When I put my engine together I left one loose and it sounded like bearing gremlins. I re-torqued all of them down to 15 wrist-lbs and it was good to go.

 

I was going to check play on the no. 1 piston last night but didn't have a log enough rod (heheh). I'll try again today.

I'll probably have a pretty long write up of stuff tonight after I work down this list.

 

I just went over all the cam caps at 125 in-lb (top of the spec) and they were all good. Oil looks fine to me as well. The darker spots look to me like the arp lube I used for my head studs.

I just checked my alternator belt and it is very loose. There also seems to be more play in the water pump pulley than there should be, when I yank on it back and forth. Going to make sure the alternator is all good before I look elsewhere.

EDIT: Getting the alternator sorted out had no effect. I'm going to try pulling the belt altogether next to rule out the water pump.

 

Drain some oil from the pan, I to a container. Shine a light to it. Look for sparkles. Paper towel is useless.

Needs an oil change anyway.

 

Remove water pump belt first.
Our failec water pump was a gates pump with the cast impeller and it failed within 5k miles. Another friend had the same failure at the same mileage.

 

While it may be something deep in the engine, (rod or main bearing) I'd spend as much time identifying the general location of the sound first even if it eventually ends up being a total disassembly.

Cheap investigations first:
1) drain the oil (FIRST) and have a look. Possibly get an oil filter can opener (don't use a hacksaw or anything that makes filings)
2) I like pulling the plug wire BUT, it looks like you are using a set of stock NA coil packs so, wasted spark ignition. Cylinders 1 & 4 plugs share a coil as do cylinders 2 & 3. Pulling plug wire for cylinder 1 cuts off the spark for both 1 & 4. similarly for 2 & 3. The significant loss of RPM may result in a quieter engine... Try reving the engine to idle RPM with the plug wire disconnected and see if the sound returns
3) I agree with sixshooter "I'd spend $10 on a mechanic's stethoscope and listen to it from above and beneath..." Listen to everything. each injector to see if one is different, the intake and exhaust manifolds at the port for each cylinder, lower block near each main bearing, etc. 15 min with a stethoscope can provide lots of info.
4) check everything with a belt - cam belt tension (were cam's pulley and belt tensioner bolts tightened?), bad water pump, alternator, power steering pump, etc. And Crank pulley (as mentioned earlier)
5) NA hydraulic lifters? possibly one is dirty, partly seized/sticking (sounds louder than a bad lifter though)

A really loose rod bearing will have a charistric double knock at low RPM something like ".....knock-knock.......knock-knock......"

 

First off, did someone say start it with the valve cover off? Don't do that.

Start tearing down the engine. Yes, it may be something like pulley bolts or flywheel bolts, with as loud as it is you'll find whatever is wrong as soon as you see it. As for the flywheel bolts, you don't need the loctite to keep them from spinning out, they don't magically spin out without the loctite, they just leak oil.

If the sound gets significantly better by pressing the clutch, there's a chance you installed the trust bearing backwards and starved it of oil. But with that much noise, there's going to be a lot of pulvurized thrust bearing in the oiling system now, ruining rod bearings, main bearings, cam journals, etc, so don't start it again. You can check for crank end play by prying the pulley against the sway bar to push the crank back, then using the throwout bearing to push it forward. Lots of videos online from the early 99-00 failures.

 

To all the people talking about glitter in the oil:
Some is normal from the rings and bores wearing in. On every engine I have built I have seen some glitter in the oil (with a flashlight) after the first 50 mile drain, even on new cars. Other than that I have nothing constructive to add.

 

Thanks for the input everyone. I'll be out of town for the weekend so probably won't have any more progress until Monday evening.

I am leaning towards just pulling the motor to diagnose; it's easy enough to do. I'm also thinking about dropping in another motor to keep the car on the road while I tear apart the other.

 

Stock coils will still happily fire the plug on the remaning lead (ie: pulling the lead from Plug #1 wont stop #4 firing)

I've done it heaps of times on both my gf's NA, and my NB when troubleshooting.


(unless you were talking about removing the plug on the base of the coils, with the power/ground/ecu, that will kill the spark in pairs)

 

Just had a go at checking the crank endplay. I don't have a dial gauge to measure properly, but it seemed normal. It was actually rather difficult to see that it was moving at all.

Another note: I've got a small oil leak at the back of the motor which I didn't have before the bad noises.

 

Bearing failure on startup is not unheard of. I've had it happen to an engine I built. Same specs, same machinist, same process as the dozen that came before it and the dozen that came after it, but something went sideways and it ate a rod bearing about 30 minutes into break-in. Sometimes **** happens and you get unlucky. Pull it apart, verify a failed bearing visually, pull it apart, flush the block and head extra-careful, have the Boundary pump R&Red, and go again. If you caught it early enough, you can reuse just about everything. Let it run too long and the metal content in the oil will scuff all the pistons. Let it run way too long and heat damage will ruin a rod or two.

 

A while ago I retapped a few taps of my turbo. Therefore i removed my exhaust manifold. Later on, when everything was reassembled, there was a horrible sound coming out of the engine bay. It sounded pretty similar to yours. After hours and hours of search, endoscoping and so on, it turned out to be the manifold gasket.
I would never ever have thought that this part is able to produce as horrible noises as it did. It sounded like there was knocking metal on metal(which likely was the case/ oem multilayer metal gasket), similar to rodknock and very loud . So may check this. Just unscrew the nuts of the manifold an torque them back down. Its may worth the 20 minutes.

 

After watching your video, it seems to sound very similar to something i went through recently. I had my head rebuilt and after we put it on and went to start the car we heard a terrible smacking noise. It sounded like rod knock, and very similar to yours. Mine ended up being that the timing belt was skipping. Visually there was nothing wrong with the cam, or the caps except one small gouge that was very small. We swapped in an extra cam that i had laying around, and replaced the one cam cap that had a small gouge in it. After that i have had no issues.

Could be something to look into.

https://drive.google.com/file/d/1-X4...ew?usp=sharing

 

Interesting. I'll check out the exhaust studs as well as timing belt again and cams again as that does sound similar. Not much time to spend on the car this week though and I'm away this weekend as well.

 

I sent out an oil sample for analysis and checked things out with a stethoscope while turning over the car with plugs pulled. Without the engine firing I could not hear any unusual noises, even with the stethoscope. Otherwise not much progress, as I've been busy with work, school, and the other car project.

 

updates?

 

​​​​​​Literally just got this back this morning. Looks like bearings to me, but I'm no expert.



Bonus pic of one of the other projects:

 

I'd also recommend checking your cam gears are bolted on tight, I had one loose that sounded like that.

 

While true your oil analysis shows larger amounts of some of those metals, there is a reason why you are supposed to change the oil about 100 miles after building an engine. it is expected for some metal particles to be in the oil. I would continue inspecting the engine to determine what could be causing the noise and isolating things at a time like the alternator / water pump belt and giving everything a good once over.