emwmarine
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| posted on 16/9/15 at 05:03 PM |
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Zetec - engine mounts - question
I am making up the engine mounts for installing a zetec on my Dax Rush.
I can fabricate the mount 'legs' as they leave the engine so that the rubber mount meets the chassis facing downwards or I can fabricate
the plate from the chassis so the the rubber mounts meet the chassis on both sides pointing downwards at around 45 degrees.
I am not sure what is best?
Part of me thinks they would be best pointing straight downwards with the weight of the engine, from the 'mounting legs' (i'm sure
thats the wrong word for them) resting on them. On the other hand there would be more lateral resistance from having them resting on the chassis
facing downwards at around 45 degrees. Although in that inclination there would be a constant shear stress going through the rubber.
Building a Dax Rush.
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ianm67
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| posted on 16/9/15 at 05:50 PM |
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The engine mount brackets on my Zetec Rush are at about 45 degrees to the vertical. The rubbers bolt to these and then the mount bolts on the other
side and then to the engine block. This method offers lateral stability, using Capri 2.8 rubbers there is very little movement at all......
Always biting off more than I can chew.....
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emwmarine
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| posted on 16/9/15 at 06:53 PM |
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Thanks Ian, that's how i'll do mine.
It's now in the right place now, so just fabricating them.
Building a Dax Rush.
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loggyboy
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| posted on 17/9/15 at 06:08 AM |
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I made mine in a similar way, its a fairly typical design.
Mistral Motorsport
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emwmarine
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| posted on 17/9/15 at 06:30 AM |
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Ah.. That's highlighted exactly the question I had.
Ian has fitted his mounts so the rubber mounts are at 45 degrees and so the vertical load puts the rubber into slight shear at all times but you have
fitted them vertically with presumably less stress at rest. But Ian's will presumably locate the engine better from a lateral vibration point of
view. hmm....
Also is it best to use round tube rather than beefy square section steel for the legs? I have seen both. Square is easier for me to cut accurately,
not that sure on how to accurately cut round section to join up against another round section accurately.
Building a Dax Rush.
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ianm67
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| posted on 17/9/15 at 08:33 AM |
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I'm not sure how much shear force the mounts will be under to be honest. They have a length of studding that runs through them and they are also
slighty compressed when you tighten up the bolts on either end. I doubt that you will suffer any issues with the mounts tearing or similar. Your
choice will ultimately depend upon how you configure the chassis plates. My chassis mounts and engine mounts are both as DJ intended (this
doesn't make it the 'right' way BTW.... !)
I'll be interested to see how you decide to proceed.....
Cheers,
IanM
Always biting off more than I can chew.....
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loggyboy
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| posted on 17/9/15 at 09:51 AM |
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quote:
Originally posted by emwmarine
Ah.. That's highlighted exactly the question I had.
Ian has fitted his mounts so the rubber mounts are at 45 degrees and so the vertical load puts the rubber into slight shear at all times but you have
fitted them vertically with presumably less stress at rest. But Ian's will presumably locate the engine better from a lateral vibration point of
view. hmm....
Also is it best to use round tube rather than beefy square section steel for the legs? I have seen both. Square is easier for me to cut accurately,
not that sure on how to accurately cut round section to join up against another round section accurately.
Once bolted up with firm mounts the movement will be mm's so nothing to be concerned IMO. Most Road cars are mounted at various angles. I have
seen upper braces added to stop rotational movement but unless your running silly power I cant see this being required.
I made my own tube notcher to do cur mine:
Wasn't perfect but did the job.
Mistral Motorsport
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MikeRJ
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| posted on 17/9/15 at 11:17 AM |
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quote:
Originally posted by loggyboy
I made mine in a similar way, its a fairly typical design.
Those mounts will break sooner or later, most likely by cracking around the welds on the fairly thin mounting plate at the engine end.
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loggyboy
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| posted on 18/9/15 at 06:35 AM |
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quote:
Originally posted by MikeRJ
Those mounts will break sooner or later, most likely by cracking around the welds on the fairly thin mounting plate at the engine end.
5mm is thin? Design is based on lots of kit manufacturers principles. On what do you base this?
Mistral Motorsport
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