Couldn't really find anything in a search and just wondering if this is common, or did it just die. I have zero compression in number 3 cylinder all of a sudden. The car is a stock 90 LX with 172, on it. It's not noisey or anything, just missing.

 

If you're sure you did it right, then you likely messed up a valve or the ring gaps are all aligned. Other possibilities include a badly worn cam lobe(s), or really messed up valve lash adjustments.

How did you determine you have zero compression, by a compression test or what?

 

did it really read 0....or do you have a little bit of compression...if so, how much?

 

sounds like a valve problem ... try to put some oil in the cylnder and check again ...

 

0 on a compression check...Hmmmm! You could have blown a piston or piston ring land or you have a broken valve train.

 

Seems like it would be really hard to actually get ZERO. If you forgot to install rings completely, you'd have to get 10 or 15 psi. Even a bent valve. It has to be something really serious, like the valve being completely gone or a big hole in the top of the piston.

Or maybe a gauge that's not working right??

 

Should have been more specific, not zero no, it was around 15 or so. When I was driving it before, over 4500 or so it would seem to miss every once in awhile then it just died all together. I was thinking valve problem but it isn't noisey, maybe lash then?

 

Maybe a leakdown test to narrow down the problem? (I guess a burnt exhaust valve.)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">Maybe a leakdown test to narrow down the problem? (I guess a burnt exhaust valve.)</TD></TR></TABLE>

burnt? you mean bent?

 

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

burnt? you mean bent?</TD></TR></TABLE>
No, but that's a possibility too. Has the timing belt ever been broken on it?

 

what exactly do you mean by burnt? and most times that a timing belt breaks, well, you'll be missing chunks of valves in the combustion chamber...i think that would be an obvious problem...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nick H &raquo;</TD></TR><TR><TD CLASS="quote">what exactly do you mean by burnt? and most times that a timing belt breaks, well, you'll be missing chunks of valves in the combustion chamber...i think that would be an obvious problem...</TD></TR></TABLE>
Never seen a burnt valve, huh. The best way I can explain it: it looks like the one small spot on the edge of the valve got hit but a cutting torch. One way it happens is when a piece of carbon gets between the valve and the seat causing a hot spot.

Remember I said it was just a guess.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Slammed2K1 &raquo;</TD></TR><TR><TD CLASS="quote">... I was thinking valve problem but it isn't noisey, maybe lash then? </TD></TR></TABLE>Another way to get a burnt valve is if your valve lash is adjusted too tight. Then when the engine's hot the valve doesn't quite close.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nick H &raquo;</TD></TR><TR><TD CLASS="quote">what exactly do you mean by burnt?</TD></TR></TABLE>
How about a couple pics? Just got the ok to tear this one down today.

 

hey that looks like one of my valves. shti my number one did't read ****. that's how i got to know my

 

lol forgat it got to be a valve ore a piston ring. my car viabrated a lot from time to time when ii came out of the highway then it would run good till finaly it got fucked up andi had to buy a used head engine which by the way forgat to change the valve seals and now burns oil in the morning like ****. i smoke the whole block

 

I wasn't even thinking burnt valve, probably what it is. The cat broke apart and clogged the exhaust and I was too lazy to fix it, being it's my beater, even though it's the only one running, that sux. Guess I have to get off my *** and finish the civ. Chris