Weird engine noise

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Superelbert

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When I start my engine, it makes an occasional "Klakk-klakk" noise. it is not regular, it is the sort of noise you would expect if a part of the engine was hitting something from low RPM shuddering/ vibration. With a little bit rev and when the engine is warm, this seams to disappear. There are no uglyt noises when I drive the car. Actually the engine runs surprisingly smootha nd quiet for its age. (non.overhauled 70's 318)

Is this something I can neglect, or do any of you reckognize such noise as a sign of imminent disaster??

Br,
 
Is this a recent development or has it been getting progressively worse over time? When you say it has a vibe/hitting sound my first thought is it's in the bottom end and not the valvetrain. Initial thought would be excessive piston clearance (piston slap) but on a cast piston, factory built engine that's not really common. Hope it's not a bearing or you may have issues sooner rather then later.

Looking forward to other responses.
 
Could this possibly be just the lifters before they pump up?

Lots of miles and oil pressure a bit low until a rev?
 
Torque converter bolts????
 
Not easy do describe a sound in a meaningfull way, thats for sure..

Well, it doesn't sound like any valvetrain issue, no clicking or ticking as you get before oil-pressure builds and the hydraulic lifters fill up.

It is certainly not something that has happened over night, but I can't really recall when I first noticed it. I had headers installed until very recently, and back then I just assumed that the headers was striking something when the engine was juddering a bit at start/ idle.

It is not a noise that I get anytime else than just after starting before the engine warms up a bit and settles to a steady idle.

I guess my fear is that this could be a bearing/ rod issue, but I have no idea what that sounds like and how bearing/rod noises behave with RPM/ load situation.

I guess the best would be to post a video clip with sound, I'll se if I can get arround to doing that a bit later.

Br,
 
TrailBeast said:
Could this possibly be just the lifters before they pump up?

Lots of miles and oil pressure a bit low until a rev?
Click to expand...

Good point beast. Wish we could here it?

I've had flexplate/conv. issues myself. Only it was bad all the time and not just cold or startup. But at this point anything is possible.
 
i just went through a similar ordeal with a 318. it is relatively easy to tell if it is valve train top end noise or a bottom end knocking. if it is a high pitch klackity klacking (as you put it lol) chances are good that the rockers are worn, valve springs are weak or in my case , a couple of collapsed lifters. a worn oil pump delaying pressure to the top end upon start up could also be the case. bottom end noise is really more of a chunking knock rather than a high pitch noise. you need to first determine where it is coming from, and what kind of oil pressure you have at start-up. without hearing it, there are many things it could be. i had a tick develop that would go away after a few minutes, which eventually got louder and then stopped going away all together. i pulled the intake and valve covers/rockers, replaced the lifters and now it is smooth as silk.
 
Superelbert said:
Not easy do describe a sound in a meaningfull way, thats for sure..

Well, it doesn't sound like any valvetrain issue, no clicking or ticking as you get before oil-pressure builds and the hydraulic lifters fill up.

It is certainly not something that has happened over night, but I can't really recall when I first noticed it. I had headers installed until very recently, and back then I just assumed that the headers was striking something when the engine was juddering a bit at start/ idle.

It is not a noise that I get anytime else than just after starting before the engine warms up a bit and settles to a steady idle.

I guess my fear is that this could be a bearing/ rod issue, but I have no idea what that sounds like and how bearing/rod noises behave with RPM/ load situation.

I guess the best would be to post a video clip with sound, I'll se if I can get arround to doing that a bit later.

Br,
Click to expand...

Thanks for the additional info.

I was a little late in my last post....lol
 
OK, just been outside and shot a few movie-clips. Figured it was best to do this wile the thread was stil warm! Oh, and thanks for all the replies so far! :)

Now, just got to figure out how to upload these clips... bear with me!
 
just had to create a youtube account first..

Now this is the first clip, starting the engine. You can se the oil pressure jumping straight up after the engine fires on the second attempt.(normal)

The engine is cold, and the clanking is now quite pronounced. It sounds quite bad on the video clip, but this has to do with the automatic audio level setting on the camera. You can allso hear the "Wuhu-wuhu- wuhu" sound from the mechanical fuel pump as a reference.
The idle is a bit slow and unstable and the clanking becommes more pronounced whenever the idel is stumbling/ dipping a bit.

[ame="http://youtu.be/n3uYt0j5opg"]302 Found[/ame]

I'll upload a second video with the engine after a minutes running..
 
OK, that worked..

Now, in this clip, the engine has been idling for a minute or two (or three) and has settled down to a more stable pace. The clacking now Hardly appears.

[ame="http://youtu.be/PnhNakXyVYg"]302 Found[/ame]

Sounds like it is making a terrible din, but again, down to the audio of the camera. In real life this sounds perfectly ok.
 
73AbodEE,

Yes, it sounds rather awfull, if that noise had been persistent, I would'nt had dared start the engine any more!

But the next clip I posted shows the engine just a minute or two later. What to make of this?
 
i had a 4.0 in a jeep cherokee that lost a rod bearing and it sounded just like that, but the knock never went away..
 
Good news!

A:

Since someone knows what a rod failure sounds like. (I don't!)

B:

That a rod failure sound dosen't go away! :)

During the first clip, If I had been able to be two places at one time, I could have given it some throttle, just taking it a bit above idle, you would then have heard the clanking disappear.
 
Could be the fuel pump. A long tube trans funnel is a handy listening tool.
 
Sounds a little more clanky then cluncky.

Could be a rod i guess? Maybe lay under the front end next time it's cold and see if it's more pronounced near the oil pan.

By the way, thanks for the video.

I got this crazy notion that the water pump impeller is starting to come apart..........any thoughts on that anyone?
 
Superelbert said:
Good news!

A:

Since someone knows what a rod failure sounds like. (I don't!)

B:

That a rod failure sound dosen't go away! :)
Click to expand...

not necessarily. start with taking all your belts off the front of the engine to rule out the water pump , alternator and powersteering

if it persists, check your flexplate bolts

make sure nothing is hitting the fan as well
 
Thanks for some great input and comments here guys!

A water ur fuel-pump issue has crossed my mind... but again, I've never heard what that sounds like. The fuel pump is perhaps not my top suspect as I replaced it when I got the car some 7-8 years ago. But for all I know, the water-pump could still be the original one.

Very good idea to remove the fan-belt! will do!!
 
OldmanRick said:
Sounds a little more clanky then cluncky.

Could be a rod i guess? Maybe lay under the front end next time it's cold and see if it's more pronounced near the oil pan.

By the way, thanks for the video.

I got this crazy notion that the water pump impeller is starting to come apart..........any thoughts on that anyone?
Click to expand...

Yep so many things it could be. If a strut rod bushing fell out , that strut rod knocking in the hole can come and go with how the engine shakes.
 
Slacked the alternator and lifted the fan-belt out of the pulleys.

Started engine, no clacking.

Put belt back on, started engine; Clacking.

Seems like i'll be ordering up a nwe water-pump in a big hurry!

I'm really not comfortable about what's causing that noise inside the water-pump!!
 
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