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Author Topic: Vibrations after changing motormount.  (Read 14706 times)
Oetker
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« on: May 05, 2009, 10:44:53 pm »

Because of teared motormount on the right side of the engine, I bought a second hand one, and mounted it on the car.
The bad mount.


The new second hand one.

Mounted.



Since the switch I got more engine vibrations in the car and at certain rpm the noise of a deep rumble.
This must be somehow connected to the mount.
I saw on internet some pics of this mount, and not one rubber is pressed the same way in the mount.
My question.
Who can show me a picture of the correct rubber setting in the mount.

Thanks in advance.



« Last Edit: May 05, 2009, 11:28:41 pm by Oetker » Logged

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Anders Dinsen
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« Reply #1 on: May 05, 2009, 11:51:51 pm »

If your engine mount used to look like this:



and now looks like this:



Then I don't think there's anything more you can do. Have you checked the other engine mounts? The stabilizer attached to the head has been reported to be a wear item, and the new engine mount could have moved some load, thereby increasing the vibrations.

I don't think the rubber mount has to be pressed into the holder at any specific angle.

Why you have more vibrations now is therefore a bit of a mystery to me...
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Lennart Sorth
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« Reply #2 on: May 06, 2009, 12:05:42 am »

Why you have more vibrations now is therefore a bit of a mystery to me...
Well having been used to a very soft one (which I bet was very quiet until it actually broke enough to make itself heard) it could be that the firm engine-mounting simply transmits more of the engines vibrations.

I had this exact experience when the bottom enginemount went on my beloved Simca 1100 many moons ago.

It could also be that your engine actually vibrates more than it should, but this has been hidden by the soft mounting ?

/Lennart
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Lennart.Sorth@matrasport.dk
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JL
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« Reply #3 on: May 06, 2009, 12:06:24 am »

When I used to play with rear engined cars they had a similar mounting arrangement but they were mounted with the solid part of the rubber in the horizontal plane. You can just see on the picture.


Regards
John
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Oetker
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« Reply #4 on: May 06, 2009, 12:13:17 am »

I checked the upper mountings and there is no play in it.
Looks alright.
The leftside mounting looks ok to.
The engine is a few cm higher now, but somehow I think there is something not right in the angle of the new mount giving me the vibrations.
Thats why I like to see a new original to compare.
The pics i saw had all different angles, so it is possible that it is not important, like Anders said.
It makes driving my car not very pleasant at certain speeds..
« Last Edit: August 03, 2015, 10:42:35 am by Oetker » Logged

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« Reply #5 on: May 06, 2009, 12:25:26 am »

It makes driving my car not very pleasant at certain speeds..
That sounds like more than it just needs getting used to.

Where does the engine rest if you remove the support from the replaced mount ? - AFAIK it is a support-mount which shouldn't take any load when engine is off or idle.

It doesn't sound right that replacing the lower (support-) mount changes the placement of the engine.

BTW - forgive me my 2.2 ignorance (I don't even have a 1.6 anymore) is there some sort of guide to make sure that engine-mount is fitted correctly - I mean how the rubber is rotated inside the bracket ?  - it looks as if both Anders's and yours are sort-of in the same position, but not 100% ? - I would think that could make a difference on the vibration dampening too.


And now we're at it - that engine-mount looks very similar to the one I have at the bottom of my XU9JA (Peug 205 1.9 gti) engine, and it is soft as well (probably close to dying) - and I have been told you can get some made of plastic (?) which normally was used in motorsports. Does anyone know these - and where to get them ?

/Lennart
« Last Edit: May 06, 2009, 12:31:15 am by Lennart Sorth » Logged

Lennart.Sorth@matrasport.dk
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Oetker
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« Reply #6 on: May 06, 2009, 12:37:38 am »

You mean this one.


This i for 106/xantia.
I tried to make it fit, but no go.
I don't know how far the engine comes down if I let hang withouth the mount because I used a support to keep it up.

In idle the car vibrates a bit more to.
« Last Edit: May 06, 2009, 12:40:11 am by Oetker » Logged

I feel like Jonah, only my fish looks different.
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Jon Weywadt
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« Reply #7 on: May 06, 2009, 08:57:03 am »

If your engine mount used to look like this:
and now looks like this:

I don't think the rubber mount has to be pressed into the holder at any specific angle.

Why you have more vibrations now is therefore a bit of a mystery to me...
Looking at your photos I can see on the old mount that the holes go all the way through. To me that tells me that the mount absorbs vibrations differently up/down versus front/back. I would think that it offers less support radially when moving towards the holes than towards the solid rubber. To make sure that it lasts the longest I would mount it so that the weight of the engine rests squarely on the solid part in the up/down direction.

On the photo of  the old mount, it would appear that the weight of the engine has pulled the bushing out of the rubber, probably because the holes were mounted "up/down"

Wether mounting the rubber in one direction versus the other causes more vibrations is not clear to me. I would try changing it, realising that if I mounted it with the weight of the engine pushing towards the holes, the mount would probably fail sooner.

One thing that I can't see for sure from any of the pictures, is if the center bushing is longer than the outer ring. I assume it is. If not you must have one, or more, washers to space it from the brackets on the chassis. Check to make sure that there is not a stress on the mount that let any of the metal on the engine touch the brackets on the chassis.
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Oetker
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« Reply #8 on: May 06, 2009, 09:23:38 am »

Quote
=====
 Check to make sure that there is not a stress on the mount that let any of the metal on the engine touch the brackets on the chassis.
==================================================================

The rubber at the side of the mounting is bigger then the holder, so no metal can touch the chassis.
On the sides of the mounting there are big rings that hold the rubber in place, preventing the engine to move to the left or right.

Here a pic of a diiferent mount found on the web.
This is probably the original mount.


« Last Edit: May 06, 2009, 09:35:43 am by Oetker » Logged

I feel like Jonah, only my fish looks different.
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« Reply #9 on: May 06, 2009, 09:38:32 pm »

One difference between my old (probably original) mount and the new one I bought from Simon (I only bought the rubber), is that the old one was cut through in two sections whereas the new one was moulded with the openings only done halfway through the rubber from either side, rotated 90 degrees either end.

Here's a photo of a spare (empty) mount and the new rubber, which a friend press-fitted for me:



Notice that you can't "see through" the rubber, whereas the old one is "open":



The advantage of the new design is that it's stronger and does not care about how it is rotated in the mount. It works the same in all directions. The old one is probably softer, but probably is best fitted with the engine being suspended on the solid sides of it - i.e. top-down with openings facing sideways. As can be seen from the photo above, my rubber was rotated, and this might have contributed to the "early" breakdown (if 26 years can be called early!) as just the static load of the engine has caused the rubber to break over time.

Your new mount is definitely better than your old one, and I'm sure the cause of the increased level of vibrations shouldn't be blamed on the mount. I'd start looking at the enigne: Are all four cylinders breathing evenly? Is there a manifold air leak? Is ignition advanced correctly?

Lennart: The 2.2 engine is supported by the gearbox mount, and the lower engine mount (the one which Oetker and I have had to replace). The upper mount is the "support" mount. I think that might be the opposite of the 1.6?

/Anders
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Oetker
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« Reply #10 on: May 06, 2009, 10:07:23 pm »

I think my second hand mount has the newer rubber bush in.
Think it is a harder compound
With the old mount i had some light vibrations in idle to, but the rumble is killing me.
Drove 400 miles last sunday to a meeting, and have the feeling in my head visiting a concert of Ramstein on the front row.

Have to consider my options to find a solution.
Finding a good mount with the original rubber wil be difficult.
« Last Edit: May 06, 2009, 10:25:35 pm by Oetker » Logged

I feel like Jonah, only my fish looks different.
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« Reply #11 on: May 06, 2009, 10:39:51 pm »

Drove 400 miles last sunday to a meeting, and have the feeling in my head visiting a concert of Ramstein on the front row.

HAHA! Cheesy

Well that is usually the trunk floor vibrating. Particularly common on open exhausts. Can be extremely tiring! Are you sure your exhaust is still sealing after you have lifted the engine a bit?

Looks like a nice meeting, there!

/Anders
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Oetker
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« Reply #12 on: May 06, 2009, 10:49:43 pm »

Next week I will control anything that can be the cause, but I think my mountrubber hast to turn about 60 degree.
Hope I can get it out in one piece.
The meeting was in belgium, and for the first time we had 15 Matra's togheter.
2x 530, 2 bagheera's and the rest was Murena.

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Jon Weywadt
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« Reply #13 on: May 08, 2009, 11:11:38 am »

One difference between my old (probably original) mount and the new one I bought from Simon (I only bought the rubber), is that the old one was cut through in two sections whereas the new one was moulded with the openings only done halfway through the rubber from either side, rotated 90 degrees either end.
They probably had too many failures with the old style mount. As you state, the new style provices equal support in all directions.

Are these new mounts made of rubber? Perhaps there is a more elastic type available in a synthetic material. Does any of you know?
/Jon
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« Reply #14 on: May 08, 2009, 03:48:42 pm »

Lennart: The 2.2 engine is supported by the gearbox mount, and the lower engine mount (the one which Oetker and I have had to replace). The upper mount is the "support" mount. I think that might be the opposite of the 1.6?
Indeed. Both the 1.6 and my XU9JA engine hangs from the two top mounts - one in either side. The bottom mount is only for stabilizing.
/Lennart
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Lennart.Sorth@matrasport.dk
Murena 1983 1.9i silver // Alfa Romeo Giulietta 2.0d 2012 white // Smart 4two cdi 2010 blue //
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