hi there
on friday i hope to drive my new engine for the first time. spec is ls6 block, ls 6 crank, carillo rods, wiseco pistons. i've been advised by the engine builder to use mineral 20-50w initially to break it in with before changing to a better oil. a few questions have come to mind tho bearing in mind i will be driving it around a disused airfield and can go whatever speed/load i need to put on it.

1. initial rev limit- if i remember 4,500rpm was mentioned as a safe first step limit while breaking in , does that sound about right?
2. how hard to load it up- the engine has been running for a few mins so far to check for leaks etc, all good so far. been run at an idle speed of around 2000rpm just while we checked for leaks then shut down. once i start driving it around i can use any gear/speed i want. the airfield has a slight incline on one bit so i can put it under a light load or give it a bit more if need be. i know not to leave it labouring in a high gear at low revs but i've heard people tell that the best way to bed rings in is to work it reasonably hard straight away while not over revving it.?
3. oil change/grade- i have 3-4 hours of tracktime available and could maybe put 100-200miles on the engine assuming no problems come up.

will that be enough mileage to then change to a better oil /up the rev limit, and if so what grade ie 5w-30 or 5w-40? car will be used for track days and sprinting so will get regular oil changes, so may not need a full spec semi synthetic?

any advice appreciated thanks

 

everyone has a different opinion on this. I'm getting ready to fire mine as well. What I've heard is 2500rpm for 20 min with dino oil. Completely cool for springs to heat cycle. Change dino oil with more dino oil. Vary rpms progressively raising them over 100-200miles taking it easy but decellerating in gear as well accellering to break in both sets of rings. Change dino with more dino. Start progressivlely loading and raising rpms over the next 500-700miles still being a little easy on your new clutch. Let it rip while you're being tuned. Go to synthetic after 1000-2000 miles.

 

yea id go with 2000 to 2500 rpm for 20 min but after about 10 min fluctuate the rpm a little this will help with break it but dont let it idle for any period of time

 

when i broke my last motor (LT1) in i ran it up to temp to check for leaks at like 1500 for five minutes let it cool and then took it out in like third gear and would go from like 2-3500 and let it de-rev itself and then move up to like 4k and let it come back down. I worked my way up to the rpm i would spin the motor to normally and then changed the oil and called it a day. I did stay with 10w40 dino oil till 500 miles though. Motor ran great with no problems. you should not need to hold it for 20mins since the cams are roller.

 

http://www.mototuneusa.com/break_in_secrets.htm

 

thanks for the replies. i've now read the link given. i was thinking of trying say 10 mins driving with say a 3000 or 3500rpm limit and then working up to say 4500rpm after that.

with the 20w-50 mineral oil i am using would it be safe to carefully work up to higher rpm given that i have the afternoon available on track to work the engine?

also given the fact i could probably do say 100 miles in the afternoon on track would that be enough to then drop the oil and replace it with semi-synthetic as i have a full trackday coming up in 2 weeks when i want to use it hard.