Engine vibration

[Rudy van Daalen Wetters]

I have a question to 250 owners regarding engine vibration. Being my first GTE, I am not sure what is considered acceptable or normal regarding engine vibration on my car. The car starts and runs quite good but there seems to be a harshness or vibration that is generated from the engine especially between 2500 to 3500 RPM. I was wondering if this is a characteristic of the V12 or should there be a further investigation done. I did notice an early editorial on the GTE whereby a journalist stated that the engine seemed a bit harsh a low speeds. Any comments would be appreciated.

Rudy van Daalen Wetters
s/n 4001

[tyang]

Hi Rudy,

These V-12 engines are known for their smoothness, and they are not supposed to vibrate like you describe. There are number of sources to your problem. Most often it can be from the drive shaft being out of balance, but if that doesn't solve it, the flywheel can be a source, and then worst case, crankshaft. I wouldn't discount an axle shaft either, but I would check the easiest thing (driveshaft) first before jumping to conclusions to the other suspects.

Tom

[Rudy van Daalen Wetters]

Tom,

Thanks for the information on my vibration problem. It definitely seems too harsh and I think the driveline is a good place to start. I had the same problem on my GTV 2000 due to a bad joint (rubber donut, I believe). The vibration seems to transmit directly into the transmission shifter on the GTE while driving.

Regards,

Rudy van Daalen Wetters
s/n 4001

[tyang]

Hi Rudy,

You have a 80-90 percent chance of it being driveshaft related. I'd check the doughnut, and the driveshaft. The only pain in the butt is getting to it. You'll have to remove at least the passenger seat. The center console will have to be pulled and put to the side, and the transmission tunnel will also have to be removed. There's a particular sequence the drive shaft has to be unbolted to get it out, but I can't remember the details. If you're going to do this yourself, I can try to find out, or maybe someone reading can chime in.

Good luck!

Tom

[Rudy van Daalen Wetters]

Hi Tom,

Thanks for the advice regarding the driveline. I think that I will try to do the work myself. I like the odds that you quoted and feel you are correct. I remember changing the donuts on the Lancia Appias which became quite troublesome when they started to split. Even though the donuts looked great, once removed you could finally see that they had completely separated internally. I have no record of any work being done to the driveline on my GTE so I think that it is the first thing to check out. Also, would you recommend having the flywheel and clutch balanced as a unit?

Rudy van Daalen Wetters
s/n 4001

[tyang]

Hi Rudy,

If you're going to balance the flywheel, the clutch assembly should definitely be done with it.

I don't want you to do things twice, but perhaps you could have the drive shaft balanced first, drive it with just the transmission cover back on, and see if the problem persists. If there is still a problem, address the flywheel.

Does the vibration change depending on what gear you're in? With the drive shaft turning at different speeds than the flywheel, perhaps you can tell what's vibrating.

Tom

P.S. I'm sure others on this forum are experiencing similar problems, and would be interested in what you find. Keep us posted!

[Matt F]

Does the vibration change depending on what gear you're in? With the drive shaft turning at different speeds than the flywheel, perhaps you can tell what's vibrating.

That's a great diagnostic question, Tom.

Rudy, do you feel the same vibration at that RPM range when the car's at a standstill in neutral? If not, that's good news!

--Matt

[Rudy van Daalen Wetters]

Tom and Matt,

Here is the best way I can describe an answer to your questions. First, with the car warmed up and standing still in neutral, I revved the engine until I feel a vibration or harmonic resonance at about 2800 RPM. My reference (crude but it works) is that I can feel it and see the inside rear view mirror shaking to the point whereby the image becomes blurred. Below and beyond that point, the rearview mirror becomes useable. However the transmission shifter stays still and does not have the any oscillation as when it is running in gear. Once in gear and driving, the shifter and the mirror vibrate at an annoying rate. At low speeds or when the overdrive is engaged, things seem a lot smoother. I hope I have conveyed something that is understandable. I know this car should be a lot smoother. Thanks for the input.

Perhaps a combination of both engine and the driveline?

Rudy van Daalen Wetters
1963 GTE s/n 4001

[John Vardanian]

Rudy,

I have had vibration occur after a clutch change. But, if you haven't had any replacements of the sort then...

A friend had a similar vibration in a 275 engine (fitted in a Lusso) and the problem was chased down to a bush at the point where the gearbox nose shaft and the ceankshaft meet. Sorry, I do not know the details.

john

[Rudy van Daalen Wetters]

John,

I am sure that the clutch was changed at some point in the car's lifetime. The rubber donut looks old, though. I think I'll try Tom's advice and start with the driveshaft and donut and see what happens. I did notice that there are no cotter pins or safety wire on the nuts securing the donut.

Rudy van Daalen Wetters
s/n 4001

[John Vardanian]

Rudy,

If the vibration happens at standstill then you should consetrate your efforts from the transmission noseshaft forward. The driveshaft is irrelevant.

On the flip side, have you checked to see if all twelve cylinders fire? Remove the exhaust shields and with the engine running put a drop of water on each exhaust outlet pipe to see if all evaporate at the same rate.

john

[Rudy van Daalen Wetters]

John,

I pulled the plugs and they look like are firing ok. I will try your test anyway to see if they are all consistent temperature wise with no intermittent misfire. My gut feeling is that two things are going on because I get vibration at standill and more pronounced when driving. The shifter really starts to rattle quite a bit when driving. All I can do is check it out one at a time. I understand that the clutch is balanced with the flywheel and crank. That would be a major undertaking. I wonder if the clutch and flywheel could be balanced as a unit first?

Thanks for the input.

Rudy van Daalen Wetters
s/n 4001

[tyang]

Hi Rudy,

Yes, you can have the flywheel balanced with the clutch.

I'm concerned that there is vibration without moving because this points towards something before the transmission.

Tom

[Rudy van Daalen Wetters]

Tom,

I hear what you are saying....looks like I have some work to do.

Will keep you posted.

Thanks,

Rudy van Daalen Wetters
1963 GTE s/n 4001

[tyang]

Hi Rudy,

You can try removing the transmission and try running the engine without it and the clutch assembly. This would narrow it down to just the flywheel, or the crank being out of balance.

Tom