bearing clearances? any idea?

always faster

iTrader: (6)

(ANGRY MODE ON ): No i dont know what are my clearance.I ve paid top dollar for a forged shortblock completely assembled from pan to valley cover,including front cover with timing chain and oil pump except head(first one) to avoid any of those problem.The first one last less than 600miles because of 2 ovalized bad crank journal that could have been probably seen by taking the time to measure the journal(i didnt want to state it but now im pissed)...

Now the second one seems to work for now,was even built with my morel lifter and heads again to prevent any stupid issue since they are supposed to know what they are doing.I did pass the 600miles mark but now i get low oil pressure at idle.My guess is probably like you are thinking.Instead of having something like .020'' of bearing clearance i probably got .027" to .030" of clearance wich would lead to a low(poor) idle oil pressure.

I should have gone with Proline or HKE to have my block built and assembled.I ve done the job twice,a lot of time consuming and stress.And after all this i still got some issue...Im totally sick and tired of all this If this engine ever fall on me...

(ANGRY MODE OFF ): thanks to all for you advice i ll try the 10w30 high mileage to see if this boost up my pressure a little.By the way the comments made in this reply are only made by me (Eric) and doesnt include anyone except me.

Wound-for-Sound

A big clearance really isn't to big of a deal. I run .0030-.0032 on my BBC stuff. with .007-.0075 cylinder walls. Just remember like I tell everyone that looks at my oil pressure at an idle, "just because theres not as much pressure doesn't mean there aint flow". A sbc calls for like 6 lbs. at an idle. just go for 10 PSI per 1K rpms. I think your pressures look fine, I'm just assuming that your clearances are a little larger than you think. I would have no issues running a thicker oil in this thing, It just means it won't be as easy to wipe off or flow when you shut it off. It'll also give you a little thicker of a wedge in between your crank and rods/mains. Diesels run 15-40 and last forever. Just thin it down in the winter to aid in cold flow characteristics.

sabastian458

iTrader: (5)

I dont think you have an engine problem with that oil pressure. Like whats be said, the oil weight is whats causing the "low" pressure at idle when at temp.

My LS2 C5Z oil pressure gets down in the high 20's when the oil temp is in the mid 230's. It is a stock LS2 oil pump, untouched. My oil pressure gauge is down on the plate above the oil filter. (factory is on the valley plate behind the intake) I run Amsoil 10w30 oil. I use to run the 0w20 (or is it the 0w30) OSS race oil, but the LS2 burns that, but doesnt burn the 10w30.

The TTC5Z06 I had for a few month would be low 20's at idle when at normal oil temps.

always faster

iTrader: (6)

Well after all those great info,and since im a now convice that i will not break anything with my 24-27 idle pressure, i ll leave it like this and keep an eye on it.If it ever stay too low to my taste ,i will maybe use some M1 Ow40(available at my NAPA store ) or maybe some Shell Rotella 5w40 (available at my canadian tire)

After the nest 6000 miles ill be using some 0w30 Red line wich is much thicker even if its still a 30w oil.

Thanks