E30 M52 Prop Shaft Options [24v M50 + 318is Getrag g240 Gearbox] BMW Drive Shaft Length Guide | 051

Описание: E30 M52 Prop Shaft Options [24v M50 + 318is Getrag g240 Gearbox] BMW Drive Shaft Length Guide | 051

In this video I explore which prop shaft (AKA drive shaft if you're in the US) I can use with my BMW E30 M52 build.

To transfer the new M52 power to the rear wheels of my E30 build, I need a prop shaft that fits. This is quite important because the prop shaft will potentially be spinning beneath the car at 6000rpm, and a improper fit might end up in disaster for my E30 chassis.

Luckily, with an M5X swapped E30, there are some good OEM options you can use which are quite cost effective. However, which one you can use is quite specific to which gearbox you select.

My specific combo is as follows:
1990 Facelift 316i Manual BMW E30 3 Series Coupe
M52B28 24v 6-cyl Engine
E30 318is Getrag g240 Gear Box

It would have been ideal to use the ZF 5-speed gearbox for my M52 swapped E30, however they have become prohibitively expensive based on the fact they're rare, robust and in demand for various high-power E30 engine swaps. As a result I opted to stick with a Getrag G240 as a much more cost effective option. It also meant I had a better selection of differential final drive ratios which should again help keep the cost down in purchasing one down the line. If I had gone with this I'd have needed the front half of an E36 prop shaft, and the rear of an E30 prop.

Although my 316i came with a g240 transmission as standard, I opted to pick up an E30 specific 318is g240 gearbox after one came up cheap locally, these have a longer output shaft than the standard g240. I did this primarily to simplify which prop shaft I required for my build.

According to the forums, I could use a 325i propshaft which would be a direct and perfect fit for this combo, and these prop shafts are relatively easy to source compared to some of the more unusal models.

Getting under the E30, I measured the overall length of prop shaft I needed which turned out to be 147cm with the rubber flex disc guibo already installed, and the measurement between the gearbox flange and the centre bearing mounting holes is 62cm.

I had 3 prop shafts, the original 316i prop, a pre-facelift 320i manual prop shaft, and a newly acquired 325i manual propshaft from a facelift.

Interestngly the early prop shafts are a smaller tube than the later ones, this is apparently because the later ones used a thinner walled tube, so bigger isn't necessarily better in this case.

Another key thing to note between the facelift and pre-facelift drive shafts is the center bearing. The bearings are quite different between the two, and while you can install either on any BMW E30 prop shaft, which chassis you have because the centre bearing mounting holes are positioned differently. You must use the correct centre bearing.

I measured each prop shaft which is not quite as easy as it sounds thanks to the 10cm splined section. I ended up using the slotted centre bearing mounting hole as the central point.

The rear diff side of all E30 prop shafts are the same length, and of course thje centre bearing mounts to the chssis and is immoveable. So really if you've got the right prop shaft bearing the only concern is the front half of the shaft and whether it fits up between the CB and the gearbox output flange.

I include a table of E30 prop shaft lengths in the video.

The 316i prop is way too long, which was anticipated. The 320i prop shaft is too long by 1cm, which means it would have potentially fit with a normal 316i g240 gear box. Fortunately the 325i drive shaft was the perfect length so I went ahead and fitted it up to the car.

You might notice that the 325i prop shaft is looking brand new. when I received it i found that the universal joints were extremely notchy, more than I was comfortable with. I looked into how to change the UJs myself, but as they are staked in from factory, similar to the steering linkage which I struggled with, I opted to send it off for a full refurb with Dunning and Fairbanks Ltd who refurbish prop shafts. They replaced the UJs, rebalanced it and gave it a fresh paint job.

It's crucial that you use a balanced prop shaft or you will get a bad vibration which may result in the prop shaking lose and flailing under the car, destroying the chassis. It's not worth the risk.

To tighten up the the prop shaft, you need to be able to rotate the shaft. because the car is currently fitted with an open diff, I was able to just jack one rear wheel up to rotate the shaft by hand.

I also fitted the heat shields that protect it from the exhaust.

For more helpful how-to guides and restorations: https://www.spannerrash.com/

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#bmwe30 #e30build #m52