A1 Clutch/tranny question

[Bill Miller]

Ok, this one has me stumped. I'm putting my HP Rabbit together, and I've run into a problem w/ the clutch. When everything is bolted up, I get no resistence on the clutch arm, other than the internal spring that's on the arm. I first thought that the push rod had some how not been installed, so I pulled the tranny, and sure enough, there was the push rod. It moves when you actuate the arm, but it does not seem to be hitting the disc on the pressure plate. Swaped in another trans (4K), and still the same issue.

This is a 1.6 motor w/ a 190mm clutch/pp/flywheel (4-puck clutch, lightened flywheel). Is there any difference in the push rod for the earlier cars vs. the later cars? Maybe the plate on the pressure plate? I'm really at a loss on this one.

TIA

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MARRS #25 ITB Rabbit GTI (sold)
SCCA 279608

[16V GTI]

Is the bearing in the fifth gear cover? I did the same thing a while back and took off the cover and there was no bearing to contact the pushrod to push it out far enough.

[racer_tim]

Bill, don't the lightened flywheels machine off some of the "depth" of the flywheel? Wouldn't taking that 1/2" out of the mounting area of the flywheel need to be put back into the "rod" that goes through the tranny from the lever arm to engange the Pressure Plate?

I haven't looked closely at how the Pressure Plate and Flywheel attach with the stock flywheel, but you could also just attach a stock flywheel and see if you have contact. That would then point to the above fix.



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Tim Linerud
San Francisco Region SCCA
#95 GP Wabbit (Bent)
http://linerud.myvnc.com/racing/index.html

[Eric Parham]

Bill, the 4-speed pushrod is shorter.

[Bill Miller]

Tim,

Most of the lightened flywheels I've seen just have the extra material cut off past the starter ring. The pressure plate actuall sits inside that ring. I've also seen ones that have had the casting marks, etc. machined off.

What I have heard is that when you resurface the flywheel, you have to also machine an equal amount off the mounting surface where the pp and fw contact each other. This keeps the 'static' distance between the pp and fw friction surfaces the same. If you only machined the fw friction surface, you would lower the static clamping force on the clutch between the pp and fw, thereby promoting clutch slippage.

Anyway, I figured out what the problem is. When this particular fw was machined, it looks as if a considerable amount of material was taken off the contact surface where the fw meets the pp. I took the fw/clutch/pp in question off the car and assembled them on the bench. The rivets on the straps that hold the pp friction surface to the pp backing plate were pushed ~3/8" away from the backing plate. In addition, there were maybe .050" - .075" of travel left on the pp friction surface.

I had a stock pp/c/fw laying around, so I assembled that on the bench as well. What I noticed was the distance from the outer edge of the clutch spline to the 'pocket' in the thrust plate where the push rod rests was ~.470" deeper on the problem clutch than on the stock clutch. This means that the push rod would have to travel that .470" farther to even contact the thrusht plate. I don't think there's that much 'extra' travel in there. That coupled w/ the fact that the problem clutch only had .050" - .075" of travel left, made this a pretty shakey situation. In fact, I have no idea how this clutch ever worked (if in fact it ever did). I thought possibly that maybe it had a 4-spd in it w/ a 5-spd push rod. I don't know, but I don't think this setup could have ever worked.

It doesn't matter now though, as I ordered a new 210mm pp and 4-puck clutch setup that I'll mate w/ a known good 210mm lightened flywheel, and that will be that. It just sucks that I had to waste time w/ it, and install 2 different trannys, and still have to do a full clutch job and another tranny install. I've got a lot more that I need to do before Labor Day! http://Forums.ImprovedTouring.com/it/frown.gif

Thanks to everyone for their thoughts and help.

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MARRS #25 ITB Rabbit GTI (sold)
SCCA 279608