Atom 4 Breakin?

[rickra]

I am about to take delivery of a new Atom 4. I will use it almost exclusively on the track. What are the breakin recommendations for the car?

[John Scherrer]

Here's a partial extract from the Atom 3.5 Handbook that's relevant ..
(mostly written by Bruce Fielding)


Running In / Breaking In
There is no ‘hard and fast’ rule for this but the main things
that need bedding in on a new Atom are the clutch, tyres
and brakes. We feel that you don’t need to rev engines too
high but you do need to make them work early on. The power
difference can be noticeable for machines that aren’t babied
through the first hours of their run in, so just drive the car
‘normally’.

The reason you need not be too gentle out of the box is
difficult to accept for people who remember the good old
days. Machining standards are so much better and hence the
tolerances are much tighter, that there simply aren’t “rough
edges” to smooth off, which used to be the case. Metallurgy
and casting techniques have also improved, so the wear
resistance and consistency of the metal is much, much better.
Couple that with the quality of modern oils, which coat the
surface more thoroughly, degrade less and bond much better
with the metal, particularly over time, and you can get a
modern engine with 20,000 miles or more on the clock that
hasn’t loosened up - and may never do so fully.

So you need to cause a degree of wear in the engine’s early
days before surfaces become too polished (as opposed to
“bedded in”) to loosen the engine. This is why the bores in
new engines have a light cross-hatched surfaced honed onto
them. If they do become too polished, the oils can’t bond
properly, the engine will remain tight and seal badly. The
initial high wear rate declines quickly as the surfaces polish,
so the period you have available to get the engine bedded
in is very short. There’s virtually no effect on longevity, and
remember, internal friction is the enemy of power and torque.
It’s vital to use varying load conditions, whatever the load
level. Different throttle positions, revs, gears and loads will
prevent pattern-related wear in the early stages.

Letting the engine run down (engine braking) is also good, as
this encourages oil up the sides of the pistons to sweep out
debris, though it’s not ideal to drop down through the gears.
Don’t labour the engine (low revs, wide open throttle).
Don’t use the full rev range initially with only an occasional
blip to the red line. Change the oil early (at between 500
and 1000 miles) to clear all the microscopic bits of metal out
of the system. After the initial change you’re OK to use the
full extent of the rev range. The clutch won't be properly
'bedded in' until you've done 1000 miles, so avoid full
throttle openings and fast starts.

CAUTION: Don’t forget to change the oil
and filter after 500-1000 miles.

A suggested running in regime:

First 200 miles
60% rev’s max and never full throttle.
Supplied running in oil

200-500 miles
75% rev max, full throttle further up the rev range.
Supplied running in oil

500-1000miles
85% rev’s max, full throttle further up the rev range.

1000 miles on
Nail it!

All the way through this, warm it up first, never let
the engine labour, use the gear box up and down as
often as you can, and try and avoid motorway use.

TIP: The unoffcial advice for running the car
is to ‘drive it like you stole it’ from day one!

[JT1020]

I’ve already read this but just read it again due to johns efforts with the detailed answer.

Very helpful

[John Scherrer]

Thanks for your comments

.. though it only took about 5 seconds of cutting and pasting !

[JT1020]

… I’m shocked and appalled … you still searched and given the recommended advice for this.