Engine Rattle

[bfarroo]

The engine in the spirit is making a weird rattle at about 3500rpm and above. I went through and pulled all of the accessory belts off and it's still there so none of them are bad. Below 3500 the engine is smooth as glass. Revving below 3000 has no abnormal noises. I tried listening to different areas of the motor with a screwdriver to the ear and can't really find anything overly loud. The motor is relatively new. Rebuilt it about 2 years ago and has about 15-20000 miles. Just changed the oil and looked it over and there were no metal flakes or anything abnormal in the oil. Any ideas where the rattle could be coming from? I can also get the motor to make a clunk noise just off idle when snapping the throttle. I'm going to check the TC bolts when I get a chance and see if I can move the flywheel. I put everything in to spec and used loctite. I don't think there are any bearing issues as I've never seen any metal flake in the oil. I left the balance shafts in when I rebuilt the motor and just tensioned the chain back up. The motor had a little over 200,000 when I tore it down.

[trannybuster]

Check the crank pulley, it may be coming loose and the belts are keeping it quite at idle..just a thought. Where abouts is the rattle? I know tough to pin point.

[turbovanman²]

Post a vid, it could be wrist pin noise or piston slap.

[bfarroo]

The noise seems to be coming from the passengers side of the engine although it's one of those noises that always sounds like it's in the opposite side of the engine depending on where your standing. The rods had new bushings installed at the time of the rebuild also so hopefully there's no wrist pin noise. I'll try to get a vid up next weekend. I'm out of town this week for work and won't be back until friday.

[bfarroo]

Here's a video of the engine running, This time it almost sounds like it could be coming from the head. I'll probably dig into it tomorrow some time. If you have any suggestions before then post them up. I'll probably start with pulling the VC and looking the cam, rockers, lifters over. Then pull the pan and check bearing and the ballance shafts. In the vid the short rev's are below the 3500 rpm area then I bring it up above and that's where you can hear the noise. My camera isn't the best so there's some background noise but the second time I bring the RPM's up and hold it at the end you can hear it pretty good.

http://youtu.be/laESj9JGVFI

[BadAssPerformance]

Havn't heard that one... sounds upper end, maybe pull the valvecover and look for a loose rocker or something?

EDIT: before pulling that... use the broom handle or stethescope to listen around... could be intermediate shaft/oil pump area maybe?

[bfarroo]

I tried that with a old antenna a little bit last week and didn't seem to find anything out of the ordinary. I'll listen around some more before I start pulling things apart.

[bfarroo]

I went through and spent about 15 minutes listening to different areas and it sounds like it's coming from the bell housing area. I guess I'll have to loosen the trans and pull the covers and see if I can see anything. I'm not making any huge power with this car so I wouldn't think the flex plate would have cracked but who knows. I think I used the flex plate that was on the car when I rebuilt everything so it probably has 250,000+ miles on it. Everything was put together with high strength loctite and torqued to spec. The trans was a known good one that came from a low mileage Daytona and has the typical VB mods. Any other things I should look for. I spent some time listening around the Int Shaft and didn't hear anything abnormal there. Also when going directly to the trans I could hear the pump wind up when revving but everything sounded smooth in there.

[RoadWarrior222]

Well if you pull the trans pan and there's aluminum and brass dust, it might be stuff on the input shaft knocking together due to bushing wear.

[BadAssPerformance]

Loctite should have worked, but could be flex plate torque converter bolts?

[black86glhs]

It sounds like piston slap, but I wouldn't think it would come on so suddenly at that RPM. Would expect to hear it before that.
Maybe it has something to do with cyl #4 only? Lifters? Rockers?

[bfarroo]

The TC bolts are tight and I tried moving the flex plate around as best as I could and nothing there seems to be loose. I'm draining the oil now and I'm going to pull the pan. I'm hoping it's something simple like the balance shaft chain is loose. We'll see.

[bfarroo]

I didn't find anything out of the ordinary in the motor. The balance shafts chain was a tad loose but nothing I would think would cause the noise. There is a bit of play between the two shafts but no more than the unit I pulled from the 91's motor when I rebuilt it and left it out. I'm going to put the pan back on and I guess the next step would be to pull the trans. I should be able to run the motor with the trans out if I bolt the flex plate back up and fasten the start down some how shouldn't I. Why can't these things be easy!

[RoadWarrior222]

mounting the starter could be iffy, could try starting it with an impact on the crank bolt, but you have to pull off while it's still spinning.

[black86glhs]

Just disconnect the torque converter from the flexplate and push it away from it. Start the engine and see if the sound is still there. No need to yank the trans.
If it is there after that, then pull the trans and inspect the flexplate. Does the sound change rpm if you put it in gear and brake torque it? If it happens while doing that at a lower rpm, I'll bank on the flexplate is cracked.

[trannybuster]

if pan is off check the one of the mains, they make a terrible noise at higher rpm and no load on engine and they will run for some time like this.

[bfarroo]

Here's what I ended up finding. The Auxiliary shaft bearing completely delaminated and came apart. Not sure how it could have happened. The Aux shaft bearings were replaced when the motor was rebuilt with a new set I got from FWD. I believe they were mopar bearings. Anyone else ever seen this happen? The rest of the bearing is still in the motor and fullt intact. Oil feed holes were lined up and are still lined up. Oil pump and shaft gears are in perfect condition.

[black86glhs]

Belt a little too tight.

[135sohc]

durabond PDG-26.

[bfarroo]

Belt a little too tight.

I actually have the belt tensioning tool and also check with the 1/2 turn on the long end of the belt.