Board logo

Excessive engine movement
neilp1 - 16/11/11 at 06:44 PM

I've put the engine in on 50mm rubber mounts I had lying around but now think I have excessive engine movement.

Can I purchase stiffer rubber mounts? If so where from?

I did originally have it mounted on 25mm mounts but had to lift the engine as it was too low.

Cheers, Neil

britishtrident - 16/11/11 at 06:58 PM

which 50mm mounts did you use ? Look at Jaguar Xj6 series 1 to 3

jacko - 16/11/11 at 06:59 PM

Description
Description
This is how i stopped mine moving side to side
Jacko

mark chandler - 16/11/11 at 07:10 PM

Or diesel landrover, much cheapness from Bearmach or craddocks

Nickp - 16/11/11 at 08:57 PM

quote:
Originally posted by mark chandler
Or diesel landrover, much cheapness from Bearmach or craddocks


I've got 'landy' ones and they seem good and stiff (oo'er Matron).

neilp1 - 16/11/11 at 09:02 PM

quote:
Originally posted by Nickp
quote:
Originally posted by mark chandler
Or diesel landrover, much cheapness from Bearmach or craddocks


I've got 'landy' ones and they seem good and stiff (oo'er Matron).


Are the landy ones 50mm though?

[Edited on 16/11/11 by neilp1]

Mark Allanson - 16/11/11 at 09:08 PM

My Landy mounts

Rescued attachment DCP_0542sml.jpg
Rescued attachment DCP_0542sml.jpg

Nickp - 16/11/11 at 09:11 PM

quote:
Originally posted by Mark Allanson
My Landy mounts

Rescued attachment DCP_0542sml.jpg
Rescued attachment DCP_0542sml.jpg


That's the fellas, so 50mm they ain't.

Hector.Brocklebank - 16/11/11 at 09:24 PM

What about a radical idea of designing the engine and chassis mounts to place the load directly through the " rubber isolator" part of mount instead of placing the tension through the wrong plane, some are designed to operate at their optimum with a direct loading with both sides of the metal mount angled as required by the isolator.

Nickp - 16/11/11 at 10:20 PM

quote:
Originally posted by Hector.Brocklebank
What about a radical idea of designing the engine and chassis mounts to place the load directly through the " rubber isolator" part of mount instead of placing the tension through the wrong plane, some are designed to operate at their optimum with a direct loading with both sides of the metal mount angled as required by the isolator.


Mine (as supplied by BMW) are angled, so should improve matters in the 'wrong plane' dept

britishtrident - 16/11/11 at 10:51 PM

Normal UK/US RWD practice in the 1960s/70s was to angle the mounts so centre lines of the mounts intersected just above crankshaft the idea was to limit movement due vibrations induced by unbalanced forces created by the motion of the connecting rods.

Neville Jones - 17/11/11 at 10:04 AM

quote:
Originally posted by britishtrident
Normal UK/US RWD practice in the 1960s/70s was to angle the mounts so centre lines of the mounts intersected just above crankshaft the idea was to limit movement due vibrations induced by unbalanced forces created by the motion of the connecting rods.


Where on this planet did you read that load of technocrap?

Have you ever actually, really, in person, looked at the mount configuration of a yank/aus/uk 60's/70's V8? Or straight six? Or even four? Look at the mounts on the original humble crossflow, or precrossflow? The cranks would have been in the bottom of the sump, or above the inlet on some, by your statement.

The angles were and still are to account for sideways forces, and keep the (very soft nowdays) engine mounts in compression, and not shear. Although there were and still are exceptions, depending on the specific internal structure( the bit you can't see) of the rubber mount.

Cheers,
Nev.



[Edited on 17/11/11 by Neville Jones]

britishtrident - 17/11/11 at 04:11 PM

Well done Mr Jones not only have you again demonstrated your lack of any insight or knowledge into automotive engineering, but demonstrated yet again your innate nastiness.



quote]Originally posted by Neville Jones

quote:
Originally posted by britishtrident
Normal UK/US RWD practice in the 1960s/70s was to angle the mounts so centre lines of the mounts intersected just above crankshaft the idea was to limit movement due vibrations induced by unbalanced forces created by the motion of the connecting rods.


Where on this planet did you read that load of technocrap?

Have you ever actually, really, in person, looked at the mount configuration of a yank/aus/uk 60's/70's V8? Or straight six? Or even four? Look at the mounts on the original humble crossflow, or precrossflow? The cranks would have been in the bottom of the sump, or above the inlet on some, by your statement.

The angles were and still are to account for sideways forces, and keep the (very soft nowdays) engine mounts in compression, and not shear. Although there were and still are exceptions, depending on the specific internal structure( the bit you can't see) of the rubber mount.

Cheers,
Nev.



[Edited on 17/11/11 by Neville Jones]

coozer - 17/11/11 at 04:14 PM

I have Peugeot 205 Diesel spec mounts on mine and they've been Ok. I have a engine steady bar for excessive activities such as track days.

Hector.Brocklebank - 17/11/11 at 06:40 PM

quote:
Originally posted by Nickp

Mine (as supplied by BMW) are angled, so should improve matters in the 'wrong plane' dept


As you were NOT the original poster, my comment would have no bearing on your setup whatsoever, as I have no prior or existing knowledge of your system other than the information provided after the fact, so I'm sorry but I fail to see the relevance of your post quoting mine, maybe I'm missing something...................

British trident, as Obtuse as Neville Jones comes across as on many occasions, I think he was (in his own inimitable style) trying to explain that your theory on Harmonics might require how shall we say require a little "revision"

For example just take a look at the mountings on a MkI Ford Fiesta way up high on the O/S and WAY WAY down low on the lower gearbox cradle, both above and below the plane of the crank.

But who knows maybe Ford made the system that way with harmonics in mind, as anything is possible. I know (from personal experience) that something as simple as a exhaust mounted too rigidly on the MKI XR2 made them miss-fire at 2500RPM due to nothing more than fitting the manifold to gearbox strap on a full janspeed system so it is not outside the realms of possibility that there may be some research having been done by the manufacturers on engine mounting harmonics/resonance isolation earlier than what we would consider to be the case today.

Neville Jones - 17/11/11 at 07:26 PM

quote:
Originally posted by britishtrident
Well done Mr Jones not only have you again demonstrated your lack of any insight or knowledge into automotive engineering, but demonstrated yet again your innate nastiness.
quote:


Innate nastiness??? You gotta be kidding. Someone's got to have the necessaries in their underwear to call your bullshite for what it is.

You don't have to be an engineer to look at the majority of cars engine mounts, and realise that out of balance conrods don't have a lot to do with the design, though NVH comes into the equation.

First job of the engine mount is to support the engine. I would think that that point is fairly clear, even to the drunkest and most drug confused brain.

Next job is to absorb and insulate the structure from engine vibrations, caused not only by the odd balance issue, but harmonics as already mentioned, and the audible noise generated in an engine.

Now, everyone go out and look at their car's engine mounts, and work out from BT's great hypothesis, where the crankshaft should be. Then look where it actually is.

I'm sure dear Mr.BT has got a book full of howlers like this one still to come, I look forward to the amusement these bring.

Cheers,
Nev.

Nickp - 17/11/11 at 08:50 PM

quote:
Originally posted by Hector.Brocklebank
quote:
Originally posted by Nickp

Mine (as supplied by BMW) are angled, so should improve matters in the 'wrong plane' dept


As you were NOT the original poster, my comment would have no bearing on your setup whatsoever, as I have no prior or existing knowledge of your system other than the information provided after the fact, so I'm sorry but I fail to see the relevance of your post quoting mine, maybe I'm missing something...................


I was just kind of agreeing with you, and pointing out that mine happen to be angled as such
Don't be paranoid fella, we're not all having a 'pop'.

ShaunB - 17/11/11 at 11:41 PM

I recently swapped to the Vibratechnics mounts from Rally Design <linky>. Despite what the page says they are 40mm high, but I was able to fit a 6mm spacer underneath and still get full engagement on the nut. In appearance they are similar to the Landy ones above but have an extra rubber segment, my engine is now very firmly mounted unlike the wobbly 50mm rubber blocks. I have video showing my engine moving ~15mm either way when cornering on track with those, and when I have a bit of coming together with another racer they moved over 30mm which was enough to smash my dizzy cap on the chassis rail! It won't happen again!

Shaun.

neilp1 - 18/11/11 at 10:19 PM

I've just got two off tiger the ones they use on their R6 race cars, so I try them!!