Engine tick/knock/clank

[Acidic]

Ok so my SHO started making a new sound....

it's a tapping... or a knocking.. kind of like a can hit with a drumstick.

It's a steady volume, and it get drown out by engine noise so it doesn't get louder...

it starts right when you start the engine and you can hear it getting one last clack in as the engine turns off...

It's definitely coming from the accessory side of the engine and as best as I can tell it's not coming from an accessory itself...

I have clutch chatter and it's not on the same cadence... the clutch chatter sounds like something loose chattering with vibration, this sounds like something on a schedule....

Rod bearings where done about 30k miles ago..

I check the butterfly's by disconnecting a vacuum tube from the small round cylinder on the back of the intake... it didn't change anything

any ideas? it's not any slower, there is no hesitation (with the A/C off), or anything else while driving but it's a very disconcerting noise...




:::: EDIT :::: Current Symptoms and Results of Troubleshooting from post #22

Well I got the harmonic balancer off today and the keyway and balancer look fine?!? I didn't have time to pull the timing sprocket but I'm a little lost now. Here is a few things I'm thinking about:

A) The rod bearings where done 20k miles ago by SHO parts NW so I doubt they've gone bad

B) Mike at SHOPNW seems to remember the previous owner possibly buying parts to fix crank cancer so maybe once I get the sprocket off I might find the crankshaft is worn...

C) Cam chains or cam chain tensioner?

D) The timing belt is tight and when the crank is moved the cam sprockets move in perfect unison so that's another strike against crank cancer...

E) The harmonic balancer was very tight...

F) I did pull the belts and run the car... the noise continues without the acc belts on....

I have pictures of the keyway and the balancer... I'll post them soon...

:::: EDIT ::::

 

[Devin]

Did you try running without the accessory belts just to check?

 

[dantheman68]

search "crank cancer"


educate yourself on it, sometimes you can stop it before it gets bad, i dont mean to scare you, but its good to know

Have you ever had the crank pulley off?

 

[LeddZepp8687]

search "crank cancer"


educate yourself on it, sometimes you can stop it before it gets bad, i dont mean to scare you, but its good to know

Have you ever had the crank pulley off?

x2

Or you could have a bad timing belt or tensioner like me. My noise was from the belt slapping around in there. Possibly even a cam CHAIN or cam chain tensioner.

In my case a timing belt tensioner and a front 60k fixed some sounds but the cam chain tensioner on the rear head still makes some noise every now and then.

 

[Acidic]

ok so the plan is first run the engine with no belts... if it still knocks take off the outer timing cover and inspect the belt and the tensioner then inspect for crank cancer... It'll be a couple days before I can get to it but I'll do it soon

 

[dantheman68]

ok so the plan is first run the engine with no belts... if it still knocks take off the outer timing cover and inspect the belt and the tensioner then inspect for crank cancer... It'll be a couple days before I can get to it but I'll do it soon

Just dont run it long like that, remember you dont have a waterpump hooked up

 

[Acidic]

well it'll only take a minute to hear or not hear the ticking... I just need to find a place where I can work undisturbed that has jackstands.... I'm living in an apartment complex right now

EDIT: If the timing belt tensioner is the problem where can I find one new?

 

[tgsho]

I have been looking for a while for a timing belt tensioner. I found one made by Dayco for $57.89 free shipping from planetautoparts.com.

These guys have FAST shipping and fast service, its Sunday and Ive been in touch with them regarding my order several times today.

The reason Im posting this is because I have searched the forum on where to buy one and noticed the only thing that comes up were posts of people buying OEM tensioners for more than $100. So this post is for reference and future search results.

Dayco 84078 Timing Belt Tensioner
$69.99 + Tax or free shipping online from Checker Auto Parts (CSK or PartsAmerica.com)

or from planetautoparts.com for $57.89 with free shipping.

Thanks

Rhett

The ford ones are over 150 bucks I think...

 

[Acidic]

The ford ones are over 150 bucks I think...

Any ideas on the quality? If it's a solid part I'd definately go for it.

EDIT: looks like they are $100 at CSK... $58 at rockauto

 

[Devin]

Well, I haven't driven with mine yet, but the one that I got from Planet auto parts rolled nice in my hand, was very solid and felt just like the OEM one I took off the engine.

 

[SuperHO]

....I picked my timing belt tensioner up for my MTX last year sometime for about $40-50 (can't remember, don't have the reciept) at Advanced Auto. Had to wait a couple of days, but it was worth it.

 

[Acidic]

Well it looks like I'll be getting some practice... my wife's '91 325i just sprang a leak in the water pump... funny thing is her parts come to $80 and mine come to $300.... imagine that...

 

[Acidic]

well I just got an email from the previous owner, he said he did the timing belt not long ago.... I emailed him back to see what other parts he did. If he didn't do the tensioner that would be my first hope (not enough of a mech to make a guess)... I think tomorrow while I'm out buying parts for the wife's BMW I'll pick up a mech stethoscope and try to nail down where the sound is coming from...

Also I was driving the other day and a new symptom started:

While driving I get pauses in acceleration, I've been nice to it and not going over 4k rpm so it only happens under 4k as far as I can tell.. it's the exact symptom I was getting when running the A/C when the car wasn't making the noise.

The second symptom is that it won't hold idle correctly when the clutch is first depressed after driving. It will bounce between 1k-1.5k rpm for about 2-3 cycles then it revs a little higher and settles right around 1k. It's never had odd idle surges before.

Any suggestions based on the new symptoms? I'm hoping it's just the tb tensioner because I can't afford much more, but the timing belt being done recently also opens up the possibility of crank cancer. I have Friday blocked off for troubleshooting the problem before I spend all day Saturday doing the water pump/timing belt on the wife's 325i...

 

[DemonNeno]

This isn't going to answer any questions, but do these replacement units come with a replacement spring as well? The search on napa's part states that there isn't a spring with it. TIA!

Good luck with the fix!

 

[Acidic]

just a bump for the new symptoms... in post #13

 

[DemonNeno]

have you scanned the codes? Timing issues can cause quite a few different problems with a ECM vehicle. I'm having very similiar issues and have gone through everything. It even gave me a cam and crank sensor code, but dead crank sensors **** the car. Mine still ran. IAB were also an issue with it. This suddenly happened to my car after snapping a couple pressure plate straps. Never idled the same.

FYI, the spring isn't included with the tensioner.

 

[Acidic]

have you scanned the codes? Timing issues can cause quite a few different problems with a ECM vehicle. I'm having very similiar issues and have gone through everything. It even gave me a cam and crank sensor code, but dead crank sensors **** the car. Mine still ran. IAB were also an issue with it. This suddenly happened to my car after snapping a couple pressure plate straps. Never idled the same.

FYI, the spring isn't included with the tensioner.

Well with the noises coming from the timing area I doubt it's eletronic, though a bad water pump leaking on the crank sensor might cause problem they usually just **** the car outright as far as I can tell... I'll be doing a teardown tomorrow so I'll hopefully get it diagnosed...

 

[Sammy~D]

put pics up whule you are doing it

 

[Acidic]

put pics up whule you are doing it

that is the plan... I'll have my laptop and camera with me

 

[Acidic]

It's CRANK CANCER!! :cry: :cry:


Sigh, well I tore it down today and used my mech stethoscope to pinpoint the noise and it's definitely coming from the crank. Check out the pics of the inside of my timing cover too, you can see the red dust. I didn't have time to pull the harmonic balancer to check how worn the keyway/crank/timing sprocket are... I have videos but they are huge and would need to be resized... I will have pics of the keyway and such tuesday when I go to tear down the bottom end. Tomorrow I'll be doing the wife's 325i though... In any case I'm really ready to go throttle the guy I bought it from.. this car has had a transmission and now possibly an engine in just 3 months of me owning it... RAR...