Engine Break-In

[Keags5.2]

I've come to the conclusion that a proper break-in involves putting the motor under load withing the first 10 minutes of start-up. From everything I've read it seems this comes with the most success and least side effects (glazing from idling too long or revving without the car under load). Question is how do you do this without having to wait for the thermostat to open and let all the coolant flow through the system? The car has to get up to temp for that to happen which would require idling or revving a bit no?

 

[PatrickStapler]

Just drive it...seems there will be some sort of flow even at start up.

 

[Keags5.2]

Just drive it...seems there will be some sort of flow even at start up.

Okay, I assume the majority of the coolant will be in the car before the first start up. So I can just drive it around and monitor the overflow tank and add when needed?

 

[67GTA]

I've come to the conclusion that a proper break-in involves putting the motor under load withing the first 10 minutes of start-up. From everything I've read it seems this comes with the most success and least side effects (glazing from idling too long or revving without the car under load). Question is how do you do this without having to wait for the thermostat to open and let all the coolant flow through the system? The car has to get up to temp for that to happen which would require idling or revving a bit no?

This topic seems to bring as many opinions as “what brand oil should I use?” I chose to follow the Mahle break-in instructions since I used their pistons & rings - link below.

1. Prime the oil system. I used the oil pressure port on the oil cooler adapter - fed with a Motive Power Fill. This was done on the engine stand with the cam covers off so I could see the oil was flowing through the entire valvetrain, but can be done at any point before 1st start.

2. Their instructions say to fire the engine as quickly as possible. On the Mustangs, if you hold the throttle to the floor while cranking, it allows the engine to build oil pressure without starting. As soon as you release the pedal, the car should fire. Not exactly as their instructions read, but I think they’re more concerned about a no-start situation that could fuel wash the cylinders.

3. Once it fires, go immediately to 25-35% of max rpm and hold steady to make sure everything is stable. If everything is OK, then varied RPM’s between 25-35% of max rpm for 15-30 mins

4. Ring seating under load. There’s instructions for street or dyno. I went with dyno, going through the part throttle pull sequence and working up to WOT redline. (Yes, major pucker on the first WOT pull!)

Still too early to tell on longevity, but ring seat is good with no blow by after the first few track days.

https://www.us.mahle.com/media/usa/motorsports/mms-break-in-recommended-procedure-web.pdf