Rebuilt LT1--Break in oil?
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Racer
Joined: Oct 2003
Posts: 429
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From: Plains Ga.
Rebuilt LT1--Break in oil?
What oil is recommended to break in a freshly rebuilt LT1 with and for how many miles? I normally use Mobil 1, but I was not sure about using it for inital break in.
Race Director
Joined: May 2001
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Any quality non synthetic is typically suggested for break in. People will claim that the rings won't seat properly with synthetic, etc. I wouldn't be so concerned with that rather than just the money issue. You're gonna be changing it several times in short order so you might as well use the cheaper oil.
Personally I would start it up with DINO oil and run it for 10-30 minutes and change it. Drive it for about 100 miles and change it again. Then 500, then 1000. Then if you want, swap it to synthetic. and go about your regular change interval.
Personally I would start it up with DINO oil and run it for 10-30 minutes and change it. Drive it for about 100 miles and change it again. Then 500, then 1000. Then if you want, swap it to synthetic. and go about your regular change interval.
Race Director
Joined: Feb 2003
Posts: 11,672
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From: Lake Wylie SC
Originally Posted by Nathan Plemons
Any quality non synthetic is typically suggested for break in. People will claim that the rings won't seat properly with synthetic, etc. I wouldn't be so concerned with that rather than just the money issue. You're gonna be changing it several times in short order so you might as well use the cheaper oil.
Personally I would start it up with DINO oil and run it for 10-30 minutes and change it. Drive it for about 100 miles and change it again. Then 500, then 1000. Then if you want, swap it to synthetic. and go about your regular change interval.
Personally I would start it up with DINO oil and run it for 10-30 minutes and change it. Drive it for about 100 miles and change it again. Then 500, then 1000. Then if you want, swap it to synthetic. and go about your regular change interval.
My kinda guy, into overkill. However, after spending all that money on the rebuild, replacing the oil frequently is a great idea. I'd go to Mobil 1 at the 500 mile change.
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
I used Mobil's dino oil, changing at 150 and then at about 11-1200 (if I remember right) switching to syn-blend, then probably went another 1K or so and went back to M1. Don't quote me on exact numbers, I've slept since then! 
Race Director
Joined: Jul 2004
Posts: 16,795
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From: Lake Havasu City, AZ
I agree with Nathan. Any recommended oil (API classification and SAE viscosity is fine) On any new car I change my oil at 100, 250, 1000 and then every 3000 miles thereafter. there is no need for a synthetic during this process BUT it won't hurt anything... it just costs more.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Originally Posted by Nathan Plemons
Any quality non synthetic is typically suggested for break in. People will claim that the rings won't seat properly with synthetic, etc. I wouldn't be so concerned with that rather than just the money issue. You're gonna be changing it several times in short order so you might as well use the cheaper oil.
Personally I would start it up with DINO oil and run it for 10-30 minutes and change it. Drive it for about 100 miles and change it again. Then 500, then 1000. Then if you want, swap it to synthetic. and go about your regular change interval.
Personally I would start it up with DINO oil and run it for 10-30 minutes and change it. Drive it for about 100 miles and change it again. Then 500, then 1000. Then if you want, swap it to synthetic. and go about your regular change interval.
Change it, change it, change it, . . .
No matter how well or how many times you wash the block before assembly, there's always some trash that gets missed.
Jake
Racer
Joined: Sep 2004
Posts: 323
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From: Muncie Indiana
What Did the Genereal do
It seems to me that when our cars were new from the dealer they came straight from the factory with Mobil 1. and 0 miles on them.
The original owners probable drove the car to the first recommended oil change and continued to put Mobil 1 in the engine.
If any body would know what to do for a new tight engine it would be the manufacture.
If it is good enough for the Manufacture to use Mobil 1 for the breakin and expect it to be driven 3 to 5000 miles before it is changed then they must have some kind of testing information to support this position.
I am old enough to remember all the hoop la with rebuilding engines and break in periods. Most of that was because rebuilds generally were not flushed and cleaned out before assy. so the local garage that did the job wanted to protect himself by haveing you do all these different break ins.
Most reputable engine rebuilders today have equipment to get the engine as clean as the manufacture off all the small pieces of machine particle left in the engine before reassembly.
And finally todays filters are far superior to the ones of 25 years ago.
The original owners probable drove the car to the first recommended oil change and continued to put Mobil 1 in the engine.
If any body would know what to do for a new tight engine it would be the manufacture.
If it is good enough for the Manufacture to use Mobil 1 for the breakin and expect it to be driven 3 to 5000 miles before it is changed then they must have some kind of testing information to support this position.
I am old enough to remember all the hoop la with rebuilding engines and break in periods. Most of that was because rebuilds generally were not flushed and cleaned out before assy. so the local garage that did the job wanted to protect himself by haveing you do all these different break ins.
Most reputable engine rebuilders today have equipment to get the engine as clean as the manufacture off all the small pieces of machine particle left in the engine before reassembly.
And finally todays filters are far superior to the ones of 25 years ago.
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Race Director
Joined: May 2001
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The way I look at it is this. Most performance rebuild engines are built to a better tolerance than the production engine may be. Even if everything seats properly with synthetic it's just a good idea to change your oil in short order. A new engine can run very hot which will destroy oil in no time. Changing it very quickly after a rebuild allows several things.
1. It prevents you from destroying the viscosity of the oil due to heat
2. It washes all the assembly lubricant out the engine
3. It allows you to inspect the oil for any metal shavings, alerting you to potential problems before it's too late.
Technically you could probably put synthetic in it from day one and drive it until the first scheduled oil change, BUT why would you? Regular oil and a filter will cost you less than $20, it's just really cheap insurance. I know if I drop $10k into a motor I'll be willing to spend the $20 for the inspection.
The final answer is that there is no "right" answer. Personally I'd spend the money and change the oil 5 times more often than I NEED to in the first little bit of a new engine, just because it makes me feel better.
1. It prevents you from destroying the viscosity of the oil due to heat
2. It washes all the assembly lubricant out the engine
3. It allows you to inspect the oil for any metal shavings, alerting you to potential problems before it's too late.
Technically you could probably put synthetic in it from day one and drive it until the first scheduled oil change, BUT why would you? Regular oil and a filter will cost you less than $20, it's just really cheap insurance. I know if I drop $10k into a motor I'll be willing to spend the $20 for the inspection.
The final answer is that there is no "right" answer. Personally I'd spend the money and change the oil 5 times more often than I NEED to in the first little bit of a new engine, just because it makes me feel better.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
I'm with you Nathan.
I wash and dry the block at least five times, clean all the internal parts (rods, pistons, rings, bearings, etc.), and wipe everything down with lint-free (computer) cloths before I lube and install them.
You'd be surprised what comes off on those cloths.
In spite of all that, I still change the oil and filter right after the engine has run long enough for the oil to reach normal operating temp and I've set the timing and topped off the coolant level.
Jake
I wash and dry the block at least five times, clean all the internal parts (rods, pistons, rings, bearings, etc.), and wipe everything down with lint-free (computer) cloths before I lube and install them.
You'd be surprised what comes off on those cloths.
In spite of all that, I still change the oil and filter right after the engine has run long enough for the oil to reach normal operating temp and I've set the timing and topped off the coolant level.
Jake
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
You can never damage anything by changing the oil too frequently. But conversely, you WILL damage parts if your engine oil interval change was delayed too long.
Dont be lazy or cheap and do as Nathan suggested. Your car will thank you.
Dont be lazy or cheap and do as Nathan suggested. Your car will thank you.
Le Mans Master
Joined: Jan 2003
Posts: 8,596
Likes: 19
From: Portland Oregon
Originally Posted by John Robinson
It seems to me that when our cars were new from the dealer they came straight from the factory with Mobil 1. and 0 miles on them.
The original owners probable drove the car to the first recommended oil change and continued to put Mobil 1 in the engine.
If any body would know what to do for a new tight engine it would be the manufacture.
If it is good enough for the Manufacture to use Mobil 1 for the breakin and expect it to be driven 3 to 5000 miles before it is changed then they must have some kind of testing information to support this position.
I am old enough to remember all the hoop la with rebuilding engines and break in periods. Most of that was because rebuilds generally were not flushed and cleaned out before assy. so the local garage that did the job wanted to protect himself by haveing you do all these different break ins.
Most reputable engine rebuilders today have equipment to get the engine as clean as the manufacture off all the small pieces of machine particle left in the engine before reassembly.
And finally todays filters are far superior to the ones of 25 years ago.
The original owners probable drove the car to the first recommended oil change and continued to put Mobil 1 in the engine.
If any body would know what to do for a new tight engine it would be the manufacture.
If it is good enough for the Manufacture to use Mobil 1 for the breakin and expect it to be driven 3 to 5000 miles before it is changed then they must have some kind of testing information to support this position.
I am old enough to remember all the hoop la with rebuilding engines and break in periods. Most of that was because rebuilds generally were not flushed and cleaned out before assy. so the local garage that did the job wanted to protect himself by haveing you do all these different break ins.
Most reputable engine rebuilders today have equipment to get the engine as clean as the manufacture off all the small pieces of machine particle left in the engine before reassembly.
And finally todays filters are far superior to the ones of 25 years ago.
One thing one has to remember is that the "General" pre-runs the engines on a test stand before they are installed in a chassis. By pre-run I mean that the engines are assembled then mounted onto a test stand, where an electric motor is attached to the crankshaft. The engine is then spun up to between 2000 and 2500 RPM where it is tested for a period of time, I heard two to three hours but I am not sure myself. Various tests are made at this time, engine vacuum, oil pressure, visuals for oil leaks and such. Once the run in is done the oil gets changed at the factory. At least that is what got from a GM factory employee a few years ago that worked at the Tonowanda engine plant. And that's why for the most part you can drive it like you stole it when it gets to you at the dealer.
I would definitely use dino oil for break in. Especially since I would dump it at the first couple hundred miles, then at 500 and once more at 1000. Seeing how cash is harder to come by these days, less than 10 bux for 5 to 7 quarts of dino oil depending on your sump capacity sure beats 20 to 35 bux for Mobil 1 synthetic. Don't get me wrong I run Mobil 1 in all my rigs so at every oil change interval I have a potential for having to buy nearly 20 quarts of that stuff!
