Help!!! Series 3 transmission question.

[Anthony & Susan DiBattista]

Alpiners,

I have a question on the manual OD transmission. I have a late Series 3 GT OD. When I depress the clutch to the floor the motor really drops it’s revs then stalls. Not a problem when shifting through the gears but a challenge from a stop. I do not remember this before the slave cylinder was replaced. Could someone explain to me how the clutch internals work. I do not understand if you are disengaging the engine from the trans how this could happen. Could the new slave cylinder over stroke the clutch? Any help and or tutelage would be appreciated.

Thanks in advance,
😥

[James & Susan Ellis]

While this may seem like a funny question… what happens with the oil pressure when you push the clutch in… does it drop like a rock? what you discribe sounds like the engine has spit the thrust washers. Try this with the car running and the hood up have someone press the clutch pedal down while you watch the bottom pulley on the engine if it moves forward when the clutch is depressed you have a thrust washer problem. If you find this to be the case do not start or drive the car, the more you run it the more it can eat up the crank.

[Anthony & Susan DiBattista]

Thanks for the help Jim!

I performed your test and here are the results;

The oil pressure only dropped slightly with the clutch depressed and it was not instantaneous. Kinda like a slow drop about 2 seconds after depressing the clutch, following the RPM’s of the motor. One thing though, the motor was not up to full temp. Does this matter?

I had my daughter depress the clutch all the way in, at least I hope her leg was long enough! I watched the lower pulley. It did not seem to move at all. The engine vibrated but I could not see any front to back movement of the crank. I just hope Chelsea had the pedal all the way to the floor. I will recheck tonight if necessary.

I also depressed the clutch until I heard it disengage, about 3/4 to the floor. The motor did not loose RPM’s and I could shift into any gear. Would the crank only move forward at the very bottom of the clutch stroke? I did not have time to road test the car. I will tonight if needed. Jim, any ideas from the results of the test?

Again, thank you!
😯

[James & Susan Ellis]

Thinking… supose it could be over extending the pressure plate if the slave unit use to be on the wrong side of the bellhousing and someone welded an extention on the rod then got moved to the correct side… just thinking out loud.

[mikephillips]

This type problem can also occur if the throwout bearing is worn down to the steel or the carbon insert breaks up. Had that happen once years ago.

[James & Susan Ellis]

How does that happen? does the drag from the cast iron part of the throw out put enough drag on the engine to cause it to die?

[Anthony & Susan DiBattista]

Jim and Mike

Some more info, I hope it helps. I took the car out last night and brought it up to operating temperature. Now when I push the clutch in all the way the car stalls. It does not stall with the oil cold and the clutch depressed. It only slows the engine down and it vibrates side to side. I also watched the oil pressure when the engine was hot. When I depressed the clutch it acted the same, kinda like a slow drop about 1 seconds after depressing the clutch, following the RPM’s of the motor. Although the car stalls so quick when it’s warm. At that point the oil pressure drops to zero which will happen.

I did not have a second person to watch the crank shaft, but I would think that it would move with or without the oil being cold. Let me know if I’m wrong.

One last question, can you change the rear main seal without removing the engine?

Best Regards and as always thanks in advance!!

[James & Susan Ellis]

I think you have a thrust washer problem from everything you say it points to that in my opinion. Now that is not to say it could not be the throw out bearing. Either one you pull the engine… then if the throw out is good you go from there. There is no rear main seal.

[johnny-ringo]

💡 My vote is it’s the clutch bearing that’s so worn that it isn’t able to push the pressure plate the required distance and the metal “holder” (and not the carbon stuff) is grinding into the pressure plate and stopping the engine. The difference between what happens when it’s cold and hot is just a variation of the same problem as the clutch engages a tad more or less. Just an opinion, however.

[Tom and Joanne Ehrhart]

How about all the above. It is normal for engine RPM to dip a couple hundred when depressing a clutch if engine idles at about 900 to 1000 before depressing the clutch. It could be, bad eng trust bearings, worn out release bearing (pad), or even a very poor state of idle tune. The issue none of us knows is, the actual drag or load when the clutch is depressed. It’s kind of a subjective feel that an experienced person needs to assess.

In my experience your symptoms are a result of idle tune combined with release bearing friction. But what the hey, you are planning on ripping it out in the fall anyway. Crank the idle up to 2000 and get on with your summer. Enjoy the thrill of Alpining.

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