Tapping noise seemingly from top end....VID

supra90turbo

shaeff is FTMFW!
Mar 30, 2005
6,152
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I swear you people are the most rodknock-happy crowd I've ever seen...

Jason7mgte said:
sounds exactly like mine did thought it was valve train nope rodknock !! my car was stock boost always HA join the club sell your car or get a cheepo jdm motor
Most retarded post I've read in a while.
Sell the car? Why not fix it?
Putting in a "cheepo jdm motor" has the same chance of having a bad headgasket/spun bearings as his current engine.
Find out what's wrong with the engine, Floto, and repair as necessary.

BoostedFloto said:
i REALLY dont think its rod knock because all of the tests and listening points it to upper end
 

Supracentral

Active Member
Mar 30, 2005
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johnathan1 said:
Sounds like rod knock to me...

mk3ftMFw said:
yeah people that say tapping isnt a rod knock are wrong. Its not always evident cause you can barely shim a rod bearing. Tapping can be a knock. I was told time after time it was a cam shaft with bad clearance, and its not.

socc924 said:
I am possitive that is rodknock. Trust me on this one. Just pull it. I think I wasted twice as much time trying to diagnose sounds then it would have taken me to actually check. Pull the motor, and check the bearings.

People... Read this and stop making complete fools of yourselves....

http://www.supramania.com/forums/showthread.php?t=20486

You absolutely, can not diagnose an engine noise over the internet. PERIOD

And anyone who says they can, is without a doubt, an idiot. Think you are special and you can? You are an idiot.

Before you hit reply. Did you read the link above? No? Here it is again:

http://www.supramania.com/forums/showthread.php?t=20486

Read it. Just shut up, and read. Try very hard to resist the urge to hit reply and start ranting at me how you know what this noise in his motor is. You don't. And neither do I.

It could be rod knock, it could be something else.

But that post above will help him find it. You people won't.

Read the link, learn something. Try. It's fun. Really.
 

socc924

Member
Mar 31, 2005
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Ok... guys. I will predict the ending of this. Floto will spend countless hours and $ diagnosing the problem. He will pull belts, already removed the valve covers, maybe even the head. He will exhaust every option he think it can be and then he will finaly resort to actually checking the bearings. He will find out its a thrown rod bearing. I am willing to bet on it. IF I'm wrong, THEN call me an idiot. Besides, it realy is not that hard to actually check if its a rod bearing. If your completely lazy you can unbolt the motor mounts and remove the few things that get caught up and raise the motor a few inches. Then the pan can be removed.

Rod knocks are loudest at higher speeds (over 2500 RPM) Feathering the gas pedal may result in a distinctive back rattle between 2500 and 3500 RPMs.

Just thought you might want to edit this because it is not always true. Sometimes the tapping will only be at lower rpms and will go away when you rev it. And it is misleading because when reving the motor, the tapping might get drowned out by the rest of the noises and may seem quiter.
 

johnathan1

Supra =
Aug 19, 2005
5,056
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Downey, California, United States
SC, I have read that post you linked to at least twice.

I was just posting what I think the sound in the video might be...It would be really stupid to say that I think that the problem IS, without a doubt, ROD KNOCK...because I have no way of testing anything over the internet...

I was only offering my input on the subject, and posting what I thought it sounded like.
 

drbowser3

The Doc is in...
Jan 17, 2006
215
0
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Tampa,FL
I think he is pulling the motor and going to go over everything. I know he was wanting to swap heads. So hopefully he finds the problem and its nothing too crazy to fix.....Good Luck Bill. If my car is done I can come help if needed.
 

87soup

F*CK SMOG CHECKS!!!
Jan 23, 2006
864
0
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Sacramento
My N/A did that same noise for about 2K, then it started to slowly lose oil, it would also burn the oil a nasty dark brown... Then about 1K more miles and it got louder, and faster then it threw a rod!

I think it would have threw out sooner but, i used that Lucas 20W 50 oil, it gave me a higher oil pressure and smoothed out the sound!

GOOD LUCK!!!!
I hope it's not rod knock!!!
 

speed

Gone. Email me.
May 27, 2006
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www.timduganphotography.com
I've got a similar situation goin on with mine, but as far as i can tell, mine isn't nearly so loud, and is only coming from the rear of the intake cam. Due to my recent "mishap", i'm guessing its a bad valve. I really don't want to, especially since its sunny now, but i'm gunna have to take off the head and make sure everything is honkey dorey. Yuck.
 

jdub

Official SM Expert: Motor Oil, Lubricants & Fil
SM Expert
Feb 10, 2006
10,730
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Valley of the Sun
Guys - It's very difficult (if not impossible) to determine what and where a sound comes from on the 7M. It's hard enough in person, much less a sound clip or video on the internet. There is no way you can listen and say it is definitely one thing or the other. All you really can do is point out the thread SC posted above or suggest checking the valve shim/cam journal clearances. That's about it...the person there, with the car, has to make the call.

On any given motor, it could be the valves, it could be piston slap, could be the piston connecting pins, could be an exhaust or EGR cooler leak, or it could be the rods. The only thing a person can do is eliminate the possibilities...doing the easiest things 1st is what I would do...i.e. the valves. If you think you have a problem, you have to listen with a stethoscope and think about what you're listening to.
 

socc924

Member
Mar 31, 2005
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I know that I can not be 100% possitive that it is a rod bearing. But I think that my experiences with other 7m's gives me a pretty good idea. That sound is all too familiar. If the guy asked if he should just replace the motor or have a mechanic rebuild it my advice would have been much different. But he checked the most obvious things and even went as far as to remove camshafts. Now I think its time to check the most likely thing. I will tone down my confidence from now on when I make suggestions.

Plus, what makes diagnosing rod knock so difficult is that different motors sound different. Rob knock on a big block V-8 will sound different then on 2 liter 4 cylinder. And add to that, a bearing can cause knock in different ways and to different degrees, makes if very difficult. But I have heard that same sound on two different 7m's. I mean exact. Dead on.
 

SupraDread

New Member
Aug 21, 2006
153
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New York
This is a shot in the dark and here it goes check your CPS sensor make sure that it is in properly and that the gear teeth are not crashing into the cam ring gear. It happened to me and I waited to see what the noise would do, utimately my CPS broke and i had to replace it upon which i discovered where that top end noise was coming from. Then I replaced my rod bearings.
 

mk3ftMFw

Mini Toon Burnout!! FTW!!
Jan 24, 2007
95
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my rod knock sounded like a light tap, member after member said a rod knock would sound like a bowling ball in a dryer.

This is not true at all, maybe if you let the rod knock continue then, in time, it will. Also, the tapping noise did not get louder it just got quicker when i revv'd.
 

Adjuster

Supramania Contributor
Go to Harbor Freight.
Spend less than 10.00 on a cheap engine stethoscope. (It looks like the one your Dr. uses to listen to your heart, but has a long metal rod at the end instead of the round diaphram they place against your chest.)

You can use a broom handle, but don't forget to remove the broom first! And watch out for moving parts. (Just wrap your fist around the end of the broom, hold one end to the engine in various places, and the other to your ear with your fist acting like an ear cup.)

I've had a "knocking" sound from a failed front idler pully bearing. (The one for the AC IIRC.) It sounded like the motor was going to die any moment, but was a 20.00 fix. (Replace the bearing, just remove the snap ring, get the right Timken replacement and your good to go.)

Those cam journals don't look that bad. I've seen worse work just fine.

Check the CPS as noted, also check for other failed accessory bearings. (Easy to do, just remove the serpentine belts and start the motor for a few moments. DO NOT RUN IT VERY LONG. It has no coolant moving without the water pump hooked up via the belt, and it will overheat. You can't run your motor without a timing belt. (I'm assuming you know this. :) )

My guess if it's not piston slap, and goes away when warmed up, is either a valve out of clearance spec, or a failed accessory drive bearing.

Good luck. I hope it's not a rod bearing, but I'd check all the easy stuff first before you pull the motor and go for the bearings.
 

GrimJack

Administrator
Dec 31, 1969
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Ok, I was going to keep my mouth shut, but I can't resist.

Here are the things that I've heard sound like rod knock at one time or another.
- Fried rod bearings. (duh...)
- Dead piston
- Dead valve
- Dead valve guide
- Loose crap in the head - ball bearing, nut, bolt, all kinds of crap that people have forgotten about while reassembling
- Loose crap in the block (oilpan, anyway) - same as the above note for the head
- Loose crap behind the timing belt cover - this was relatively bad, the cam gears exploded shortly afterwards, pretty certain the noise was a piece of them rattling around just before they completely self destructed
- Loose crap in a cylinder. Too big to go through the valves, was rattling about, sometimes it would get caught between the piston and head / valve and make an ugly noise, sometimes it would fit and be quiet
- Valve shims out of spec
- Exhaust cam missing CPS tooth
- CPS missing tooth
- Broken flexplate on the automatic transmission
- Loose flywheel bolts
- Loose main pulley bolt
- Dead main pulley
- Dead main pulley key
- Noisy injectors
- Exhaust leak, especially on the EGR
- Dented oilpan hitting the crank
- Dead alternator
- Failing waterpump
- Dead clutch spring - one of them had self destructed, one big piece of it was left in the clutch plate, rattled nastily as the engine idled, got worse when engaging / disengaging the clutch
- Dead motor mount - entire engine would shake, causing a rattle in time with the RPMs

These are just the ones that I can remember off the top of my head. There are more. LOTS more.

SC's thread makes sense, after having exhausted that I would resort to pulling the engine and tearing it apart. Eventually I'd find the culprit.
 

CACressida

The Cressida Whore!
Feb 19, 2007
124
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Modesto, CA
Lol, I had the same sound in one of my 7Ms and people told me it was a stuck valve. So I drove this thing for 300+ miles a bunch of times and you could litterally hear the knocking about 3 blocks away. I just kept on driving the car thinking its just a stuck valve. So it lasted a good yr and a half, then one day, the car came to a stop after the knocking got rediculously loud after curiousity got me to keep the engine revving at the rpm where the knock was very very noticeable the most. Towed the car home, parked it, 3 days later, started it and it was very loud knocking noise. Drove it up the driveway into the garage, took off the head and piston number one rod bearings were crap.

As a matter of fact, I got a vid of my car with this knock. Alil over a year and a half with this knocking. Redlining, burnouts, smoke shows, drifting, what ever I could throw at it. If you really don't want to diagnose the problem, just think of it as a sticky valve and the problem wont stop you sooner than if you keep thinkin about what it is.

http://videos.streetfire.net/search/Cressida/0/df0e72cd-e4f3-4586-a1b9-dfa199d1a18e.htm

Sounds familiar?