engine break-in period
Dennis Lee
suggests that the rpms should be kept between 2 to 4 thousand. With a 5
speed manual, I can easily control this and go to 65mph without revving
it much higher.
So which one should I heed? Staying below 55mph or not revving the
engine too hard? I'm curious how either will effect my engine wear. I've
already racked up 500 miles and cruise at 60-65 mph on the highway.
AJR
are going. I would say to go as fast as you want to without going above 4000
rpm. Just my opinion.
~@~
Dennis Lee <lee...@mitre.org> wrote in message
news:37D7FE7C...@mitre.org...
Dan G.
it or don't lug it either.
Be gentle!
Dennis Lee wrote in message <37D7FE7C...@mitre.org>...
JTL
rebuilt. I was able to ask the Master Toyota Technician that did the
work a few questions. One of the was "should I drive it any
differently during the break-in period." He told me to "just drive
it." He told me to check the oil and it was important to change it at
3,000 miles. I will change the oil, and switch to synthetic at 1,000,
then change it every 3,000 afterwards. I guess there could be
differences between the V6 and your 4 cylinder, but I would not worry
too much about - you bought a Toyota didn't you?
Jack
In article <37D7FE7C...@mitre.org>,
Dennis Lee <lee...@mitre.org> wrote:
> What is the significance of staying below 55mph? The manual also
> suggests that the rpms should be kept between 2 to 4 thousand. With a
5
> speed manual, I can easily control this and go to 65mph without
revving
> it much higher.
>
> So which one should I heed? Staying below 55mph or not revving the
> engine too hard? I'm curious how either will effect my engine wear.
I've
> already racked up 500 miles and cruise at 60-65 mph on the highway.
>
Sent via Deja.com http://www.deja.com/
Share what you know. Learn what you don't.
jden...@my-deja.com
extremely tight. As poof of that, anyone who has ever purchased a brand
new Toyota and measured the gas mileage from the very first tank of gas
will universally report that their mileage for all tanks subsequent to
the first one increased significantly. Why do you think this is?
Internal friction, possibly?
In a brand new engine, there is a finish applied to the cylinder walls
via the honing process. On a microscopic level, these honing marks look
like the Rocky Mountains. Lots of tall sharp craggy peaks and steep
narrow valleys. The honing pattern carries critical oil to the rings
for adequate lubrication during break in. After just a few thousand
miles, these honing marks have had the tops of the peaks removed but the
valleys remain. They still carry oil, however. Internal friction has
reduced significantly because the surface area of the cylinders has been
reduced and the sliding action of the rings across the honing marks has
begun to seat the rings to the bores, reducing friction. Suspended
metal particles, small enough to pass through the filter, aid in seating
the rings to the bores. These particles are small enough, however, to
avoid interaction between bearings and journals because they ride on a
much thicker film of oil. The film strength of the oil begins to break
down, further aiding in the seating of the rings to the bores, until, at
the prescribed 3000 mile oil change, metal carrying and film strength no
longer provide break in enhancement.
This process continues for several thousands of more miles. In fact,
new Toyota engines don't fully 'relax' for a good 20K miles.
Now, if you decide to be extra 'kind' to your motor and change the oil
very early at say 1000 miles, you short circuit the ring seating
function of the first 3000 miles on the old oil, thereby potentially
prolonging the process. If you further decide to switch to synthetics,
with their enhanced film strength (that's why they work so well in gear
boxes) you will prevent adequate ring to cylinder contact thereby
further reducing the break in process. Either way, what you end up with
are cylinders that carry too much oil, (not so much as to cause visible
smoke, of course, but enough to shorten catalytic converter life) and
poor ring to cylinder mating, thereby compromising maximum compression
development.
If you take this new engine and drive it like a bat out of hell right
off the showroom floor, too bad. Because of the tight clearances and
very high surface areas associated with new engines, it is very easy to
develop hot spots within the engine. With uneven thermal loading of the
engine, ultimate running tolerances will be out of whack. During break
in, what you are using the engine to do is machine itself to final
running tolerances. Ask any machinist what happens when the two center
cylinders on any engine block get overheated while trying to machine
them. If you drive between 2000 and 4000 RPM you limit the linear
velocity of the pistons in the bores, thereby keeping localized hot
spots due to friction under control. If you drive below 55 MPH you
limit the amount of power the engine is called upon to produce. By
limiting the amount of power, you limit the amount of fuel consumed
thereby limiting the amount of heat produced. Similar reasoning applies
to the owner's manual recommendation on avoidance of cruise control
utilization for the first 500 or so miles. If you drive your engine at
a fixed 55 MPH for prolonged lengths of time (more than about 5 minutes)
you do not spread the thermal loading of the engine very evenly. The
tops of the pistons reach a certain temperature and stay there. The
same applies for the valves, bearings, rings and so forth. You end up
with a 'standing wave' effect. By varying the amount of power the
engine is called upon to produce by varying the speed of the car, you
prevent this effect because the temperatures of all the internal
components are constantly changing, thereby reaching an average
temperatrue. Keep in mind that a modern car cruising down the highway
at a steady 60 MPH is only generating about 15 - 20 HP.
I'll get off my soapbox now.
In article <7rb63b$du5$1...@nnrp1.deja.com>,
Dennis Lee
I was looking for. I wish I had known about the cruise control though.
I've been using it a lot on my commute to class.
The only other question I have is the VVT-I but I'll start another
thread for that.
Dennis
Rick Jones
>
> I just got my V6 T100 back from the dealer after the engine was
> rebuilt. I was able to ask the Master Toyota Technician that did the
> work a few questions. One of the was "should I drive it any
> differently during the break-in period." He told me to "just drive
> it." He told me to check the oil and it was important to change it at
> 3,000 miles. I will change the oil, and switch to synthetic at 1,000,
> then change it every 3,000 afterwards. I guess there could be
> differences between the V6 and your 4 cylinder, but I would not worry
> too much about - you bought a Toyota didn't you?
>
> Jack
Jack, friction is actually good for seating rings, maybe wait a bit
longer before the synthetic conversion??? ;-)
***Rick Jones***
***Toyota Master Diagnostic Technician/ASE Master/L-1***
*** http://www2.netcom.com/~ssauer40/webpage.htm ***
ICQ# 32113742
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