NS Dev
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posted on 15/12/04 at 06:02 PM |
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Engine Mounting rubbers??
Next question, do engine mounts have to be arranged at an angle? I have thought about it and can't really see why, but nearly all rwd cars have
the mounts in a vee shape. The sierra is an exception I suppose.
I have made some lovely mounts, which present the rubber mounts (round ones with a thread each end from Rally Design) flatways on to the plates on the
chassis. Can anybody see a problem with this arrangement?
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PioneerX
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posted on 15/12/04 at 06:08 PM |
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If I remember correctly the Vee shape is mainly for production reasons as it allows the engine to almost selfcenter as it is lowered into the car.
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NS Dev
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posted on 15/12/04 at 06:12 PM |
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Ahhh, that's the sort of answer I wanted!! Keeping the mounts flat means I can alter engine position easily, which is nice as it is bloody tight
in the ST chassis! (in the gearbox area, 5mm between 'box and chassis in several places!)
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PioneerX
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posted on 15/12/04 at 06:16 PM |
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I actual have my engine mounted at a 1.5deg ange to the chassis center line and the tunnel modified to remove room from the passenger foot well so I
could regain enough room for my feet on the drivers side and still get the Carlton box as far back as possible.
There are pictures on my website but I dont think the tunnel mods would be easily noticable unless you
see the size of the passenger bulkhead compared to the drivers then it becomes obvious what I did.
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NS Dev
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posted on 15/12/04 at 06:23 PM |
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ok ok mine probably aren't that lovely either!!!
I'm using the 35mm thick mounts in heavy duty rubber, but the cup idea is a good one, may try that, thanks!
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Mark Allanson
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posted on 15/12/04 at 06:32 PM |
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The theory is that the slant of the mounts should be a 90° to the crank. This means that the compressions will always be directed straight into the
rubber mount and no angular strain. Then you have to allow for the mass difference between the engine above and below the crank and the resistance of
the manifolds etc
Far too bloody difficult, I just used landrover mounts flat onto the chassis!
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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NS Dev
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posted on 15/12/04 at 06:37 PM |
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That's ok then Mark!! (otherwise I'd have to start asking how you get 90 deg to the crank with a vee shape.......I'm confused!!)
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PioneerX
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posted on 15/12/04 at 06:40 PM |
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I guess like everything else, engine mounts are a compromise between the ideal, the possible and the manufacture requirement.
Personally my mounts are MGB rubbers on angles mounts to make them match the orginal mounting hardware of the Carlton engine I have. I ment to take
the engine mount rubbers when I took the engine out but forgot. When I asked the Vx garage for them they wanted £100 for the pair as they are rubber
mounts in a metal shell, much like the metal cup idea.
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britishtrident
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posted on 15/12/04 at 06:56 PM |
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UK and US practice from the mid 50s onwards was to have the mounts in a V intersecting around the bottom of the cylinders bores --- this is supposed
to reduce lateral rocking motioin and reduce the movement of the engine under cornering loads, but I suspect the real reason was it was easier to
insert the engine and drive train already mounted on the front suspension subframe from bellow. Prior to that UK manufacturers used a single large
rubber mount bolted to the front plate of the engine below the crank pulley and a short torque reaction rod --- which in many models gave endless
trouble.
German manufacturers tend to favour mounts similar to the Sierra.
[Edited on 15/12/04 by britishtrident]
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Volvorsport
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posted on 15/12/04 at 07:34 PM |
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your engine mounts should diverge through the centre of gravity of your combined engine/tranny so that any roll couple can reacted without the engine
putting a lot of torque on the engine .
if your engine is 120 kgs , thats a fair old weight that needs resisting when you corner at one G . follow that manufacturers design and you wont go
far wrong
www.dbsmotorsport.co.uk
getting dirty under a bus
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NS Dev
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posted on 15/12/04 at 10:07 PM |
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I see the point about divergence through the CofG, but tricky to follow the manufacturer when his installation was transverse and mine is
longitudinal!!
Get the idea though, although having heard opinion on here, I'll leave it as it is for now and see what happens. It was the torque reaction that
bothered me most, but it sounds like I'm not alone in the way i have done things!
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britishtrident
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posted on 15/12/04 at 10:15 PM |
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Using flat mouts the mounts should be far apart and the rubbers high up ---
There is set of Westie Vauxhall angled mounts on ebay just now.
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NS Dev
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posted on 15/12/04 at 10:18 PM |
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Mine are far apart but down on the chassis, however, the angled pieces going up to the block mount plates only rise by 1" ish as the engine is
pretty low in the chassis anyway (lower than a Westy)
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Dale
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posted on 15/12/04 at 10:38 PM |
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My methood may not be right but it seams strong (there will be an extra brace on each side to the bottom plate) This will alllow easy engine hight
adjustment and there is nexst to any movement on the engine under torque. The tubes have 2 rear axle bushings on each side from a full size crown
victory police car.
Dale
Rescued attachment engine mount.jpg
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NS Dev
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posted on 15/12/04 at 10:45 PM |
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that's very much like the "escort world cup rally" type mounts used on rally escorts in the uk, very strong indeed!!
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