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TurboSupra7
April 25th, 2005, 12:37 PM
I just recently (about two months ago) purchased my 1990 Supra Turbo w/ manual tranny. I absolutely love this car and it runs great, it boosts strong and pulls hard until redline. Lately though I've noticed a kind of clunking sound at idle. Once I start accelerating the noise disappears, either that or I can't hear it over the exhaust and engine noise. The strange thing is that it doesn't always make the sound, but over the past week or so it has been doing it pretty much every time I drive the car. Sometimes the sound is very quiet and the radio must be turned down to hear it, and sometimes it's fairly loud, and I can feel the vibration through the shifter. Klunk, klunk, klunk, and a quick rev makes it disappear. Please help, I don't want my new car going to the shitter!
-Nathan-

scottiedawg66
April 25th, 2005, 02:01 PM
whats ur oil pressure. change out your oil and run 20-50, if this cures the clunk cluck as you describe, you have rod knock. My car clicks at idle due to vavles, not rod knock.

~scott

lagged
April 25th, 2005, 02:43 PM
whats ur oil pressure. change out your oil and run 20-50, if this cures the clunk cluck as you describe, you have rod knock. My car clicks at idle due to vavles, not rod knock.

~scott


the heavier oil wont "cure" anything. all it MIGHT do is quiet the sound for a little while. itll come back, rest assured.

scottiedawg66
April 25th, 2005, 03:51 PM
thats my point.

~scott

TurboSupra7
April 25th, 2005, 04:37 PM
are you guys confident that this is rod knock? Would a bad throwout bearing or old gear oil in tranny cause this at all? I really don't want to have to get rid of this car

TurboSupra7
April 25th, 2005, 04:38 PM
Oh and oil pressure is as it should be...

IJ.
April 25th, 2005, 04:39 PM
The throwout/input gear bearing can make a noise but is easy to isolate...

Push the clutch in and it should stop if that's it!

TurboSupra7
April 25th, 2005, 04:55 PM
Well I guess that isn't the problem then, because the noise continues whether the clutch is pushed in or not.
Damnit this is fucking bullshit. I blew all my money on some piece of shit, how long is this thing gonna last? If that is the deal then I guess I'll restart my search for an AE86 corolla.
One last thing, why can't I hear this noise any other time that idle, shouldn't it get progressively louder with RPM?

IJ.
April 25th, 2005, 04:59 PM
With the increase in revs the oil pressure comes up fills the gap between the bearing and crank and the noise goes away.

Eventually the bearing wears enough that the oil can't achieve this anymore and you get the knock all the time.

americanjebus
April 25th, 2005, 05:06 PM
what if you have an auto. i put mine in drive and i get this weird sound as if the tranny wasnt alligned with engine right i put it in neutral and its gone but it does this seldomly. almost as if i hadnt harnessed exhaust and i know i did.

GrimJack
April 25th, 2005, 05:32 PM
Many things can cause a knock sound at idle. Most of them are loose or broken parts. See if you can figure out where the sound is coming from in general - is it louder on one side of the engine or the other? Could your engine mounts be broken? What RPM does your idle sit at? How far up do you have to rev it for this noise to go away? (Get someone to report the RPM from the driver's seat while you rev it manually from under the hood.)

Rod knock usually starts at about 2500rpm, and gets more noticable across a wider RPM range as it gets worse. The easy check for rodknock is this:
- Shut off the car
- Unplug a spark plug lead
- Start the car. Noise still there? If yes, go to step 1. If no, you have rod knock on the cylinder you just unplugged.

The only time this doesn't really work is when you have rod knock on two cylinders or more. :)

VanSupra
April 25th, 2005, 06:18 PM
are you guys confident that this is rod knock? Would a bad throwout bearing or old gear oil in tranny cause this at all? I really don't want to have to get rid of this car

Check to see if your pressure plate is tight on the flywheel. Also a loose harmonic balancer that was incorrectly installed can also simulate the sound of rod knock at the back of the engine..hth

TurboSupra7
April 26th, 2005, 03:05 AM
Actually, the noise only happens at idle, even the slightest rev makes the sound disappear until it returns back to a steady idle and the noise comes back. My idle tends to sit at an even 650 RPMs, however sometimes it will sit at around 1000-1100 RPMs which I don't understand either.
Also the sound seemed to be emanating from the rear of the motor, but I can't be sure about that until I double check, which I will do on wednesday, and I'll also do the spark plug check on wednesday as well, but wouldn't I get rod knock whether the cylinder was getting spark or not?? Because isn't the piston still going to be moving in the same way with or without the spark?? Thanks for the help guys!

TurboSupra7
April 26th, 2005, 03:16 PM
well i drove home from work today (about a half hour drive) and didnt get the sound until i was about two minutes away from home, and i noticed that the lower the idle is the louder the knocking is, for example when I have my foot on the brake or am rolling the windows up the sound gets noticably louder. I don't know if this means anything at all but I figured it may be worth mentioning. I also noticed the sound gets progressively quieter up until about 1000 rpms and then disappears, would rod knock be loud enough to hear over my 3 inch exhaust and the sound of the motor? THanks

GrimJack
April 26th, 2005, 03:22 PM
Rod knock will get louder as the bearing wears more, until it's so loud you can hear it over your stereo / engine / mac truck using the engine brakes beside you on the freeway.

rakkasan
April 26th, 2005, 03:36 PM
..... Also a loose harmonic balancer that was incorrectly installed can also simulate the sound of rod knock at the back of the engine..... Get a 3/4" socket & a long breaker bar & tighten the shit out of your HB. To stop the motor from turning, take of the tranny cover & have a friend hold a flat tip in the teeth of the flywheel. I had to do this after repairing a BHG, I had the same type of knocking sound.

Boostedstr8six
April 26th, 2005, 04:15 PM
Get a 3/4" socket & a long breaker bar & tighten the shit out of your HB. To stop the motor from turning, take of the tranny cover & have a friend hold a flat tip in the teeth of the flywheel. I had to do this after repairing a BHG, I had the same type of knocking sound.

Or just put it in 5th gear and apply the parking brake.

rakkasan
April 26th, 2005, 04:22 PM
Or just put it in 5th gear and apply the parking brake.

I didn't think of that, I'm an auto guy. :biggrinki

IJ.
April 26th, 2005, 04:53 PM
Rod knock will get louder as the bearing wears more, until it's so loud you can hear it over your stereo / engine / mac truck using the engine brakes beside you on the freeway.
Shortly followed by the little man with the hammer smashing a hole in the side of the block so he can escape! ;)

lagged
April 26th, 2005, 08:40 PM
Shortly followed by the little man with the hammer smashing a hole in the side of the block so he can escape! ;)


yikes thats a scary thought. :runs to check oil: :aigo:

huntin5L
April 27th, 2005, 12:06 PM
i get that noise also, everything seems to be ok, but mine sounds like woody wood pecker as they use to describe it in the last forum. Its annoying, but i don't think its a rod knock.

TurboSupra7
April 27th, 2005, 04:26 PM
yeah that describes the sound pretty damn well...

americanjebus
April 27th, 2005, 04:39 PM
mine sounds exactly like a f250 turbo diesel. cept not as loud. its like i can hear the cams spinning like in the f250 thats best way i can describe mine

Shawndude
April 27th, 2005, 11:31 PM
The sound could be anything. From an exhaust leak, to loud alternator bearings or a blown engine.

Buy a mechanics stethoscope for about 10 bucks, and track it down. The crystal ball of sound analysis, doesn't work too well over the internet.

TurboSupra7
April 28th, 2005, 01:07 AM
Where exactly can I find the bolt to tighten the harmonic balancer? It seems pretty tight back behind the engine, doesn't look like I could fit anything back there. Thanks

GrimJack
April 28th, 2005, 01:23 AM
It's the BIG on in the center of the BIG pulley on the front of the engine, near the bottom. The one that all the belts connect to.

TurboSupra7
April 28th, 2005, 12:08 PM
alright I'll give that a shot, anyone know the torque spec on that thing?

GrimJack
April 28th, 2005, 12:58 PM
Lots. Seriously, IIRC it's supposed to be like 180 or something ridiculous, just tighten it as hard as you can.

IJ.
April 28th, 2005, 04:12 PM
197! My tq wrench ends at 200 ;)!

huntin5L
April 28th, 2005, 06:27 PM
you think it may be the harmonic balancer?

Blue87T(Dan)
April 28th, 2005, 06:40 PM
Is this something that you hear when you inside the car with the windows up at idle but can't hear if your outside the car with the hood either up or down?

Have any fuel mods been done to the car?

Dan

huntin5L
April 28th, 2005, 06:46 PM
for me, i hear it inside my car at idle with the windows up and when you lower the windows you can't hear it pretty much at all

huntin5L
April 28th, 2005, 06:48 PM
can't hear it outside of my car other than the lifter tick.

Blue87T(Dan)
April 28th, 2005, 07:18 PM
^^ Have any fuel mods?

huntin5L
April 29th, 2005, 01:29 AM
no fuel mods

Bigdough666
April 29th, 2005, 04:55 PM
Make sure everything is tight.

When I 1st started my car after my rebuild, everything was cool, then all of a sudden I got this SUPER LOUD NASTY KNOCK, and I was like WTF?? Took the front cam cover off, and turns out the cam gears werent tight, so they were hittin the cover.

Does it sound like popcorn? OR marbles in a can? If so, it could be detonation, which is also bad. Using 93 octane? Hope its not rod-knock, good luck with it.

americanjebus
April 29th, 2005, 05:04 PM
Cam Gears!!! I Love You Dude

Bigdough666
April 29th, 2005, 05:22 PM
Cam Gears!!! I Love You Dude

I take it that was the prob? But ease up with the L word there buddy. :ugh: :nuts:

TurboSupra7
April 29th, 2005, 11:36 PM
well in my situation, as previously stated it sounds like a woodpecker peckin on an ol' oak tree or somethin. I can't hear it inside the car with the windows up only when the windows are down, and when I put stress on the engine (i.e. windows being rolled up or down, or putting my foot on the break) it becomes twice as loud. I assume this is due to the drop in RPMs under stress, for the most part I can't hear the sound at all until stress is put on. Sometimes however it will do it without any added stress, but as i said it gets much louder with the stress. I think i overused the word stress, hehe.
Still haven't had a chance to tighten up that HB as I dont have proper tools at my current residence, but do ya'll think it may be worth checking those cam gears? Thanks.

TurboSupra7
April 29th, 2005, 11:52 PM
Also, I don't have fuel mods, unless the previous owner did them, put I'm almost positive that I don't.

huntin5L
April 29th, 2005, 11:53 PM
man im gonna take an mpeg and try hosting it somewhere

huntin5L
April 30th, 2005, 12:16 AM
alright guys took the mpeg does anybody know where i can host it.

huntin5L
April 30th, 2005, 12:31 AM
im trying putfile.com out we will see

TurboSupra7
April 30th, 2005, 12:34 AM
yeah, I'm interested to see if u have the same sound I'm gettin.

TurboSupra7
April 30th, 2005, 12:35 AM
oh wait, u said u can't hear ur sound outside of the car, I can definitely hear mine outside of the car. oh well maybe I'll take an mpeg as well, what kind of camera did u use?

huntin5L
April 30th, 2005, 12:38 AM
sony cybershot 5 megapixel dsc-v1

huntin5L
April 30th, 2005, 12:38 AM
i just hear valve tick outside my car, you can hear it in the vid ill host it should be up shortly

huntin5L
April 30th, 2005, 12:57 AM
DAMN, GOT TO TAKE ANOTHER VID...Has to be less then 10mb...ill have it up in 10 minutes don't go anywhere lol

huntin5L
April 30th, 2005, 01:08 AM
GOT IT! SHORT BUT YOU CAN HEAR IT, THE DDDDDDDDDDDDDDDDDD...LOL CHECK IT OUT
http://www.putfile.com/media.php?n=MK3

TurboSupra7
April 30th, 2005, 01:54 AM
checkin it out right now

TurboSupra7
April 30th, 2005, 01:56 AM
sounds to me like your valves clacking, I had a bronco that sounded just like that, because the lifters weren't getting enough oil to them.

TurboSupra7
April 30th, 2005, 01:57 AM
mine is less of a clack and more of a knock, knock sound. Damn I need to get a video camera so you guys have a better idea of it.

huntin5L
April 30th, 2005, 01:57 AM
okay

huntin5L
April 30th, 2005, 02:00 AM
u have to play it a few times it breaks up

huntin5L
April 30th, 2005, 02:01 AM
did you get yours

TurboSupra7
April 30th, 2005, 02:08 AM
well I don't have a vid camera to use, I'll see if I can borrow a friends sometime in the next few days, I'm not even sure if I know anybody that has one but I'll ask around...

huntin5L
April 30th, 2005, 02:09 AM
yeah i don't know but if anybody has any ideas of what the hell that is enlighten me. Here is the link again.
http://www.putfile.com/media.php?n=MK3

turbo where you from?

TurboSupra7
April 30th, 2005, 02:17 AM
Kansas City, KS. U?
If u wanna chat supras or RX-7s feel free to contact me on AIM
My ID is TurboExtasy (yeah I know it's a stupid name)

huntin5L
April 30th, 2005, 02:19 AM
lol, yeah mine is BOB81ISU feel free.

GrimJack
April 30th, 2005, 04:55 AM
Well, it's safe to say that it's not a GOOD sound. Doesn't sound like rod knock to me though... honestly, it sounds like someone left a socket wrench under the valve covers.

IJ.
April 30th, 2005, 05:03 AM
GJ: I agree that doesn't sound like RodKnock!

It's like it's something rotational rodknock is usually only on the firing stroke so there are gaps in the noise,
that's all the time!

huntin5L
April 30th, 2005, 11:21 AM
yeah i don't think it is. I also run 10w30 is that bad, the motor likes to eat it up too, about a quart in 1k miles

Bigdough666
May 1st, 2005, 02:54 AM
Im willin to bet its valve clatter. Mine is doin the same thing. Im taking it to getthe valves adjusted this week.

chriso
May 1st, 2005, 03:10 AM
Sounds to me something either rotating like something hitting the timing cover or maybe an injector, spark plug or valve clanking. Just my .02 cents from listening to the video. Maybe a loose bolt in the flywheel.

huntin5L
May 1st, 2005, 05:06 PM
yeah i think it might be valve clatter, what do you think it will cost to have that adjusted?

huntin5L
May 1st, 2005, 05:08 PM
It is so constant and the noise doesn't change, so i almost positive it is nothing rattling.

TurboSupra7
May 2nd, 2005, 11:54 AM
alright guys I tightened the shit out of the harmonic balancer, and voila, no noise as of yet....thank you good people of the forums!

huntin5L
May 7th, 2005, 09:36 PM
hmmm...changed my oil to 20/50...The noise is still there also tightened my hb for giggles. Still nothing. Can't figure this one out, cause i can't hear it under my hood, only in the car.

suprarcr89
May 7th, 2005, 10:00 PM
good to see it fixed ive had the harmonic balancer problem myself....

enjoy your supra

huntin5L
May 11th, 2005, 07:08 PM
I think i f-n figured it out. I took my car into the shop today at my work. Sure enough he said it was my blower fan making the noise. I was like ok, didn't believe him. I got home a minute ago and started slowly turning the key to the off position, when i did that it go to the point where the rpms dropped dead to below zero as if the car was off. But, it wasn't. The car was on, but it turned off the blower inside the dash somewhere. No more noise. So just by chance of doing that i found my problem. Now, where the hell is that blower motor in the dash. Anybody?

chriso
May 12th, 2005, 03:12 AM
Now, where the hell is that blower motor in the dash. Anybody?

Behind the glove box

huntin5L
May 12th, 2005, 08:22 AM
It sounds like its behind the guage cluster.

Travisimo
May 12th, 2005, 01:15 PM
huntin, I have the exact same sound, but I get it very randomly. I drove around for 10 minutes hearing it, got back home and read here for 20 minutes. I go back to the car and its gone!

huntin5L
May 12th, 2005, 02:30 PM
It is sooo annoying. Sometimes its worse than other times. It gets worse when revving the motor Too. But at a standstill it just gets annoying. It is like an echoed knock. Does anybody have any ideas about how to get to it. It sounds like its behind the guage cluster somewhere.

huntin5L
May 12th, 2005, 06:02 PM
Anybody know?

TurboSupra7
May 12th, 2005, 06:41 PM
maybe u should check your speedo cable, that seems like it could possibly make that kinda sound, especially if u hear it from behind the gauges...

huntin5L
May 12th, 2005, 06:48 PM
well i can't hear it outside the car or underneathe the hood

huntin5L
May 12th, 2005, 06:50 PM
where is the speedo cable at. How could a cable make that noise though

huntin5L
May 13th, 2005, 08:16 AM
actually, it is not a fan...Now it has been narrowed down to some kind of pump that is making the noise. At least that is what my neighbor thinks anyways. God i hate that sound. But at least i fixed my boost problem. One of the two (roughly)2 inch hoses on the gold or copper pipe that runs right behind the 3000 pipe needed to be clamped. No more boost trailing off. Holds boost perfectly now.