Vibration at High RPM (even in nuetral)
 

Hello 4g69ers!

I have an issue and can't figure out what it could be. Any help/advice is greatly appreciated.

Short story:
Vibration at 5500rpm+. I can hear it and feel it in the shifter. It was previously vibrating/rattling at 4500rpm+ (see long story). It sounds like a phone vibrating on a desk, times fifty, coming from the motor side and I can feel it in the shifter.

Long story:
My release bearing was wearing out. 1 week before I was scheduled to take it in, it shattered. It went into the shop, I got a full timing belt job done as well as a new clutch, flywheel and motor mounts.
After I got it back, I could hear the vibration described above at around 4500rpm. I took it back to the shop. They re-checked their work, verified it was done properly. Sent out the clutch/flywheel to get balanced and replaced one transmission mount and sent me on my way.
Now, I can hear it at 5500rpm, same vibration and feel in the shifter as before. This happens with the clutch in/out, in neutral or in any gear. Same amount of vibration at the same rpm in any of those situations.

Any advice as to what it could be? The shop just shrugged and said they didn't know what it was. Besides that, it drives fine, no issues at all. I'm sure it's not healthy to drive this way though, it sounds and feels awful.

Here is a video. It doesn't do the noise/vibration any justice though. I purposely slowed down before 5krpm, I also didn't want to hold it in the rpm where it makes the noise/vibration in fear of blowing something up.

Mods are in my signature.

http://www.youtube.com/watch?v=0N45nKNDhEk

Thanks again!

Your oil pump balance shaft is out of phase. Take your car back to the place that screwed up your timing belt job and have them re-do it.

yeah, check the timing marks, the rear balance shaft sprocket won't line up perfect, the mark on the sprocket needs to be half a tooth before the mark on the block (clockwise rotation), when lined up perfectly on the crank sprocket...

it could also be the front balance shaft, this is more common due to the fact that there are no external indications of the angular position of the shaft, and will result in a more violent vibration.

i posted this a while back, hope it helps...

https://www.evolutionm.net/forums/10122220-post129.html

Thanks guys! With that new information I did a search on here and came up on some good threads.

These in particular in case anyone lands here on a search:
https://www.evolutionm.net/forums/04...vibration.html
https://www.evolutionm.net/forums/04...cranswick.html

Oil pickup is loose inside the pan. Just a guess. I have seen this happen before.

You have a valid point, loose parts is always a possibility, however if it was fine before, and after a clutch/flywheel and timing belt service, it's likely incorrect procedure or timing alignment causing the issue...

btw, did they just resuface the flywheel? or did they do any cutting to reduce weight?

Resurfaced. The mechanic said from a scale of 0-10, higher than 10 being unacceptable, the balance of the flywheel/clutch was at a 7. This is why he told me he was 99% sure this was the issue and sent it off to be resurfaced/balanced. They ate up all those costs though and will also eat up the next set of costs when I take it back again.

It just sucks since this is my only car at the moment (got 3 kids/job) and they are not giving me a loaner car for the down time. This is why I turned here to dial in the issue better and help these guys out :( I should have asked you guys the first time around.

have them double check the position of the front balance shaft...using the screwdriver method...

if you lived near me, i would lend you one of my cars, and do the work for you :)

I think I can make it up to Canada and back down in a weekend lol.

Just spoke to the owner of the shop. He said he swears it's not the balance shafts. He said when I took it the 2nd time they re-did the timing and ensured it was spot on.

He thinks they over tightened a bolt on one of the mounts since they touched pretty much all of them or something is a little loose and touching something at high rpm. He said that it would also explain why the vibrations moved in rpm.

:confused:

I'm going to take it in next Monday so they can play with the bolts while I'm there. I'll have them check the position of the balance shaft using the screwdriver method too. I can probably check that myself this weekend tho..

Thanks, I'll update this thread after they're done.

I've answered your question already. The timing marks will line up on the timing and balance sprockets as he would see and he will think he had done it correctly however the oil pump sprocket needs to be spun 360* again and the balance of the sprocket should favor spinning counter clockwise. If you line up the timing mark and it favors wanting to turn clockwise then it's out of phase. and needs to be spun one more full turn. It spins half the speed as the intake side shaft so it is semi common for shops to screw this up as they have a 50% chance of lining it up out of phase.

Thank you and I appreciate it very much!

They didn't want to hear any of this on the phone :crap:.

I will definitely take all this information with me when I go back to the shop. I wouldn't want to mess with it myself since it's under warranty at the moment, otherwise I would be off exploring.

I'll probably have to sit there for an hour while they mess with the bolts before they will really start hearing me with the info you've given me.

Thanks again.

One quick question to be extra sure.. assuming the mechanics of the access port are straight forward, if it's off by a full rotation, it will pass the rear screwdriver access port check, right?

Thanks!

This sounds exactly like my problem and it never made that sound until after I had the timing belt replaced. I didn't notice it because I hadn't pushed the car near 5,500rpms for until about a month or so after it was changed. Definitely going to bring my car to a shop and see of this is my problem.

screwdriver method is used for the front shaft, line up all timing marks by hand and shove the screwdriver in...

Oh, I thought there was another one for the rear balance shaft..