<VV> Which Oil

[Frank DuVal]

Smitty, don't forget they also used cast iron rings sets for fast break 
in! These ring jobs were only expected to last 50k miles back then. Just 
long enough to recoup the ring job money spent and then sell it.

Frank DuVal



On 5/20/2015 8:01 PM, Smitty via VirtualVairs wrote:
> 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.