It’s definitely not a 10W30 engine. I’d say a minimum HTHS of 3.8, which is the low end for a xW40.
Newly rebuilt bbc 489 stroker. Break in thoughts?
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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.
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.
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?
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.
Yes, I'd personally be running 20w50 Vr1 black bottle or a 40 grade Euro oil.
Yep. The A3B4 xW40s typically come in around 3.7-3.8 HTHS which is my target for just about anything with stock bearing clearances. That includes my deleted LML, my son’s 6.2 F350 and my daughter’s 22 3.6L Acadia.
I arrive at 3.7 in my LML by mixing 15w40 and 10w30 Duron together, Duron 5w40 is already @ 3.7 HTHS. All have the same additive chemistry according to the tear off booklets.
I’ve gone through several pails of SAE 30, 40 & 50 over the years, but noticed a fuel economy hit over multi grades. BBCs like their SAE 40.
Somebody mentioned break it in on a dyno. Perfect if you have an extra thousand bucks with nothing better to spend it on.
Speediagnostix / Total Seal did a break down of 26 popular break-in oils which I found interesting.
https://www.speediagnostix.com/total-seal
As someone who is 600 miles into an LS3 break-in myself, I wish I had watched some of the videos from Lake up front (The Motor Oil Geek). I started with Driven break-in oil for the first 5 hours of the engines life, then drained and replaced with Valvoline VR1 20w-50 (dino only). While it seems like the chemistry in these new break-in oils can seat the rings super fast, I didn't catch that until I was moving into my second fill of VR1. I plan to run the dino for about 800 miles (changing at 300 miles, and then again at 800 miles) and will then switch over to synthetic.
If I were able to start over, I'd run at least 2 oil changes with the break-in oil from your vendor of choice (or engine builders), before switching to the final oil I would plan to run. It seems like the old school 1K miles on Dino as part of break-in before moving to synethic is no longer a hard requirement with the newer break-in oils out there.
I'd also recommend some type of oil analysis so you have a better idea of how the engine is doing, along with starting your trend analysis early.
Just my 2 cents.
-and Hook em'
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