Ok, so about 2 weeks ago I was on a short drive over to a friends house to drop off some stuff, and the round trip is about 3 miles. When I was leaving I noticed a knocking sound at part throttle. it doesn't make the sound at idle, and I kept it out of boost once I heard it and limped it home. Since then I've had it up on stands and this weekend I got a chance to drop the pan. Here's where things get weird. The rod bearings are all good. Not a single spun one, and not one looking worn. What the hell could have been causing that knock? Torque converter bolts are tight too.....
knock knock.....who's there?
- Thread starter jbeier
- Start date
SCOOBY DOO
BASED CANADIAN PATRIOT!!
- Joined
- Feb 18, 2007
We ran across a broken cam button spring one time.
marleyskater420
still needs to learn
- Joined
- Aug 14, 2004
A knock as in a ticking noise?
Have you checked your driver side header for any cracks?
Can you describe the "knock" in more detail, please?
When it "knocked" did the car sputter and hesitate at all, as if the engine was almost dying or something?
Have you checked your driver side header for any cracks?
Can you describe the "knock" in more detail, please?
When it "knocked" did the car sputter and hesitate at all, as if the engine was almost dying or something?
ttypewhite
Well-Known Member
- Joined
- Oct 1, 2001
I would remove the serpentine belt and start the car. I had a knock before and it turned out to be my alternator.
It's definitely not a tick. I've heard lifter tick, and I've heard exhaust leak tick many times over the years. Unfortunately I've heard rod knock a few times as well. It really sounds like rod knock, but more subdued, a bit quieter than a solid knock. I'm gonna take off the belts and see if it still makes the sound, and if that doesn't do it, I'll probably disconnect the torque converter, wire it back and see if I can still hear it. Might be a cracked flexplate. If that doesn't do it, I'll check the cam button spring. I'll report back what I find.
- Joined
- May 28, 2001
Earl is likely familiar w/ "ticks". He's seen them during his yrs as a sex counselor.......
well, considering mine is an '84 and doesn't have the serpentine system, it's not gonna be a tensioner, unfortunately. I'm hoping it's one of the accessories. It actually might be the A/C compressor, since there is no refrigerant in the system, and there probably hasn't been for a decade or so. So no lube, and although the clutch hasn't been activated, the belt is still on it, so it is at least spinning the pulley.
If all else fails just turn the radio up
Welp, it's not the accessories. I haven't checked the flexplate yet, but I'll be surprised if that's it, just because it really sounds louder close to the front of the engine, up high on the driver's side. Almost sounds like it's coming from the coil pack, which is impossible. I'm contemplating taking off the driver's side valve cover to check the rocker shaft. A mechanic friend of mine says it's possible to be coming from a wrist pin too, which I suppose isn't impossible, but I've never heard of a wrist pin failure on these engines.......
SCOOBY DOO
BASED CANADIAN PATRIOT!!
- Joined
- Feb 18, 2007
Wrist pin failure...look no further. I had one come loose and score up a cylinder.
A broken rocker shaft on the very end is not at all uncommon. The rocker curls right up and you end up with valve lash. A broken rocker button isn't uncommon either. They're made of plastic and over 30 years old.
Rafs-T-Type
Not so Senior Member
- Joined
- Mar 8, 2009
I swear I need to invent a treadmill for cars that's a little bit rough of a ride for hunting down squeaks, rattles, and ticks.
OK, it's been awhile, but I finally got a chance to drop the pan again and recheck rod bearings and first time check wrist pins. Rod bearings are still 100% good. Wrist pins are all ok EXCEPT number 1. with number 1 at the bottom of it's stroke I can physically reach up and wiggle the piston up and down in the bore without the con rod moving. What the hell. Did Buick make these pistons out of bubble gum? Luckily, the wristpin is still firmly in the rod as far as I can tell, because the pin didn't wander into the cylinder wall. Anybody got a con rod with stock piston still attached they can donate to the cause or sell cheap? I'm just gonna replace the bad one.
Actually those pistons are tough as hell with steel support plates around the wrist pin bores.
That's assuming you still have original pistons.
If you're SURE the pistons moves relative to the wristpin, I'd go ahead and pull the head and get it out. That way you can make sure you don't have some crappy cast cheep-o's in there. Plus, you can look around and see if there's any other collateral damage. In that case, you might need a different plan than just shotgunning one used rod/piston and running with it.
That's assuming you still have original pistons.
If you're SURE the pistons moves relative to the wristpin, I'd go ahead and pull the head and get it out. That way you can make sure you don't have some crappy cast cheep-o's in there. Plus, you can look around and see if there's any other collateral damage. In that case, you might need a different plan than just shotgunning one used rod/piston and running with it.
Similar threads
