i have what i think is an engine knock... but when i pull the plug wires one at a time... the knock never goes away... I was told that this is how you can test for rod related noises. the cylinder with the knock should quiet down when you cut the spark, do to the removal of the stress on that rod.
I know this was the case before on my old cavalier... pulled wire #3 and tick went away.... but now this one is making a far worse noise than my other one... but it is uneffected by the wires.
so what else could this be? i cant seem to track down the source of the tick (it just echos thru the entire block and engine compartment.)
I hope to pull the oil pan soon... but trying to get some ideas before i really tear into her.
its a pretty easy test if youve got about 45 minutes to spare.
just follow your chiltons directions to remove the oil pan and then check for any play in the rods.
there is usually a little bit of wiggle laterally along the length of the crank but there should be ZERO play vertically into the cylinders.
removing the sparks doesnt always work if its too far along.
z24 - CAI - Magnaflow Cat - PaceSetters
--exhaust and unorthadox pulley soon
yeah, that was my next step.... Had to do that on my last one....
Was just hoping there was something more i could try before i got to that. it isnt that hard to remove the oil pan... but draining all the fluids and removing the balence shaft and all is a PITA.
Well sounds like this is a bad knock, and if it was a rod bearing removing spark might not make it go away. This is a fresh motor correct? How many miles on it?
Also wanted to add that you can not reach every rod with the oil pan off, because of the balance shaft assembly (unless you removed it).
Edited 1 time(s). Last edited Monday, July 07, 2008 11:00 AM
FU Tuning
John Higgins wrote:Well sounds like this is a bad knock, and if it was a rod bearing removing spark might not make it go away. This is a fresh motor correct? How many miles on it?
Also wanted to add that you can not reach every rod with the oil pan off, because of the balance shaft assembly (unless you removed it).
No, this is far from "fresh" this is a different cavalier that i picked up cheap to fix and use as my driver while i worked on the other one.
this engine is original to the car and has like 150k on her.... so rod knock is a real possibility.
and i am all too familiar with the balence shafts... i was planning to remove it as well...
I have another engine that i traded some stuff for back when i was working on my original cavy. it is a "supposedly" perfectly running 2.4L out of a grand am with 100k miles on it. the guy offered to let me drive the car and hear it run before he pulled it out of the car... but i didnt have the time.
so i am torn between just swapping the engines and putting this "good running" 100k engine in this driver car... or keeping this car as is, and just hoping some rod bearings will fix it up.
either way is a gamble. one cost me $80 for some bearings and a saturday to slap them in... and cross my fingers hoping that is all it needs and the rest holds up.
or i can swap in the 100k mile spare engine... that takes a good bit of time... but costs me nothing... but then i just gotta hope that engine doesnt develop some issues too soon here.
I just did the same thing. had a knock. it was echoing through the whole motor. But it was a heavy knock so bottom end. Just remove oil pan and balance shaft doesn't take long. Wiggle the rods, just like was said above they will move slightly side to side but not up or down. Take the two nuts of the rods and take out bearings.
If you can't get the oil pan free turn over the motor, if you cant get it off that stud from the tranny use a socket or wrench to take it out and oil pan will come straight down..
just an update.. the aforementioned engine and knock was indeed a rod bearing... bearing was pretty shot... and there was a flat spot on the crank... so i am yanking the engine and replacing it....
BUT... back to my original cavy..... fully built engine... all forged internals... less than 2000 miles on the rebuild.... just the other day i started to hear what sounded like a mild rod knock....
like you can kind of hear something at idle.... but barely... but where i noticed it is right around 2500-3000 rpm under no load.... like coasting along at 55mph.. still in gear but foot hardly on the gas.... like so when the engine is like "floating along" with no ressitance from tranny, and no pressure from combustion.... then there is a mild tapping sound that seems RPM related.
My original engine did this at first... and it slowly got worse, and eventually spun bearing #3 and lost oil pressure which killed the rest of the bearings. SOOOO dont want a replay on this engine...
so i pulled it in the garage and dropped the pan.... but to my suprise, all the rods felt like brand new... tiny bit of latteral play, but tight as hell radially. so i really doubt it is a rod bearing....
and there was almost nothing at all in the oil... maybe the slightest hint of metal fuzz on the oil plug magnet. but nothing at all in the pan, or in the oil. So nothing appears to have gotten chewed up or worn....
at idle car in neutral... you can hear the it more noticably from behind the drivers front tire than anywhere else...
i would think it was a rod bearing.... but inspection of rods and drain oil suggest that is not the case....
what else should i look into?
(also, for those into tuning and HPT... i have noticed significantly more KR since i started hearing this noise... so what ever it is is tripping my knock sensor.)
yeah i had the same problem back in Dec. but im about to put in my new crank and bearing
Wrist pins? Everyone always goes for bearings but nobody seems to look into the piston/rod wrist pin.Those can get wollered out and the rod pushes the piston up to TDC and it ticks then again at BDC it ticks.Even with no spark.Check it out.There should be no vertical play in your piston with the piston rod steady.
<br>
98 Cav,2 door,5 speed,2.2L. I'll pull the stickers and repaint when I get around to it.Get off my nuts.Thanks and have a great day =]
