 Flywheel Enigma - HELP!, flywheels step measurements??? |
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| gfulcher |
 Jul 20 2004, 12:35 PM
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#1
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Diagnosis: Automobilitus. Prognosis: Terminal  Group: Members Posts: 122 Joined: 3-January 04 From: San Francisco, CA Member No.: 1,501 Region Association: Northern California  |
Hey all...
My 2.6L "big four" is at my engine builders for it's every-other-year refresh, and he's got the flywheel up on the lathe right now - in taking the measurement of my flywheel, he finds it to be .890 for the step from the center to the disk surface. The two specs listed for 914 flywheels is either .950 or .834. Mine is right in between. The clutch functioned fine when removed, although there was a little bit more wear around the outside of the disk than the inside. Anybody have any clue if there were other flywheels produced with an in-betwix step measurement, or, if this was originally a .950 flywheel and subsequent surfacings over the years has brought it to .890, would machining it down to .834 be a detriment? Thanks in advance! Any insight would be appreciated as he's got the sucker on the lathe right now and doesn't want to go through another setup... -greg fulcher '72 Porsche 914 2.6L Big Four |
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| Jake Raby |
Jul 20 2004, 12:40 PM
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#2
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Boston Bob must be helping you, he emailed me earlier with the same question. What does it measure now?
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| gfulcher |
Jul 20 2004, 12:59 PM
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#3
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Diagnosis: Automobilitus. Prognosis: Terminal Group: Members Posts: 122 Joined: 3-January 04 From: San Francisco, CA Member No.: 1,501 Region Association: Northern California |
QUOTE(Jake Raby @ Jul 20 2004, 01:40 PM) Boston Bob must be helping you, he emailed me earlier with the same question. What does it measure now? Hey Jake.. Yeah, Bob is doing the work. He said he asked you as well... The current measurement of my flywheel is .890 - pretty much smack dab in the middle of the specified numbers. Thanks, -greg |
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| Demick |
Jul 20 2004, 02:05 PM
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#4
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Ernie made me do it! Group: Benefactors Posts: 2,312 Joined: 6-February 03 From: Pleasanton, CA Member No.: 257  |
The critical measurement is from the friction surface that the clutch disc wears on out to the surface that the pressure plate bolts to (the step just inside the teeth on the outer diameter). This measurement should be .886" +- .008"
You must also make sure there is adequete clearance for the flywheel bolt heads. So the distance from the face where the flywheel bolts sit out to the friction surface must not be less tahn .4330" There are other critical dimensions as well, but these are two of the more important ones. Demick |
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| Jake Raby |
Jul 20 2004, 02:35 PM
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#5
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Engine Surgeon Group: Members Posts: 9,394 Joined: 31-August 03 From: Lost Member No.: 1,095 Region Association: South East States |
Clean up the flywheel surface and measure what has to be removed to do so... Then take the same PLUS .025 off the the top step... Thats my way of doing it..
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| crash914 |
Jul 20 2004, 02:45 PM
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#6
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its a mystery to me Group: Members Posts: 1,826 Joined: 17-March 03 From: Marriottsville, MD Member No.: 434 Region Association: MidAtlantic Region |
Hey Greg!!
I have a new flywheel measuring at .840 and an old one at .830.... It seems that the drawings and specs are off...others are seeing the same thing... see you later, herb... PS, I should have my BIG 4 on the road soon.....2666 cc......yea baby!! (IMG:style_emoticons/default/rocking nana.gif) |
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