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Re: Engine startup and break in (long)
In a message dated 7/11/03 6:11:21 AM Pacific Daylight Time, Jon writes:
<snip>
> Congrats TJ!! You and Dan.. (and hopefully soon me..) it's good to
> hear long term projects
> coming to term!
Oh, yeah, it sure is. :-)
<snip>
> Like the breaking in new cams.. I've never heard about that.
This is for new cams or followers, if you're reusing the old stuff in their
original positions, you can skip this step.
The new cams and followers need to get used to one another (that's a
technical term) so one usually starts the engine and keeps it at about 1500-2000 rpm's
for about 20 minutes. The "high idle" speed is because the engine oiling
system isn't efficient enough for this purpose at regular idle speed (about 900
rpm). Use plenty of cam lube before the engine is started.
>Or, the
> varying opinions on how to get the rings properly seated and not glazed,
> so the car won't burn oil. (I've read the Hastings site, Braden,
> sounds like running the engine w/o load is not a great thing in that
regard)
My engine guy has me drive the car up a long, steep hill in a gear/speed
combination that almost lugs the engine. Apparently this seats the rings fairly
well and fairly quickly.
> Anything else on having a good startup and early break in? How long and
> what kind of driving is the way to go?
Follow the directions in the owner's manual for engine break in. My 77
Alfetta 2L instructions are to drive below 3500 rpm for the first 300 miles and
below 4500 rpm for miles 301-1000. After that, the engine is mostly 'broken in'
and you can rev freely.
During the break in period (from the owner's manual) -
- Let the engine warm up for a couple of minutes at low revs before driving;
- Do not drive at max recommended speeds for long periods during driving;
- Never fully depress the accelerator pedal during driving; and
- Now and then release the accelerator pedal during driving;
I change the oil/filter immediately after the cam break in period to remove
any left over metal shavings.
I change them again after 500 and 1000 miles, for the same reason. After
that, it's normal change intervals and depends on your driving and oil choice. As
I have had all new seals installed in my engine, I will eventually use a fully
synthetic oil (Mr. Graves wonderful article not withstanding), but only after
several thousand miles of Castrol GTX 20W50.
There's a head nut torque procedure repeated below. I got it off the AD from
a Tom Sahines post in late 1997. If it's correct, he gets the credit. If it's
not, blame me for reposting it. I'm putting this back on the AD without asking
Tom first, so I apologize to him if I am posting something of his he did not
want reposted.
************
For the Alfa 2L engine -
Upon first assembly the head is torqued cold to 59 ft-lbs. the nuts, washers
and threads are clean and oiled. The head is then retorqued after warm up to
62 ft-lbs. without loosening the nuts. The sequence for this is as follows.
9 10
5 6
1 2
4 3
8 7
The cross pattern is listed in many books but was revised. The old procedure
seems to persist because it was not widely published.
After 500 miles the nuts are loosened ONE AT A TIME, ENGINE COLD (remove
radiator cap first to relieve any excess pressure in the cooling system) in the
above order and the threads and washer are lubricated with oil. That nut is
then torqued to 65 ft-lbs. Finish all of the nuts in sequence. ONE AT A TIME
LOOSE THEN TIGHT!
[Editor's note - I believe Fred further suggested removing the radiator cap,
squeezing (and holding) the top hose, and reinstalling the cap (then releasing
the hose). This creates a small vacuum inside the cooling system and will
help reduce coolant leak while retorquing the head nuts.]
This same procedure is used once a year to retorque the head. If the nuts are
not backed off and oiled before retorquing uniformity cannot be guaranteed.
The torque will be influenced by the friction between the nut and washer and
any rust that may have accumulated on the threads.
Using this technique I have seen many Alfa 2L engines exceed 75000 miles
before the head gasket has shown any signs of leaking.
----Also, from a follow-up post----
I concentrated on the 2L engine and forgot to list the torque values for
other 4 cylinder engines. I use the same procedure as for the 2L engine on all of
these engines. Upon retorque I add 2-3 ft-lbs to the hot value and use that
for the duration. A problem can occur if the head was torqued to a higher value
by the previous owner or mechanic. If the head is now retorqued to a lower
setting it could develop a leak over time. Be sure that your torque wrench is
correctly calibrated.
1300 Normal Veloce 750 & 101 42 cold 45 hot
1300 105 series (junior) 45 cold 48 hot
1600 46 cold 49 hot
1750 54 cold 56 hot
Someone else will have to post information on the V6 as I do not work on
these cars.
TOM SAHINES ARA TECH HOT LINE SAN JOSE CA
************
Thanks Tom for all your help and expertise.
The above are my choices (except where otherwise noted) and your mileage may
vary.
Tom
Seattle (have I mentioned what a wonderful place this is to vacation in the
summer?)
6310123
7711615
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