Hi All.

Oh shit, I gave her a good thrashing today and now I seem to have a tapping

coming from the engine mainly on the overrun when i back of the gas

sounds horribly like a stretched rod.

what I am wondering is are zx,s prone to this and can I get the pistons out the bottom of the engine with the crank out or do I need to take the heads off?

Any advice would be appreciated as I havent had it very long and havent

stripped one of these before.

First,get it diagnosed as the little ends mate!-could be a follower,sound very similar.

Second,to get the piston/rod assy's out heads need to come off.

Ok, thanks for that mate,I just went for another listen and if I slowly build the revs to

2000rpm and slowly back off a bit it taps , otherwise nothing so if it was a follower

would it tap all the time or just under these circumstances like a small end does?

Also is there anyone in the north wales area who would know the difference?

Never heard of a Z stretching a con rod. :confused:

 

Are you sure the rattling is coming from the crank?

 

You could have thrown a bearing.

Never heard of a z stretching a rod, now that sounds encouraging,it isnt a big end kind of tap though and its only when Its on the balance between accelerate and decelerate, no other time.

Do you know for sure where abouts in the engine its coming from? Could it just be 1 tappet making noise.

>> Oh shit, I gave her a good thrashing today and now I seem to have a tapping

 

Did you check the oil-level ? and, did oil pressure drop ?

if it is low, then there's a good chance a big/small end has gone.

..sounds like a rattling sound which can be heard best between 2000-3000 rpm.

 

>>can I get the pistons out the bottom of the engine with the crank out or do I need to take the heads off?

 

if the sound gets less or disappears when disconnecting a particular coilpack it's a small end for that particular cylinder.If it's stays the same no matter what coilpack you disconnect, it's most likely a big end.

Small ends can be replaced with the engine in place and by dropping the subframe and oilpan (although the crank needs to be undamaged)

Big ends are best replaced with the engine out, the same is for when the crank is damaged and needs to be replaced/regrinded.

 

-Eric

Thanks for that eric,but no it has very good oil pressure and it has not lost any at all . the oil has just been changed to millers and is at the top of the mark on the dipstick.

I,ll go and try the coilpack test and see what that says.

Did you mean the small ends with engine out and big ends through the sump ?

Srrae Its very difficult to tell where its coming from, seems to be rear center and louder on top than below,its the way it only taps as I back off that makes me think

small end.

I had a stretched rod ,or oval small end I should say on my vmax and the symptoms were the same,when I stripped it I could hardly tell it had gone but the tap was scary.

mains knock on the over run too, would doubt very much if its a small end, considering theres an oil jet squirting up into the crown of each piston,it could have had valve bounce and bent a valve or damaged a tappet. if it was a spun shell, it would have probably thrown the rod by now there would be next to no oil pressure.