How long do I have to run in my CG10 engine ? Its just after getting new bearings and piston rings. Thanks
How long does a rebuilt engine have to be ran in for?
- Thread starter k10micracutout
- Start date
Paul Smith
Site Supporter
I would normally do couple of hundred steady soft miles (a tank of fuelish) then gently increase my speed and way I drive for a few hundred more.
This is just me but others may do differently
This is just me but others may do differently
pollyp
Club Member
varies with type of rings, bore machining quality, oil spec.
my JE forged pistons took over 7k miles to fully bed before it stopped burning loadsa oil, but mines a different case.
I use a controversial Motomans break-in method which is to warm it up,
drive on quiet roads in a pulse & glide type of manner (apply controlled heat n load but without overheating & glazing the oil),
progressively apply more n more load & rpm in a controlled way (combustion pressure forces the rings to bed hard against the coarse bore)
and as soon as possible (only have a small window of time available to match the rings to the coarse bores before the machining marks mostly wears down and bed-in slows down. if the rings aren't fully bedded by then, it may cause more blowby and less power and it'll be harder to resolve without rehoning).
tis all explained on his website
http://www.mototuneusa.com/break_in_secrets.htm
here's my initial startup, had a major problem of loose big-ends :/
http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-80
fixed the big ends and resumed break-in.
the side timing chain cover was loose and my catch-can was plumbed wrong way which caused all the big oil leaks btw.
http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-83
1000-1500 miles hard bed-in on mineral oil and then change to ur preferred oil
my JE forged pistons took over 7k miles to fully bed before it stopped burning loadsa oil, but mines a different case.
I use a controversial Motomans break-in method which is to warm it up,
drive on quiet roads in a pulse & glide type of manner (apply controlled heat n load but without overheating & glazing the oil),
progressively apply more n more load & rpm in a controlled way (combustion pressure forces the rings to bed hard against the coarse bore)
and as soon as possible (only have a small window of time available to match the rings to the coarse bores before the machining marks mostly wears down and bed-in slows down. if the rings aren't fully bedded by then, it may cause more blowby and less power and it'll be harder to resolve without rehoning).
tis all explained on his website
http://www.mototuneusa.com/break_in_secrets.htm
here's my initial startup, had a major problem of loose big-ends :/
http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-80
fixed the big ends and resumed break-in.
the side timing chain cover was loose and my catch-can was plumbed wrong way which caused all the big oil leaks btw.
http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-83
1000-1500 miles hard bed-in on mineral oil and then change to ur preferred oil
Last edited:
10 laps of the TT course and hope for the best 
Thanks for all yer help guys.
