[FC] Mikes dropped valve seat

[Ken Hand]

 OK, IF you have NO money and are strapped for something to drive I just might agree with you on a lot of your points because I have done most of what was said below. That was 30 years ago and the parts were a little newer and you could still get low time semi virgin used parts. That is rare today. Not to long ago I put a used head on a on an engine and guess what? It proceeded to drop a valve seat! I had to do the job over and provide another head at my cost.

I don't know about taking the other head off myself but with the one head the one seat can be repaired for a little more than a used head and be guaranteed for the seat not to come out! Here is where I go a little farther and say replace all the seats and then put the worry of dropping valve seats behind you for that head. 

And, Sorry, adjusting lifters running is like living in the dark ages. Any valve can be adjusted with the engine NOT running and NO mess, well, a couple of drops of oil.

 

Ken Hand
248-613-8586
www.corvairmechanic.com
 

 

-----Original Message-----
From: Andy . <rumbleseat66 at hotmail.com>
To: corvanatics at corvair.org
Sent: Thu, Mar 4, 2010 5:42 pm
Subject: [FC]  Mikes dropped valve seat



I just can't join the chorus and suggest taking the other head off just for the 
heck of it.  To say that the passenger head is on the brink of dropping a seat 
after 45 years just because the drivers side just did is questionable logic to 
me.  Seems like a waste of time and money to mess with the bank with perfect, 
even compression and no known problems (I assume).  Not to mention the risk of 
pulling a head stud out of the block.  That opens a whole 'nother can of worms.
 
A fresh valve job and cleaning of the combustion chamber on a good-running-order 
head I bet will not net you 1-2 additional horsepower.  I would even suggest 
that an aggressive valve grind by a ham fisted non-Corvair machine shop could 
even increase the likelihood of future seat failure.  Grinding/twisting of a 
valve seat cannot be beneficial.  Staking can be though I guess.
 
Given this is one of three or more corvairs he has, probably none being primary 
transportation, this motor might not see 5,000 miles a year.  The signature is 
listed as a 110hp 65 van, but he is looking for a 95hp head???  
 
If that were the case (relative few miles/year), and it was mine, I would find a 
decent used head with tight guides, lap the valves by hand, check for full 
contact / pattern of valve and valve seat with machinist dye or a magic marker, 
reuse my viton orings, put the sucker on and enjoy the van another 10 years.  
And have the warm feeling that I made it run like new again for < $100.
 
But if I found that I could stick my thumb down the valve guides of the busted 
head indicating a million miles and the passenger side needed a valve cover 
gasket and pushrod tube o-rings replaced anyway, then I could see tearing the 
other side off.  
 
Also, if you adjust your lifters running and you are not an ace at it... 6 
lifters hammering is a lot easier to deal with than 12 lifters pecking (or 
"peckers lifting" as my Dad would always say).  That fancy 3 angle valve job you 
got is not worth a damn if you run a valve into a piston trying to decipher the 
difference in sound of 11 hammers banging anvils vs. 12 banging... LOL  And of 
course, assuming factory exhaust, the driver's side is far easier to adjust 
(more room, less exhaust noise, no 500 degree hand warmer / skin-melter aka 
muffler)
 
If you have both heads off and the blower housing off (as suggested to service 
bearing and gaskets) then you are only 12 little rod nuts away from honing and 
re-ringing the darn thing and replacing those rod bearings..... where does it 
stop?????  Might as well thermal coat those piston tops while they're out...  
after fly-cutting them and milling the heads for optimal quench... hello custom 
pushrods...  also better replace those tired valvesprings so an extra 100 rpm 
can be squeezed out of 3rd gear when you are climbing a steep hill on a 2 lane 
road with 19 cars behind you... pedal to the floor, knowing 4th gear would be a 
speed-losing proposition.
 
With all this said, some tongue-in-cheek, I spend many hours prepping any head I 
use.  Of course, if the motor is sick and needs it, by all means do it.  But 
just for the "fun" of it?  No.  Cleaning and deflashing can be done fairly 
completely on an installed head.  IMHO, the odds are heavily in your favor of 
NOT dropping another seat anytime soon.
 
Also, I just heard on MSNBC the other day that all dropped valve seats prior to 
August 30, 2010 are officially George. W. Bush's fault.  There will be no more 
dropped seats after that date.   But if any are dropped, it will still be GWB's 
fault.

 

YMMV