Breaking in re-built LS, break-in oil, rings seating, misc. questions

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Dec 7, 2012
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I am re-building a 5.3 LM7 for my Regal. I think I might finally be able to get this car going next summer... pretty excited.

I have some misc. questions for breaking in this re-built motor. I am doing everything myself beyond sending heads to the machine shop. Was going to go a complete slap it together Junkyard build but once tearing it more down, I am putting some choice pieces in it and saving in other areas.

I am no pro but should be a decent enough motor.

Build is:
- 2005 LM7 5.3 iron block, stock crank, polished
- new King main and rod bearings
- Gen IV rods
- Summit ProLS forged pistons, new Mahle rings
- 243 heads off of a LS4, cleaned, OE valves, double valve springs
- BTR V2 trunnion upgraded and OE set of rockers
- 228/230 cam, 112 LSA, .585 lift

So after I assemble the motor, next spring, I'd really like to run it on a stand for a little bit. I am under the impression you should put a load on a new motor to seat the rings. I wanna hear it run to make sure it sounds OK before putting it in the car.

Would running it idling for 5-10 minute hurt it? I also would like to get it warm enough to drain the oil of the Lubriplate within it. Could I run it 10 minutes and leave the oil? Would the Lubriplate in the oil hurt it?

What about once the motor is in the car and you idle it to let it warm up, check coolant, trans fluid level etc? Would that hurt the rings breaking in?

If so, how should you approach breaking it in?

My last question is, what should I use for break in? Should I get a dedicated break in oil? I see some fellas near me selling SAE 30 for a good price?

I have on hand:

Mobil 1 EP 5W-30, Mobil 1 EP HM 5W-30, Rotella Gas Truck Synthetic 5W-30, Rotella T4 15W-40, Rotella T6 5W-40, Traveller 15W-40, Valvoline Daily Protection 5W-30, Valvoline VR1 20W-50
 
Despite the reams of data floating around, it really does not seem to matter much how you initially treat an engine.

We did hundreds of dyno runs, many of which were on brand new engines. Some full race engines, some for emissions testing. But this was not the dyno run of today, with a quick run up to full RPM then down. After initial leak checks and briefly loaded warm up runs to seat rings, we held brand new engines at high output at each RPM point. Often under very high boost levels. No joke, some engines were 1.7L and pushing 700HP.

Not once did we notice any undue wear, piston scoring, bearing failures, etc. The only issue I remember seeing was a nearby team on a different project (not our group) that had an experimental turbocharged V8 with a ring gap WAY too tight. The rings heated up under full boost closing the end gap up, and the engine partially seized. Our team knew better than to run 0.003 inches of ring end gap.

Put another way, most of the ring and cylinder wear happens over a very long period of time, with 150 million piston strokes. Not during a normal break in.

Think about a boat engine. It's asked to perform at high loads right away, often with less than ideal coolant temperatures.
 
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Despite the reams of data floating around, it really does not seem to matter much how you initially treat an engine.

I couldn't agree more!

In my experience......The vast majority of rebuilt engine failures are caused by assembly errors, Piston to wall clearance, Ring gap, Cylinder wall finish & Bearing clearances are critical.

Fitting new pistons usually require some Honing & of course Forged Piston require more clearance than Hypereutectic Pistons.

I would use the Rotella 5w30 for initial start, Run it to operating temp, Then dump the oil & swap filters.

I've sent many engines straight to the chassis dyno with 10-20 minutes of total run time.
 
If the cam isn`t a roller pulling the intake and inspecting the lobes for scratches might be a good idea given the problems. with bad cam material. Not sure an inspection camera would work.
 
If the cam isn`t a roller pulling the intake and inspecting the lobes for scratches might be a good idea given the problems. with bad cam material. Not sure an inspection camera would work.

All LS engines use roller lifters.

Not to derail Redhat's thread, But......The precursor to a wiping a lobe on a flat tappet cam is the Lifter stops rotating thus also stops the Pushrod from rotating. I always pull the valve covers to check pushrod spin.
 
All LS engines use roller lifters.

Not to derail Redhat's thread, But......The precursor to a wiping a lobe on a flat tappet cam is the Lifter stops rotating thus also stops the Pushrod from rotating. I always pull the valve covers to check pushrod spin.
Thanks, momentary brain fa rt on rollers in LS motors.
 
If the cam isn`t a roller pulling the intake and inspecting the lobes for scratches might be a good idea given the problems. with bad cam material. Not sure an inspection camera would work.
What aftermarket cams have had issues with cam material or heat treating? The only ones I’m aware of are the stock Hemi SADI cores, and AFM/MDS engines after the roller lifters have lunched the rollers and the wheel seizes and starts hammering the lobe.

However, impact spalling is not necessarily a material failure, when impact loads exceed the surface strength of the selectively austempered ductile iron hardening which is only about .020” thick. None of the flame-treated or through-hardened aftermarket cams have shown this from what I’ve seen.
 
Thank you all for the info. Good info! Am
I over thinking the notion of “glazing the cylinders” and not having the rings seat properly? I keep reading that online and maybe they’ll seat just fine by running it normal?
 
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