CRANKSHAFT DAMPER

CD's with partsbook, workshop manual, original sales brochures, instruction booklet, ads.
gfmanitto
Posts: 172
Joined: 06 Jan 2009, 00:10

CRANKSHAFT DAMPER

Unread post by gfmanitto »

I just recently discovered that the Flaminia engines come with a second flywheel, described as Crankshaft Damper, at the front of the engine shaft, which is at the opposite side to the traditional flywheel.
It is composed by 2 discs that are driven in motion by means of a clutch system and springs.
I'm curious to know what is its function . Anyone know how to help me?
Does it need some kind of maintenance, as there are two clutches and a bearing?
From the spare parts manual you can see that there are 4 types depending on the engine models.
Thank you. Greetings.
FL30
Posts: 264
Joined: 30 Sep 2009, 19:17

Re: CRANKSHAFT DAMPER

Unread post by FL30 »

The engine does not produce an even rotation. Every combustion leads to a turning impulse followed by slowdown of torque until the next firing. The job of the crankshaft damper is to reduce the vibration caused by this. The two disks work as an "absorption mass" for the vibration peaks.

It is common that all the components of the damper stick together, so that it only works as it would be one piece of material like a second flywheel.

In order to get it working again you have to dismantle it, clean the metal surfaces very well, replace the O-ring, and clean the surfaces of the friction rings. You can do that by putting a sheet of sandpaper grain 360 or 400 on a plain table and then grind the rings carefully over it.

Once it it assembled and mounted to the crankshaft, you should be able to turn the two mass disks a little with some force without the crankshaft turning. The disks are only held by the spring forces like a friction disk.

There is no need for maintenance after the system is properly assembled. You may watch some pictures here (you have to scroll down a bit to: 4.2 Schwingungsdämpfer):Flaminia crankshaft damper The text is in German, but you can click on the pics to enlarge them

The damping system itself is the same on all engines, it is the pulley that is different.
Hubert
gfmanitto
Posts: 172
Joined: 06 Jan 2009, 00:10

Re: CRANKSHAFT DAMPER

Unread post by gfmanitto »

Hubert, I read only today your kind and well documented answer.
I raised the question because I think that the engine of my GT 3C shows excessive vibration, therefore I'm looking for finding the origin.
Someone pointed me the damper and, after your notes, I think it is worth of an inspection.
But it seems to me hard to access for its removal from the engine without the removal of the engine itself from the chassis, notwithstanding the instruction, reported on the Shop Manual 1/8, that suggest only to remove the radiator and the water pump. Therefore I am interested of an opinion about this matter.
FL30
Posts: 264
Joined: 30 Sep 2009, 19:17

Re: CRANKSHAFT DAMPER

Unread post by FL30 »

According to my experience it will not work just removing radiator and water pump. You may be able to open the center bolt but there is not enough space to get the pulley off the crank. You will have to lift the engine quite a bit, but maybe not to take it out completely. If you dismantle the four bolts of the engine supports you can lift the engine with a hydraulic jack. Probably that will give enough space for removal.

When you say that you have some serious engine vibrations, I would say the reason is to be found somewhere else, not at the vibration damper alone. A typical source of really disturbing if not annoying vibrations is the transaxle shaft. These vibrations increase from about 1500 revs and become much stronger up to 2500 revs. Above that they feel to decrease again although i´d say they are still there, you only do not feel them that strong.

It would be worth testing the engine with the transaxle disconnected. Very important: before removing the transaxle mark the position of each component (aluminum flange on flywheel, if you dismantle that, front transaxle tube to flywheel/alu-flange, rear transaxle tube to gearbox, clearly, so you will be able to place it exactly in the position it was before. Also make sure that you do not mix the connecting bolts (triplets on each position) there are shorter and longer ones and some of them may have flat heads.

best regards

Hubert
Hubert
gfmanitto
Posts: 172
Joined: 06 Jan 2009, 00:10

Re: CRANKSHAFT DAMPER

Unread post by gfmanitto »

I found the vibrations increased (vibrations are sensible starting at 2300 RPM and returns to reasonable level at 3200 RPM) after the reassanble of the whole mechanics after a general overhaul and repainting of the body. In this occasion the gearbox was dismantled and overhauled but the engine was not affected by any maintenance. Of course every rubber damper on the body was replaced and I can say that work was accomplished by expert people.
After my compliance about the increased vibrations some research was done disconnecting the transaxle and I was told that the engine could be the cause...After that he mechanic, because of other priorities, could not help me anymore, so now I am on my own.
Geoff
Posts: 103
Joined: 22 Dec 2008, 04:54

Re: CRANKSHAFT DAMPER

Unread post by Geoff »

Most common vibration issues are around the driveshaft. When the gearbox was disconnected, did they disconnect the driveshaft from the engine? Try that to start with.
Geoff Goldberg

1952 B20 s.2
1957 B24 s.6
1959 Appia Berlina s.2
euromech
Posts: 1
Joined: 01 Jul 2021, 02:20

Re: CRANKSHAFT DAMPER

Unread post by euromech »

did you ever resolve your vibration issue ? I too ran into this exact same problem and narrowed it down to the engine, not driveshaft related. recently found the dampener clutch plates were stuck on one side. hoping repairing it will reduce or eliminate the vibrations
gfmanitto
Posts: 172
Joined: 06 Jan 2009, 00:10

Re: CRANKSHAFT DAMPER

Unread post by gfmanitto »

Last year the transmission was checked replacing nut and bushing-flange of the 3 joints (flexible coupling and vibration damper were in order). Then a specialist aligned the whole transmission train, measured the vibrations of the 3 joints and and balanced in situ the 2nd and 3th but not the first one because high engine vibration hampered him.
After suitable finding, the engine was found out of timing and was timed properly. Also the front crankshaft damper was dismantled and checked, but found in good order.
Vibration decreased and now it should be necessary to balance the remaining 1st joint. In my opinion it should improve still.
Recommendation is to [u]find a good alignment[/u]t working on the vibration damper guide and if necessary "working" on the engine and gearbox finding suitable placement on their seats...
Post Reply

Return to “70 Flaminia”