N52 Z4 Coupe - Clutch & DMF replacement - a Few Q's

R

Roundozo

Senior member
 Hampshire
Hello everyone,

Today some shiny new parts arrived, yay (however also slightly dreading the replacement of these!!)

Here are some pictures first as everyone loves pictures!!






I have a few more questions that I can’t quite work out from TIS on the process of this. First of I will point out that this is for the N52 3.0 as this is a magnesium block so it requires different bolts and many to be single use only.

1: The bell housing bolts would appear to be one use. Is this also the same for the flywheel & clutch cover plate bolts?
A: does anyone know a good supplier of these or is it best to go to the dealers?

2: Are the prop shaft coupling (bought one of these as well) bolts single use too?

3: and the BIG questions really,...........reading through TIS is states to torque up the bolts to a certain torque (I can do this bit as I have torque wrenches) and then use a torque angle tool to complete. Is this 100% necessary as I don’t have one?

4: Does anyone know the length of M10 or M8 bolt I need to fix the exhaust back together after removing the remnants of what’s left there at the moment.

5: Lastly, the DMF appears to me to already have the roller bearing inserted. Can someone confirm by looking at the last picture?
 
I've not done this job... Yet.

I'd get all bolts from BMW.

For torque angle I've done it with a protractor when there is room!
 
Angle tightening is vital on newer fixings, and much more accurate than just torqueing them up. Get yourself a decent gauge, they aren't expensive or you could run into all sorts of problems later on. I'd be tempted to go to BMW for the bolts. as no doubt they will all have a specific tensile strength. This isn't a job you want to be doing again!

And yes, the spigot bearing is already installed in that DMF.

Mike
 
Is there even enough room down there to put a torque angle gauge on there though? Can you use them further up the socket set if you know what I mean?
 
Roundozo said:
Is there even enough room down there to put a torque angle gauge on there though? Can you use them further up the socket set if you know what I mean?
Click to expand...
You can put the angle gauge at the ratchet end of an extension, you just need something near the gauge to reference it off.
 
For angle tighten I just use my eyes. It's usually 90 or 180deg.

You can use a cheap angle gauge like this
http://www.ebay.co.uk/itm/Professional-1-2-Drive-Torque-Angle-Gauge-Car-Garage-Tool-Set-Adjustable-Metal-/311589864034
or this
http://www.ebay.co.uk/itm/Laser-0949-Torque-Angle-Gauge-1-2-D-/271336252680

The first one has to cope with the torque though (might break?)

As for re-using the bolts, I always re-use the propshaft bolts and I also reused the clutch plate bolts.
I think I'd replace the flywheel bolts. Aluminium bolts should always be replaced.

BMW advises to replace all zns bolts (zinc coated bolts, so also the propshaft bolts), probably for corrosion and seizing probems. But my car is garaged and I almost always use antiseize and havent had any problems.
But replacing never hurts. If you tinker a lot the costs can be considerable over time though.

Your new flywheel already has the centerbearing.
 
Yeah, those are a few of the gauges I've been looking at. They seem pretty cheap so not an issue there.

I've been over to my local BMW garage to get the bolts etc (also picked up some exhaust gaskets). Boy is it expensive! With VAT they all come to £85 for just bolts and gaskets! Ouch. (Does include sump plug and gearbox plugs).

Right then, just a few more bits and pieces to get and I should be good to go. I'll take some pictures during the process but please don't expect a good DIY guide. I'm rubbish at making those.
 
Do you lot think a 60mm length M8 bolt will be long enough to join the manifold to the exhaust? I presume it will and if too long I can always cut it down a bit. Obviously if I buy too short I'm stuffed!
 
Roundozo said:
Do you lot think a 60mm length M8 bolt will be long enough to join the manifold to the exhaust? I presume it will and if too long I can always cut it down a bit. Obviously if I buy too short I'm stuffed!
Click to expand...

Hi,
M8 x 40 will be long enough (Don't forget your washers either side of the flange - The original is M10 with quite a generous amount of clearance).
Stu.
 
stupot67 said:
Roundozo said:
Do you lot think a 60mm length M8 bolt will be long enough to join the manifold to the exhaust? I presume it will and if too long I can always cut it down a bit. Obviously if I buy too short I'm stuffed!
Click to expand...

Hi,
M8 x 40 will be long enough (Don't forget your washers either side of the flange - The original is M10 with quite a generous amount of clearance).
Stu.
Click to expand...

Good point, almost forgot about washers! Was going to go with M8 in case I can't drill out all of the old studs.
 
Roundozo said:
stupot67 said:
Roundozo said:
Do you lot think a 60mm length M8 bolt will be long enough to join the manifold to the exhaust? I presume it will and if too long I can always cut it down a bit. Obviously if I buy too short I'm stuffed!
Click to expand...

Hi,
M8 x 40 will be long enough (Don't forget your washers either side of the flange - The original is M10 with quite a generous amount of clearance).
Stu.
Click to expand...

Good point, almost forgot about washers! Was going to go with M8 in case I can't drill out all of the old studs.
Click to expand...

Hi,

I drilled out my old studs 6.8mm and then tapped them M8, now it's held together with M8x30 cap head bolts that are covered in ceramic anti seize grease.

Your probably already aware of this, but the material the original studs are made of work hardens really easily - Use your drill at it's slowest speed and use plenty of pressure (And cutting grease/fluid) - And after a lot of swearing and achy arms you'll be fine......... :thumbsup:

If you have cobalt drills use them - normal HSS drills just aren't up to the job :!:

All the best - and let us know how you get on.

Stu.
 
Yeah, got myself a big ass drill with a lot of weight behind it and some cobalt drill bits up to 8mm. Just bought some washers. Gone for stainless steel M8 bolts and then copper M8 nuts. I've got some copper slip I'll pop on there too.
 
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