6000 rpm shouldn't be enough to float the valves. The fact that you see
something in the cylinder indicates that it either sucked some form of
debris like a loose nut into the cylinder, or else it dropped the valve
seat. Either one, jamming the valve open, could leave enough clearance up
top for the rocker to pop out. A less likely scenario could also be that a
chunk of the piston crown has broken off and gotten between the valve and
the seat.
The only thing to do at this point is to pull the head and see what's in
there. Also drain the oil and look for the lash pad and pieces of the
mousetrap spring. You may need to drop the pan to find them, but that's not
a big deal. If you don't find them look carefully down the front cover and
see if any bits have wedged in with the timing chains. Also carefully
inspect the cam lobes for any damage from flying debris.
> -----Original Message-----
> From: owner-datsun-roadsters@Autox.Team.Net
> [mailto:owner-datsun-roadsters@Autox.Team.Net]On Behalf Of Daniel Neuman
> Sent: Sunday, November 21, 2004 7:07 PM
> To: datsun-roadsters@Autox.Team.Net
> Subject: Checked the bad cylinder and.... HELP!?!?!?
>
>
> Hello All,
> Got the okay from SWMBO to spend the afternoon checking the car out.
> I pulled the spark plugs first and they all looked good maybe like I'm
> running a little rich. Then I popped the valve cover and found this....
> www.madmadscientist.com/intakevalve.jpg
>
> This was not what I was expecting to see... The rocker
> arm/follower for the
> intake valve on #2 was sitting off to the side!?!?!?!?!!?!? The
> little round
> slotted disk that sits on top of the valve and keeps the follower in place
> was missing?? I looked all around the head? Where could it of gone? I
> peeked in thru the spark plug hole and saw a piece of something sticking
> out. It looks like that slotted disk thing (what the hell is it called
> anyways??) somehow worked its way down and is caught by the
> intake valve. I
> could move the piece a little bit but I can not pull it out. I tried to
> compress the valve spring by turning over the engine(by hand) hoping the
> thing would drop out so I could grab it with a magnet but no
> luck. I think
> I just managed to rotate it around and I can not see it anymore.
> But if you look at the picture the valve stem is lower than the
> intake valve
> next to it so I think it must be stuck in their somewhere.
> What do I do know??
> Should I pull the head off and look around?
> From the sparkplug hole I can see some small marks/gouges on the
> piston top
> from my piece of mystery metal. They are not big but how bad can they be
> and not require a new piston??
> Before this fateful ride there were no weird noises when I started the car
> up and it idled and ran fan. It seems like my valve clearances would have
> to be WAAAY out for that slotted disk thing to get away from the follower?
> I was revving the engine pretty high just before it happened would valve
> float of done this? I have a 6000rpm limit chip in it though
> Is there any hope that I can still fix this cheaply? Like pull the head
> gently buff out the gouges in the piston and reassemble? The
> valve seat is
> probably tore up?
>
> Help!!!
> Daniel Neuman
> Oakland CA
> 69 2000
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