<VV> Head Work

[Bob Gilbert]

Just an update..

I took it to a highly recommended local engine/head rebuilder. There were
many aluminum heads in the work area so I wasn't too worried.

That being said I did drop off copies of the relevant pages from the shop
manual.

He couldn't get the guide out with his driving tools so rather than damage
the head he machined it out. I assume he drilled it out but didn't think to
ask.

He installed the new guide (reaming it as well), the new valve and seat and
then popped the other valves, visually checked everything and lapped them
all and then pressure tested the head. 

All done in the same day and for $75 which I feel was money well spent.

The head is now back on and hopefully in a day or two I will get to find out
how an UltraVan runs on all 6 cylinders!

Regards,
Bob


-----Original Message-----
From: Chris & Bill Strickland [mailto:lechevrier at earthlink.net] 
Sent: August-15-09 4:40 PM
To: bgilbert at redshift.bc.ca; VirtualVairs
Subject: Re: <VV> Head Work


>1) What is the standard procedure for removing valve seats?  
>

call it a 140 and follow what Seth said, or did you mean guides? For 
seat work you send your head to a qualified and recommended Corvair or 
Porsche specialist if you want to be sure the job is done right

>2) ... heating the heads to 425-450F ... is one way ...
>

Back when Corvairs were a dime a dozen, nobody thought twice about using 
a valve guide driving tool and pounding them out cold -- since I have 
done this rather often, it still doesn't occur to me that there may be 
another way, but that might be different, now that I have an oven in the 
shop for doing this sort of thing.  Not sure how that heating thing 
might affect future valve seat retention -- 450 would be pretty warm on 
an operating engine, and are we "sure" of the oven temp readings? You 
have a calibrated infrared gauge?

check out your replacement guide to see which way you would install it, 
and take the old one out backwards.  make sure the part going through 
the head is clean, first.  Probably, therefore, you'd do exhausts from 
the combustion chamber side.

More importantly, after they are installed, you ream them to correct 
size, ie, to fit your valves -- a better choice is to have them honed.  
I prefer brass guides in Corvairs, or bronze.

One, yeah, I'd do it cold, but really it is no big deal to disassemble 
the head when it's on the bench -- a hammer and socket will take care of 
the keepers and then it is apart -- five minutes work at the most.  
Installation goes slower - you can rent a valve spring compressor if you 
don't have one, or borrow it from your neighbor, but once you have it 
apart, it sure gets tempting to do a valve job or at least relap the 
valve faces, which you should do anyway on the one with the new guide.  
Then there is the question of why only one guide? are you sure it is the 
only one that needs replacement?  What is so special about that one that 
the others in that head (or the other side of the engine) didn't see? 
Stuck valve do to gum deposits? I'd be checking the rest of them, too. 
One does not want to repeat the head R&R unnecessarily ...