Prepare for the worst / expect the best

UK forum for general and technical discussion about the Z3 roadster
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Prepare for the worst / expect the best

Post by Southernboy »

With the Z3's getting on in years and as a direct experience over the past weeks with sourcing a decent gearbox for a Z3 project car I am engaged on.
I have removed and fitted 3 gearboxes to the project car. Each newly fitted box has been unserviceable. Two had input / output bearing problems, and the third sounded as though it was an empty can full of stones rattling in it.
Here in South Africa, the policy with the breakers is one of "you pay your money and take your chances". They will supply a repalcement box if the previous one is no good. As above this could go on endlessly - fit / remove / fit / remove etc etc.
The bottom line is this, what will you do if your existing box fails and your baby sound like it's wailing while you drive because one of the bearings has gone. Firstly, finding a suitable replacement which is working 100% is difficult enough, second, how long will that box last, and last what is the cost of re-building a gearbox.
The first and last points are possibly the most pertinent. Wisdom would suggest you source and alternate box now have it fully tested and store it for the eventuality. It is always re-saleable at a good return. There will be other people who will face the issue and be sure buyers for a good tested box.
The cost here in SA of re-building a gearbox is scary, and if it's a BMW box it's positively bank breaking !
Bearings are expensive, labour is expensive, and if the syncro's are shot on one or two gears (usually 1st and 2nd) you're likely going to send your car to the breakers given the costs of repair.
If you check the part number of your box and find which other models of BMW were fitted with the same box, this will help your search for a replacement. I discovered that even one of the 7 series was fitted with the same box as my project Z3.
Next, look for as low a mileage donor car for the replacement box. When you think you've found one, first thing is to ask the seller to drain ALL the oil from it. Check to see the quantity of oil (should be aprox 1.3 litres). Check the colour of the oil - should at least be reasonably transparent - NOT BLACK!!. Do a thorough examination of the drain plug. it is magnetic and any metal bits will be lodged there. Any piece of "steel" coloured metal will tell you there is significant damage to gears. Copper / brass coloured chunks will indicate syncros and bushes. Don't buy it if any of the above issues present.
If the plug only has microscopic brass and copper coloured particles mixed in with a general black sludge, you're pretty safe. Any large (1mm or more) bits - don't buy !.
Anyhow, I hope if / when you're faced with this requirement, my advice will help you somewhat.
"Normal is overrated"
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Gazza
Joined: Tue 04 Oct, 2005 20:58
Posts: 9521

  M roadster S54
Location: Romford Essex

Re: Prepare for the worst / expect the best

Post by Gazza »

Good advice indeed. I thought the Zed gearbox was more or less bulletproof.

I’ve managed to source a spare auto gearbox for my Mustangs, also rebuilds cost around £900.

How much were you quoted for a rebuild on the Zed gearbox ?
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

Z3 S54 M roadster Image, BMW Z1, BMW M3 CSL, Z4M Coupe
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Prepare for the worst / expect the best

Post by Southernboy »

Re-built gearbox here is around £ 1200.
Makes me feel ill just considering it as a last resort. Worst is, they only give a 6 month warranty on any parts used. Makes me wonder if they use non OEM parts and almost expect you to be back for more punishment at some future time... :fade
"Normal is overrated"
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Juvvajuvva
Joined: Sun 06 Nov, 2016 16:52
Posts: 87

  Z3 roadster 2.8

Re: Prepare for the worst / expect the best

Post by Juvvajuvva »

Test drive and buy an MOT failure car, buy the car, break it, fit the good box, sell the ready of the parts, get your money back=
Good box for free 😀👍👍
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Southernboy
Joined: Thu 07 Oct, 2010 12:39
Posts: 6436

  Z3 roadster 3.0i
Location: Johannesburg

Re: Prepare for the worst / expect the best

Post by Southernboy »

Good thinking... except out here we don't have such cars. Failing an inspection is only for those who abide by the law. All others pay bribes to the officials. The Z3 project car I am busy with came with a "clean bill" from an official testing office.... hahahaha... the seller can't sell without that certificate, so you pay a small bribe of around £50 and off you go with an official genuine clearance.
"Normal is overrated"
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