Clearances & Viscosity

[beanhead]

Curious..those of you that know your clearance numbers, what weight oil do you run? I'm at .0027 main/.002 rod and it's been recommended I run a 15 or 20/50 on my 440+.060(It gets hot here).

 

[lewtot184]

you'd be fine with a straight 30wt. 20/50 is too heavy for those clearances. maybe a 15/40wt. you can try a 10/30wt with the tight rod bearing clearance. i'm .0027 on the mains and .0025 on the rods and I alternate between 10/30 and straight 30 a lot, depending on weather. 15/40 seems to be a reasonable compromise.

 

[66Satellite47]

Seems like the type of use would be the main factor. How high RPM does the motor regularly see? Normal driving, lite oil makes sense, drag racing high RPM different deal.

 

[beanhead]

15/40 is what I have, I may try a 30 when we get consistent 90+ temps here and see how the pressure acts. I was mainly just curious what people use with known bearing clearances, and what they may consider 'loose' or 'tight' on a B/RB mopar.

 

[bm02tj]

One thing if oil is to heavy it will be slow draining back to pan so keep rpm down till oil is hot