sparkey914

Hi guys,
This is my first post here, but I've been mining the know-how on this site for awhile, a belated thanks for keeping me on the road.

I have a 2000 TL (155,000) which started a quiet ticking noise a winter ago while the engine was warming up. "Hey, she's got miles." The winter eventually went away, the ticking went away, and I promptly forgot about it, until this past winter showed up, along with the ticking, though a bit louder. Now it's spring and the ticking is still there, louder still, gets quieter when engine warms up, but no longer goes away completely.

Did all the superstitious stuff, timing belt, both tensioners, valve adjust. No luck. Broke down and took it to the dealer, who told me the front center cylinder (#4?) wrist pin is knocking, no big deal, they've heard much worse, put some Lucas in, learn to live with it or rebuild the engine.

I verified it is indeed said cylinder, pulling the coil wire on that cylinder kills the noise (and trips Mr. "Check Engine").

So here's my question(s):

How long has she got? a city block? 1K? 10K? more? I'm concerned I'm driving around with a live grenade under the hood. Not a long commute, but I don't want to be on the side of I-95 in Tony Soprano Land at 2 am.

Alternately, what about a "surgical strike" - I just want another year out of her, if it is the wrist pin and / or crank bearing, can I just pull the head and the oil pan, fish out just the offending piston and replace its wrist pin / bearing? (I've done valves and rings on a much smaller 4-banger without removing the block.)

A full engine rebuild is off the table, she's showing her age in other areas, but I'd really like to NOT pony up big bucks for a fresh ride this year. Creative solution, or waste of time and money???

98vtec

When is the last time a valve adjustment was done?

sparkey914

Valves done 3 weeks ago.

Found a general engine diagnostic site that says if the noise goes away when you pull the plug wire, it is most likely piston slap or busted ring. Wrist pins fail rarely in modern engines, and a rod knock would still knock, combustion or not.

Further suggestion is to squirt a little motor oil down the offending cylinder's plug hole on a cold engine, then button it up and start it. If the noise is at first gone, then comes back, it is a busted ring. Plan to do this test shortly.

98vtec

A busted ring doesn't tick.

I'd also be very careful doing that "trick" as the electricity going through the coil is very powerful and if it doesn't go through the plug it will find somewhere else to relieve itself and potentially damage electrical components.

Typically though, that is relative to diagnosing rod knock. Not necessarily piston slap or rings. When you remove the ignition source and ultimately drop a large amount of force on the top of the piston (and down to the rod bearing) it will deaden the noise if you have a rod bearing problem.

sparkey914

Yeah, I guess any noise a busted ring would make would not be heard outside the engine.

So I tried the oil test and no change. Nice smoke screen though.

But what about that rod knock? The rod should be hard against the crank at top dead center what with all that compressed air/fuel mix pushing back, no? So where would the hammer noise come from? *Bottom* of the cycle? Hmm, I could probably see where in the cycle on a scope if I can find a cheap contact microphone.

BTW, I'm pulling the switched 12 v off the per-cylinder coil, so the coil doesn't even fire. No load, no current through the ECU transistor.