328 Flywheel and Clutch weight

Removed my clutch and flywheel today and checked weights on them in case anyone else is interested:

Flywheel 7.2kg (15.84lbs) Flywheel appears to be un-touched (no lightening or resurfacing) note that this is a Swiss Market flywheel. It is even stamped "CH" for Switzerland. I have NO idea what the significance of that is. If anyone knows the difference between a Euro flywheel and Swiss do tell!

Pressure Plate 6.4kg (14.08lbs)

Friction Disc 1.91kg (4.20lbs) not new but not much wear either.

Throw-out Bearing assembly 680 grams (1.5lbs)


Bellhousing 10.4kg (22.9lbs) this is the weight that you would "see" as you pull it off to do a clutch change. In other words top gear and shaft still installed, throw bearing fork in place etc. Meaning..... it should not be difficult at all for one person to remove it alone, from a weight perspective (not that you'd be able to get two people in that tight space anyway).

 

Just a couple of guesses here, but since the US and CH versions have catalytic converters (and different gear ratios?), either:

1) the pins in the flywheel that trigger the ignition events might be positioned a few degrees different, or

2) since they also mark some of the valve opening/closing events and timing events on the flywheel, if these specs are different, maybe it's just these markings that are different

for euro vs US vs CH versions.

 

So about 35 pounds of spinning mass

Is a 308's any different?

 

Some interesting thoughts Steve. I would have thought they would simply duplicate U.S. timing since the probably had, back then, the toughest emissions laws (and maybe still). Not certain about this but guessing. Also, by applying or removing a ground wire you can select different set of timing maps from the ignition module. However you could be right on either account.

 

Yes, 34~35lbs. Don't know about the 308's. Hopefully a 308'er will chime in.

 

I had my flywheel weighed before and after it was lightened. It started just shy of 16 pounds and ended up at about 8.

I didn't weigh the pressure plate, but your weights sound about right.

Does anyone make a light pressureplate, besides Nick and Quartermaster??

hth,
chris

 

How did you lighten your flywhel, and did you notice any difference?

 

Tilton,
OK products,,, !
(BTW, I hate that guy, drives a vett, leached off his Dad's company. Doesn't know crap.... etc.)

But, you have to machine your flywheel to make them work.
(simple machining)

Edwardo

 

But, you have to machine your flywheel to make them work.
(simple machining)

Edwardo

Please explain the "To Make Them Work" part

 

I believe that you have to drill and tap 6 mounting holes,
then, to make room for the disc or discs, machine a circular groove, where the clutch bites.


Mark E. has done one.

Edwardo
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Here you go.

I had it done by a famed local machinist, rejoicing in the name "Stormy Winter". It required no additional machining to come int balance.
I noticed a definite improvement in willngness to gain revs, but not as much as the improvement in the 4 cyl toyota race truck or my 4 cyl 914, probably because there was not as great a percentage of mass, (inertia) removed.

It cost $400, but i would do it again.

hth,
chris
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Hi Chris,

I thought your flywheel was only reduced by about 2lbs. (not 8lbs.) Are you talking about a different flywheel?

Erich

 

Hi Erich,

The above wheel was originally from my 77 and weighed 16, (almost) pounds. The backside has been slimmed a bit too.

best,
chris

 

Thanks Chris. I wish I'd done all this during the winter. Driving season is coming!

 

A couple of questions:

- do you need to lock the gearbox and/or crankshaft to remove the lower transfer gear?
- if so, what method did you use?
- can you confirm that the flywheel can only be put back in one position, and not 90 or 180 degrees wrong?
- maybe a couple of pictures, please ?

Thanks !!

Rui - about to help a friend do the same job next week

 

Hi Rui,

The flywheel can not be installed in the wrong position. Not 90 degrees out, not 180 etc. etc. I tried each possibility.

I put my car in 5th gear and applied the handbrake. Then I used the Hill Engineering/Ricambi America special socket with an air impact gun (after bending back the securing tabs on the nut). I simply would not want to try removing this nut without the special socket or an impact gun. I have no doubt it has been done by others but I would not want to try it.

I know also that other people have made up their own socket and I applaud their effort. I hate to spend big money on one-off special tools that you use 3 times in your life but in this case I'm glad I did. Making my own by grinding away material to leave teeth would mean spending quite a lot of time to get everything right and even then the fit would probably not be perfect. Also, then you should start with a socket of harder material (impact socket) or you risk an accident using a normal metal socket with an air gun. The socket cost $102 but there is no damage to the nut so I will reuse it. A new nut is $29 so I'm happy I did not need a new one. The top gear uses the same nut and I removed it also because I'm completely disassembling the bellhousing for proper cleaning. So...... when I re-install the two nuts I will put them in opposite positions (not on the shaft they came off of) and with a little luck the collar that you punch down on to lock the nuts in place will be in different positions allowing me to bend a "new" area of the collar.

If you make your own socket you might not be able to get enough torque on the nut when you re-install it. This could lead to very expensive problems if it loosens. I would be much more comfortable making my own socket to remove the similar special locking nut for the steering wheel. I don't think this is as critical. You might ask "How can that not be as critical? It would be bad news if the steering wheel came off while driving!" Well, I think you would feel the play/looseness in the steering wheel long before it got to the point of coming off and then you could tighten it again or get the "proper" socket if needed.

What kind of photos are you interested in?

 

First of all thank you very much for your time and effort!
We know something is wrong with my friend's car since the PM mark is aligned with cylinder nº 1 but on the front bank !!! (As seen on the cam cover). That makes for a 90º difference ...

That's ok to remove the lower transfer gear nut. Don't you need to lock the crankshaft to remove the flywheel ?
I do have the special socket. No stress there ...

Exactly why I've bought one long before I needed it (and friends will need it first )

Well, the back of the flywheel (the one that faces the engine) would be great to make sure the sensor actuator is in fact in the same position. It has been said that there are different types of flywheel for different markets. We would like to make sure it's the right one ...

Assuming that the reason why the flywheel can't be put in the wrong position aren't the bolts pattern, it would be great to look at whatever makes that happen. You see, I'm very suspicions that it is in fact in the wrong position and I want to be prepared to understand why ! (or what happened)

Again thanks for all your help!

 

No problem Rui. Glad to help.

I wish I were there to have a look at your friend's car becasue I'm certainly curious too.

The flywheel bolts came off very easily with the air gun. I would guess that even with a hand wrench and socket it would not be too hard to get them off.

The two pins that induce a small signal into the sensors are indentical and cannot be re-installed in an incorrect position. They are 180 degrees away from each other.

The offset when you have the flywheel incorrectly aligned is about only 1mm. In other words the misalignment of the two holes is very slight but visible. I found that when the flywheel is not aligned correctly 2 of the bolts will not fit. It MIGHT be possible to force these bolts in if you were careless and using an air gun (which would certainly damage them). That's just a guess but I can't imagine someone installing them by by hand with a socket and being able to get them in the holes. Having said that, just looking at the holes on the flywheel you would never guess that they are not all equally spaced. See photo below of the holes on the end of the crankshaft.
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Excelent !
I'm very curious too ... next week we'll have more info !

Your help is very much appreciated

 

Hi Erich,

We have confirmed that the flywheel is in fact out of place .... We wanted to be absolutely certain so we've put piston nº1 at TDC (using piston position) and double checked that all cams are in place. No signs of the PM mark on the flywheel...

We've then put a mark at the top of the crankshaft pulley (kind of a PM mark) and rotated the crankshaft (clockwise, of course) until the PM mark has shown up on the flywheel. The difference between the two marks is about 135º. That makes for 90+45 which is consistent with the bolt pattern in your picture !

We are now sure that we do need to remove the bellhousing, clutch and flywheel and see what happened. This could get ugly ...
Could you please take a picture of the flywheel on the side that faces the engine? We would like to compare with ours and make sure the sensor actuators are in the right place when we get there

Thanks,

Rui

 

Hi Rui,

Interesting....

My flywheel and clutch are gone now for machining but I took some photos before.

By the way, I did not realize this until Sven-Martin Osterroth showed me the other day (he's the guy that does the timing chain conversion for 308/328's and works in the racing division for Sachs clutches and flywheels). I had made the assumption that one of the flywheel holes was not spaced exactly the same distance from its two neighbor holes (Never really looked closely) and that was the keying method. In fact, one of the holes is located slightly closer to the center of the flywheel and that's what provides the keying. Maybe you already knew this so it could be old news!

Erich
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Before removing the bellhousing why not take out the bellhousing sensor that is closest to the rear of the car (the one that is easiest to get at)? Then turn over the engine until one of the pins on the flywheel is visible through the hole where the sensor was mounted. Then turn the crank exactly 180 degrees. You should (better) have the second pin show up in the hole. If not, they are not 180 degrees apart.

 

Erich,

this is excelent information, thanks !
Can you locate the PM mark on this photo ? Just curious to know if the sensor actuators would be close to the PM mark ....

 

Exactly my idea with the previous question, but I would need to know the relative position of the PM mark and pins to be sure.
Any ideas ?

 

As I said I don't have the flywheel now but.... from a technical manual drawing I have and using a protractor I measured the angles. One pin is located 38 degrees before the PM1-4 mark and the other is located 142 degrees after the PM1-4 mark. Again, the two pins are 180 degrees apart from each other (142 + 38 = 180).

Neither pin will be visible in the holes (with the sensors removed) if the flywheel is at PM1-4.