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Hanging prop centre bearing mount
pmc_3 - 21/3/22 at 04:15 PM

When I had my prop made I was asked where I wanted the centre bearing so I gave measurements that meant it would sit above one of the horizontal chassis rails for ease of mounting. What I didn't think about was the vertical box section supports for the transmission tunnel coming off that rail so I can't bolt it to a plate on the side of the tunnel like most people seem to. It's pretty thin wall box for the trans tunnel so I don't want to bolt through it even with crush tubes.

The bolt holes are on the bottom of the centre bearing mount. What I'm thinking of doing is welding a bit of 25mm angle between the tunnel uprights and then spinning the centre bearing mount and bolting through the angle so the centre bearing is hanging from it. I think that would be easier than trying to bolt it from underneath. Can anyone see an issue with that?


Rallychris - 21/3/22 at 05:15 PM

The likely downside is assembly process and/or serviceability - the centre bearing housing on a mainstream vehicle is typically mounted from below so it can be removed with a cross member and allow the propshaft to be dropped out of the vehicle without disturbing the gearbox or diff.

Will you be able to remove / refit it once the car is panelled up if it mounts at the top? Do you care?


ReMan - 21/3/22 at 05:48 PM

Picture to assist?


Mr Whippy - 22/3/22 at 07:42 AM

Most 7's don't need a center bearing since the car is so short. Anyway hanging the center bearing is not an issue, however I'd imagen there is a quite considerable torque and potential vibration going thought it so I'd use quite a substantial bit of angle. I'd also make sure that the shaft from the engine to the bearing is level. I'm assuming the rear section is telescopic to cope with suspension movements and it's not going to be pulling on the bearing or the bearing can slide on the propshaft by design?

Again a picture would be helpful.


pmc_3 - 22/3/22 at 08:09 AM

I was planning to make part of the tunnel top removable so I can get access to the bolts from the top.

It's a bike engine with live axle so prop is 2 piece with centre bearing and sliding joint on the rear section. In the picture it's resting on a bit of 40mm box section. The prop is sloping down slightly as the engine output is higher than the diff (both flanges are parallel to each other)

2022-03 -21 21.33.22 by Pete Clayton, on Flickr

[Edited on 22/3/22 by pmc_3]