Newly rebuilt bbc 489 stroker. Break in thoughts?

[userfriendly]

Our rod bearing clearance is 2.1995 and mains at 2.7488. How does this factor in for the oil weight?

It’s definitely not a 10W30 engine. I’d say a minimum HTHS of 3.8, which is the low end for a xW40.

 

[97prizm]

Howdy all,

We are installing a 489 roller striker motor in my old suburban this week. Per the builder recommendation, he wants 10w-30 break in oil for the first 50 miles and wants moderate to heavy acceleration with engine braking to help seat the rings (we chose comp cams break in oil). Once 50 miles hits, he wants me to drain the oil and filter and put new 10w-30 or 20-50 in and drive the piss out of it.

I really like Mobil 1 15/50 for my climate and price (Austin Tx, hot summers). However I’m fearful of putting in synthetic too quickly. Will this stop the rings from seating with a synthetic too quickly?

Should I run vr1 10/30 or 20/50 til 1000 miles and then switch to the Mobil 1 15/50?

View attachment 293280

The last time I had Valvoline VR-1 it said not recommended for vehicles with catalytic converters. Will your engine builder change the oil? Might be cheap insurance as if something goes wrong how likely is the engine builder to cover it under warranty?

 

[Txaggie76]

The last time I had Valvoline VR-1 it said not recommended for vehicles with catalytic converters. Will your engine builder change the oil? Might be cheap insurance as if something goes wrong how likely is the engine builder to cover it under warranty?

This is for an 85 suburban with x pipe exhaust and no converters.

 

[Txaggie76]

It’s definitely not a 10W30 engine. I’d say a minimum HTHS of 3.8, which is the low end for a xW40.

What weight should I run?

 

[Cujet]

What weight should I run?

I'd suggest a robust 30 viscosity to start with, it is still a good choice. Remember keep oil temps out of the stratosphere and there won't be any issues with your nearly 3 thou main bearing clearance. Do this by not running too hard or too long.

Again, a drain n fill at 50 miles is a great idea. After which I'd use at least a 40 viscosity, and prefer a 50.

Edit to add: No matter what you choose, make sure to manage oil temps carefully. I'd not let oil temps climb too much above 200 in that rig. 205 is fine, 245 is not a good idea.

 

[Txaggie76]

I'd suggest a robust 30 viscosity to start with, it is still a good choice. Remember keep oil temps out of the stratosphere and there won't be any issues with your nearly 3 thou main bearing clearance. Do this by not running too hard or too long.

Again, a drain n fill at 50 miles is a great idea. After which I'd use at least a 40 viscosity, and prefer a 50.

Edit to add: No matter what you choose, make sure to manage oil temps carefully. I'd not let oil temps climb too much above 200 in that rig. 205 is fine, 245 is not a good idea.

Thanks. Sounds like my 15/50 Mobil 1 will be a good fit.

in the interim until I hit 1000 miles, should I use the vr1 20w/50 over the 10/30?

 

[Hohn]

Our rod bearing clearance is 2.1995 and mains at 2.7488. How does this factor in for the oil weight?

Those are not valid clearance numbers. Those might be actual journal diameters (in inches), but without the bearing IDs you have no idea what the clearances are.

Do you understand the difference?

BBCs are nominally 2.200" crank pin OD and 2.75" mains OD.


What is the clearance?

 

[userfriendly]

Those are not valid clearance numbers. Those might be actual journal diameters (in inches), but without the bearing IDs you have no idea what the clearances are.

Do you understand the difference?

BBCs are nominally 2.200" crank pin OD and 2.75" mains OD.


What is the clearance?

I thought he meant 2.2 thousands rods and 2.75 thousands mains.
Anyway, I don’t see the point of running xW30 on a 4.25” crank. There’s nothing to gain over 15w40 as a starting point and a lot to lose. Thin around and find out. Maybe learn from what happened when GM put 0w20 in their 6.2L.

 

[Hohn]

I thought he meant 2.2 thousands rods and 2.75 thousands mains.
Anyway, I don’t see the point of running xW30 on a 4.25” crank. There’s nothing to gain over 15w40 as a starting point and a lot to lose. Thin around and find out. Maybe learn from what happened when GM put 0w20 in their 6.2L.

Yes, I'd personally be running 20w50 Vr1 black bottle or a 40 grade Euro oil.