Hi All,

Recently sold my Z to a friend,my car had full heads rebuild,various inlet and exhaust valves,new cambelt,headgaskets and all connected paraphanalia after my cambelt slipping!

Problem now is the car has lost all compression on NO 2 cylinder,and i mean ALL!! not even a small puff[graham norton] comes out of this cylinder.All other cylinders are around 170psi.

This car gave no other signs of problems,just dropped a cylinder and this is what has been found.Just to say,when the valves snapped due to the belt failure,NO valves were replaced in this cylinder,but they were pulled and checked at a brill engine builders[QUASAR,CHESHIRE].

Guess what im tryin to ask here is,has anyone ever had the compression rings do a shitter on them or a piston crack or "hole"?I doubt whether this is a valve problem but i could be wrong,this car has done about 1200 miles since rebuild and carries no other fault on the engine at all,no noises,overheating or anything,just this "no compression"..!!

Any suggestions before the heads get torn off AGAIN would be gladly appreciated!

Many thanks,

GARY

Only one way to find out - cylinder leak down test. This will point to either piston/rings, inlet valves or exhaust valves. Any competent garage should be able to do this easily for you...

 

HTH

 

CheerZ,

 

Andy

Sounds like a valve has got stuck open. Perhaps there's something stuck to the valve or its seat, like a piece of broken spark plug, etc.

 

Sorry I can't be of more help though

Get enough detting then you can hole a piston - just when you lift off at high speed and slam the foot down again. Other possibility is a burnt valve or seat - maybe lots of ticking over hot in traffic during the hot weather recently?

 

When it was rebuilt, did each good valve go back in its own nicely worn to fit seat? One put in another seat might not seal so well then burn due to a bad contact surface not taking the heat away.

 

If you've absolutely no compression then its head off time unfortunately unless you can see a stuck open valve or camfollower with the cam cover off.

Thanks for repiles,just to answer a few questions!! All valve seats were re-cut and valves lapped in to relevant seats,i seen this being done so its a defo!!Cant really see how a valve would be stuck down?Broken spring?wouldnt the piston give it a smack if it was stuck to any degree?Like i say,no "ill" noises from the unit,just this no compression miss!

Car defo didnt have any detonation probs,new owner is pretty knowledgable and would have checked at the first instance of any noises!He is beyond conciensious!

Just looks like the heads comin off AGAIN,thought i had got rid of my zx woes when the car went,obviously not!!!Its like a bad fart!!follows me round and makes me feel ill!!but also makes me smile!!ha ha!!

Eggy farts dont empty ya pockets as quick as a Z32 tho..!

Cheers to all,

Gary

take it back to the garage and get them to fix it under warranty then...?

waftycranker, had the exactly same thing happen a few weeks ago on a customers car after the engine had been rebuilt, ran for a week ok but then was left for a few days in storage and when restarted it had misfire, after a check found zero compression on number 5 cylinder.

 

Engine was stripped by the builder again and although nothing looked wrong they changed the followers on that cylinder and hey all back to normal with good compression, seems like you defo have the same problem.

 

Jeff TT

Sounds like the lifters are getting jammed 'jacked out'. This will hold the valve open even when the cam is off lobe.

 

Just a thought...

 

CheerZ,

 

Andy

sounds feasable!!Its defo worth poppin the cams out to have a look anyway i suppose,i wonder if givin them a bit of a tap with a hammer shaft down the side of the cam,ala,vauxhall style,may do the trick.?As ya can tell,tryin to get away with as much as poss here.

Or should the heads just be ripped off!!Tis a ball ache tho aint it!!!

Thanks again,

Gary