Proper engine break-in
Thread Starter
Instructor
Joined: Aug 2003
Posts: 148
Likes: 0
From: Mitchell, Indiana
Proper engine break-in
Hey guys, I just got another LT1 motor put in my car and was wondering if there was any certain break-in method to extracting more performance out of it. How should I drive it for how long before i can start running it hard? Your helps appreciated
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
After building mine, this is how I broke it in. After running it in the garage long enough to verify that all systems were go, I took it out and made repeated runs in second gear (automatic) up to 5,000 rpm and then immediately backed off letting the engine decelerate the car back down to 15-20 mph and then repeated. About 15-20 times of this and your rings will be seated as well as they can be. Then just drove it normally and changed the oil at 150 miles and again at 1250 miles. Within a couple hundred miles of initial break-in, I was running it to redline. My clearances are by design, a little looser than stock. If yours are not, maybe wait until after that second change to run all out. I broke it in on Mobil dino oil and went back to synthetic at the 1250 mile mark. Nearly 6,000 miles on it now with no oil consumption at all and no problems.
Intermediate
Joined: Oct 2004
Posts: 42
Likes: 0
the best way that i know of is to run some good non-synthetic oil in it for 500 miles and then change the oil and put a good synthetic oil in it. the theory on the non-synthetic oil is that the synthetic oil doesnt alow the piston rings to seat as well/fast.
I've also known of those who start it up, get it to temp, check for leaks and then go out for a good hard run.
as for me i like the first way best, those i know who have done it that way have run better that those who dont.
The best thing i can tell you to do is just what you are dooing. gather up as many opinions as possible and decide from that.
I've also known of those who start it up, get it to temp, check for leaks and then go out for a good hard run.
as for me i like the first way best, those i know who have done it that way have run better that those who dont.
The best thing i can tell you to do is just what you are dooing. gather up as many opinions as possible and decide from that.
Instructor
Joined: Aug 2004
Posts: 245
Likes: 0
From: Tampa FL
Originally Posted by Dan Parker '96
Build it. Get it up to temp. Check for leaks and any obvious problems.
Then run it like you stole it.
The naysayers are pussies.
Then run it like you stole it.
The naysayers are pussies.
Le Mans Master
Joined: Feb 2002
Posts: 5,970
Likes: 20
From: San Marcos Texas
To add to this "After building mine, this is how I broke it in. After running it in the garage long enough to verify that all systems were go, I took it out and made repeated runs in second gear (automatic) up to 5,000 rpm and then immediately backed off letting the engine decelerate the car back down to 15-20 mph and then repeated. About 15-20 times of this and your rings will be seated as well as they can be. Then just drove it normally and changed the oil at 150 miles and again at 1250 miles. Within a couple hundred miles of initial break-in, I was running it to redline. My clearances are by design, a little looser than stock. If yours are not, maybe wait until after that second change to run all out. I broke it in on Mobil dino oil and went back to synthetic at the 1250 mile mark. Nearly 6,000 miles on it now with no oil consumption at all and no problems."
I would also change the oil after the first run in. The assembly lubes that are used to put the engine together need to come out as soon as possible. After the first 30 mins. of running I drained my oil and it was nasty. The breakin is incredibly hard on oil. Turns it into "water" it breaks it down very fast.
I would also change the oil after the first run in. The assembly lubes that are used to put the engine together need to come out as soon as possible. After the first 30 mins. of running I drained my oil and it was nasty. The breakin is incredibly hard on oil. Turns it into "water" it breaks it down very fast.
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Burning Brakes
Joined: Apr 2002
Posts: 934
Likes: 0
From: MO
Originally Posted by Dan Parker '96
Build it. Get it up to temp. Check for leaks and any obvious problems.
Then run it like you stole it.
The naysayers are pussies.
Then run it like you stole it.
The naysayers are pussies.
If its gonna break I want to be close to home, so back it out of the drive way and hammer it!!! 
I alos agree with using reg. oil for breakin, I too have heard it helps seating but also its only going to be in there for a very shot amount of time so its also cost effective!
Intermediate
Joined: Oct 2004
Posts: 29
Likes: 0
From: lawrysh pa
Originally Posted by chriswtx
To add to this "After building mine, this is how I broke it in. After running it in the garage long enough to verify that all systems were go, I took it out and made repeated runs in second gear (automatic) up to 5,000 rpm and then immediately backed off letting the engine decelerate the car back down to 15-20 mph and then repeated. About 15-20 times of this and your rings will be seated as well as they can be. Then just drove it normally and changed the oil at 150 miles and again at 1250 miles. Within a couple hundred miles of initial break-in, I was running it to redline. My clearances are by design, a little looser than stock. If yours are not, maybe wait until after that second change to run all out. I broke it in on Mobil dino oil and went back to synthetic at the 1250 mile mark. Nearly 6,000 miles on it now with no oil consumption at all and no problems."
I would also change the oil after the first run in. The assembly lubes that are used to put the engine together need to come out as soon as possible. After the first 30 mins. of running I drained my oil and it was nasty. The breakin is incredibly hard on oil. Turns it into "water" it breaks it down very fast.
I would also change the oil after the first run in. The assembly lubes that are used to put the engine together need to come out as soon as possible. After the first 30 mins. of running I drained my oil and it was nasty. The breakin is incredibly hard on oil. Turns it into "water" it breaks it down very fast.
Large Impressive Member
Joined: Jul 2003
Posts: 65,811
Likes: 71
From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by chriswtx
To add to this "After building mine, this is how I broke it in. After running it in the garage long enough to verify that all systems were go, I took it out and made repeated runs in second gear (automatic) up to 5,000 rpm and then immediately backed off letting the engine decelerate the car back down to 15-20 mph and then repeated. About 15-20 times of this and your rings will be seated as well as they can be. Then just drove it normally and changed the oil at 150 miles and again at 1250 miles. Within a couple hundred miles of initial break-in, I was running it to redline. My clearances are by design, a little looser than stock. If yours are not, maybe wait until after that second change to run all out. I broke it in on Mobil dino oil and went back to synthetic at the 1250 mile mark. Nearly 6,000 miles on it now with no oil consumption at all and no problems."
I would also change the oil after the first run in. The assembly lubes that are used to put the engine together need to come out as soon as possible. After the first 30 mins. of running I drained my oil and it was nasty. The breakin is incredibly hard on oil. Turns it into "water" it breaks it down very fast.
I would also change the oil after the first run in. The assembly lubes that are used to put the engine together need to come out as soon as possible. After the first 30 mins. of running I drained my oil and it was nasty. The breakin is incredibly hard on oil. Turns it into "water" it breaks it down very fast.
Burning Brakes
Joined: Nov 2001
Posts: 920
Likes: 0
From: Cherry Hill NJ
OK - that's a good reason to use non-synthetic, knowing that it will be changed quickly. I mean. if synthetic is slicker, so to speak, it should help seat quicker, all other things being equal.
Team Owner
Joined: Sep 2003
Posts: 88,393
Likes: 2
From: eville in
Originally Posted by Corvette Kid NC
After building mine, this is how I broke it in. After running it in the garage long enough to verify that all systems were go, I took it out and made repeated runs in second gear (automatic) up to 5,000 rpm and then immediately backed off letting the engine decelerate the car back down to 15-20 mph and then repeated. About 15-20 times of this and your rings will be seated as well as they can be. Then just drove it normally and changed the oil at 150 miles and again at 1250 miles. Within a couple hundred miles of initial break-in, I was running it to redline. My clearances are by design, a little looser than stock. If yours are not, maybe wait until after that second change to run all out. I broke it in on Mobil dino oil and went back to synthetic at the 1250 mile mark. Nearly 6,000 miles on it now with no oil consumption at all and no problems.
if it's a roller cam 
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
And so the synthetic debate rages on. About two years ago there was a long debate on here about using synthetic oil for break in so I did a little research and posted the phone numbers and points of contacts I had spoken with at the time. Here was the skinny both Comp Cams and Mobil 1 did not recoment synthetic for break in. If you are sure your machinist has honed the cylinders the same way GM does to seat the rings (Actualy the cyl walls but thats a diferent debate) then you should be fine but if not I would recomend breaking motor in the way the manufactures say with non-synth oil. Two parts make me feel this way 1. The maker of the oil recomended by GM (Mobil One) says NOT to use sythetic for break in and Comp, the maker of the cam I am using, makes the same statment.
Former Vendor
Joined: Jun 2001
Posts: 7,204
Likes: 6
From: St Marys PA
I say they are like kids. Teach them early what you expect.
I started mine, ran it home, brought it back to the dealership (8miles). Checked it for leaks etc, changed the oil - Took it to the dragstrip.
Corky started his, changed the oil, and took it to the strip.
Do not move to synthetic for at least 1000 miles.
I started mine, ran it home, brought it back to the dealership (8miles). Checked it for leaks etc, changed the oil - Took it to the dragstrip.
Corky started his, changed the oil, and took it to the strip.
Do not move to synthetic for at least 1000 miles.
