Running in a rebuilt engine

[mr9lt]

Ladies and gents

Simple question. Following a rebuild of a Tuscan 4L engine whats the best way to break in a new engine to maximise the repair???

[Mustang Baz]

Guidance from any dealer would be to treat the engine as you would a new one and follow the running in guide in your manual. If memory serves, first 1000 miles up until the 1k service would be no more than 3k revs even once warm (always < 2.5k revs until warmed to 50 or 60c); from 1,000 to 1,500 miles, I think you can slowly move through the rev range to app 3.5k, and then from 1,500 to 2,000 miles, you can move this up further to 4k revs. There are times post 1k miles when it is encouraged to briefly go above 4k revs (for 5 second blasts) - guidance from John Ravenscroft if I remember (bedding in piston rings??).

I was very careful on this, and perhaps more "sensitive" than others on PH as regards the rev ranges - possibly because mine was one of the early 3.6li rebuilds (compared to 4.0li) from reading here/speaking to others (mine is a Aug 2003 car).

Your dealer should be able to give you more clear guidance, but the above worked well for me. Once past 2k miles, you are free to stretch the legs. I am now getting close to my 6k service and the engine appears to be running well (rebuild Aug 05).

>> Edited by Mustang Baz on Wednesday 1st February 16:33

[gazzab]

never labour the engine.
dont be afraid to put your foot down but dont rev. ie dont drive like a granny as this wont help with running in.