Time for a rebuild?

[OneLethal87GN]

I have a bad sound coming from my engine when I rev it up. It sounds like a big marble rattling around in a cement mixer drum. It isn't very noticable at idle but when I bring the rpms up over 1500 you can hear it very good. It goes up and down with the rpms. I first thought my water pump had gone bad due to an antifreeze leak, but after replacing it, the leak is gone but the sound isn't. I thought of taking the valve covers off, but the sound seems to be coming from the front of the engine, towards the bottom. I am getting knock on my SM just at idle and even worse knock when I rev it up. I haven't driven it since replacing the pump. The oil looks to be at a good level. Is it time for a rebuild or could it be something simple like a spun bearing or something that would cost less than $500 to fix? I don't want to hurt the engine so it will not be driven until fixed. Also, that sound of having a big marble inside my engine isn't very cool when you're out on the streets with the tops out. By the way the engine is stock and has about 156k on her. Maybe I can just take the front cover off and the marble will fall out and my problem will be solved?

BTW, if it is time for a rebuild, how hard would it be to just stuff a 4.1 in there? What other parts would be needed? What year 4.1 to look for and what kind of cars have them? Thanks.

 

[MSDGN]

Could be as simple as the tensioner pulley bearing...remove the serpentine belt and spin the pulleys on the accessories...also could be a loose bolt on one of the accessories such as the AC compressor...they're infamous for coming loose...also try running the engine without the belt...if the sound goes away it's one of the accessories...if everything there checks out then remove the pan and have a look...if all looks good then remove the front cover...etc...if that's the original timing chain you're most likely due for a new one...you need to try and narrow down exactly where the sound is coming from by using a mechanics stetoscope or old piece of garden hose...

 

[steve hughes]

Before you pull the pan you might also want to check the balancer to see if it's loose and the torque convertor bolts and look at the flywheel. They sometimes crack or break and make strange noises.

 

[OneLethal87GN]

As I look at the engine while it is running the balancer seems to be shaking quite abnormally. I shook on it while I had the belt off and it felt tight to me. Hopefully I'll get a chance to get under the car and check all the bolts tomorrow. I'll also take the belt off tomorrow and see if it's an accessory. I still wanna rip that ole 3.8 out and slap a 4.1 in that baby. I just don't know how hard it is to match a 4.1 up to all this 3.8 stuff. Anybody done this swap?

 

[d0n_3d]

i have that same sound in my car and have had it since day one...many have told me it was a loose cam sensor underneath the car...also the other culprits were mentioned eariler...i need to check this myself...it's bugging the **** outta me

 

[turbot2112]

dont want to scare ypu but i had a noise very similar to what your explaining. i checked everything and changed a few things, then finally when i pulled the motor i found a busted main cap. good luck

 

[OneLethal87GN]

To narrow it down...... took the belt off.... same noise.... took off one plug at a time.... noise, but alot softer sounding.... checked torque converter bolts.... all are tight. I had the crankshaft bolts come loose once, but it seems the only way to get to them is to either pull the motor or the tranny. Still looking for info on that 4.1 swap too. Thanks.

 

[blackbuick87]

If the noise gets quieter with the plug off that usually means a bad main bearing

 

[Rob B]

I had the crankshaft bolts come loose once, but it seems the only way to get to them is to either pull the motor or the tranny

Main caps or rod caps? Flywheel bolts? What came loose?

 

[OneLethal87GN]

I believe he said the bolts that hold the crankshaft to the flywheel. I got under the car to see if they were tight, but I saw that only a tranny removal or engine removal would allow access to them. The reason he found them loose was because he was taking my tranny out for a rebuild. I will just save up for a higher stall conv. and while having it put in I'll tell the tranny guy to check them bolts again. If I take the oil pan off what should I look for in a bad bearing?

 

[blackbuick87]

Originally posted by OneLethal87GN
If I take the oil pan off what should I look for in a bad bearing?

You need to pull the main caps off. start with the cylinder number that stopped making noise when you pulled the plug wire off. When you pull the cap look at the bearing and crank journal and see if there or signs of scuffing or the bearing "spinning" or moving in the cap

 

[gnsrule]

If the flywheel bolts were loose, thats probably your noise. Makes for what sounds like a rod comeing out the side of the block kind of noise. Flywheel bolts can be tightned in the car. Unbolt the tranny and run a couple of 6" tranny bolts in a few threads and pry the trans back a few inches. Unbolt the trans mount too
Drain your oil and look for a silver tint, if it looks good, maybe you got lucky.
Just my o2

 

[OneLethal87GN]

I'll try to take my car somewhere that has some kind of room to put it in while I work on it. It's too much to keep jacking it up everytime I want to work on it. I can't leave it jacked up because we're not supposed to work on our cars in my neighborhood. I actually wanna try to fix it all myself but with no torque wrench it'll be too risky to just tighten bolts to what i feel is good. I guess it's time to search Ebay for a torque wrench.

 

[OneLethal87GN]

about the spark plug thing...

The noise got softer every time I pulled a different plug wire off. It wasn't just one certain wire. The reason probably being that with a wire off the engine wasn't running too good and didn't idle as high or as smooth therefore making the noise softer.

 

[blackbuick87]

Well dont forget some bearings serve more than one cylinder, so the sound may not totally disappear since the opposite cylinder is still firing and will also cause a knock.

Sounds like a bearing so far