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My newly aquired 1974 Turbo has a slipping clutch when the turbo kicks in. 

So my mechanic and I theorized that it was either worn or wet (oil leak)

Measuring the wear based on distance traveled of the clutch mechanism tells us that the clutch is close to 90% new, so wear is not an issue

looking inside the bell housing and the clutch looked dry all around, but maybe we are missing something.

Couple of side observations, could not confirm the transmission was a Getrag from any visible markings, although we are looking up the part number IMG_5327.JPG

Hypothesis

different transmission and not built for Turbo with wrong Pressure Plate. 

I am assuming it should have a Sachs Green dot 228 mm Pressure plate but we could not confirm

We will be taking the tranmission down shortly to further investigate.

Any suggestions/corrections from the rest of the group?

 

 

 

IMG_5176.JPG

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Based on the information you have provided about disc thickness, oil free disc/pressure plate and the slippage occurring when the turbo kicks in leads me to a few possible conclusions. 

 

1. The pressure plate is bad and can't provide enough compression force under high loads. Either the spring plate tension has weakened or the friction surface is worn too thin. Replace with factory original or seek an aftermarket heavy duty clutch for street use.

2. The flywheel may be worn out. Usually they need to be turned like brake rotors when they show a groove being formed where the disc makes contact. If the flywheel does show a groove then that might account for your slippage as well since the pressure plate housing is bolted to the outer portion of the friction surface which doesn't see any wear. So your disc and pressure plate might be fine but with the additional wear on the flywheel friction surface increases the gap to be covered with the throw of the pressure plate spring. Once you have removed the transmission and pressure plate/disc setup, verify that no ridge has developed around the edge of the flywheel friction surface. If so have the flywheel turned, just be careful not to exceed the minimum thickness recommended by BMW.

3.Both the pressure plate and flywheel friction surfaces are worn beyond max limits allowable preventing 100% transfer of power from the flywheel to the transmission. 

4. At some point the possibility exists that the 228mm clutch and flywheel were replaced with the smaller size 215mm setup. Why? Cost most likely, lack of parts available or maybe he had some spares laying around. Easy way to check is to measure the disc or check the part number if appropriately stamped.

5. Possibility that your disc thickness measurement might be off. I personally think an accurate measurement can't be made unless the disc is removed since its impossible based on the bell housing design to have a direct line of sight of the friction disc. Recommend double checking that once the clutch has been removed.

 

If in doubt replace the entire clutch and pressure plate setup. Don't do one or the other. Its like washing your feet and putting the same dirty socks back on. Good luck

 

 

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Thanks for that information Fu! its very helpful to think through some of these possibilities

 

My mechanic is a BMW trained mechanic that started working for BMW in 1970 and was a specialist in Transmissions trained on 2002s so I think his measurement is accurate but it does not matter anyways as we will drop the transmission all the way to get to the bottom of the issue. 

Given that this is a 100% authentic 2002 turbo lastly owned by a collector I am assuming that cost reduction was not a motivation for the two previous owners as everythign else that was done on the car over the years was ALL using 2002 Turbo OEM parts. So I am speculating that he would have wanted an OEM Turbo Trainy.  Also I just got the car 1.5 months ago and have driven it about 700 miles with no issues whatsoever driving it hard and to the limit, it just started happening so I am unsure that the clutch assembly is the wrong size or a weaker pressure plate  as it worked perfectly for that period of time. I am puzzled however that this happened out of the blue. We will of course check the dimmensions, wear on Clutch pad as well as flywheel and springs. 

 

Finally given that this car is 100% original I am trying to stick to original OEM Turbo Clutch assembly both in dimenssion and pressure, I have checked with a variety of vendors including one in Germany that specializes on 2002 Turbo parts and they do not have the OEM clutch on hand. If there are no OEM clutch kits for the Turbo to be had, are you aware of any alternatives that would get the job done?

 

Thanks again

Didier

 

 

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On August 11, 2016 at 10:30 AM, Frenchplane said:

The last bit of information you provided makes the answer simple. If the slippage just started and occurs when the boost comes on indicates your clutch is starting to go bad. It doesn't take  a BMW certified mechanic to know this. The design of any manual transmission and its clutch from any manufacturer follow the same basic principles. This problem won't be caused by the master or slave cylinder nor the transmission itself. The master and slave cylinders would either have a total failure preventing you from changing gears when the car is running or a soft squishy feel that is either a slow seepage around the internal sees or air in the system. Neither one of these is your problem. The transmission itself is entirely made up of gears, shafts and bearings. Typically the 2nd gear synchro goes out and causes a grinding noise when shifting from 1st to 2nd gear. Symptoms of mechanical problems with the transmission will be along the lines of roaring noises from bad bearings, vibrations and or the inability to shift into gears. None of these issues will cause your current problem which leads me back to the clutch setup. A clutch kit includes the pressure plate, friction disc and the release bearing. Kit costs roughly $300 to $700 depending on where you buy it from. The original part numbers listed on BMWs 2002 turbo parts microfiche have all been superseded over the years.

The original numbers are as follows:

pressure plate                        21211202452 or 21211205294

disc plate                               21211203951 or 21211205295

release bearing                      21511204224

The current numbers are as follows:

pressure plate                       21211202033

disc plate                              21211223097 or 21211223671

release bearing                     21511204224

These parts are available through BMW mobile traditions or estore-central.com . The last one mentioned is a direct line to the BMW warehouses in Germany. I can think of 10 other suppliers in the USA and Europe which you can do an internet search to get their information. Ireland Engineering is another one based out of California and specializes in OEM and aftermarket performance parts for the 2002.  I have also seen Sachs kits on EBAY and AMAZON every so often.

As far as your transmission  being correct for your car you will have to find more information on the casing. The part number in your picture is the part number for that particular piece which only tells us whether it goes on a 4 speed or 5 speed.

The original turbo transmission does have its own part number

4 speed type                       23001204410

5 speed dogleg type           23001200814           is listed for use across several models and is not turbo specific.

If you want to know for sure that your transmission is original and place your faith in the fact the 3 previous owners were staunch BMW fanatics, all you have to do is verify your car VIN of 429XXXX matches with the number on the rear of the engine block where the top most portion of the transmission bell housing mounts. You can then do the same for the transmission which should have the same exact number stamped on it as well. If they don't match then your car isn't completely original in the eyes of car collectors. That being said, most cars that collectors are buying were never intended to be collector items. They were all designed to be throw aways in the sense that once their useful life was up they wound up in the junk yard. So the likelihood of your car having all the factory installed part is rare. Engines were often removed and replaced with a new engine or factory overhauled engine. BMW intentionally ground off the original VIN and re-stamped it with a new number that indicates its an overhaul. Same thing occurred with the transmissions as well. Unfortunately  BMWs parts inventory for all 2002 models is quickly dwindling. When I was overhauling my engine I ran into many problems locating parts that were needed. Persistence and patience are the key to finding most parts but some you will never find. Hope this helps. 

Kirk

 

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Edited by Fufighter42

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Hi;

I have never posted here, and am new to the FAQ, but would like to add a few thoughts, since I am in the process of freshening my Turbo after 10 years on the blocks.

 

I just went through this exercise 3 months ago.

 

First, IIRC, (but need to consult my original orange parts books and my research) , the 21211202033 is a replacement and not the original part for specific use on the Turbo, it is a "Tii clutch" or rather for a 2 Liter motor, naturally aspirated, and  which does not have the same pressure, nor made for the same horsepower. I have not heard of a  Sachs "green dot" 228 mm PP, but if you provide the part number stamped on the part, I can look it up in my references and tell you what car it was intended to go in. There is no cross reference that I can find for the original OE Sachs PP according to Sachs and my archives.

 

I have replaced the clutch several times, and the last PP ("HD" from Sachs) / Disc ("HD" also) ended up being incorrect as far as the inner and outer diameters matching the proper raised portion of the flywheel. Now, I never have had slippage at any time on the street or track, but the fact is the clutch was wrong. By ~10mm inner and outer, which is a significant proportion of the friction surface. I thought it was correct, it looked fine and measured right, until I took it apart and found the wear marks to delineate the actual wear surface.

 

The clutch system I chose as a replacement was the part from an E30 M3 as the size is the same (228mm), and the stated Hp is similar, but even these are becoming scarce and replaced with parts of lesser specification and higher sales volume.

 

I would not recommend a really heavy duty clutch, as what will happen is when you engage the clutch over time,  the increased pressure will push the crank against the center bearing and cause undue wear, and thus slop fore / aft of the crank.

 

Secondly: If by remote chance, the clutch was replaced, I suspect that the flywheel was not resurfaced correctly with the right amount of step. If not, then as the new disc wears in, it will slip, even though the measurements are correct through the measurement port. I have experienced this on cars where the owner did not have a specialist familiar with the proper step dimension do the work.

 

What is becoming commonplace with BMW and the suppliers is that the "specialty" parts such as the Turbo clutch are no longer made, and the companies consolidated. The knowledge base is becoming lost, and their is no interest on the part of BMW to make or have made the correct OE parts. What they provide is "a part that may work" but not the correct nor OE part.

 

HTH,

 

Ted

 

Edit:

 

To address the transmission question, I referred to the "02 Restoration Guide" by Mike Mc Carthy in which he shows transmissions used in '02s but are not stock.

 

The transmission shown in your pictures is a Getrag 245 /4 OD or a 245 /10 CR, from an E21 car,  but you will have to check 5th gear to be sure or stampings on the "flat" or a casting in the bell housing. This is different from the Turbo or '02 transmissions in that the clutch slave cylinder is bolted to the housing, and there is a clip holding the bar that the TB rides on. I had a 245 / 10 at one time, but decided not to install it in my Turbo as it was not correct. I might add that the TO bearing is a different length from the OE types, which will make for some interesting clutch action.

 

Edited by Einspritz
Update regarding the transmission in the pictures

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Kirk thank you for your input, and as already stated! WOW nice motor. I have been traveling out of the country so not able to respond in detail. I have forwarded all of your observations and recommendations to my mechanic and we will into all options for fitment once the transmission and clutch are out. We will try to source as best as possible OEM car correct parts and will give you a full read out once we have accomplished the task along with pictures for the benefit of others. 

Ted thanks for your input as well. We have definitely decided not to go with an HD clutch for the reasons you state. Also thanks for the clarification on the transmission, disappointed to here that its not an original but speculated as such..

PS with exeception of transmission everything is either original in great condition or stock OEM replacements accross the whole car. So I am happy with that at least.

Keep you guys posted

Didier

 

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So here is an update on my clutch issue

I have taken the Transmission down and now have the clutch apart and it is clearly the wrong clutch/pressure plate. As is seen from picture below its a blue dot, so for a standard 2002, not Tii and certainly not for my Turbo. Hence the reason why the clutch started to slip even though it was basically new. 

 

My mechanic inspected all other components including flywheel and determined all is up to specs. So now the question is to where I can find the Sachs Green Dot that was supposed to be in Turbo to begin with. Does anyone have suggestions?

My mechanic is well connected to the 2002 community but he has had no success in the past two weeks. Any help would be greatly appreciated. I had sourced  www.wallothnesch.com  from my uncle in Europe and when I called them they indicated that they did not have any in stock. I am now pretty desperate to find the right clutch./ PP . 

thanks in advance

 

Didier

 

 

Clutch.jpg

Flywheel.jpg

Gearbox.jpg

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Hi Didier;

 

The Orange Parts Book from "back in the day" lists the OE pressure plate as either 21 21 1 202 452 or 21 21 1 205 294 superceeded by BMW to the Tii 21 21 1 202 033 and the disc as 21 21 1 203 951 or 21 21 1 205 295 which is superceeded by the Tii 21 21 1 223 097

 

IIRC, (my references are not here to confirm in the old Sachs catalogs) but there is no cross over from another BMW nor another manufacturer. So, what I did was search for a compatible 228mm system and similar Hp and Torque. I found that the M3 E30 / S14 (Sachs Kit KF775-01) was the closest match for a Sachs clutch. The modern Sachs references do not have a listing for the Turbo, and there seems to be no cross reference backwards from the BMW number to an equivalent Sachs.

 

Now, you may consider having one made from some race suppliers, but in my view, the Hp and Torque specs from BMW are not necessarily accurate; they are low and you would need a dyno for that, and your Hp and Torque would be dependent on the fuel you use....... and consider what I said above regarding an excessively strong pressure plate.

 

Attached are the specifications from BMW for other 2002 models so you can have an idea as to the clamping pressures, as these are not supplied by Sachs.

 

Please let me know if I can be of further help.

 

Kind Regards,

 

Ted

BMW Clutch Specification.pdf

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Ted thanks for the additional information

we decided to go with an e30 M3 clutch based  on previous conversions with other 2002 turbos that we had researched

Original clutch assemblies are virtually impossible to source and even the part number reference does not always tell the truth

Anyway once we get the trainie back in and install a custom short shifter we will test it out. 

 

For everyone else I have a couple of questions 

 

1) On another note, do you have any idea where I can source 2002 turbo coolant hoses? We are about to do a full flush and want to make sure we change all hoses, some of which are originals.

2) I was talking to a BMW 2002 expert yesterday at a car show and he suggested that BMW AG is now building and selling factory KKK turbos, has anyone heard of this?

 

Didier

 

 

 

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On ‎10‎/‎17‎/‎2016 at 0:00 PM, Frenchplane said:

Ted thanks for the additional information

we decided to go with an e30 M3 clutch based  on previous conversions with other 2002 turbos that we had researched

Original clutch assemblies are virtually impossible to source and even the part number reference does not always tell the truth

Anyway once we get the trainie back in and install a custom short shifter we will test it out. 

 

For everyone else I have a couple of questions 

 

1) On another note, do you have any idea where I can source 2002 turbo coolant hoses? We are about to do a full flush and want to make sure we change all hoses, some of which are originals.

2) I was talking to a BMW 2002 expert yesterday at a car show and he suggested that BMW AG is now building and selling factory KKK turbos, has anyone heard of this?

 

Didier

 

 

 

What is your update on the e30 ///M3 clutch? Eager to hear!

 

BMW Klassik is still trying to work out the new/old turbo charger. I will contact them again to see if there is an update.

 

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