<VV> Diagnose engine "knock" ? valve seat damage

[Mark Durham]

Charlie, the fact that there is cylinder heads full of carbon may have been
"The knock".

Its easy to take apart a head if you have the right tools. There is a valve
spring compressor that Clark's sells, that would work, but check with your
local club members and see if someone has one. It will compress the valve
spring so you have access to the two valve keepers at the end of the valve
shaft, remove the keepers (use a magnet), and the spring can be unloaded
slowly and the valve should slide right out of the valve guide. The intakes
may have valve stem seals on them.

If you have no known history, it is suggested you measure the valve stems
and the valve guide bores for clearance, and check the springs for spring
tension. Fix/replace what needs done, and lube up the valves and guides and
put it back together. Clarks sells some .002 oversize valves, if things are
a little worn, and a .002 reamer but not so bad things need replaced. There
may be spring shims under the springs, keep them and the springs together as
a set if you are going to reuse the springs because that sets the spring
tension, adding or removing shims.

If you are just going to clean them up, that's fine, but you should be aware
that lots of carbon in the combustion chamber can be from using too much oil
and that usually means a ring job, for both sides.

My 62 102 engine is stock original at 68K miles, as far as cylinders go, the
heads have been redone, but I noticed when I started the car the other day
with the temps at 34F, the left bank took almost 5 minutes before it quit
puff puff puffing blue smoke from Cyl #2, when it warmed up, it stopped.
Well, that is worse than last year this time where it would puff one puff
and no more after sitting for awhile. So, there is a trend and its not good,
so, I'm taking the heads off and am going to re-ring the barrels this fall.
So, I will be looking at my heads, too.

regards  Mark Durham
On Fri, Oct 15, 2010 at 10:35 PM, Charles Lee <Chaz at properproper.com> wrote:

> Wow !  I would have bet that # 3 would have an obvious indication of valve
> seat damage, but it does not show any valve seat displacement ?
>
> www.yourbuyersinn.com/Cars/Corvair/1967MonzaCylinderHeadRemoval.htm#CombustionChambers
>
> I'm still convinced that #3 vale seat was the cause of my "knocking" when
> the engine wasn't even warm enough to do that ?
> Would the area around the valve be worn if the seat was loose ?
>
> The combustion chamber is wet though and the top of # 1 and # 5 are chock
> full of carbon, probably from messing with the carburetors, trying to get
> them right.
>
> Any ideas ?   I've never removed valves before, so what do I need to know
> that will surprise me if I try this ?
>
> Thanks again guys !
> Charlie
>
>
>
> ----- Original Message -----
> From: "shortle" <shortle556 at earthlink.net>
> To: "Charles Lee" <Chaz at ProperProper.com>; <virtualvairs at corvair.org>
> Sent: Friday, October 15, 2010 5:41 AM
> Subject: Re: <VV> Diagnose engine "knock" ?
>
>
> > Odds: Even money. Did you have good compression in all 6 cylinders before
> > you replaced the parking brake cable?
> > Timothy Shortle in Durango Colorado
> >
> >
> > -----Original Message-----
> >>From: Charles Lee <Chaz at ProperProper.com>
> >>Sent: Oct 15, 2010 12:43 AM
> >>To: virtualvairs at corvair.org
> >>Subject: <VV> Diagnose engine "knock" ?
> >>
> >>What are the odds that I'll find a dislodged valve seat on #3 ?
> >>
> >>Charlie
> >>
>
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