cashyn

hi guys whats the best method of running in after rebuild ? the engine has been bored and the crank was done whilst in bits i need to know best oil and grade also how long before i can give it some ? thanks Neil.

Steve Whitehorn

iTrader: (13)

Theory is
Thrash it - it wont last as long but will make more power
Take it easy It will last longer but will make less power.

Every one has a different view
My view on it

Mineral oil.
Running in map - nice and safe rev limit 4k - keep it to 3.5k
Engine under load. Engine Braking a gear too low up hills to bed the bores in
500miles. Drop the oil out

Semi Synthetic
Drive it harder but dont thrash it
500miles drop oil out

Fully Synthetic
Re Map - to the full map
Drive it like you stole it

cashyn

thanks i have been told by scooby clinic to dissconnect the actuator is that a good idea ?

RICHARD J

iTrader: (4)

If youv got a boost gauge just drive it off boost this is the most important thing rather than rev limits. Run it on mineral oil for 1000 miles with an oil & filter at 500 miles then go to fully synthetic & most important is a remap before you allow it to boost & thrash it.

f4la k

iTrader: (1)

Everone has their own methods. Ask your builder what he thinks..

dynamix

iTrader: (3)

Indeed.

Personally I run mine in hard but I want peak power from my own engines.

I guess the engine builder will be warrantying it therefore it is their instructions that count most.

Alan Jeffery

It helps to know what it is you're actually doing.
It primarily concerns the bore.
When the process of boring and honing is carried out, there is retained a certain amount of "roughness" about the finish, best described as having a valley depth in the little grooves left on the surface.
The trick is to allow the piston and rings to bed in to this new surface, finishing up with a less frictional surface on each.
The Impreza engine in particular is prone to running in issues, as with the bore lying on its side, oil pooling in the grooves can result in a smoky start up for longer than could be acceptable.
Mineral oil is chosen for running in as being less slippery than fully synthetic, and more likely to allow friction to do the job of bedding in.
As far as the bore itself is concerned, all that's involved is to run the piston up and down it enough times. If a high rpm is chosen the risk is of the extra heat caused by friction in the early stages resulting in a breakdown of lubrication leading to bore damage.
Loading up the piston by running boost is fine if done in brief stages, as it applies more pressure to the ring face, although too much can again damage the bore.
If you're running a racing engine, and don't have much time to spare before a meeting, running under boost for a period, then allowing the engine to drop back on the over run continually is as good a method as any.
Of course, you won't actually get any more power from an engine just by flogging it during running in, it's just that you may shorten the time period involved.
We change the mineral oil at 50 and 500 miles, along with the filter, then switch to semi at 1000, no fully before 2000.

MalcB

Exactly as was done on my new build (ET) 2.1 stroker.
Now done 16K and running as sweet as...... and it doesn't use any oil between my self imposed 3K oil change intervals.