Pressure Plate Bolt Clearance |
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Pressure Plate Bolt Clearance |
aggiezig |
Feb 13 2019, 12:00 AM
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#1
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Porsche Wannabe Group: Members Posts: 319 Joined: 13-January 16 From: Los Angeles, CA Member No.: 19,557 Region Association: Southern California |
Howdy 914World
I am in the process of reassembling my car and decided to go ahead and mount the clutch and pressure plate to the flywheel. I've only done this a couple of times before on VW beetles, so not a whole bunch of experience here but seems pretty straight forward. When I mated everything up together, I noticed there was quite a bit of gap between the pressure plate ears and the flywheel mating surface (probably .25" or so). But, I figure this may be normal and the ears cinch up when you go to tighten the PP down. However, I did run into an issue when snugging everything up. There doesn't appear to be enough clearance around the PP to use regular hex head bolts. IE: the socket can't fit on the bolt head. Also, by the time I got them as far tightened as I could, the heads were at or below the level of the starter ring. Is this normal? Should I be using allen head bolts here for the clearance? I read on this post about machining clearances out of concern that perhaps my flywheel was machined improperly. On that diagram, my "A" measures 21.60MM which would appear to be out of spec. Here are some pics of the situation: (IMG:http://www.914world.com/bbs2/uploads_offsite/i.imgur.com-19557-1550037644.1.jpg) (IMG:http://www.914world.com/bbs2/uploads_offsite/i.imgur.com-19557-1550037645.2.jpg) (IMG:http://www.914world.com/bbs2/uploads_offsite/i.imgur.com-19557-1550037646.3.jpg) What do you guys think? Is this normal / do I need allen head bolts? Or, is something strange going on here. |
jcd914 |
Feb 14 2019, 01:00 AM
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#2
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Advanced Member Group: Members Posts: 2,081 Joined: 7-February 08 From: Sacramento, CA Member No.: 8,684 Region Association: Northern California |
To me the concern is not really the position of the bolt heads, if you can tighten the bolts to proper torque they will do their job. Or you can use allen bolts.
The issue I would be concerned with is the machined step from the surface the pressure plate bolts to the clutch surface of the flywheel. You said yours measured 21.6mm and the spec is 22.5. That means as yours sits now that pressure plate is compressed 0.9mm farther than designed. The fingers of pressure plate will be recessed in further than normal, farther from the throw out bearing and the pressure plate may not be able to move away from the clutch disc enough to release the the clutch, it may bind mechanically. I have never seen a pressure plate mis-machined in this manner before always the other way around, the step being too deep. I would probably disassemble the clutch and pull the flywheel and carefully measure it using the specs in the other thread you refer to. See what you have to work with. Jim |
rgalla9146 |
Feb 14 2019, 06:50 AM
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#3
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Advanced Member Group: Members Posts: 4,621 Joined: 23-November 05 From: Paramus NJ Member No.: 5,176 Region Association: None |
To me the concern is not really the position of the bolt heads, if you can tighten the bolts to proper torque they will do their job. Or you can use allen bolts. The issue I would be concerned with is the machined step from the surface the pressure plate bolts to the clutch surface of the flywheel. You said yours measured 21.6mm and the spec is 22.5. That means as yours sits now that pressure plate is compressed 0.9mm farther than designed. The fingers of pressure plate will be recessed in further than normal, farther from the throw out bearing and the pressure plate may not be able to move away from the clutch disc enough to release the the clutch, it may bind mechanically. I have never seen a pressure plate mis-machined in this manner before always the other way around, the step being too deep. I would probably disassemble the clutch and pull the flywheel and carefully measure it using the specs in the other thread you refer to. See what you have to work with. Jim (IMG:style_emoticons/default/agree.gif) The next issue will be fastener clearance at the flywheel-to-crank bolts. If the right distance between the mounting surface and the friction surface was maintained the disc will no doubt be contacting there too. Best to remove the flywheel and review the basics. Also, no dowels ? |
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