<VV> questions, questions, questions

BobHelt at aol.com BobHelt at aol.com
Wed Dec 5 23:44:22 EST 2007

Hi Everybody,
I sure wish that those new Corvair heads with an improved cooling fan were  
ready today. I'd buy a setup for sure. But I'm really tired of just reading  
about them. In fact, it's getting redundant.
So I'd like to see a change of subject for a while until something concrete  
happens on the heads. 
With this in mind, how about all you experts make some discussion on the  
following subjects?
What do you think are the implications of the fact that the latest API  
designated oil rated SM has no upper limits on the amout of phosphorous (ZDDP to  
you) it can contain?  That means the SM oils can have plenty of Phos if the  
rules are followed. Of course this SM oil must not have a GF-4 rating (which is  
evidenced by a Starburst on the front of the container). And furthermore, It  
must not have any other Sx ratings along with the SM. If there are further Sx 
 ratings, the the max PHos will be that of the Sx rating.
The EM carburetors have a fuel inlet hole to the bowl of 0.058 in. The LM  
carbs's inlet hole is 0.084 in. But both major vendors are offering   inlet 
seats with larger inlet holes (and these are for all years of carbs).  What do you 
think might be the mixture implications of using inlet seats with  larger 
than stock inlet holes? And how might a newbie compensate for this if it  
requires any adjustments?
Most stock Corvair pressure retard units are spec'd to start retard at  about 
2 psi and be fully retarding at about 4 psi. This would imply that all  
retard is "in" at 4 psi, and for any additional boost the retard is flat.   The 
1963 turbo test report indicates that for that year engine, the retard does  
start at about 2 psi, BUT the retard is applied linearly with further boost  all 
the way up to about 10 psi. That would say that the retard starts at  2psi and 
is all "in" at 10 psi. This latter application of the retard seems to  be more 
logical for detonation control.
What do you think? Which way do you see the retard being applied?  Which way 
is best in your thinking? Do you have any experiences to  relate?
How about some dicussions on these subjects for a change?
Bob Helt

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