<VV> 140 heads MY opinion

[iscdirector]

Tim, my research findings have led me to believe the same thing you are stating here concerning lifters and valve adjustment. I firmly believe that many Corvairs are being driven around with valve trains that do not work well and it seems to be very common with rebuilt motors. This is one of the main causes of valve seats falling out, as well as other problems, but of course it is not the only cause. I thought for a while that it might be because we can't get "real" Corvair lifters anymore but I changed my mind when I realized that GM changed in 62 to using the same lifter they were using in V8's and straight 6's (see1962 P&A catalog) and did away with special valve springs for Corvairs. But here is the bottom line, if you connect a handheld vacuum gage to your motor and the needle isn't steady at idle no matter what you do to carbs, tune, or valve adjustment then you have valves that are being held off their seats by the lifter and the heat from
 the valves is not transferring into the seat. This does not allow the seats to heat as quickly as the head. The head heats up quick because it's aluminum and the valve seat stays cold and then looses its interference and falls out or is sucked out by the intake stroke. This is why many valve seat failures happen after the car has only been driven a few miles and the motor is not even up to full temp. The bad aspect of the thicker, over size seats being put in many heads today is that the larger mass takes more time to heat up so it can exasperate the problem. The key is valve train that works like it should.
Dan Kidder
Daytona Beach FL

--- On Thu, 7/31/08, N2VZD at aol.com <N2VZD at aol.com> wrote:

From: N2VZD at aol.com <N2VZD at aol.com>
Subject: Re: <VV> 140 heads MY opinion
To: virtualvairs at corvair.org
Date: Thursday, July 31, 2008, 3:50 AM

i have been running 140 heads on my rampy for @10,000 miles now.  i  feel tha
t most failures of the valve seats can be tracked to any signs of past  
overheating or valves adjusted a touch tight (as loose as you can do without 
noise  
is better, because of time spent against the seat getting rid  of heat). some 
of the valve seat trouble may even be in the selection of  lifters. some do 
not have the travel of the original corvair lifter. i weill be  removing those 
heads soon for other reasons , but they seem fine so far.   they had all new 
valves and such done when i put them on.only thing i watch very  carefully is 
any signs of pinging...but i think the octane cut pistons are  helping a lot. 
next engine is a 140pg (RN) with no octane cut , and 95 heads for  the 64 coupe

with a/c and a powerglide.
that's my take on 140 heads. you just dont ever want to hear any signs of  
pinging or detonation , and they seem to treat you like any other corvair 
heads.
regards, tim colson.