Hey,

I've a '92 Crown Vic with a 4.6 that has this constant tapping noise. It seems to be coming from the top end and two of my more mechanicly inclined friends agree. Since it's on the top end I don't think it's a rod so I would say it was a lifter the way it sounds but since a OHC engine like this doesn't apparently have conventional lifters what could it be and how would I go about fixing it.

Just a side note it drives just fine with no hesitation or anything irregular and the oil pressure is fine. Thanks for your time.

 

Welcome to the forum.
It's not an exhaust leak is it? These can sound like lifters ticking. Also, it could be the fuel injectors ticking. Some times they get loud with age.

 

I would check your plugs. Friend had a tapping that sounded like that and his truck (1999 Lightning) launched a spark plug. Luckily it backed it's way out so far that it did't take the threads with it and was able to screw it back in without having a major fix. This issue exists in the 4.6's as well as the other mod motors with those SOHC heads before 2002.

 

LxMan1 - thanks for the welcome & the advice...and no it's not an exhaust leak but I hadn't thought of the injector thing. I guess I need to break out the Stethoscope and listen against the tip of each injector and then along the cylinder head.

2000BLK54 - I look into it...thanks

 

Get this - it could be PISTON SLAP... or more accurately, a harmonic caused by the piston hitting the cylinder wall in a certain way...

I've heard this exact same thing from other people here on this site and others, so ...

My '97 Cougar does it - I beat the snot out of it, and it stops doing it for months at a time.

But, do the good old "screwdriver" test - use it like a stethascope and touch various points of the motor (be careful of the belts) and touch the other end of the screwdriver to the bone in front of your ear. You'll hear all sorts of things, but if you can't find the location of the tapping, it's probably piston slap.