Quote:
Originally Posted by venik
I've encountered lifter tick alot in my 3/s owning years. I usually change the oil when it shows up, but every oil change ive had to change it earlier and earlier. Now I can't get rid of it at all, except I'm not sure if it is the same lifter tick. Usually my lifters would tick only at idle and low rpm cruising. But the tick I currently have goes away at idle and low rpm cruising, and comes back with a vengeance with any acceleration at all. The more load the louder it is, until I reach boost then it seems to go away. 3rd and higher gears give me a constant lifter tick regardless of rpm. The car drives like a champ though, I have some cold start issues but I think it's just my tuning. So do spun bearings show any performance decrease? I have normal oil pressure btw. Could my car run this well if it is a valve slapping the piston?
Yesterday I tried the ATF fluid thing and seafoam to get rid of it, if anything it got worse. And it's hard to tell where its coming from because it only does it under load. So is there any way besides a stethoscope to find out for sure if it is lifter tick? edit: that is, before I actually change the lifters
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You can usually get a rod to start making noise by slowly opening the throttle while standing over the engine. The old guy that showed me called it "singing", but at one certain rpm, you'll hear that rod start "singing" if you have a rod bearing out. I'm not talking anything high, probably under 2500 rpm. And don't rev it, just slowly open the throttle, and you'll hear a very rapid consistant knocking. Almost like what pinging sounds like, only a lot louder.
You can also take a long screwdriver and put the metal end on the engine and your ear against the handle, and you'll be able to pinpoint where the noise is loudest. But you really don't have to if the above works, because if it did, you'll find which rod was bad when you pull the motor.
Also if you had a bent valve or your timing was off enough that the vavle was hitting the piston, you'd definitely notice some idle issues, and it probably wouldn't run very good at all. When a rod bearing starts to go out, you usually get what your getting at certain rpm. Eventually it starts doing it all the time as the bearing gets thinner. Or the bearing will spin while your getting on it and the rod will come out through the pan. Right now, the way you describe it, it probably hasn't spun yet, its just worn to the point where the oil (especially as it gets older) can take up the space between the crank and the bearing any more. Every symptom you've described is normally that of a rod knock.. I'm not sure about under boost though... maybe the pressure is keeping the noise down... Not sure, never diagnosed a rod knock on a turbocharged car before...