>First of all the reason I tore my motor apart was it was only running
>on 3 cylinders. I figured out why fast enough. Once the head was
>removed I saw one of the valves wasn't closing. One of the retaining
>bolts on the airfilter back plate had fallen out and been sucked
>inside my motor and was holding the spring open.
I assume you found the nut between the valve and valve seat. Correct?
> The good news is I
>can't see any where that the piston was touching the valve. So my
>first question is should I pull the valve springs and check for wear
>on the valve stem?
Even without seeing a mark on the piston, it is very possible that
the valve was bent. If so, the valve will not be able to seal against
the valve seat... replace the valve.
> Then what constitiutes a "valve job" and how do I
>do it?
Usually the valves are "surfaced" on a valve grinder, giving them
a nice smooth sealing surface.
The valve seat, in the head, is also surfaced, to restore its sealing
surface. Tell the machinist you would like a "3 angle" valve job,
and are glad to pay him/her extra for the extra work.
I really need to show you a drawing, but if you have the valve
at a 30 degrees angle (guessing at the moment, can not recall
the angle), the extra angles allow for better flow of the incoming,
or exhaust, gases. Typically a 15, 30, 45 angles are ground into
the seat... only the 30 is used for sealing the valve.
I have a valve spring compressor ("C" looking tool that compresses
the valve spring, while pushing up on the valve from below). If
a head it pretty good, sometimes all I need to do is use a little
valve lapping compound and "polish" the valves to the seats to
get a good fit. Remember the valves rotates as the engine is
running, and the valve seat also helps transfer the heat from
the valve to the cylinder head. If you do not have the valve
spring compressor, nor the measurement tools, I'd take the
head to a machine shop.
Deliver the head, with the springs and valves in it, to a machine shop.
Also bring along the valve stem seals when you drop off the cylinder head.
>Where can I get the proper valve seals?
Any of your friendly roadster part houses should have them.
> Secondly on my motor
>I have a cast iron head (66), but on the spare motor I have (67)I have
>a aluminum head. Is this normal? should I switch heads?
Either one is fine. The Iron heads are less likely to warp if over
heated (which was common on poorly maintained roadsters). Aluminum
is lighter, and disappiates heat better. For a street car, cast iron
is fine.
Cheers,
Tom
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