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Discussion Starter · #1 ·
I've got this god awful knock that turns into a grind coming from my motor. The thing is, it is much too slow of a knock to be the rod, and in addition, the sound can be made to go away by waiting a couple minuites and then turning the car on and leaving it to idle. Any acceleration and it's like what sounds like pure hell on the metal parts, but not nearly fast enough of a grind to actually be from a moving piston. Maybe 1 full second intervals.

I pulled my injectors. Maybe they need a good cleaning. Filter is relatively new, but the car did sit for about a year or so, but it's been driving for a couple months now without issue.
 

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Discussion Starter · #2 · (Edited)
I've got this god awful knock that turns into a grind coming from my motor. The thing is, it is much too slow of a knock to be the rod, and in addition, the sound can be made to go away by waiting a couple minuites and then turning the car on and leaving it to idle. Any acceleration and it's like what sounds like pure hell on the metal parts, but not nearly fast enough of a grind to actually be from a moving piston. Maybe 1 full second intervals.

I pulled my injectors. Maybe they need a good cleaning. Filter is relatively new, but the car did sit for about a year or so, but it's been driving for a couple months now without issue.
Here is a YouTube video of the noise

Like I stated before, the sound disappeared for a short while.

Does rod knock noise disappear?

Piston Slap maybe?

The car also stalls out when put into gear. Automatic transmission.
 

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That certainly does sound like hell. Have you inspected the timing belt to see if it maybe jumped timing?

Try listening with a long screwdriver to your ear and placing it on the cylinder head and then block etc to try and pin point where it may be coming from. This one has me stumped.
 

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Discussion Starter · #5 · (Edited)
Hard to tell, but does sound like hydraulic lock, or pre ignition, did it stall or did you turn it off? Have you checked coolant level and oil for water?
Well, it did happen right after I got gas at a grocery store.... I had a terrible feeling about getting gas there, too....

In the video, I turned off the vehicle.

I'll make another video of it stalling. Seems like a the lights go dim on the dash when it stalls from what I remember, but that is likely due to the slowing alternator now that I think about

So far, I've checked inside my cylinder head for a dropped valve or out of spec cam lobe, pulled the fuel rail and cleaned the injectors with brakleen and applying power so it flows, although they seemed to be working fine.

Hydraulic Lock... I did replace my oil, but it went right into the closed oil pan so I didn't get a good look. The vehicle was at a solid 190° at a stop light when it showed it's ugly head. Wouldn't any water have just evaporated in that environment?

Yesterday morning I tried to star the vehicle, but forgot I didn't plug in the injectors 4 and 2. The car did turn over and run, and there was no noise.... Related?
 

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Discussion Starter · #6 ·
That certainly does sound like hell. Have you inspected the timing belt to see if it maybe jumped timing?

Try listening with a long screwdriver to your ear and placing it on the cylinder head and then block etc to try and pin point where it may be coming from. This one has me stumped.
Lol leave it to me to at least come to the forum with fresh content! I'll give it a listen.
 

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Well, it did happen right after I got gas at a grocery store.... I had a terrible feeling about getting gas there, too....

Yesterday rning I tried to star the vehicle, but forgot I didn't plug in the injectors 4 and 2. The car did turn over and run, and there was no noise.... Related?
Hmm 2 interesting comments here's a long shot I did have customer with a B20A6 engine who had used some stale fuel he had sitting around, it had gummed up some of the valves, just long enough to allow a small back fire into the inlet manifold, before the valve had time to close, after a few minutes it cleared up, later in the week he called me over to check why it wouldn't start? When trying to start it it had zero compression? After pulling the cylinder head all the inlet valves were stuck open, he said it was running well after I had looked at it, went home turned it off, but came back next day to start it it wouldn't start? After pulling the head all 4 inlet valves were covered in a sticky brown gum, this gum was so strong I had to soak the valve stems in solvent and hammer them out, I initially thought someone had put sugar in his tank, but after smelling the stale fuel it was obvious it was the cause. We ended up draining the tank ad flushing out the fuel lines etc.

Long story, but this happened within 10 minute's of adding the stale fuel.
 

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Discussion Starter · #9 ·
Another question, have you done a compression test?
I have not but the compression loss is definitely yes. That or the pre-ignition/detonation is sucking the power deliver from the other strokes.

I just got back from home depot with the Klein Tools borescope for android. Only $39.99 how awesome is that?

Anyway. I ran the motor just for about 30 seconds to do what @Wing8806 suggested and listen around for the sound. I wasn't really able to find any new developments.

Then, I removed my plugs and the 3rd cylinder had a plume of smoke released. This I imagine, could be from me stopping the car at just the right time and the exhaust never had the chance to vacate. The plug was absolutly covered in oil.

The inside of the spark cylinder is dry, but I guess that doesnt mean there still couldn't be a leak from the valve cover gaskets getting into the piston chamber. Could a leaking spark cylinder gasket cause pre-ignition/detonation?

The boroscope did not suggest there was any oil in/on the piston. Nor any carbon buildup.
 

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That or the pre-ignition/detonation is sucking the power deliver from the other strokes.

Then, I removed my plugs and the 3rd cylinder had a plume of smoke released. This I imagine, could be from me stopping the car at just the right time and the exhaust never had the chance to vacate. The plug was absolutly covered in oil.

The inside of the spark cylinder is dry, but I guess that doesnt mean there still couldn't be a leak from the valve cover gaskets getting into the piston chamber. Could a leaking spark cylinder gasket cause pre-ignition/detonation?

Could a leaking spark cylinder gasket cause pre-ignition/detonation?
Detonation — can be caused by stale fuel with a low octane rating causing the fuel to pre-ignite or auto-ignite in the combustion chamber

Is it definitely oil on the #3 plug? not a gummy deposit?

Just listened to the video again does sound like a diesel (detonating)
 

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I pulled my injectors. Maybe they need a good cleaning. Filter is relatively new, but the car did sit for about a year or so, but it's been driving for a couple months now without issue.
I just reread that it sat for a year, the fuel would definitely be gum up injectors and inlet valves,can you use the borescope to see the back of the valves ?
 

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Discussion Starter · #14 ·
I just reread that it sat for a year, the fuel would definitely be gum up injectors and inlet valves,can you use the borescope to see the back of the valves ?
I just performed a valve clearance adjustment. The cylinders I suspected the least (1&2) were spot on.

The exhaust valves on cylinder 3 were 0.003" too loose.
The intake valves on cylinder 4 were 0.002" too tight.
The smaller lobe on 3&4 were 0.002" too loose.

I saw your replies and went back out and I pushed on the valves. A couple seemed to require additional strength, but there was not a "stuck" feeling to them, and the additional effort could be attributed to the angle I was in trying to depress the valves.

The boroscope has too long of a camera fitting to be bent at a good enough angle to see on top of the valves, but I was able to see under them, and from there, nothing seems odd.

While the vehicle sat for a year, for the most part, there was no gas in there at all. That was intentional.

Prior to the sit, the engine had a major overhaul, I'm talking virtually every piece of hardware with the exeption of the mighty expensive (like, I only got a couple new valves, and the old ones were machined at a shop, and I didn't get new cams, and only needed a couple LMA's).

The cylinder head I got was surgically clean. Ported and polished got a great deal on it too.

That was all installed, then it sat with like a half gallon of gas in the tank for a year because of a bastard of a oil pressure problem followed by a transmission problem, both of which @Wing8806 was patient enough to help guide me through. It was a doozy.

I pulled the gas filter, and I realized, I really don't know what normal gas smells like, lol. So a friend of mine came by and let me smell his gas cap. Smells the same, and the filter was clean.

So was the fuel rail when I removed it for inspection when I cleaned the injectors out, too. Should I go ahead and put back the valve cover or is there additional checks in the cylinder head you'd like me to perform?
 

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I saw your replies and went back out and I pushed on the valves. A couple seemed to require additional strength, but there was not a "stuck" feeling to them, and the additional effort could be attributed to the angle I was in trying to depress the valves.



So was the fuel rail when I removed it for inspection when I cleaned the injectors out, too. Should I go ahead and put back the valve cover or is there additional checks in the cylinder head you'd like me to perform?
Try pushing the valves again they must 'snap shut' and slide up and down quickly if one or two are a bit slow to return you definitely have gum in the stems, you might try carb cleaner into the intake while running to clean them, gummed valves are a common occurrence in cars that have sat for such a long time.

I know it wil be messy but you could try starting the engine with the valve cover off, (put plenty of rags around soas not to make to much of a mess), start up and watch the valves, if any are stickey you will see them 'snap' back to the rocker and you will hear it and the engine will 'misfire', although not technically a misfire, it is burning back into the inlet manifold for the extra split second that the valve takes to close. This makes a weird noise in the inlet manifold.
 

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Discussion Starter · #16 ·
Try pushing the valves again they must 'snap shut' and slide up and down quickly if one or two are a bit slow to return you definitely have gum in the stems, you might try carb cleaner into the intake while running to clean them, gummed valves are a common occurrence in cars that have sat for such a long time.

I know it wil be messy but you could try starting the engine with the valve cover off, (put plenty of rags around soas not to make to much of a mess), start up and watch the valves, if any are stickey you will see them 'snap' back to the rocker and you will hear it and the engine will 'misfire', although not technically a misfire, it is burning back into the inlet manifold for the extra split second that the valve takes to close. This makes a weird noise in the inlet manifold.
So, spark plugs, wires, injectors, all connected, and run it like normal, with the valve cover off?

I had the same thought... But wont oil get all up in my spark cylinders?
 

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Discussion Starter · #17 ·
Try pushing the valves again they must 'snap shut' and slide up and down quickly if one or two are a bit slow to return you definitely have gum in the stems, you might try carb cleaner into the intake while running to clean them, gummed valves are a common occurrence in cars that have sat for such a long time.

I know it wil be messy but you could try starting the engine with the valve cover off, (put plenty of rags around soas not to make to much of a mess), start up and watch the valves, if any are stickey you will see them 'snap' back to the rocker and you will hear it and the engine will 'misfire', although not technically a misfire, it is burning back into the inlet manifold for the extra split second that the valve takes to close. This makes a weird noise in the inlet manifold.
So, I don't think I'll be trying the run the motor with the valve cover off thing... But I went out there with my vlave adjustment tool (best $15 bucks I ever spent) and pressed directly on the rockers and I was able to get a satisfying and quick snap and contact sound with all of my valves.
 

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Try pushing the valves again they must 'snap shut' and slide up and down quickly if one or two are a bit slow to return you definitely have gum in the stems, you might try carb cleaner into the intake while running to clean them, gummed valves are a common occurrence in cars that have sat for such a long time.

I know it wil be messy but you could try starting the engine with the valve cover off, (put plenty of rags around soas not to make to much of a mess), start up and watch the valves, if any are stickey you will see them 'snap' back to the rocker and you will hear it and the engine will 'misfire', although not technically a misfire, it is burning back into the inlet manifold for the extra split second that the valve takes to close. This makes a weird noise in the inlet manifold.
So, spark plugs, wires, injectors, all connected, and run it like normal, with the valve cover off?

I had the same thought... But wont oil get all up in my spark cylinders?
Just fill the spark plug tubes with rags, you really want to see that the valve working are ok when the noise starts,if you can't connect a 'misfire' with the noise, then I could be wasting your time, its hard to diagnose from so far away. all I can do is make suggestions based on what you can see, feel and hear. its kind of like going to a doctor, he has to ask question to narrow down the issue, so try to notice what happened, when it actually started, did you change anything, was it running fine before you added the fuel at the store, fitted a new part before it started etc, one thing might give me a clue as to what is wrong, I am still leaning to a stale fuel issue, the problem with the gummy fuel the injectors squirt the fuel directly onto the back of the valves, this allows it to wick up the valve steam, when the engine gets hot the bad fuel turns to 'sugar' (not actually but its a good approximation) and when it cools it turns into 'toffee' (again just a comparison) if this happens is some cases you will need to hammer them out, Hope this helps.
 

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I pulled the gas filter, and I realized, I really don't know what normal gas smells like, lol. So a friend of mine came by and let me smell his gas cap. Smells the same, and the filter was clean.
But this is after adding fresh fuel to the tank so I guess I should have thought about that first, it would now smell ok.
also is the noise getting any better less noisy fading or getting worse staying the same?
 
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