[FC] Mikes dropped valve seat

[Andy .]

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


 
 
 
 
 
 
 
 

 		 	   		  
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