i was getting on it in first, shift at 8k, missed second and hit rev limiter in nuetral... the engine shut down instantly... it would not restart.. no ticks not knocks no grinds nothing... i popped the hood everything looked fine (checked battery terminals and fuel pressure) i towed it home and pulled the spark plugs, heres what i found cyl 2,3,4 spark plugs were fine.. but cyl one the spark plug shattered.. the hammer was broken off and the threads were partially broken off.. any know what caused this, i dont know if i piston hit it (i doubt it) or if a valve bent and hit it... i also did a compression test which was extremely weird..

cyl 4 - 15 psi
cyl 3 - 30 psi
cyl 2 - 0 psi
cyl 1 - 0 psi

i need help

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2wheelhunter &raquo;</TD></TR><TR><TD CLASS="quote">

cyl 4 - 15 psi
cyl 3 - 30 psi
cyl 2 - 0 psi
cyl 1 - 0 psi
</TD></TR></TABLE>

you do know how to do a compression check, right

 

yes.. everything was don correctly except for a warm engine.. WOT turning the engine over without the F/I fuse thanks!

 

more help?

 

well..by the looks of the compression test you probably bent valves.

 

try to do a full turn over with the crank pully. if it only does a 180 and locks. then you bent something

 

my buddy had a similar problem we were driving and he missed a gear and the engine did the same thing cut out no knocking and he had to replace the motor the damage was the number 4 piston it was to damaged to rebuild and rods and stem was bent

 

if u did it right... and theres no busted piston then you have bent valves.... no question about it

 

to get no knocking sound and for the motor to turn over freely that leads me to believe the valves couldn't have been too messed up....but by the looks of the test....damn 0psi on two cylinders? pull the head and inspect for cylinder wall damage and piston damage......if thats good inspect the dome of the head and valves...might as well get some stiffer valve springs, stronger retainers and new valves

 

Yep, motor is shot.

The spark plug was probably damaged from a piece of the valve guides, if not partof a broken valve itself.

During the overrev, the retainers failed, and the valve slipped down far enough for the guides to fall into the chamber. If you did it REALLY bad, the valve contacted the piston ann broke off. You don't hear a knock because it might me stuck sideways in the intake port.

Don't ask me how I know this.

I doesn't make sense how this can happen with just a missed shift in neutral.

 

first of all you did a leek down test if those are the # its not possible to have that low of compression, unless ur missing two pistons. replace the plugs and try to start it. it should still run even if you did that.

 

I work for Ferrea Racing Components and we make a valve and spring/retainer kit for the S2000. I just bought a spare head to build up that had dropped a valve and scattered the loose parts throughout all three other cylinders. Without pulling the cylinder head off, you should be able to remove the valve cover and find something wrong, like barely any valve lash on problem cylinders, and if a valve dropped you'll definitely find that one.

 

no dropped valves.. no stuck valves...

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 140sx &raquo;</TD></TR><TR><TD CLASS="quote">first of all you did a leek down test if those are the # its not possible to have that low of compression, unless ur missing two pistons. replace the plugs and try to start it. it should still run even if you did that.</TD></TR></TABLE>

not true.. if a valve is bent (stuck open) then you wont get compression

replaced all spark plugs (cleaned debris from cyl 1) and tried to start.. a litte back-fire but no start.. obviously the engine wont start if theres no compression.. off with the head

 

Broken timing chain. Valves in #1 cyl. got struck by the piston. Valves in #2 are open a little.

 

The valve guides on this motor blow *****. Same thing happened to my car. Ended up pulling the head and had a machine shop fab new/stronger guides as well as replace all the valves.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by realblag &raquo;</TD></TR><TR><TD CLASS="quote">Broken timing chain. Valves in #1 cyl. got struck by the piston. Valves in #2 are open a little.</TD></TR></TABLE>

how? we turned the engine over with the valve cover off... and watched the cams move.

damn valve guides

 

You didn't mention pulling the valve cover off.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2wheelhunter &raquo;</TD></TR><TR><TD CLASS="quote">damn valve guides </TD></TR></TABLE>

What's wrong with the valve guides? You don't have the head off yet, right?