I made a post about this a while ago and nobody seemed to know what I was talking about.

I've had 3 higher mileage d16 motors do this now, so I'm not crazy.

When the engine is cold and driven under very light acceleration around 3k, or right at that point where I am maintaining speed, I hear a very noticeable knock or tick. As the motor starts to warm up, it gets more and more faint. After it's fully warmed up, it's gone. When it's really cold out, I hear it between every shift until it warms up.

First thing that comes to mind is excessive clearance somewhere that swells when it gets hot, lowering the clearance / noise. What do you think? Other people must have this same issue. The last 3 d16s I had all did this same exact thing.

 

if it was piston slap it would be crazy cold and when its hot the pistons expand a bit so it should be quieter. i think its just a natural thing for d15/d16s to have a slight valve tick its nothing bad. they just do... its a staple they are known for like the LS motors valve ticks and deep deep sucking sound LOL. Rod knock is more of a clunk and constant, valve tick is a tick lol , piston slap usually when cold but more ticky also

 

But since it only does it at the point where the motor isn't under a load (accel or decel), it tells me its something like a rod bearing or a pin that can freely move when the motor isn't under load. I've been driving the one I have now for a quite a while, and it seems to be slowly but surely getting worse over time.
It's definitely not normal, very audible.

What sucks is it's not like I can drive it and put my stethoscope on the motor. I cant reproduce it in the garage, and I can only do it on a cold start. I'll check the valve lash and some other things, and if I dont find anything, I guess I'll leave it until it gets really bad.

 

if the noise goes away when the engine gets hot, then its most likely piston slap. a spun bearing doesn't go away, it gets worse and will eventually kill the engine.
excessive valve lash will always make noise hot or cold.

im willing to bet its piston slap

 

You're right, I agree. I have had multiple indications of both on Honda motors. They were all sudden instances though, not gradual like this. Valve noise is usually obvious.

Piston slap meaning between the piston and the pin, or on the ring lands?

 

piston slap is either when the cylinder gets tapered really bad and allows the piston to rock back and forth, usually on the bottom of the cylinder. Or the skirt of the piston broke off and is moving around at the bottom or top of the stroke. more often then not, tapered cylinders are the cause. semi easy fix if you catch it in time.

 

Piston slap is perfectly normal, mine does it, and it still runs great.

I let it idle until the idle drops and then just drive it nicely untill it gets to normal temp.

 

my connecting rod bearing is done and i am goin to replace it .. but im not sure i need to install a larger sized bearing or just a stock sized bearing please help mee out ...

 

as i was saying my engine is knocking and i need to replace the connecting Rod bearings but im not sure whats size too use .. Stock or Larger sized
its a 1992 1.5 Automatic Honda Civic

 

i wouldnt say its perfectly normal. a tapered cylinder thats allowing the piston to move in a direction other then honda intended is not normal, ESPECIALLY if its caused by a broken piston skirt.

 

how do you know your connecting rod bearing is done?
chances are if the bearing is spun, your gonna have to get the bearing surface bored out and get a bigger (thicker) bearing installed.

 

youd be better off just buying another 1.5 unless you wanted to build your 1.5 . if you just plan on leaving the engine stock, it would be cheaper and easier to get another used 1.5

 

Your correct, however it is impossible to prove this without taking the engine apart and finding out for sure.

Quite a few people I know Including my self will agree, Piston Slap is normall.

Also, this came from a guy that has been working on honda's for longer than I have been alive.

 

Piston Slap is caused from excessive piston to cyl wall clearence. It always goes away once it warms up; thats one way to tell if you have a piston noise or not like others said.

 

I'm aware of what the normal piston slap noise is, for I've had fully built / sleeved motors which allow for that above normal piston to wall clearance. This sounds different though. I think I will make a video to show you guys.

Even if I allow the motor to warm up for a while, I still have to hit full operating temp and then some to eliminate the noise. I usually hear the noise all the way in on my 2 mile drive to work.

With that extra clearance, it means I can boost it, right?

 

I have seen that said before, more clearance means the piston can expand more.
Some say it is better to boost high milage motors ,but idk?

Are you low on oil?

I remember my friends car making some sort of noise and we played it off as piston slap. Turns out it was a rod bearing on its way... out of the block.


I think the very important thing is, It goes AWAY. If this were rod knock it wouldn't be going away.

 

might be normal,but its not good. i guarantee your engine never slapped when it was new. its from excessive movement which causes excessive wear.

true, only way to see if you have piston slap, you would have to tear down your block

 

I am not saying my car did this when it was new, I wouldn't be a happy camper if it did.

It is just a sign of age, a very normall sign of age.

With 200+k parts are going to get tired, it just a fact we deal with. Honda's motors are extremly reliable, but there isnt anything you about wearing parts over time.

 

ino but i cant afford that right now so i just removed the oil pan and head to install new connecting rod bearings so in eed to use thicker bearing do you by any chance no the size measurements thnx

 

Never do anything without precise measurements. You cant just slap in new bearings, it will never last. Tear it down and do a full rebuild or get another $100 motor.

 

You arent going about this in the correct way. You have to measure, you cant just slap bearings in and call it good. Well you can, however you will be tearing this motor down again and replaceing everything again, or worse, throw a rod, and damage the crank.

Did you spin a bearing? If so, I have seen cranks destroyed after a spun bearing, not to mention damaged conecting rods.

 

ok, i was saying that its not good, and you were saying that it was common lol glad we can disagree to agree. its common in alot of engines that get "old"

 

Exactly, even honda will say piston slap is common/normall/ ok, as long as it goes away.

If it doesnt go away, then you have a problem and something to worry about.

 

if your gonna do it this way, just send me the money, put the pan and head back on ( why did you take the head off in the first place?) and wait for your engine to blow. youd almost be better off just leaving the old one in and saving up money to get the engine rebuilt. the new bearing will not last longer then a 1000 miles and will prolly end up doing more dmg to the engine then the old spun bearing.

not trying to sound like an a$$ but theres no point in putting in a new bearing if your not gonna do it right

 

im trying to rebuild. i didnt use enough oil and now my engine knocks ,could put some lucas oil stabalizer in there itll stop the noise .But not trying to go that way i have my car tookn apart Head , oil pan, and pistons out now im just trying to find the right bearing size
Any exact measurements anyone or does it depend on how much wear the rod has