Just built a b18c6 motor up.
I hear a knocking noise yesterday pulling up after the first serious thrash. Thinking rod bearing screwed. Nothing obviously wrong and its not noisey enough to be rod and also was quiet from 2k rpm upwards as i limped back to shop 2 mins up road. Pissed off i go home and look afresh this morning. Start it up its quiet. Let it warm up. Its quiet. Take it for a drive its quiet. thrash it a little and its quiet. Come back to shop its quiet after 7 mins beating up the road and back. Restart engine 10 mins later and it sounds like a diesel again. So i pull the oil filter and cut it open, drain oil and pull sump too. Couple of flakes of shell material so i think spun rod. Pull centre mains and all rod caps from under car. Brand new. So maybe the shell material is a couple bits that were stuck under sump baffle from last engine which spun rod.
The noise seemed to be from around cyl 3 when listening to motor. Adjusted valve clearances a couple of times due to some top end noise as cam grinder gave me wrong clearances.
Compression and leakdown good.
Crank float fine.
Logging shows nothing - temps good and constant as is voltage and anything else.
Searched the forum and see suggestions of lmas and ac/ps belts and crank pulley as possible causes. Most people haven't pulled bearing shells so the threads kind of go downhill from there.
I used the original oil pump and relief valve. Stripped them and they were good. Maybe i should have replaced.

Just hoping someone else has seen the same problem.

 

when it does it again. pull one spark plug wire out at a time while its on to see which cylinder is knocking

 

piston to head clearance ?

 

what cams and springs? went in the same head?

i had a very similar problem, my vid is still floating around. went back to oem cams and no problem (lobes worn or cam not straight) make a very similar sound to rod/bearing knock.

 

How was the piston to wall clearence? Piston slapin the walls? In my experiance piston slap is a variable RPM thing. (happens at one RPM but not another).

 

Piston to head just over 40 thou.
Cams have a little more lift on main cam than stock but quite a bit more duration. low/mid are about 40 thou up and a little more duration.
Valve springs to suit cams.
All clearances are good to go.
Still scratching head here.
Oil pressure valve had some shiny spots and a tiny metal particle sat on top. Who knows wtf????
Thanks for input guys.

 

what is your compression and gas used?

 

Compression 13.6
Shell v-power
Fresh built motor

 

Its not spark knock is it?
Have you tried taking some timing out of it? Thats some high compression for pump gas.
Sound clip?

 

Doesn't sound like knock and its only under 2k rpm when hot but you never know. I have the sump and centre mains and pressure relief valve out of it at the moment.
Waiting on a new pressure relief valve to arrive then i will try it again. The valve had some tiny polished marks at the top and there was a minute piece of metal jammed up on top of it, god knows how it got in there!!
Will try and get a sound slip.
I noticed the power steering pump belt was a little too tight also.

 

Perhaps your onto something with the pressure relief valve sticking from debris.
Do you have a oil pressure guage by chance?
Stock bearing clarances? I cant see how the ps belt could affect it, but who knows. you could remove the belt and retest if your unsure...
good luck!

 

Somebody seems to have stolen my pressure guage so i will get a new one and take reading when i run the motor next. Is it better to take a main gallery check or is it ok the just take it off the blanking bolt by the vtec solenoid?

 

I would probably check the main galleries or where the stock dummy unit resides. Even though theoretically, the pressure should be the same, I think it would be more accurate.
What weight oil are you running and what are your clearances if you dont mind me asking?

 

10w/40 at the moment.
I think the clearances were 1.6thou main and 1.5thou big end off top of my head. The build sheet is at work and i'm at home. I built the bottom end 6 months ago so its hard to remember.

 

http://www.youtube.com/watch?v=hKwVIeGMJEY

sound like that?

 

Pretty close to that but a little less of a clack and more of a dull sound. It seems to be coming from lower and more to the front. I will try and pull the cam belt cover and run it again. But weird thing is i can start car up and it will be quiet, have to thrash it up the road then come back with it hot before it MAY make the noise.
I'm hoping it may be the oil pressure relief valve. Going to blue the end of it and spin it in the pump later on as it didn't look like it was seating in there properly.
Forgot to add i have darton liners installed. Sure that has nothing to do with it but you never know. Could be new materials singing differently. Who knows.
Thanks for all your input guys.

 

dam, well if it never happens when its cold, and more often when its hot, and goes away from 2k rpms and up...Sounds like all the symptoms of a rod knock...
Try like someone said before and pull injector clips or plug wires to see what cylinder is really making the knock. And if the noise goes away when you disable that cylinder, thats another sign its a rod knock...
Good luck!

 

Well started it up again today.
Its still knocking. Listened very carefully as it warmed up. Definately noisey around the cam belt area. Checked belt tensions. Still noisey.
The ignition advance at tickover was 20 degrees. Backed it down gradually to 10 degrees. Noise did not change.
The fans then decided they would not come on so it decided to start overheating a little. I gave up and went home.
Will try it again when i get 5 minutes with the cam belt covers off to see if that points to anything.
Anyone know what noise the water pump will make when its had it? Just weird that fans did not come on yet water temp was too high. Is the fan temp control in the radiator and the ect pickup in the block? That might say something.

 

From what ive seen, water pumps sometimes make a light knocking noise when they go out, but ive seen some that make no noise at all...
Since its a fresh rebuild, i would assume the waterpump is OK.
I think the "fan/temp switch" is by the thermostat housing. 2 pin connector. When it hits a certain temp, it closes the circuit and the fans come on.
You can unplug the connector and jump it to see if your fans are working...

 

Connector was unplugged. I was going to get the motor out the other day so one of my customers/friends offered to do it for me as i am very busy right now. He had only got started when i said to hold on and decided to pull sump and big ends first with engine still in. Well in my rush to find 5 minutes for the car it got missed.
I found one of the cam pulley bolts was loose. Hoping it was just that. Again i can't believe i missed it, very embarassing. But my own projects are always done in the spare 5 minutes per week i have. Going to test drive in a bit, just have some valve seats to cut first. Wish me luck.

 

I had a similar knock sound on my buddy's b20 vtec and it may sound crazy but it ended up being the crank pulley moving back and forth on the wood ruff key, the key was either worn or in wrong and didn't fit quite right so the pulley was rocking back and forth on it , and it only did it randomly. Made it sound like rod knock from drivers side of block.

 

Well it seems good now. Looks like dumb **** here didn't torque that one bolt right. Makes sense as i was missing the one cam bolt and it came in from honda a few days later. Car good now Thanks for the help guys.

 

Good to hear you found the source of your noise. So the Cam gear bolt being loose made that noise? Interesting!!! It could have been alot worse.
Its easy to make mistakes, dont sweat it. Just be glad it didnt do any damage!

 

GOOD THREAD!!

 

Still can't believe it was that. The noise was worst on the block around cylinder 3. The rocker cover was pretty quiet. But i've been thrashing it around since (aka running it in) and its dead quiet. Shows how tough it can be tracing a noise i guess.