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

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


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

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

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

MVI 3267 - YouTube

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

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

MVI 3267 - YouTube

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

[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.