Best guess if this sounds like a timing chain

[Xvetteowner]

My 1987 WE4 85k mile car makes a noise that sounds like marbles ratting from the front of the motor from about 2000 rpms to around 3000 rpms with it being most audible at about 2000 rpms. It could still be happening after 3000 rpms I'm just not hearing it. The noise does not follow any rhythm. Sounds like marbles in a can. The timing chain is original. What I know about the car's engine is limted, the vacuum is a rock steady 16 psi at about 800/1000 (Hard to read the factory tach)Replaced the plugs which seem fine, maybe a little rich, fuel pressure is 36 with line on. I don't know if this means anything but the engine will run rough at about 1500 rpms, Like a slight shake in it. Its not there at idle. There is no smoke blowing out the pipes but I do get clear water dripping out and carbon build up on the pipe inside. I know at worse case this could be a bearing. Is there a way to check the chain before taking the engine apart? I have removed the belt and the noise is still there. The car is not used other then start ups for a few months. I'm still sorting thing out with it. Thanks for any input.

 

[usetaboost]

Anyone else think this could be a cam sensor problem???

 

[Xvetteowner]

I checked the cam sensor

Its not loose. I removed the cap, other then what looked like rust on the inside of the cap on one side it looks fine. I've used the search section and I see I'm not alone with this issue.

 

[usetaboost]

bad tensioner or pulley maybe? I've read about this before but can't remember what the hell it was

 

[Danster]

I thought I've read a few threads If I recall that indicate marbles in a can could be coming from the converter area. The bolts may need to be tightened.

If this incorrect, I apologize!

Dannyo

 

[Xvetteowner]

The cat was removed

The noise is there even with the belt removed. Timing chain maybe hitting something?

 

[86 TR]

Anyone else think this could be a cam sensor problem???

Could be a cam sensor problem. I had an 87 GN with about 90,000 miles that would make a tick, or rattling sound when cold. But would improve as the car warmed up. Turned out the cam sensor was bad. You couldn't tell physically by looking at it, but once I took it apart you could tell it was quite wore.

Just my $.02.

 

[Just a Six??]

When it happened to me it was a flattened rod bearing. To test it unplug each injector 1 at a time & see if the noise goes away any at idle. I know its at 2K RPM for you but Exact Same as mine was. At idle it was obvious it was #1 cyl.

 

[jskarateka]

I had the same noise on my 87 GN

I had the same noise on my 87 GN when I first bought it and started to restore it. Drove me %&#@ crazy. The bracket that holds the alternator, AC, power steering pump, etc. was loose, but not loose enough to be obvious. Check yours out. On mine 1 bolt was loose and the other 2 were broken off in the driver’s side head! They were rusted in so I think they may have snapped when someone took it apart and they just put it back together and left it. 10 hours of swearing later I had them out and the threads clean, sore back but problem solved.
BTW thanks to everyone on this site that answers these posts. I’ve been reading posts on this site now for a few months and I only wish I would have found it sooner, would have saved me a lot of time and money.

 

[Xvetteowner]

Thanks for all the good ideas

Funny thing is I'm not so sure its coming from the front of the engine. I was sure yesterday but not so sure today. Could be from the back or ever top of the engine. At this point I'm hearing things from all sides of the car. Even the cat making a funny noise. My wife and kids are starting to look at me strange. It's time to close the garage. In fact I hardly even hear it today from the engine bay. Could still make it out from the front seat

 

[jskarateka]

It was the same with mine, I couldn't tell where it was coming from. Only people were looking at me funny even before that.

 

[Dabigguy]

What exhaust do you have, Flowmasters have been known to come apart inside and make a hellova noise when the exhaust resonates.

 

[Xvetteowner]

Stock exhaust ( No cat)

I need to do a better job of pinning down were the noise is coming from. Front,back, top ect

 

[ccognetta]

Your Problem

The same thing happened to me, sounded like when we were kids with a playing card in a bicycle wheel noise. I checked all over. It turned out that when the dampner/balancer is going through the bracket for the crank sensor
it was swipping it just so slightly.

Untighten the bolts and slowly hand crank the move over as you keep adjusting it so that you don't have any rub. You can take the the first 2 plugs
out to help you, but I just muscled it.

 

[salvageV6]

Intercooler brackets, and any accessory bracket, belt tensioner, power steering pump loose and falling off, all can make those crazy noises too.

 

[SloGN]

My 1987 WE4 85k mile car makes a noise that sounds like marbles ratting from the front of the motor from about 2000 rpms to around 3000 rpms with it being most audible at about 2000 rpms. It could still be happening after 3000 rpms I'm just not hearing it. The noise does not follow any rhythm. Sounds like marbles in a can. The timing chain is original. What I know about the car's engine is limted, the vacuum is a rock steady 16 psi at about 800/1000 (Hard to read the factory tach)Replaced the plugs which seem fine, maybe a little rich, fuel pressure is 36 with line on. I don't know if this means anything but the engine will run rough at about 1500 rpms, Like a slight shake in it. Its not there at idle. There is no smoke blowing out the pipes but I do get clear water dripping out and carbon build up on the pipe inside. I know at worse case this could be a bearing. Is there a way to check the chain before taking the engine apart? I have removed the belt and the noise is still there. The car is not used other then start ups for a few months. I'm still sorting thing out with it. Thanks for any input.

I had this smae problem 10yrs ago. It tur4ned out the 2 center main caps were broke and it allowed the crank to flex enough for the timing chain tensioner to come loose and the chain was slapping around.

 

[Razor]

Whats the oil pressure at idle?

You can check the chain by dropping the oil pan and looking for plastic debris.. while your down there you can inspect the bearings...

That is if the sound appears coming from down low.

 

[dr_frankenstein]

My timing chain makes the same noise..... so loose you can hear it slapping around in the timingcover. yea it needs to be changed... but im curious as to how far it will go.


my 4.1 is going on 280K + miles though.

A.j.

 

[Xvetteowner]

It coming for the Coil pac area ( I think)

When I put a screw driver to the alternator I can hear the noise nice and clear. But this noise was there without the belt on so I it don't think its the alternator, water pump etc. Almost sounds like a losse rocker. I pulled the codes with a paper clip and got no stored codes. The hunt goes on. Taking it to a place in CT, I think its called Kash Garage.

 

[KevinB]

Maybe it's in the trans or the converter. Put it up on jack stands and get under it with the car running. See if it is louder down there.