<VV> Which Oil
Smitty
vairologist at cox.net
Wed May 20 20:01:02 EDT 2015
Smitty Says; I'm afraid I have an opposing opinion to to a lot of what has
been said here. In the first place there is no break in required on modern
engines because of the precision fit of mating parts. They can put
synthetic oil in them from day one with no problems. If you ever read the
test procedure for modern engines it goes something like this. Fire the
engine up from stone cold and take it straight to 6,000 rpm. Run it that
way with restricted controlled coolant until the oil reaches 300 degrees.
Bang, shut it off. put it in a deep freeze environment till the block
reaches minus 15 degrees. Fire it up again straight to 6,000 revs. Repeat
the process 7 to 10 times. Tear it down and admire their engineering skill.
Don't expect your Corvair engine to handle this kind of treatment. Just be
aware that you can't talk about oil in modern engines at break in time when
you are talking about your Corvair. That's apples and oranges.
Now for a couple of opinions. The reason for the gruesome cross hatch in
the cylinders is not especially good for your engine. Back in the day and
even now people believe you have to do that to get a break in. Bull
feathers. It reason for it is that mechanics learned way back that if they
used a fine hone even in a straight round cylinder that the guy whose engine
overhauled would be back in about a week bitching up a storm because his
engine was showing smoke at the tail pipe. Maybe he would want to give the
mechanic the benefit of the doubt an wait a month before he really got bent
out of shape. If he were patient it would eventually break in and he would
have beautiful cylinder walls with perfect fitted rings. Mechanics soon
learned that they could avoid the problem by making a very aggressive finish
on the cylinder walls and the rings would seat very quickly. The fact that
they were filling the crankcase with steel grit and reducing the life of the
engine by 20,000 miles didn't bother them a bit. The customer was happy.
I have yet to build a smoker I use a 220 grit Sunnin hone to square the
cylinder. Then I reverse the hone from end to end in the cylinder two or
three times with the lightest cut I can get without chatter to break off the
high spots on the ridges. That's it. And it's not going to smoke. I have
some other sacred cows to step on the toes of if you are interested. Just
remember, this is my opinion. It may be backed by 60 years of engine
building but it is still an opinion and you are welcome to yours.
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