Thursday, September 16, 2010

Denied!

Rule One: Test before you put it ALL back together.

Monday night, I got the rest of the engine wiring and hoses on, the exhaust, the bumper... Started the engine up (it cranked for about one second and lit off without touching the throttle... I love EFI).... All looked good.

I knew I would probably need to adjust the clutch cable before taking it for a spin. That's when I noticed that the clutch arm does not budge. At all. Well, it wiggles with the minimal play that the shaft has naturally, but otherwise, it was completely immobile.

Long story short, on Tuesday, I called AMS to consult with Steve again. He recommended that I remove all the new parts and bring them in, along with the old parts and as much other information as I could gather. Tuesday night, I fooled with it for a while, still looking for something, but pulled the parts out and got them ready to go.

This afternoon, I took everything in to AMS and we determined that everything should be all the right components. He suggested a couple of things to check concerning cable adjustment and clearances. I also consulted a couple of BTW folk. At this point, it's a mystery to all, but my mission is to measure and test to see if I can find what's not making up.

So, when I got home and got started, about 8PM, I first checked that the throwout bearing, fork, cable and pedal were all moving freely.

 Reassembled, same thing.

I pulled it apart again. I did some measuring. I put a straight edge across the mounting face of the transaxle and measured to the face of the throwout bearing. It was 2.68 inches. I also put the straightedge on the face of the pressure plate collar thingy and measured to the engine block face that mates with the transaxle. It was 2.81 inches. These two together should mean that, once assembled, the throwout bearing should be resting about 1/8" from the pressure plate. This corresponds with the expected range of motion for the assembled clutch.

I verified that the clutch arm has it's full range of motion while disassembled.

I also compared the old and new throwout bearings:

Though they are constructed in rather different ways, all the dimensions that matter appear to be identical, or at least compatible.

While I had it apart, I attempted to use a steel plate and some clamps to verify that the pressure plate can indeed move when pressed. It does. There was not a reasonable way to press the clutch and verify that the clutch disk is released when it is pressed. I have in mind a custom tool that could test that, but I was not prepared to fabricate such a tool just then. I put it all back together again, with the old throwout bearing, and verified that nothing had changed.

"Insanity: doing the same thing over and over again and expecting different results." - Albert Einstein

While I had the camera ready, I documented the free play in the clutch arm while assembled and it corresponds with what I would expect.

So, I have decided that unless some radical new information comes to light before bedtime Thursday, I am not going to be able to drive the trike to the benefit/show this weekend.

I will, however, tow it in to the show. We are auctioning off a donated paint job and this trike has the paint from a previous auction and we hope to drum up lots of interest in the auction!

Thursday, September 9, 2010

Clutch Reassembled

I dropped by Automotive Machine and Supply after work to procure parts and consult the oracle. Steve verified my concerns that there was supposed to be a collar on the pressure plate for the throwout bearing to contact and further that it's absence is the real reason the throwout bearing jumped the tracks. He also verified that the play in the input shaft is normal, though he agrees that I should change out the seal.

So, $86 dollars later, I have a new clutch cover and pressure plate, as well as the clutch fork and such.


Besides, the old pressure plate and fingers were more damaged than they first appeared:


Note the bent fingers at the lower right. They were not really apparent with the cover installed.

The installation of clutch fork included the usual minor trauma. Installation of the clutch cover gave me a new problem that make me chuckle.

My clutch pilot tool has a ring for a handle and it was too big to fit through the collar on the pressure plate. I applied a bit of heat and a bit of sculpting and now it fits.

Otherwise there were no particular difficulties with the physical installation, other than the usual big hands in a small space issues...

After the delays, I got the engine bolted on and decided that it was late enough that I didn't want to tear in to the wiring, fuel, exhaust and bumper. They will have to wait for Friday or Saturday...

Transaxle Work

I got all but the four bolts pulled off Tuesday night, then finished pulling the engine out last night.

It looks like there was no really serious damage done by the rogue throwout bearing. The fork was pushed too far and the throwout bearing jumped off it.


You can see the broken finger and a piece of a chewed up spring clip laying on the bottom of the bell housing. The remaining clip holding the throwout bearing has been ground against something as well. At the time of the event, the engine was still running, but in the process of towing it home, the broken finger apparently jammed between the flywheel and the bell housing, preventing me from starting the engine.

Once off the fork, it appears that the bearing landed such that the fingers on the clutch pressure plate rubbed against the bearing carrier. You can see the galling on the bearing carrier in this picture:


 It remains to be seen whether the damage to the pressure plate fingers is significant:


Some pressure plates have some kind of disc attached to the fingers, like this:


... but this one never has, at least not while I've had it. I'm not sure whether or not it's missing, but since clutch operation seems reasonably normal without it, I'm going to assume it's ok without it.

Speaking of assumptions, I took a guess that some fairly severe looking play in the input shaft of the transaxle might have been a factor in the damage done. Upon clearer thinking, I now realize that this shaft is not left hanging out there, but is rather supported by the pilot bearing in the end of the engine crankshaft. Duh! I am going to replace that seal while I'm in there anyway...

Picking up parts on the way home tonight; it's entirely possible that I may have this thing mobile tomorrow...

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