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EFV-8 Club Forum / General Ford Discussion / Pressure plate bolts

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Posted By Discussion Topic: Pressure plate bolts -- page: 1 2     Johns46coupe 09-24-2010 @ 12:02 AM reply profile send p.m. Member Posts: 68 Joined: Apr 2010 After receiving new pressure plate bolts from Roy with no shoulder, I called him and we discussed the shoulder issue. Roy said that since the bolt's major diameter at the threads is the same as the diameter of the shoulder, the shoulder really isn't needed for centering. When I used Roy's bolts to install the pressure plate and disc and torqued them to 20 pounds, I noticed the pressure plate was not tight up against the flywheel. There was a gap of around 1/16 or so. On removing the bolts to check things out further, I noticed the threads on the tips of the bolts were smashed a bit. The bolts were a little too long and were bottoming out. I ground off about three or four threads from the end of each bolt and reinstalled the assembly. The pressure plate is now flat against the flywheel at all three flange areas (where the three pairs of bolts are). I think the problem may have been bolts a bit too long and previous re-surfacing(s) of the flywheel making the holes a bit shallower. John 37don 09-17-2010 @ 4:57 AM reply profile send p.m. Member Posts: 24 Joined: Jul 2010 I ordered new bolts from Roy and they had no shoulder so I called him.He said that they changed with the 8ba and the major diameter of the two bolts is the same. Don ole_Bill 09-15-2010 @ 6:22 AM reply profile send p.m. New Member Posts: 165 Joined: Dec 2009 As we say here in Tennessee - "I done did it". 40 Coupe 09-15-2010 @ 5:25 AM reply profile send p.m. Senior Posts: 1675 Joined: Oct 2009 it would seem easy enough to bolt the pressure plate to the flywheel with grade 5 bolts and forget it. I will share this it is not nice to see the pressure plate enter the passenger compartment in three pound pieces, destroying the back of the engine block and the front of the transmission in the process, and possibly causing much damage to the leg. there are tremendous forces involved. Modern fasteners for the pressure plate are grade 8 and the original bolts do have a special shoulder. Call Roy and talk to him about what fasteners he is selling for this critical attachment. ole_Bill 09-14-2010 @ 8:52 AM reply profile send p.m. New Member Posts: 165 Joined: Dec 2009 Proxie35 - Flywheel to crankshaft is not the problem. Flywheel was installed at the machine shop and is as you described. This message was edited by ole_Bill on 9-14-10 @ 8:53 AM ole_Bill 09-14-2010 @ 8:50 AM reply profile send p.m. New Member Posts: 165 Joined: Dec 2009 Being the hard-headed type (and a novice at this) I used regular grade 8 bolts (couldn't find grade 5 locally) with a lock washer. First problem, 3/4" wasn't long enough, barely catching a few threads. I bought some 1" bolts and installed everything. Second problem, when I finished and pulled out the alignment tool (engine is on an engine stand, mounted sideways) the clutch plate was visably misaligned. I pushed the alignment tool back in, took it out, pushed in back in, etc. Finally I loosened the flywheel bolts and manually aligned the clutch, then tightened the flywheel. Alignment tool still fits, but is obviously not meant to fit this way. Lesson learned: listen to my friends at EFV8 forum and "do it the way Henry did it". proxie35 09-13-2010 @ 9:01 AM reply profile send p.m. Member Posts: 74 Joined: Jun 2010 Bill, I've just put the Flywheel,Pressure plate,& Clutch on my 49 engine. There are two Dowel pins (6387) to aline the Flywheel with, four shouldered selflock bolts (350816-S) & a locking ring (7609) used to connect the flywheel to the crankshaft. Ford "Did Not" use lockwashers on the flywheel bolts. Hope this helps. Stroker 09-12-2010 @ 3:42 PM reply profile send p.m. Senior Posts: 1460 Joined: Oct 2009 Ole Bill: You got excellent advice from many of the Forum contributors on the need to NOT USE common 5/16's cap screws. The clutch cover bolts act in the same way that alignment dowels do on many precision applications. It is very critical, given the mass of a clutch cover to get it absolutely centered. When I have had engines balanced, I always include the flywheel and clutch cover as parts I want balanced. A few thousands of eccentricity allowed by common hardware cap screws is like having an unbalanced tire spinning at 3000 rpm. The problem is; many generations of "parts-changers" may have simply substituted the parts they lost with stuff from the hardware store. Yes, the clutch will "work", but unless it is precisely centered, it will most likely create a vibration especially at high rev's. flatheadfan 09-12-2010 @ 9:55 AM reply profile send p.m. Member Posts: 450 Joined: Oct 2009 old Bill- Pressure plate bolts are special bolts. Note the picture below. The three bolts (from different flywheels) all have a shoulder on them. If you look at the bolts holes on the flywheel you will see that the threads do not start at the surface. The top 3/16" has no threads and this is to accommodate the bolt shoulder. The purpose of the shoulder is to prevent micro-oscillations of the bolt by locking the shoulder to the flywheel. Without the shoulder micro-oscillations can become macro-oscillations which can cause oscillations in the pressure plate which in turn can result in you having a "bad day". You may want to think about that when you are turning 3000 rpms. Tom 37RAGTOPMAN 09-12-2010 @ 7:39 AM reply profile send p.m. Senior Posts: 1960 Joined: Oct 2009 Ole_BILL You need to use the correct shoulder bolts like Kubes40 said, otherwise you may risk problems down the road, these shoulders center the pressure plate so it is dead on center, regular bolts leave a little side play, in each mounting bolt hole,and may not be dead on center,and if off set you will have problems, Just my 3 cents worth, 37RAGTOPMAN and KEEP on FORDIN !

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