NTS MX5 Build

[Big Vern]

Originally Posted by robo

I think big vern is right, the nose of that diff needs to be well and truly controlled. When you think that a few thousand rpm and a dropped clutch that pinion is trying to climb that crownwheel, that beam across the back is only there to hang the diff unit in place the rest of the forces go to the front mount. i had a quick look round the mx5 fourms and there are dozens of failures with a thousand reasons why, I dont know if I would want something as hit and miss as that an inch from my spine. You could also fabricate a steel brace to run the whole length of the thing and bolt it through the ali bit. It could crack then but at least it would all stay in there.

Bob

Thank you Bob, at least there are a few of you who can see the problem.
Using an the old mx5 engine mount as the front diff mount ain't gonna work. Engine mount is not designed to work in tension!
1.8 mx5 puts out 149N.m torque/5000rpm at the flywheel.
=183N.m/4070rpm to the propshaft in 5th gear (0.814:1)
Diff ratio= 4.3:1
=787N.m/946rpm at the driveshaft. Thats whats trying to twist the diff out of the chassis
There's no way the tired old engine mount can handle anything like that tension - the rubber will tear away from the steel backing - just try lifting an engine out of the car without undoing an engine and you'll easily see its not up to the job.

Nathan,
I'm trying to pee on your bonfire, far from it, If only I lived closer I'd come round to see for my self and help out with a solution. There are a few good ideas already coming on here.
Do you have a dxf of the chassis in that area I might be able to look at possible solutions a bit easier.

BV