Was thinking about this on the ride into work this morning. What's more important to seating rings, heavy engine load or more heat? I find myself watching my egt constantly and I can get the temp up there pretty good with a nice long pull at around 0 vacuum to like 3 psi. In fact the temp is equal to a say 3rd gear pull. Either way both pulls end with a long engine brake to bring the temp back down to idling range and let the vacuum help out the process. What do u guys think?

 

Load and Heat, they both play a role, which is more important? I am fond of load.. but i'm sure people will have their opinions.

You need LOAD on the car to seat the rings..the wont seat just sitting idling @ 200 degrees food for thought.

 

1.) How do you feel about boost (positive load) for breaking in rings?
2.) How long is the window to seat the rings?

 

I would also have to agree Load is far more important. Load is what is going to give you higher cylinder pressure and get that pressure behind the rings expanding them into the sleeve. This would do a better job wearing the rings into the hone then heat expansion

Muckman brings up a good point. My last build i did about 5psi with load. This was on a tuned map tho, after i cracked my sleeve i had the same tune and maintained the same Bore diamter so i felt comfortable doing so. First build it was tuned on the dyno so it saw boost right away. I feel its ok to use boost with load as long as its either tuned or being dyno tuned by a professional.

I alwasys felt one heat cylce to check for leaks after a new build then go out and get some load and engine braking to get them seated. Then off to the dyno, or one heat cycle then tow to dyno.

Im not sure the window to seat rings, but i would say asap after the first heat cycle.

 

im very curious to this as well. my goal for this thread is to discuss some theory/practices and results.

i know that if at all possible im doing wide open pulls like 3/4 of the way up in the rpm band within the first 10-20 miles. my most recent build i got stuck in some traffic and wasnt able to get some serious load until maybe 30 miles. by 50 miles my compression was up to 210 on a 10:1 engine and all the oil had burned off the pistons and whatnot from assembly.

i often have a little contest with myself to try and see how many inches of vacuum i can pull on decel, as the more you load it the more vacuum it seems to pull. my record was over 27" lol.

 

is that a steady 27 reading? or just a quick spike and levels off....I get 25.2 as a steady reading on decel....its drops to about 24ish in lower rpm....but about 2500 its at 25.2

 

It was steady but then again it was a one time thing. Normally it will go to 25.3 or 25.6 for a few seconds and then settle into 24.9 to 25.3 once the cyl temp gets back down to the idle range. Normally at idle with no electric load its 23.2 and it goes to 22..5 or 22.8 with load. Seems as the gm 3bar sensors read in .3" intervals.

I wonder if there is a window like we were thinking about that if you didn't really load up the engine then you should use the "take it easy" break in method instead?...