Hemi bearing clearances

[oldhp]

Hello Everybody, I have read this forum for along time, decided to join.
I just bought a new 2012 Ram Express. Already lowered rear end 2" with Ground Force spring/shock kit. Next thing to be installed is the PCV oil catch. Rest of truck will keep as is.
Now...the question. Are the Hemi block's rod/main bearings clearance the same as in the 1500 w/MSD as the 2500/3500 w/o MSD? I always thought oil viscosity was based on rod/main bearing clearance. Yet 1500 w/MSD=5W20...while 2500/3500 w/o MSD=5W30.
With the exception of the MSD system do both HEMI blocks have the same internal clearances, parts etc?
Thanks In Advance
oldhp

 

[Chris142]

rod and main bearing clearance has not changed in 80+ yrs. there is a spec that determines clearances depending on circumference. too little and the bearing won't be properly lubricated and too much will hammer the bearing out quickly.

 

[LeakySeals]

You hearing something from the engine?

 

[DemoFly]

The Ram Express is what I am saving up my pennies for!

I'm jealous.

 

[Rob_Roy]

I doubt there is a difference in clearance, but the engineers may be compensating for a higher oil temperature on the heavier trucks...which are more likely to tow heavy loads.

 

[Shannow]

Nah, you can run 0W-20 in a V-10, towing the USS Nimitz broadside on up the vertical side of the Grand Canyon, at 65MPH, with a 110F headwind.

The OEM recommendations in this case are obviously old school thinking.

 

[SteveSRT8]

All the new gen Hemis are the same basic engine.

Chrysler recommends 20w, 30w, and even 40w for the SRT's.

Just remember your warranty is predicated on specific requirements!

 

[RANDYZ]

The MSD is what requires the 20wt oil.

 

[SteveSRT8]

MSD works fine with almost any oil, but warranty is the reason he MUST use 20w.

 

[Zaedock]

Originally Posted By: Chris142
rod and main bearing clearance has not changed in 80+ yrs.

Engine internal tolerances have decreased due to improvements in manufacturing and materials, but clearances remain typical for mass produced vehicles.

 

[oldhp]

OK, Same short block for all. Lifter/MSD unit not in heavier pulling trucks.
I'm pretty much old school but learning.
Is standard Valvoline 5W20 ok to use for 5000 mile/6 month OCI's?
Truck 99% of time goes 23 miles to work, sits 9hrs, goes home.
I never pull or haul anything, except leaves in fall.
Or would Valvoline Durablend 5W20 be better option?
Thanks
oldhp

 

[Rocko1]

The "you MUST follow your manual" people will say each engine has appropriately engineered oil passages and using anything but the recommended oil viscosity will cause irreversible damage! Hogwash. Use what you want after you research it yourself. Engineers job is to get the engine just over warranty period or 100K, he has not upside to your engine making it 250-400K miles.

 

[mechtech2]

Clearances are getting smaller.
Note that going from .0028" to .0020" doesn't sound like a lot, but it it huge .
Mfrs have tightened things up a bit to spread the hydrodynamic wedge of oil and load a larger area. Larger clearances isolate a smaller and thus more highly loaded section.