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MX5 Engine Mounting in Locost
quinnj3 - 30/4/23 at 09:33 AM

Hi All,

I've just completed one of my engine mounts. I think they are fine as is but I just wanted others opinions on strength. Should I cap over them to close them in? Engine is just a standard Bp unit putting out about 140bhp on a good day. I don't intend turbo charging any time soon. They have been fab'ed from 3mm steel.

I have designed for full positioning of the engine. Left/right, forward/back, a couple of degrees of rotation and height can be adjusted with shims.

Engine mount 2
Engine mount 2


Engine mount 3
Engine mount 3


Engine mount 4
Engine mount 4


Engine mount 5
Engine mount 5


Lower engine mount
Lower engine mount


Lower engine mount 1
Lower engine mount 1


motorcycle_mayhem - 30/4/23 at 10:36 AM

I made very similar looking open brackets from 4mm mild steel to support a Perkins 4182 in a Land Rover, again a 3 bolt fixing in a similar place to that on the crankcase you've pictured. No issues in use.
Pictures indicate a good visual quality of Mig welding. To me, no expert in anything, my opinion is worth nothing, I'd be happy with what you've done.


pewe - 1/5/23 at 01:08 PM

I'd be inclined to horizontally cross brace those between the outer edges to stop the sides flexing outwards at their mid point under load.
Probably belt and braces but whilst they're accessible worth doing.
Nice welding BTW.


ReMan - 1/5/23 at 03:33 PM

Looks good to me. As above i'd just cap over to going the two outer edges for good measure


quinnj3 - 3/5/23 at 09:33 PM

Thanks all. I'll take your feedback on board. For now I'm going to leave as is but I've plenty of time to change my mind before they get painted/powder coated. What I think I will do is buy a heavier duty washer. The mudguard washer I have in is probably too light

[Edited on 3/5/23 by quinnj3]


bi22le - 3/5/23 at 10:21 PM

Personally 3mm steel sounds a little thin, but it looks about right on the pics. At a later stage you could just brace with a little rod. You can't do too much as you will want access, not too just do the bolts up but often oil will settle on the mounts and you will want to wipe them clean.

Another observation is the proximity of bolt holes to the welds. The stresses will radiate out from the bolt head landing, they are close to the welds on 2 bolts which may crack the weld area. Keep an eye on them areas.