My engine is noisy around 3k rpm - w/ pics of internals

General engine questions/issues that aren't specific to the other categories
 Reply
User avatar

My engine is noisy around 3k rpm - w/ pics of internals

By teal_dx
- Sun Aug 26, 2007 6:43 pm #21188 Lately, I've noticed that my engine is noisy from around 2400 to 3200 rpm. It is not a low pitch knocking sound, but similar. I thought maybe it could be pre-detonation but I retarded the timing and it is still the same.

The motor is a D16z6 with Eagle forged Rods and forged SRP 75.5mm pistons. The block was bored .020 and recieved all new bearings & micropolished crank. The motor has 1600 miles on it.
Now I've read that forged pistons are noisier than cast... but this noise has only been happeneng for the last 400 or so miles.

The valves were just adjusted around 1000 miles, everything on this motor is brand new or OEM except for the parts above, and ARP head stud kit and XTD stage 3 clutch and 8lb flywheel, and MSD Blaster 2 external coil & cap.

I have zero sound deadening on the car, so I can hear a lot more engine noise than usual through the firewall, so I'm not trying to be too paranoid.... Maybe I just have a loud motor - it runs absolutely perfect.

The sound has me a little concerned though because I'm ready to put the turbo on it and I'd hate for something bad to happen after all the time/$$ that went into this setup.

Also oil pressure is about 50 psi while cruising around town in 5th gear, ~ 25 psi at idle in neutral, and ~ 75 psi while accelerating. I broke it in giving it a little more RPM over time. the car does not smoke at all and the engine runs so strong that I have not even been in as big of a hurry as I should be to get the turbo on. :lol: (slowly but surely)
Last edited by teal_dx on Wed Sep 05, 2007 12:50 am, edited 1 time in total.
User avatar

By Sire
- Sun Aug 26, 2007 9:57 pm #21210 Sounds like the rod bearings... :? You could check by pulling of your sparkplug cables one by one while letting the motor run, if the sound stops, that's the cilinder wich has a worn out rod bearing...
User avatar

By 1993 Civic Si
- Mon Aug 27, 2007 1:27 am #21220
Sire wrote:Sounds like the rod bearings... :? You could check by pulling of your sparkplug cables one by one while letting the motor run, if the sound stops, that's the cilinder wich has a worn out rod bearing...


Boy that would be an absolute shame if that's what it is... :(

But, it does sound internal. I almost hate to ask, but have you tried listening under the hood, or does it only knock under load?

Good luck with it...
User avatar

By teal_dx
- Mon Aug 27, 2007 1:55 am #21225 good suggestion, I'll try that test tomorrow after work.

Something else I noticed, it is less noticable and first and 2nd gear, it gets most noticable in third and then fourth, then 5th gear.

Tonight driving home, the temp was in the 60's for the first time in a while and I could still hear it sometimes but not as loud as usual when I am driving it during the day.

Also, it is most noticable at light or moderate throttle. If I'm giving it some prdal, it seems to not be there, but maybe it is just being covered by the intake noise.
User avatar

By teal_dx
- Mon Aug 27, 2007 1:58 am #21226
1993 Civic Si wrote:But, it does sound internal. I almost hate to ask, but have you tried listening under the hood, or does it only knock under load?

Good luck with it...


If I put my head around the motor and hold the throttle body around 3k, it sounds like it is coming from the top of the block.
User avatar

By ohDirka
- Mon Aug 27, 2007 2:03 am #21227
teal_dx wrote:good suggestion, I'll try that test tomorrow after work.

Something else I noticed, it is less noticable and first and 2nd gear, it gets most noticable in third and then fourth, then 5th gear.

Tonight driving home, the temp was in the 60's for the first time in a while and I could still hear it sometimes but not as loud as usual when I am driving it during the day.

Also, it is most noticable at light or moderate throttle. If I'm giving it some prdal, it seems to not be there, but maybe it is just being covered by the intake noise.


maybe the off-roading had something to do with it lol :eekdance:
User avatar

By teal_dx
- Mon Aug 27, 2007 2:39 am #21234 haha you heard it in person, it was hard to hear with the windows down though.

btw, that noise we were hearing on left turns was the inner fender splash guard rubing on the tire :thumb:
User avatar

By teal_dx
- Mon Aug 27, 2007 3:19 am #21239 I just finished doing some research on symptoms of bad rod bearings... another symptom is back rattle, a vibrating sound when you let off the gas. I have this at higher RPM 4-5k.
Fuck, it looks like I'm in for a re-build instead of installing this turbo kit :(

They also said that eventually it will turn into a double knock as the bearings wear more and the rod has more movement, eventually coming in contact with the head.

I'm hoping that by catching it early, I can just drop the oil pan and replace the bearing through the bottom instead of removing the whole motor or pulling the head off.

:x :x :x :x :x :x :x
User avatar

By Sire
- Mon Aug 27, 2007 7:49 pm #21287 I hope it's just the bearings dude... Just make sure you get the right size... :thumb:

Good luck...
User avatar

By teal_dx
- Tue Aug 28, 2007 1:28 pm #21318 I read the manual and they say to pull the head. I don't see why I couldn't just leave the whole motor/tranny in the car, head on, and remove the oil pan & oil pickup & main girdle.

That gives me access to all 4 rod bearing caps w/o pulling the head right?

I'm hoping that since I caught it before it got too loud that only the bearings will need replaced since they are not spun. :pray:
User avatar

By york62
- Tue Aug 28, 2007 4:57 pm #21329
teal_dx wrote:I read the manual and they say to pull the head. I don't see why I couldn't just leave the whole motor/tranny in the car, head on, and remove the oil pan & oil pickup & main girdle.

That gives me access to all 4 rod bearing caps w/o pulling the head right?

I'm hoping that since I caught it before it got too loud that only the bearings will need replaced since they are not spun. :pray:


i can see removing the head because when your ready to pute it back together you will have to be able to move the piston and rod back down on the crank
User avatar

By teal_dx
- Tue Aug 28, 2007 5:13 pm #21334 I was thinking I could just get the room by turning the crank some?

I'm wondering because if I can do this w/o taking too much apart, I'll get on it right away. If it is going to be a longer project, I'm going to have to put it aside for now and wait till I have plenty of time.
User avatar

By chnzgoofball
- Tue Aug 28, 2007 5:41 pm #21341 aw that sucks... u just rebuilt the car too...
User avatar

By teal_dx
- Tue Aug 28, 2007 6:46 pm #21349 I'm still not sure what could have caused it to happen... it was fine for the first 1000 miles, so I'm not pointing my finger at the engine builder who did the machine work and assembled the bottom end.

Next time I may as well use plastigauge and do it myself rather than spend a lot of money to pay a professional. If I had built it myself the first time and had this happen I would understand. But I wrote a big check to the builder so it's a bigger kick in the nuts now.
User avatar

By Sire
- Tue Aug 28, 2007 8:57 pm #21388
teal_dx wrote:Next time I may as well use plastigauge and do it myself rather than spend a lot of money to pay a professional. If I had built it myself the first time and had this happen I would understand. But I wrote a big check to the builder so it's a bigger kick in the nuts now.


Don't you have warranty on the work, I mean, it's only been 1000miles... :? You could at least try...?

And you should be able to change the bearings without removing the head, when you need the clearance, just turn it at the crankpulley like you said... :thumb:
 Reply
Return to Engine - General