stupid question time
 

Hi all -

After installing my ATI balacer/damper, I've got a vibration I never noticed before - 1400-2200rpm or so, no/light load, clutch in or out, moving or not. Then again, I never noted an absence of vibration either, but I think it's recent. Searching came up pretty well empty. :bang:

Backstory - balancer bolt backed off at a track day, towed home, apart three weeks while waiting for parts to show up. Car has 70K, drivetrain is original other than revshift trans and diff bushings.

I'm going to swap the OEM one back on to rule out the balancer. I guess that would "rule in" the clutch? Or maybe the motor mounts?

I'd like to be able to swap the balancer and run the engine to check the vibration without bothering to put the belts/radiator back in.

Anyone know if that's safe to do or not? Going to run it no more than 30 seconds, probably more like 15. I figure it's fine, but hate to take a chance and blow something up only to have you lot laugh at me saying "how could you be so stupid?!"

You can run it for a little while. Starting out cold, I would run it no longer than a minute, and not do it again until it is cold again.

I'm worried your vibration is internal damage but I'm hoping for you it is not! My next best guess would be motor mounts.

:confused:
Any thoughts to specifics?

It ran hot but was shut down immediately (though restarted for 30-sec or so to get off track). Didn't run out of oil, didn't lose (much) coolant, no oil in water or vice versa, seems to make the power it always did... just this funny low-load vibration.

I was wondering if anything could have gone awry running it without the balancer for ~30 sec; medium load, 2-4K rpm. Thought I just tossed the serp belt, hoped to finish out the lap if it didn't overheat.

I've seen the truck motors so hot they melted the intake and they were fine after the melted/leaking/broken parts were replaced. This was on trucks owned by equipment rental companies that ran to the floor to get to a remote site and broke mid way only to sit at idle and do more damage after.

You'll be fine.

Thanks for the reassurance, much appreciated.

I'm going to retorque the various bolts first, to be sure there's nothing screwy going on before swapping.

Sure would (will?) be nice to drive this thing without worrying myself about it.

The vibration is marginally more notable with the clutch engaged and in neutral. Don't know what that means, if anything.

Do you still have the dual mass clutch? I would not suspect your crank snout would be bent from the balancer flying off but it's certainly not out if the question.

Also, you have to loosen the timing cover before you install the balancer to center the seal, then tighten the timing cover after the balancer is on the crank. This is what centers the seal around the balancer so it doesn't get torn up.

Clutch/FW is all OEM to my knowledge, certainly clunks like I've come to expect reading here...

Did not know about loosening the timing cover. No leaks that I'm aware of.

Bent cranksnout would suck a lot, but I've got to think that's pretty unlikely. The balancer was not attached to the crank, but the bolt didn't get all the way out, so it didn't actually "fly" off.

Then again, I'm new to this engine.

I'll see if I can borrow a dial indicator to go with the torque wrench...

1. Replace the motor mounts.
2. Replace the clutch.
3. Replace the Diff.

Check this out - while waiting at my buddy's shop for him to return, popped the hood and looked to see if I could note a wobble.

Nope.

But I did find the AC pulley bolts had all backed out. WTF. I didn't use a torque wrench (lacking the proper adapters) but figured my hand-dyno was pretty well spec'd.

Got a dial indicator, 250# torque wrench, red and blue loctite lined up for tomorrow.

54" - trust me man, I've been tempted to throw caution to the wind and go balls deep with mods... I can afford it, haven't blown money willy nilly at a car in twenty years (well, I *did* restore my 240Z 11 years ago, but that was money wisely spent) and damn if it wouldn't be nice to have an off-the-shelf 8.8 kit (I applaud your efforts on the DIY, BTW) and a pile of engine mods to take advantage of the newfound capability.

But I've had the car for three months, about 1,000 miles (including a track day and a half). Already 1K in maintenance/upgrades. Yikes. (Oh yeah, I'll need front tires soon too!):bomb:

I'm heading into busy season at work (I'm an accountant) and really just need something reliable, comfortable, with good HVAC and heated seats to get back and forth from my 13 hour shifts in the salt mine.

If the balancer/crank check out okay, I'll see if I can train my wife into stressing the motor mounts (should be fun).

Assuming it's the clutch/FW making the vibration, any harm with running it as-is for 1-2K miles over the next four months?

I think you might have an imbalance somewhere. Did your stock balancer have any weights by chance?
Running the stock clutch/FW for another 1-2k miles will not do much harm other than annoy the crap out of you.
Just noticed you're from Santa Rosa, beautiful place.

Thanks for the info, appreciate it. My other cars are sufficiently stoneage that this thing is a treat even at its worst.

No weights on the OEM balancer.

Seriously have my fingers crossed that re-loctiting and re-torquing the AC bolts will fix it. Then I'll just look dumb for trusting the hand-dyno.

If no runout, I'll swap the balancer back. Talked to an ATI tech today, he said this was a new symptom but offered to exchange the balancer if needed.

PS - yep, nice up here, though I think the weather's finally turning... was hoping for another MTB ride while it's still nice out, we'll see how the V treats me tomorrow.

Dude, I'm in the same exact boat as you. Bought my 05 v about 3 months ago and have put 1000 miles on it at the most. Anyway, I was just strolling down the road the other day, just cruising, not on it or anything. The car started ringing at me so I look down and my temp gauge is maxed out so I immediately shut the car off to prevent any further damage. I open the hood and take a peek and both belts are off, the harmonic balancer is completely off of the snout and the bolt is laying on the undertray. WTF! I've never had anything like this happen. The car has 70k exactly on it and is completely stock so I'm not sure what the hell caused this but now I've got the car apart waiting for a new harmonic balancer and bolt and praying that when I start it back up for the first time there are no other problems. F'n car!

I don't buy it... why would the opening not be centered already... show me in the service manual where it says that. (besides even if you loosened it i would think the weight of the cover would offset it down anyways)

Man that is no joke right there, crazy coincidence.

:mad:

Will report back tomorrow... What sucks is the usual mantra of "well, if it's too terminal, time for LS swap!" doesn't really apply.

I'm blessed with plenty of room to work and pro wrench resources. Fingers crossed.

When you built the dampner did you make sure to align the dots ?
If you ever come through FF/VV you are more then welcome to compare the vibration on my V. I have the ATI also along with stock clutch but am running revshift MM's

Damper can only go together one way, got that sorted okay. Retightening the AC bolts didn't change anything.

Hard to use a dial indicator with all the aluminum... Using the AC compressor as a base, found approx .008 runout in the damper shell, approx .004 in the hub, and approx .001 at the cranksnout. Doesn't make sense, I know...

The crank flexes while turning it via the crank bolt, but springs back to just about zero, so I think the crank is okay.

Put the old balancer on, vibration is the same.

The vibration is a little worse with the clutch engaged in neutral. Maybe that's pointing to the clutch.

Off to the FLAPS for the three-jaw puller.

And here we are... back together, same as before.

My tech buddy thought it felt like the clutch, since the vibration changes clutch in or out. He was also laying-hands-on the clutch reserviour, maybe sensing something there?

So I'll run it as is until spring, unless something changes...

Thanks much to all for their help and advice.