Weird engine noise. Help!

[mikyrc]

Hi Guys, I have a little problem.
Mi car does a weird noise that i can't figureout where's comming from. It started gradually few months ago but now is pretty noticeable when driving slow at low throttle.

I attach you a sound file:
http://www.geocities.com/mikyrc/coses/engine_sound.mp3

The sound seems to come from the intake manifold side, around the fuel pressure regulator area.

It sounds like a bearing noise but i'm, not shure. I don't hear it coming from the A/C compressor or alternator or Steering pump.

Could be the oil pump going bad?
Or crankshaft bearings?
Or balance shaft bearings?

I'm lost.

I recently replaced the stock cams for 264/272 combo and fidanza adjustable cam hears. But that sound was there before replacing them.

Any help?

 

[pbrclc]

I had a similar noise on my car and it turned out to be a balance shaft bearing, so you may be on base with your guess. It was my front balance shaft but it sounded like it was coming from the intake manifold as well.

 

[mikyrc]

Replacing that bearing must be a PITA. Do i have to take the engine out?
Is there any way i can check it for shure?

I can hear it on the passenger wheel area too, but it's a bit different noise.

 

[pbrclc]

Well to be sure on my car before I started the rebuild I started the car without the BS belt and instantly the noise was gone. If your going to the trouble of replacing that bearing, why not just remove your balance shafts.

 

[mikyrc]

If i remove them, will the car vibrate a lot?
What you finally did, replace the bearings or remove the shafts?

In case you replaced the bearings do you have to use the Mitsubishi special bearing puller tools or you can do it with more "normal" tools?

Thanks a lot.

 

[pbrclc]

I had the balance shafts removed when I had my motor rebuilt, my car still ran smoothly and never had any vibration issues.

 

[eclipsh]

You need to go get yourself a mechanic's stethescope. They work wonders in pinpointing noises. It'll set you back $20 but it could save you a whole lot more money, time and aggrivation if you can be certain of the noise source before digging into the engine.

Also double check and make sure it isn't your throw out bearing for the clutch (if you are M/T). They can sound like all hell is breaking loose.

EDIT: After listening to the noise some more I doubt it is the TOB but I'd still go get a stethoscope to listen a little closer.

 

[mikyrc]

Thanks Eclipsh i'll borrow a stethescope from the mechanic's and i'll listen to it.

What i've foundout is that it seems that isn't rpm dependable but not shure. Also i can hear a more rattling sound from the passenger wheel area. And also if i press the clutch the sound still remains.
I'll keep you guys updated as soon as i have new info.

 

[mikyrc]

I'm a bit lost, i got a stethescope from a friend and i started to listen around the whole engine.

I couldn't hear any knocking or weird sounds when touching the engine around the balance shafts area, engine head, steering pump or gearbox.

It only heard a loud sound like a bearing sound on the drivers side engine suporting bracket, and A/C belt tensioner bracket.

On the A/C i could hear it too but not that much. And also on the oil pan, turbo and further part of the intake manifold. That makes me think that the sound gets emplified or something the further the part is attached to the engine???

As i say the loudest sound where when i touched the engine bracket or the A/C belt tensioner.
I took out the A/C belt just in case but you can still hear that sound.

What do you guys think it could be? Can i discard the balanceshaft bearings?

 

[95blackGsTurbo]

You can do an eliminator kit. Might as well do a timing belt while you are at it since you will have to take the timing belt off. To get both shafts out you will have to remove the front motor mount and crossmember to allow the motor to tilt a little bit. Here are links for replacing the timing belt and balance shaft eliminator kit to give you an idea. It is pretty straight forward if you follow the directions and have some basic mechanical knowledge. With stock motor mounts you won't really notice the vibration too much. It will free up a little power as well not having to turn those shafts.

http://vfaq.com/mods/timingbelt-2G.html
http://vfaq.com/mods/balance-shafts.html

You can buy a kit here.

http://www.slowboyracing.com/more.php?id=1114&

 

[mikyrc]

Thanks Adam, i have already read those Vfaq at least 3 times, ha, ha, ha..

But as i said i'm still not shure the balanceshafts are the problem as the sound isn't comming from that side of the block (using the stethescope).
And the other bad thing is that the timming belt is only 15.000 miles old, i replace it like two years back. But i didn't replace the autotensioner and one of the pulleys as they looked good back then.

Just a question, what if i just replace the rear balance shaft for the small stubby shaft and take out the B belt and leave the front balance shaft in place?
I don't care about weight loss as i'm not racing with my car, it's a 100% street car.

 

[eclipsh]

You can leave the front balance shaft in, no problems there, but it sounds like you've ruled that out as a problem. I'd recommend that you address the current issue first

Since the sound is loudest in the timing belt area, my next steps would be:

1. Put a little lube on the AC Tensioner pulley. See if the noise goes away or softens. If it does, pull the A/C belt and see if the noise disappears. I can't recall if the belt also runs the water pump, so if it does, make sure to turn the car off before melting everything down.

2. I'd also listen more carefully to the oil pan. Have you drained your oil lately to see if there is any debris in it? If you can't find the noise elsewhere it may be worth pulling the pan .

3. If that isn't it, I'd say pull your accessory belts and timing belt covers. Re-attach the crank pulley and at least the water pump/alternator belt, sart 'er up and see if you can pick up the noise from your other pulleys. IF you do this you'll have to be very careful not to get the stethoscope tied up in the belts, so if you do this be safe about it. I.E. you're doing this at your own risk and could kill your engine or rip a body part off if you screw it up. Doing this would be dangerous and I would only do it if you cannot find another method.

 

[mikyrc]

REplaced the two timing belt pulleys and also checked the tensioner arm free play.
It had a bit of freeplay in/out and side to side. As i didn't have a new one to put it in, i bended tha washer a bit so it had no lateral movement.

But the car still does the sound. And maybe now is even notticeable at iddle, when before wasn't??

I found a very small trace of oil maybe coming from the oil pump sprocket area, but i replaced the seal like 4000 miles ago or so.
Could that oil pump bearing have a bit of free play and make that noise?

I'm about to order a complete oil pump assembly and new balance shaft bearings or maybe eliminate them directly and see.

The crankshaft bearings can't be worn with only 64k miles, don't?