Knocking noise

[Hazwan]

I have this knocking/rattling noise that is apparent around 2000-3000rpm but quietened down on 4000rpm onwards. Heres a video Knocking sound - YouTube (http://youtu.be/xEBHX2Mzctw)

Is that piston slap? Or rod knock? How do I differentiate between them two? Or is that something else?

I do have this mark on my cylinder walls when I did my headgasket. I know I should have gone with full rebuild but money was tight (and still tight lol). I was told that it *should* be fine but then I'm a noob with engines hahah
http://i.imgur.com/SEnCdP8.jpg

I'm not keeping this engine for long anyway. I would be more than happy if it last me for a year or so but I was just curious if that noise is just piston slap or something worse.

[Dr_Snooz]

Doesn't sound good. My 4g has piston slap and it sounds a lot more like loose valves than what you have there. Check to make sure that you don't have something rubbing against a pulley, but don't expect that to be the case. Sucks that you get to do an engine swap all across that beautiful paint you just did.

[Oldblueaccord]

We had a GM v-6 that had bad piston slap. It would do it cold and it would oil smoke out the exhaust. Never really hurt anything and it made it way over 150,000 miles. I got rid of it by going to 10w40 Havoline oil over 5w30 that was called for. The oil pressure was always good.

I would be surprised on a Honda this was it its something with the piston design and short skirts.

That wear is unusual looking to me since its like mid stroke in the bore but not at the top. Like the piston pins loose but the orientation is wrong.

EDIT

If you just did the headgasket I would look at the valve train also,really that motor sounds awful and I think its misfiring.

[2oodoor]

Was that piston a different shade than the other 3? There is a distinct line on the right side of that dark spot that doesnt look like the rest of the edges.

[Hazwan]

All 4 cylinder walls have the same spot. Which distinct line are you referring 2oodoor?

What should I look for with the valve train? Timing is spot on, valve adjustments are correct. All ignition components are new and I agree with it sounding rough but I think it has something to do with a vacuum leak around the #4 intake manifold gasket that is confirmed with spraying carb spray around the area and the idle goes up and went a lot smoother. Not even sure if I should go through all the trouble getting the gasket replaced if the engine has a rod knock.

[2oodoor]

Sorry, i didnt read that part, that is strange, looks like bad preignition at some time in its life. The grey spot has a streight edge on it like a crack but its probably nothing.
Knocking sounds bad, cant say for certain whats wrong, it could be bent rod or damage from compressing water.I guess you could pull the oil pan in the car and pull a couple bearing caps one at a time to inspect.
I wish I had something good to say :(

[Hazwan]

I'm not sure what my options are here now. Should I:

- get a low mileage and good condition junkyard motor and drop it right in and hope it would last - this is probably the cheapest and easiest option among them all.
- pull the current motor, get it tested for cracks (refer to the headgasket thread) and hopefully theres no major damage and replace all the bearings etc - I really don't wanna go through all the trouble disassembling the engine and only to find that the block is cracked but what exactly do I have to lose here other than few $$ from having the block/head tested and few hours/days of my time doing it?
- get a junkyard motor and build that up instead and drop it in when I'm ready? - Theres also a risk of the motor being worn/shot and rebuilding it might not be the most economical way.

If anything it would be the best time to go with A20A pistons/rods and bore out the current block and reuse the head - provided that they're in good condition.

Also keep in mind that I don't really have the tools to do a full engine build. I don't even have a way to pull the engine out really. I can borrow/buy the tools but really this is exactly the reason why I didn't do full rebuild when I did the headgasket. I try to avoid taking apart the engine for rebuild but I don't think I can avoid that anyway. Unless obviously I could find a gooooooood condition junkyard motor.

I don't know the history of this engine at all. Neither does my uncle. They could be running the engine with blown headgasket and running/beating it with contaminated oil or even ran low on oil. Who knows?!

[AccordB20A]

i had a simular knock and it turned out to be the bore not being round. Best to locate another block. no matter what it is its bad.

[Oldblueaccord]

Well i google piston slap and clicked images and the first few were just like your picture. Try it the images function is handy.

I guess try some differant oil to minimize it would be the cheapest thing to do.

[Hazwan]

Thats how I do most of my diagnosis hahah! Not just cars too. I do that when I'm sick or something :lol:

But grrr nobody can tell for sure wtf that noise is. Some said its definitely rod knock while some said piston slap especially with my cylinder walls looking like that

[dieselgus]

I am going to say you have an issue with your rod bearings. Your previous posts about what appears to be coolant in the oil makes for short lived bearing surfaces. There may be some piston noise in there as well, but either way either start looking for a complete drop in or start sourcing a rebuild kit and solid machine shop.

You can probably get away with using a heavier oil for a little while, but in the end the main fact is something is way out of tolerance and needs attention.

[AccordB20A]

my piston slap sounded exactly like a rod knock except it got quieter when the car warmed up.

[Hazwan]

Mine never went away even when its warm. I do notice this before when I first started the car cold where the knocking noise is slightly louder for about 2 seconds and it went away. I assume it was loud before oil pressure builds up or something but obviously the noise is there once the rpm is up to around 2500 like in the vid.

I'm using 20W-50 oil right now not sure what else I could use to make it go away LOL. Oh well waiting till January or so till I get the $$$ saved up anyway haha

[Dr_Snooz]

- get a low mileage and good condition junkyard motor and drop it right in and hope it would last - this is probably the cheapest and easiest option among them all.

It's a gamble. If the engine turns out to be toast, it will be anything but cheap or easy. This would be my last choice unless you have a vendor in mind with a sterling reputation in the community.


Also keep in mind that I don't really have the tools to do a full engine build. I don't even have a way to pull the engine out really. I can borrow/buy the tools but really this is exactly the reason why I didn't do full rebuild when I did the headgasket.

You need a hoist to remove the engine, or a $15 come-along and a garage rafter. An $8 ring compressor is also a good idea and a good torque wrench is non-negotiable. If you have the machine shop rebuild the head and prep the block, then most of the rest can be done with the tools you already have. Having had a used engine swap go horribly, horribly wrong, I vote for doing a proper rebuild yourself. A full rebuild won't be much more than a used engine done properly and will be quite a lot cheaper if the used engine turns out to be bad.

[Hazwan]

I think you are right. Unless I could find a used engine that has been rebuilt say 20k miles ago from someone I personally know - which I doubt I would even find one. Low mileage almost 30 year old engine is probably non-existent anyway.

I just asked around and I know someone that could lend me an engine hoist + misc tools. And I already have a torque wrench so I think I should be good to go.

I'm just worried that I might screw something up since I honestly suck at doing anything that requires precision and cleanliness. I probably would screw up with measuring the bearing clearance for example. Or I might get dirt and crap on them or something. Or put the rings wrong. Stuff like that -_-

[AccordB20A]

theres a brand spanking new a20a for sale in NZ. BRAND NEW

[Hazwan]

Fml I would kill to have that. Factory fresh > anything. Unless it was done by a real pro. And i mean real ones not some dumbass mechanic that think they're better than the engineers. Fuckers.

[AccordB20A]

if it was a b20 it would be mine but sadly not lol. they want too much for what it is

[Hazwan]

Alright so I'm puzzled with the noise still. It would come and go randomly. It surely won't go away if its rod knock right?

I pulled my timing belt cover and saw the belt randomly flop around. Is this normal? Its not much and doesn't do it all the time but it doesn't look right to me? Belt is tight btw

Belt is new but tensioner was reused. Stupid I know but I replaced the timing belt because it was soaked in oil when I did the headgasket. Belt looked new and same goes with the tensioner. I thought I would save some money lol

MVI 3266 - YouTube (http://youtu.be/4_3HtPzxP_g)

Look at the front side of the belt flopping around 0:08 and 0:14.

MVI 3267 - YouTube (http://youtu.be/PhPdWnfQfEo)

Ignore the ps belt haha

Video quality sucks so you probably won't notice unless you look closely. But it was pretty noticable in real life.

I did not see the tensioner bouncing but then it was dark and it was well hidden behind the lower cover anyway. Could it be the tensioner?!

[2oodoor]

It didnt look too bad to me. Are you losing or using any vital fluids everyday? Definatley hear the sound.

[Oldblueaccord]

Alright so I'm puzzled with the noise still. It would come and go randomly. It surely won't go away if its rod knock right?

I pulled my timing belt cover and saw the belt randomly flop around. Is this normal? Its not much and doesn't do it all the time but it doesn't look right to me? Belt is tight btw

Belt is new but tensioner was reused. Stupid I know but I replaced the timing belt because it was soaked in oil when I did the headgasket. Belt looked new and same goes with the tensioner. I thought I would save some money lol

MVI 3266 - YouTube (http://youtu.be/4_3HtPzxP_g)

Look at the front side of the belt flopping around 0:08 and 0:14.

MVI 3267 - YouTube (http://youtu.be/PhPdWnfQfEo)

Ignore the ps belt haha

Video quality sucks so you probably won't notice unless you look closely. But it was pretty noticable in real life.

I did not see the tensioner bouncing but then it was dark and it was well hidden behind the lower cover anyway. Could it be the tensioner?!


Belt looks ok to me. That's why I run them tight. Loose belt the car will ping a little in between shifts if you really bang the gears full throttle. That's the belt slap you see on off throttle messes with the timing a little.

If your knocks not gotten worse by now Id just run it.

[Dr_Snooz]

I'm just worried that I might screw something up since I honestly suck at doing anything that requires precision and cleanliness. I probably would screw up with measuring the bearing clearance for example. Or I might get dirt and crap on them or something. Or put the rings wrong. Stuff like that -_-

It's always possible that you'll screw something up. Yet you're less likely to screw up than a shop because at least you care about what you're doing. If you do screw up, you'll learn something. The manual is exceptionally good at telling you exactly how to do all the things you listed above. Just read through it carefully a few times and keep consulting it as you move through the project. For the dirt, clean your work space before starting. Then wrap the block in a big plastic bag and cover all your parts each day after you're done. Don't set up where there will be a lot of leaf-blowers in use, power saws, etc. Use lots of assembly lube and never use a ratchet where a torque wrench will do. Don't worry too much about dirt. There is always dirt circulating through the engine. That's why your oil turns black. As long as you don't wedge a sand grain in one of the rod bearings, you'll probably be fine. If you drop a bearing on the floor, wipe it off before installing it.

But like OldBlue says, run it as long as it holds, until you can afford to fix it. If I were you, I'd install an oil pressure gauge so you have at least some warning before it fails and leaves you stranded. If you're like me though, the increasing noise level will drive you to fix it long before it fails.

Belt looks fine, BTW.

Edit: Oh yeah, and before installing any oil seals from a kit, make sure that they are soft and new. There are a lot of 30 year old engine kits sitting around on parts shelves out there.

[Hazwan]

Not losing any fluid. Coolant and oil level stayed full. Knock doesn't get worse, only better sometimes. There are times where it would be barely audible which leads me to believe that it can't be rod knock?

The reason why I suspected the tensioner is because it was reused and it jumped a tooth once months back but not sure if it was just me not tightening it properly and worked itself loose or something. But when I redid the belt, I remember turning the crank counter clockwise about 1-2mm before the cam pulley would start to turn. Tensioner/belt is as tight as it can be. I can push the belt and it won't deflect and yet theres a slight lag before the cam pulley would start to turn when I'm turning the crank pulley. Is this normal?

I wanted to make sure or at least hear other people's opinion first before I start spending unnecessary amount of money on things.

I do have an oil pressure installed but its not hooked up yet. Still waiting for my T and adapter stuff before I could install the sending unit. Curious to see what my oil pressure reading would be too!

[Hazwan]

So is this loose or what Belt slack - YouTube (http://youtu.be/BaoWgAgw4iY)

[2oodoor]

Just curious if you tried using a long screwdriver and probing it to various regions of the motor:touching it to like tbe bell housing and putting the handle end to your ear, you can sonetimes isolate the area of knocls and ticks. Exampke is you can touch it to valve cover and it sounds like youre inside there loljust be careful of moving parts.

[Dr_Snooz]

Remember that you have bad bearings and a lot of rotating mass at the crank. With loose bearings, the crank will tend to continue rotating after the cam has stopped, leading to belt slack. Even if you replaced the tensioner, chances are you would still use the old spring, so it wouldn't change your situation at all.

[Hazwan]

Just curious if you tried using a long screwdriver and probing it to various regions of the motor:touching it to like tbe bell housing and putting the handle end to your ear, you can sonetimes isolate the area of knocls and ticks. Exampke is you can touch it to valve cover and it sounds like youre inside there loljust be careful of moving parts.

I did. But I can't isolate the noise origin exactly. Besides the so called knocking noise is kinda hard to hear really. I should try with a longer screwdriver or something.


Remember that you have bad bearings and a lot of rotating mass at the crank. With loose bearings, the crank will tend to continue rotating after the cam has stopped, leading to belt slack. Even if you replaced the tensioner, chances are you would still use the old spring, so it wouldn't change your situation at all.

What do you mean old spring? Timing belt tensioner spring? I thought they came as one part?

[2oodoor]

Another trick is, if the noise is audible in neutral, unhook one spark plug wire at a time at the dizzy, if the noise stops one one that is cyl in question, combustion is pushing the rod or piston to the point of knocking.

[Hazwan]

Its inaudible in idle. I have to get someone to hold the throttle at 3k rpm if i wanted to do that, which I still haven't got anyone around to help haha

I still need to hook my oil pressure gauge and see what's up tho

[Oldblueaccord]

Stick something on the cable side of the tb to get it to hold rpm.

[Hazwan]

Damn, never thought of that! Yeah I should be able to turn the idle screw up to 3k rpm where the sound is very noticeable and work from there.

Also, I think my oil pressure gauge is dead. Went through all the trouble I stalling a sandwich plate between the filter and long story short, managed to ruin the threads, some leaks, made a mess on the floor and some other shit not worth mentioning only to find that the gauge won't read shit :mad:

Why is that I have worst luck possible with this car? I swear it's cursed!

[Hazwan]

knock knock - YouTube (http://youtu.be/uqriHKqC4Co)

There. Listen for the knock around 0:16 when I put the plug wire back on. Horrible video quality though, you can barely differenciate the exhaust noise and that knock lols

[Hazwan]

OKAY this is so fucking weird. That same noise is no longer as loud when I started the car up earlier and its inaudible at idle and barely even there when I revved it up to 3k. Used to be so loud at 2700-3000rpm. Am I over-analyzing shit? What does pulling that plug wire test conclude? I mean that so called knocking noise went away when the plug wire is off. Just the #2 cylinder too. The rest doesn't make a difference with the noise.

Even if it was rod bearing noise in the vid, then WHY DOES IT GO AWAY LATER THAT DAY grrrrrrrrrrrr surely a rod knock wouldn't get better by itself?

WHY FUCK UGH THIS THING IS CURSED I'M TELLING YOU

[Oldblueaccord]

OKAY this is so fucking weird. That same noise is no longer as loud when I started the car up earlier and its inaudible at idle and barely even there when I revved it up to 3k. Used to be so loud at 2700-3000rpm. Am I over-analyzing shit? What does pulling that plug wire test conclude? I mean that so called knocking noise went away when the plug wire is off. Just the #2 cylinder too. The rest doesn't make a difference with the noise.

Even if it was rod bearing noise in the vid, then WHY DOES IT GO AWAY LATER THAT DAY grrrrrrrrrrrr surely a rod knock wouldn't get better by itself?

WHY FUCK UGH THIS THING IS CURSED I'M TELLING YOU

Its telling you #2 rod bearing is probably bad.

But in the end game you know the motor is bad not much you can do to it. Maybe cheat and drop the oil pan and just change the #2 bearings.

[Hazwan]

Few things that I noticed. It would make the same noise during first cold start up for the first few seconds until the oil light went away and continues to run without making any noise and even if its any its gonna be barely audible at 2700rpm onwards.

As soon as the engine is up to its operating temperature, it starts to get louder at 2700rpm onwards.

Earlier on I noticed the oil light flickering when I'm under 1000rpm when its warm. Doesn't do that when its cold, ever.

I plan to take the pan off tomorrow and pull the #2 cap and see whats up. IF they appears to be fine, which I doubt it would then I'll just clean the oil pickup tube and try different engine oil since I have some cheap crappy 20W-50 oil right now. It appears to be super thin when its warm and I thought they're supposed to be thick when its warm and gets thinner when cold? I've compared the oil in my engine with the one in the bottle and the unused oil in the bottle appears to be thicker?? Perhaps the crappy oil broke down or something?

If the bearings are worn and the crank doesn't seem to be messed up really bad then I might try replacing the bearings and hopefully it would last for a while at least till I get another motor. I don't expect for this fix to last forever anyway. Remember that I have a mysterious headgasket/crack issue that was fixed by a hg sealer thing. Its probably won't last long or worth fixing anyway but bearings are cheap and worth a shot..

[MrSalty]

This is just a shot in the dark here, but: Valves?

Edit: Just read the beginning of the thread. Report back in tomorrow and let us know how it goes.

[Hazwan]

Pulled the pan off and I found this
http://i.imgur.com/sAkcTlk.jpg

http://i.imgur.com/Js1noQn.jpg

http://i.imgur.com/NBITe6r.jpg

http://i.imgur.com/NmmfMsr.jpg

http://i.imgur.com/y4cuDY0.jpg

http://i.imgur.com/q01Sjjc.jpg

http://i.imgur.com/8nEdFj4.jpg

I blame rust from the engine been sitting too long with contaminated oil from the PO. I believe its been sitting for over a year and based from that rusty oil pickup tube, I'm pretty sure the bearing surfaces aren't any better :( It was my fault for not pulling the pan off when I did the headgasket before too. Oh well...

Not sure if slapping new set of bearings gonna buy me some more time. Should I even bother fixing this? Keep in mind that block sealer fix is a ticking time bomb. It may or may not fail again and my headgasket issue might or might not come back. I know the best option is to get a whole new motor.

I kinda want to replace the bearings and call it a day and hope it would last for a few thousand miles at least until I could get another engine or should I just save the money, park the car and find a replacement engine right now?

[Oldblueaccord]

Pulled the pan off and I found this
http://i.imgur.com/sAkcTlk.jpg

http://i.imgur.com/Js1noQn.jpg

http://i.imgur.com/NBITe6r.jpg

http://i.imgur.com/NmmfMsr.jpg

http://i.imgur.com/y4cuDY0.jpg

http://i.imgur.com/q01Sjjc.jpg

http://i.imgur.com/8nEdFj4.jpg

I blame rust from the engine been sitting too long with contaminated oil from the PO. I believe its been sitting for over a year and based from that rusty oil pickup tube, I'm pretty sure the bearing surfaces aren't any better :( It was my fault for not pulling the pan off when I did the headgasket before too. Oh well...

Not sure if slapping new set of bearings gonna buy me some more time. Should I even bother fixing this? Keep in mind that block sealer fix is a ticking time bomb. It may or may not fail again and my headgasket issue might or might not come back. I know the best option is to get a whole new motor.

I kinda want to replace the bearings and call it a day and hope it would last for a few thousand miles at least until I could get another engine or should I just save the money, park the car and find a replacement engine right now?

Well good work on the find.

If you can get the bearings easy,cheaply id try it. Clean up the metal mess best you can.

You can rig a flexible piece of metal to push out the upper bearing and maybe with some 400 grit wet dry sandpaper clean up the crank a little and your off to the races.


I guess hindsight being 20/20 I forgot about cutting open the oil filter to see whats in it.

[Dr_Snooz]

Egad, what a mess.

[Hazwan]

Replaced the bearings earlier it was only $15 for whole set. Except.. It wasn't really a rod knock :(

Yes I am aware that my crank isn't perfect but I did get rid most of the surface imperfections. I know the new bearings could be damaged again but the same noise returned when it's warmed up. Exactly the same loudness and happens at the exact same rpm range. Went away/barely audible when it's cold and also above 4000rpm.

No more flickering oil light tho. Noise went away when I pulled the #2 wire just like before.

I think they're totally unrelated. Those messed up bearings are just coincidence probably. The more I search and watching YouTube videos about rod knock, the more I realize that mine doesn't sound like them. Found a couple of vids with the exact same noise and they said it was wrist pin noise. Makes sense but then I'm not a mechanic or have any experiences with troubleshooting engine noise so I don't know..

Stupid thing. Its cursed I'm telling you

[2oodoor]

Ooh contraire Haz, you are becoming an expert on engine noises , great thread too.
Your overall conclutions up to this point are spot on.
Oil contamination a big culprit, never use cheap oil except in urgent terms, if it is losing pressure it could be oil pump seals if that pump is like a20 pump,. If there is concern the cyl walls have divots maybe that additive called "Engine Restore" wud help. Its for real product pros use. It remains a lube similar to sae 30 , yet some how it hangs on in the finer line cracks to improve compression and it can reduce piston slap by the same means.Edit: on the other hand if this is excessive wrist pin wear the noise could get worse or change when it happens because this seems like a "radial static" type produced noise since it's erratic, diff rpm and temp when it shows up, dare I compare it to a out of balance tire to explain what I mean.

[Hazwan]

I wouldn't say an expert but I definitely learned a lot about engine noises now :lol:

I didn't replace the oil pump seal when I did the timing belt. I did not realize that I need to replace it :(

I started the car earlier (cold start after sitting for over 6 hours) and nope zero noise. Revved to 3k nada sounds just like a normal engine. I'm pretty sure it wasn't rod knock now! If my bearings are gone by not-so-perfect crank journals then the noise shouldn't come and go like this?! Not even sure wtf the noise is now.

Piston slap - only audible when its cold and disappears when its hot right? exactly the other way around in my case and doesn't really sound like it, at least from the videos I watched
Rod knock shouldn't go away when its cold. Besides I have new rod bearings and its still making the exact same noise?!
Main bearings knock should sound all the time too right?
Loose torque converter bolts? I was an idiot for not checking them while the pan is out thinking it was the rod bearings because of the obvious damage but then the sound should be there all the time and not just accelerating/under load/hot
Wrist pin - not 100% sure. Thoughts??
Timing belt tensioner? People told me that "play" in front of the engine side is normal

Ruled out accessory belt driven items
No loose parts that might cause the noise

WHAT ELSE AM I MISSING?!

Oh well I think I'll live with this noise unless I could find something else that I could try and fix for cheap/easy. I wouldn't say replacing the bearings yesterday is a waste of time and money. After all it was just $50 for all the bearings, oil, filter, pan gasket and some misc shit. Well worth the money IMO, I've learned a lot and I'm really confident to build another engine now :)

[2oodoor]

On an a20 the oil pump has a rubber seal between the two parts of the pump as well as almost identical seal between pump and block. That 'sandwiched' seal can get cracked and cause intermitant oil pressure drops. Kinda like a bad heart valve, its pumping fine but internal hemmoraging ..or low flow/radical comparison lol. The actual pumps are tough, just those seals get brittle.
Torque converter cracks and bolts are phathom noises indeed.