Engine Break-In
08-24-2005, 07:05 PM
#1
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Engine Break-In
I just completed a complete engine rebuild (new, springs, rings, cams, etc.) and I was wondering if there is some sort of concesus on the break-in period. I have asked three different tech and gotten three different answers? Thoughts?
08-25-2005, 05:55 AM
#2
Well run it in for about 500kms below 4000revs. At abt 500kms, floor it to close to red line to seal in the piston rings, drive it normally again till you reach 1000kms, do an oil change and your all set to go. Gd luck, this was the info provided to me by Ruf Germany.
08-25-2005, 08:46 PM
#4
Race Car
Proper breakin must be done in the first 100 -200 miles and below is the proper procedure:
1. Always bring engine to FULL operating temperature before high revs.
2. Drive the car easy for the first 10 miles or so, varying the rpm's from 2,000 - 5,000.
3. Then, start bringing the engine up to maximum rpm's and letting the engine bring the revs back down by coasting in gear.
4. Repeat several times in order to create maximum heat in the cylinders.
5. Drive around at lower RPM's for several more miles, remembering to vary the speed of the engine every couple of miles.
6. Repeat number 3, 4 and 5.
7. Park car and let the engine cool down overnight.
8. Repeat all the above 2 more times.
Your engine is now fully broken in correctly and can be driven hard from here on.
Jim
1. Always bring engine to FULL operating temperature before high revs.
2. Drive the car easy for the first 10 miles or so, varying the rpm's from 2,000 - 5,000.
3. Then, start bringing the engine up to maximum rpm's and letting the engine bring the revs back down by coasting in gear.
4. Repeat several times in order to create maximum heat in the cylinders.
5. Drive around at lower RPM's for several more miles, remembering to vary the speed of the engine every couple of miles.
6. Repeat number 3, 4 and 5.
7. Park car and let the engine cool down overnight.
8. Repeat all the above 2 more times.
Your engine is now fully broken in correctly and can be driven hard from here on.
Jim
08-27-2005, 02:05 PM
#5
I was wondering what type of engine you rebuilt? Seems no one memtioned rechecking the Valve Lash and the Ignition timing.
There is NO correct way to break an engine in. Every engine builder of worth all have their own way of doing this. The only thing they all seem to agree on is checking the Lash, and other similer checks after running up to temperature for a short time.
From what I have seen, they run the engine up to temperature and after a short period of time, remove the Valve Covers and recheck the lash. During this short run time, the Ignition timing is checked. Then the engine is run at different engine speeds, never idled, with very little load on it. The whole reason is to bed the Rings in against the cylinder walls, matching the 2 parts to one another. Small amounts of loads are required to get the gas behind the rings to push them lightly against the Cylinder walls. I know that different types of Rings, shape an material may require a slightly different approach, but again all engine builders seem to have their own way. I think the only thing they would agree upon is never high speed and never full load. The chance of glazing the walss ids always possible this way. The ring that needs all the work and care is the top ring. The 2nd ring does very little in sealing, it acounts for approx 80% of its use in Oil control. Both the 2nd and Oil rings get very little gas pressure to add to their force. Most of their tension is from the ring fit itself.
So, check that the Ignition timing is set correctly, the lash is correct , then run the engine at different engine speeds with very little loading. Never rev the engine up and down as this only makes the rings become unloaded and reloaded. A constant load at a constant RPM will allow the rings to become matched to the cylinder walls.
Another good thing to do, before starting the engine for the first time is to add the GM oil additive. I promise you this stuff works. It helps stop any galling happening between the Cam and rockers, or tappets, and at start up for the first time, is where most of the damage can happen.
Good luck, and use common sense here, and you will be fine.
There is NO correct way to break an engine in. Every engine builder of worth all have their own way of doing this. The only thing they all seem to agree on is checking the Lash, and other similer checks after running up to temperature for a short time.
From what I have seen, they run the engine up to temperature and after a short period of time, remove the Valve Covers and recheck the lash. During this short run time, the Ignition timing is checked. Then the engine is run at different engine speeds, never idled, with very little load on it. The whole reason is to bed the Rings in against the cylinder walls, matching the 2 parts to one another. Small amounts of loads are required to get the gas behind the rings to push them lightly against the Cylinder walls. I know that different types of Rings, shape an material may require a slightly different approach, but again all engine builders seem to have their own way. I think the only thing they would agree upon is never high speed and never full load. The chance of glazing the walss ids always possible this way. The ring that needs all the work and care is the top ring. The 2nd ring does very little in sealing, it acounts for approx 80% of its use in Oil control. Both the 2nd and Oil rings get very little gas pressure to add to their force. Most of their tension is from the ring fit itself.
So, check that the Ignition timing is set correctly, the lash is correct , then run the engine at different engine speeds with very little loading. Never rev the engine up and down as this only makes the rings become unloaded and reloaded. A constant load at a constant RPM will allow the rings to become matched to the cylinder walls.
Another good thing to do, before starting the engine for the first time is to add the GM oil additive. I promise you this stuff works. It helps stop any galling happening between the Cam and rockers, or tappets, and at start up for the first time, is where most of the damage can happen.
Good luck, and use common sense here, and you will be fine.
09-25-2005, 12:54 PM
#6
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On most engines I build,I usually start it,let it run until hot,replace oil and oil filter (you won't belive how much gunk and residue that shows up in the bellypan after the first initial startup), re-torque the head (if necessary...depending on type of head gasket) when cold, start it up and let it reach operating temperature,then I run high rpm/high load in a dyno for several minutes at a time. This is needed to seal the rings in today's engines,due to the fine crosshatching it NEEDS to be done right away,or the crosshatch will wear away before the rings are properly seated. After that has occurred,they will not seal properly. Ever.
