3.0R-B Vibration at 2500 rpm

[Blake8828]

Hi guys, some of you might remember my last thread that resulted in a new long motor for my car.
While this has fixed the rod knock there is still an annoying rumble with vibrations that i can feel through
the throttle peddle and the steering wheel. This occurs at pretty much exactly 2500rpm and goes away by
3000rpm when driving with light throttle. Engine does not need to be under load, it happens with the car
stationary too.

I was watching the crank pully this morning and discovered that the center part wobbles while the actual
pully runs with no wobble.

Could this mean the harmonic balancer is dead? This noise happened with my last engine too and it is using
the same crank pully. Also, would a broken harmonic balancer be able to rattle enough to create these symptoms?

Any help would be great, cheers guys.

[Blake8828]

http://youtu.be/PtKrMzNNj4Y

Very much like this video. Lower pitch sound, behaves
exactly the same though.

[Blake8828]

Okay, so to narrow it down further.
I removed the serpentine belt and the noise went away.

So it can only really be the auxiliaries or maybe the harmonic
balancer is quiet with no load.

All the bearings run quiet and smooth, there is a lot of end-play
on the power steering pump (not sure if this is normal) but no sideways
play. Its hard to test the aircon since the clutch is not engaged... Alternator
is perfect and both idlers are okay.

Sorry to keep posting, just trying to gives as much info as possible!

[Blake8828]

Pulled off the A/C pulley and found that the bearing is dead.
Runs fine but rattles when shook and makes gravel noise.
Still not convinced that this could cause so much noise and
vibration, but $10 for a new bearing is worth a shot!

[KiDo_Tuning]

Pulled off the A/C pulley and found that the bearing is dead.
Runs fine but rattles when shook and makes gravel noise.
Still not convinced that this could cause so much noise and
vibration, but $10 for a new bearing is worth a shot!

It may have damaged the harmonic balancer as well

[Blake8828]

I figure I might as well continue documenting my search for the noise, just in case it helps someone else out in the future.

After replacing the air-con pulley bearing (which was so bad I could make it rattle when i shook it) and the two idler pulleys
the noise is still the same.

It would seem the noise DOES still occur with the belt off and that I didn't test it for long enough, I wasn't quite sure how
far I could drive the car with no alternator.

Today I decided to check out the engine mounts to make sure they weren't torn or lose. Grabbing hold of the intake manifold
and shaking left and right I only really got maybe 2-3cm movement each way.

I then grabbed hold of the engine pitch mount and found I could rattle it around quite freely. I took it off and found that the
rubber bushing on the engine side of the mount was damaged and the steel bushing in the centre moved around freely. I'll
put a picture of it below.

So I took the car for a drive with the pitch mount removed and the noise and vibration went away! . I re-installed the pitch
mount this time adding a lot of pre-tension on it with the slotted hole. I went for another drive and found that the noise was
back but not as bad, so a very good chance this is the issue!

Next question is, should I just buy a stock mount? Does anyone here recommend an aftermarket one? Will a stronger one just add
more NVH and offer no benefits? Also are these a H6 specific part or can I use one from any gen4 Liberty?

Sorry about all the question! Any help would be great!

[KiDo_Tuning]

Torqued Solutions do a great pitch mount and any WRX or LGT one fits. universal part

[Blake8828]

Thanks. I'll check it out!

[Blake8828]

New pitch mount and the noise is still there

Seems the pitch mount must act as a medium to transmit the vibration and noise to the firewall.

Slightly off topic but the Torque Solution pitch mount is great, clutch engagement fells much more positive,
with little to no extra cabin noise.

This leaves me at a bit of a loss as what to try next. Could be engine mounts, apparently a bad mount can
cause vibrations. Any body know how much I should be able to wobble the engine side to side by hand?

I have recently purchased a Tactrix OBD2 adapter and have been doing some logs with RomRaider. At this
point I have not seen any parameter that seems to correlate with the noise. VVL is still in low lift mode,
timing advance doesn't jump around and VVT seems fine too.

Anybody know of any other parameters I can monitor to could possibly make the engine vibrate at these
revs? The noise behaves the exact same way and at the exact same revs as the video, although I have to
be moving to make it happen.

Any suggestions would be great! cheers

[Blake8828]

Okay, so this afternoon I decided to leave the vibration in the 'too hard pile' and fix an issue i'm having with the clutch pedal.

The first 1/6 of travel on the clutch pedal was always very light and the rest of the travel nice and heavy. So I adjusted the
clutch pedal push-rod in a bit and now the travel is nice and heavy right from the start.

I then took it for a test drive and have found that the vibration and noise has about 90% gone! It's still there but I can hardly
hear it... I did notice before I adjusted it that the slave cylinder wasn't even touching the clutch fork when the clutch pedal
was all the way out, so I could rattle the clutch fork back and forward a little.

Hopefully the fork and slave cylinder rattling on each other was the issue, would make sense since they're next to the pitch
mount. Can't help but worry that it may have been something to do with the thrust bearing and now that there is more tension
on it with the clutch pedal all the way up I might just be hiding another problem.

Although in case you guys hadn't noticed i'm a bit of a car hypochondriac.

[Brunsy3.0]

good to see you diving in and having a good solid go at finding the source

and a very good idea for anyone who may have the same issue to follow up and know what could be to blame, I am about to replace some bearing on my serp belt line aswell, and pitch stop I have thought about but hesitant on adding any more NVH, the engine mounts is in the same basket

hopefully you get it sorted mate and can put your mind at ease, good luck and keep us in the loop

[Blake8828]

Thanks Brunsy

If you're replacing the bearings in the idler pulleys be very careful, they're made out of softer material than I thought and
I ended up warping one and having to buy a new one. Aircon pulley bearing was surprisingly easy.

Honestly, the only extra noise I've noticed with the pitch mount is the starter motor being louder... It has made a huge
difference to gear changes, but you saw my old mount so i'm not sure if a new stock or STI one would have given me the
same result.

[Brunsy3.0]

If you're replacing the bearings in the idler pulleys be very careful, they're made out of softer material than I thought and
I ended up warping one and having to buy a new one. Aircon pulley bearing was surprisingly easy.

Honestly, the only extra noise I've noticed with the pitch mount is the starter motor being louder... It has made a huge
difference to gear changes, but you saw my old mount so i'm not sure if a new stock or STI one would have given me the
same result.

Good to know, thanks mate will keep in mind, im thinking for the cost of the bearings that I may aswell replace all of them

[Blake8828]

For anyone who is interested or having the same issue, I think I have located the problem.

Removed the exhaust header heat shields today and noticed that one was missing all the white
heat resistant material on the inside.

Took the car for a run and no more vibration or noise!

To be fair this was suggested to me earlier, though I just couldn't believe that such a small shield
could make so much vibration and noise.

Anyway, does anybody know what kind of material I can use to pack between the shield and the
header? The other side has a material that looks like fiberglass roof insulation bats...

[Brunsy3.0]

Anyway, does anybody know what kind of material I can use to pack between the shield and the
header?...

Raptor Headers FTW!!!