mike135531bubba

iTrader: (45)

I am pretty close to finishing up a build (cast iron 346, forged bottom end, HCI). I won't have a tune to begin with and my tuner is 6 miles away. I plan to use engine break-in oil for the initial start-up and am wondering at what point do you guys change it out to conventional oil. After start-up and checking for leaks, low to medium revs...

Should I keep the break-in oil and change it out to conventional after the dyno pulls?

Or change out the break-in oil to conventional oil after initial start-up/revving but before heading to the dyno?

truckdoug

iTrader: (25)

i dont use break in oil but i change my oil & filter right after the first fire and heat cycle. assembly lube is nasty gooey **** and clogs the hell out of filters in minutes.

qweedqwag

I ran it for about an hour of run time, Then ran conventional for 500 miles, then changed oil and filter. Everyone is gonna tell you something different.

mike135531bubba

iTrader: (45)

Yeah I know, plus this is a sensitive topic. I appreciate the replies though

G Atsma

Truckdoug hit on an important point; getting the assembly lube flushed out along with any metal particles, AND changing the filter SOON to get rid of it. Use dino oil to do that, only because it's cheap and you're gonna change the oil a few times with very short intervals to achieve the above.
So first change oil AND filter after first warmup and heat cycle, then maybe 100-200 miles later, then 500. After that use whatever synthetic you use and go a full interval.

SLWRDE

iTrader: (4)

Darth_V8r

iTrader: (4)

I switched from break in oil to regular oil before I filled the engine for first start. Like truck Doug said, almost exactly.

Start it, let it run in but keep rpm moving around, let it warm up, take it out and do 2000-5000-2000 rpm pulls in second, but don't clutch in on decel. Load the rings up. About 15 pulls, go home, change oil and filter.

Che70velle

iTrader: (6)

Jenson

iTrader: (32)

I did the same as darth stated on my L76 rebuild, I only went to 4500 though. For the first 100 miles I kept doing it and never stayed at a certain RPM and was always above 2000. I did use some comp cams break in oil additive though for the first 3 changes (its cheap so I thought why not). Changed filter and oil after first start/drive with loading, 50 miles total and was monitoring oil pressure. Then another change at 500 miles (still with additive) and then another change at 1500 (still with additive). At 1500 I switched to delco semi synthetic because I go it on a super sale ($2.25 a quart). I'll probably go back to the shell dino GF5 I used for break in though on the next change since its only $2.4 a quart.

mike135531bubba

iTrader: (45)

A little confused on the first part. You switched from break in to regular before even firing it up for the first time? I thought the whole point was to put in 5.5 qts of break in oil for initial start up/revving and then switch to conventional after the first oil/filter change.

99 Black Bird T/A

iTrader: (4)

That's at first thought a natural comparison but really an apples to grapefruit comparison when one thinks about it.

In short, an OEM build LS1's break-in has the deck stacked in its favor and synthetic oil is perfectly suited.

A custom build LS1's break-in doesn't have the deck stacked in its favor so there is much wisdom in using a conventional oil like VR1 or other similar oil for break in. The engines are in many way a bit more similar to the engines from 30 years ago and more break-in sensitive than an OEM engine.
​​​​​​
Let's stop and ask this question, is the typical custom build LS engine really similar as a factory built engine?

In my experience, the answer is no.

Few people rebuild to stock specs. The typical aftermarket engine will have a different ring set than factory, typically with forged pistons, more aggressive camshaft with more lift and duration and so on.

GM has their process down to an exact science. There's absolutely GM maintains very tight cost effective production tolerance with the factory parts and machining practices. Aftermarket vendors can't maintain near perfect build tolerance out of the box like an OEM auto manufacturer.

The time spend checking parts for exact tolerance is simply too costly for the aftermarket. GM controls selection of every part that goes into their engines. Basically the same type parts are used over and over in an OEM engine and held to high quality standards. Aftermarket builder is at mercy of what the customer wants with thousands of different crank, rod, piston, bearings, ring combinations possible for suppliers of various levels of quality control. There is much more of a human factor in custom aftermarket build engines than in a OEM manufactured engine.

99 Black Bird T/A

iTrader: (4)

This is amusing

​​​​​​Wiki on break in

​​​"Some users will not give credence to the engineers and will stick to their own ideas anyway; but their careful break-in beliefs are still harmless and serve roughly like a placebo in allowing them to assure themselves that they've maximized the equipment's working lifespan through their due diligence. Some manufacturers have removed break-in procedures because mechanically they are no longer useful. Other manufacturers list procedures to avoid customer arguments the manual was incomplete because the procedures were missing. The useful side effect of a "break-in at slower speeds" for vehicles is operator familiarization. An overly exuberant operator crashing the new vehicle hurts people, reputation and sales."

Will the vehicle survive breaking in the new owner...

truckdoug

iTrader: (25)

I mean I usually end up going easy on 'em at first because I'm tuning and "breaking them in" at the same time.

Darth_V8r

iTrader: (4)

It was an attempt at a humorous way of saying I don't use break in oil. Materials today are FAR different from the SBC days. And the quality of oils is vastly superior. A good synthetic like castrol edge is fine.
Quote of the day right there. Laughed out loud and got weird looks from co-workers.

Jenson

iTrader: (32)

I didnt even catch that Darth, my brain assumed you said change after start up lol