Date: Thu, 20 May 1999 11:04:32 -0700
Reply-To: Stuart MacMillan <stuart@COBALTGROUP.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Stuart MacMillan <stuart@COBALTGROUP.COM>
Organization: The Cobalt Group
Subject: Re: Recommended Breakin method for new engine
Content-Type: text/plain; charset=us-ascii
I have done some research on this and found some interesting things over
the years. I have rebuilt 5 engines, (no waterboxers but maybe soon)
and wanted to get the most life out of them. The very first engine I
rebuilt was in 1971 for my '65 MGB, and the bottom half of that engine
is still on spec for compression and oil pressure with over 200k. (I
have rebuilt the head twice.)
Here is what the "experts" have written:
1. If your engine has not be "run in" for 20 minutes by the rebuilder,
then you should do this first to break in the cam properly. This
consists of starting the engine (set everything up as close to correct
as you can so it starts immediately, no extensive cranking!) and free
running it at 2000 rpm for 20 minutes. This engine speed (no driving!)
keeps some of the downward force of the lifters off the top of the cam
lobes while they get oiled and run in with good oil pressure. (The
lifters "float" a bit from the high speed upward movement and don't
follow the top and down side of the lobe with full pressure, so the
theory goes.) This also lets you check the cooling system, since the
engine should not overheat in this 20 minutes.
If cam break-in lube was used in the rebuild, you should change the oil
now so that the extra lubrication doesn't prevent proper ring seating,
which requires some friction.
2. Next, one published expert recommends that you now find a moderate
hill and do the following: Drive enough to warm up the engine and then
go up the hill. Snap the accelerator to the floor and accelerate up the
hill (keep it legal), turn around at the top and coast all the way
down. Repeat 10 times. This seats the rings by putting compression
pressure on them on the way up, and oils the rings on the way down by
sucking oil up to the cylinders under the high vacuum created while
coasting with the accelerator released.
3. Varying your speed on the freeway is required for the same reason.
You should accelerate hard every once in a while and coast down to 45
mph or so, and repeat a few times as well as varying your speed, and
stop at 50 mile intervals to let things cool off.
4. Change the oil and filter at 500 miles. Most experts consider an
engine fully broken in at 5000 miles. Then you can add exotic
treatments like Slick 50 if you want.
I have had great success with these methods over the years.
--
Stuart MacMillan
Manager, Case Program
800-909-8244 ext 208
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