Hello All,

I have a 1984 ELCO with a V6 231, I have not had the car long but I would suspect the engine has been changed since nothing ever matches.
Here is my problem; I have a tapping coming from somewhere in the engine. I can at times hear it in my catalytic converter (maybe coming through from internal engine, not sure). The tap sounds like it coming from the passenger side of the engine. The tap is most active when the car is standing still or after I get off the accelerator. you can hear it very faintly when on accelerator or maintaing speed. Sometimes at stop it almost disappears.

I have never had the pleasure of having a thrown rod or sticking valve on any vehicle and I am wondering if this is it. One other note she will still fly on the freeway. At higher speeds I think oil pressure is up just a hair. Also this is a California vehicle if that makes any difference. Any help would be greatly appreciated

Thanks in Advance

First, welcome to ECC, Ron. Although it would be much better to hear the noise in person, from your description I would tend to suspect lifter noise. Have you tried an oil additive to see if there is any change?

Maybe a lifter or the rockers need adjusting

I can at times hear it in my catalytic converter (maybe coming through from internal engine, not sure). The tap sounds like it coming from the passenger side of the engine. The tap is most active when the car is standing still or after I get off the accelerator. you can hear it very faintly when on accelerator or maintaing speed. Sometimes at stop it almost disappears.

A constant evenly spaced tap tap tap, could be a valve train component...most likely a lifter if it doesn't do it all the time. A rattle even if slight, could be the heat shield on the catalytic converter. Try to pin point it a little better using someones help. Get your head under the hood and under the car...just don't get your ear TOO close! Burnt hair and cartilage is STINKY..it hurts too.

Don't run over your head either... Welcome aboard Ron...

What you are describing could be a number of things. Could be a rod with a too much clearance or piston slap or wrist pin slap. All of these can sound louder when you let off on the gas than when you are accelerating. Lifter noise is usually fairly constant. Checking the heat shield is still a good idea. Good luck and welcome.

Can you get a mechanic's stethoscope? They only cost a couple of bucks and can help if you're still searching.

Take care.

Thanks for all the great advice. I have added in some Slick 50 Engine Treatment. If that does'nt work I have a bottle of Lifter Lube in the garage. I am also going to pick up the stethoscope. Hopefully by mid day I will know exactly what I am up against.

Thanks Again,
Ron

all of the above can cause a tapping noise also you said that the eng may have been replaced possible a torque converter bolt or flex plate to crank bolts may not have been tighten correctly dropping the dust cover and tapping the flex plate with a wrench should produce a ringing sound good luck and welcome to ecc :)

Saga Continues,

This morning I took the dust cover off between the engine and transmission. Everything was bolted up tight, I was hoping to find at least one loose one and correct it quickly. I picked up a a automotive stethoscope the other afternoon and when I placed it on the dust cover I could hear the tap/knock. I checked the engine in a number of places to see if I could locate any tapping from the engine itself, nothing that I found.

Can anyone out there give me any ideas on what I may try next. I think the knock is coming from the torque converter, does this some resonable. I picked up a shop manual hopefully this will help me also. This tapping is driving me crazy.................

Ron

did you try tapping the flywheel with a wrench to see if it had a ring sound to it verses a dull klang if it don't ring it could have a loose bolt at the crank or a crack in the flywheel not uncommon on gm's and yes a torque converter could make noise if the turbine fins start to break loose it sound like you may have to go in deeper like pulling the tranny and torque converter back from eng to see if the flywheel loose at crank or cracked or if the noise is really coming from the tranny good luck

8) Maybe a crack in the flex plate? :?

yes unless you had one cracked you may think it silly how ever i have seen many flex plate or flywheel what ever you would like to call it over the 40 years that i worked as a dealership master tech for both toyota and buicks thee 231's tend to crack up close to the crank where they mount some times the noise will be very noticeable other times it will disappear the sound they make can very from a tapping noise to a very loud knocking noise depending on just how bad they are cracked ie longer they are driven cracked the larger the crack gets the worst the noise gets untill the car stops moving :)

I think I will be swapping out my flywheel this weekend. That seems to be the most obvious choice at this point. I tapped on it when the dust cover was off and I will most likely do it again; I don't remember it ringing. While in reverse the noise is louder and to repeat myself car still performs well, kinda rules out torque converter.

Thanks Again,

Ron

Just for kicks, remove the dust cover and duplicate the sound. Be vewy, vewy careful. You know it will bite.

Take care.

try pulling torqueconverter bolts push converter back towards tranny to give a little space between conv. and flex plate may be able to fell play in the flex plate if its bad enough and will ring even better if flex plate is good the more you tell me the more it sounds like the flex plate good luck and be really careful if you do run the eng with the dust cover off the teeth on that flex plate will definetly leave a mark and cause a aowe :( :lol:

Thanks to All,

It's over there is no more noise, my baby is riding smooth as hell. There were two things wrong first was the flywheel, it had two cracks in it; second was the catalytic converter, it had some rattling/vibration going on. I spent all my weekends for the last two months messing around with this thing, you guys got me taken care of in one week. Thanks again for all the expert advice, not only am I looking good I'm running smooth as glass.

Many Thanks
Ron

Super! :) Do you still have all of your fingers?

Take care.

I had a crack in my flexplate that ran around the bolt holes. Made a constant tapping noise like you described. Couldn't really tell till it was off though because it was so close to the bolt circle.

I actually broke a finger changing that flexplate. I was just in a funny position and ended up twisting my index finger. Hurt like heck but i finished the job anyway.

:cool:

All fingers still attached, this time I had a helper. He was'nt much help but at least he was there. I changed one once before on my 70 Chevelle and I remembered some of the tricks of the trade. I drove her tonite with no radio on just to hear the engine with no knocking............Sweet

:D happy to hear your problem is solved and yes there's nothing sweeter then the sound of a well oiled machine :lol:
i think i can speak for all glad we could help in some way 8)