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-   -   Things not to skimp on - replace the flywheel! (http://forums.pelicanparts.com/porsche-911-technical-forum/504008-things-not-skimp-replace-flywheel.html)

mthomas58 10-09-2009 07:28 AM

Things not to skimp on - replace the flywheel!
 
Did the clutch job along with an engine swap in June and opted to have the flywheel re-surfaced vs. replace to save $$$. I did not have it balanced so it could be warped and out of balance - I just don't know. I thought about this long and hard an opted not to replace - big mistake!

Anyway, I get chatter/vibration not so much out of 1st gear but really out of 2nd gear that is SUPER ANNOYING. My commute has recently changed and I find myself sitting in interstate traffic jams and the clutch chatter is driving me nuts. So much so that I'm willing to redrop the engine to replace the flyhweel.

I also wish I had taken the time to replace the intake gaskets when I had the engine on the stand for 9 mos. I'll be replacing them this weekend to fix an intake leak.

Before
http://forums.pelicanparts.com/uploa...1255101956.jpg

After: (done by The Clutchman - local mobile servicer for$60)
http://forums.pelicanparts.com/uploa...1255101980.jpg

sc_rufctr 10-09-2009 07:52 AM

Was the fly wheels taken of the engine to re surface it or was it done in place?
Did the surface have micro cracks in it before resurfacing?

The surface looks good in the second photo.

Fly wheels are cut differently to brakes and looking at the second photo it looks like it's been cut correctly.

I have "fly cut" my own flywheels and done it for people I know on my mill using a rotary table.
I built a special jig for securing the fly wheel to the rotary table and use a roller on a small jack bolted to the table to support the outer edge...

So far I have done about 10 fly wheels but most of those were just a skim to remove the glazing. If you need to cut heaps off a fly wheel to get it flat then often it will be out of balance and spec when you're finished.

trconway 10-09-2009 08:01 AM

New Flywheel
 
You had a new flywheel installed for $60? Not including the cost of the flywheel, right?

Christien 10-09-2009 08:05 AM

It could very possibly just be a clutch adjustment issue. I also only had mine resurfaced when I rebuilt my tranny and put in a new clutch. I had about 50/50 advice, but the look from my wife when she saw the Pelican invoice for the clutch and tranny bits told me resurfacing was the better option :)

When I first put it back in I had horrible chatter, exactly like you described - pretty much only going into 2nd from 1st. I adjusted the clutch and it's much better now. I still get it sometimes, so I need to adjust again, but it made a big improvement. I'd strongly suggest adjusting your clutch before dropping your engine again!

ibeaudoin 10-09-2009 08:14 AM

According to your signature, your car is a 87, so a G50.
I always thought that you couldn't re-surface a G50 flywheel.

911pcars 10-09-2009 08:18 AM

Not sure how your first flywheel was "turned". The preferred method of resurfacing frictional surfaces such as rotors, brake drums and flywheels is to use a grinding stone rather than a typical carbide cutting tool. A cutting tool will skip over heat-hardened areas of the surface leaving an uneven surface. A grinding wheel will remove these hard spots and produce an even flat surface.

As an aside, the cutting pattern produced by a lathe bit is a circular spiral, much like the grooves in a vinyl record. This produces a thread-like effect which forces one contact area to shift (like a phonograph needle). While of little significance in a flywheel/clutch disk, this can produce noise when a brake pad or brake shoe tries to move along the sprial "groove". Shops who use this type of cutting head should finish up by using a sanding disk to break up the spiral pattern. Still, not as good.

MHO,
Sherwood

zipinitaly 10-09-2009 08:27 AM

Clutch Chatter
 
I would check all my clutch adjustments first...I had the same issue and adjusted the cluth, no more problems!

mthomas58 10-09-2009 09:34 AM

Quote:

Originally Posted by trconway (Post 4943693)
You had a new flywheel installed for $60? Not including the cost of the flywheel, right?

I had the flywheel resurfaced off the car from a mobile resurfacer (equip on his truck) for a total cost of $60

mthomas58 10-09-2009 09:35 AM

Quote:

Originally Posted by zipinitaly (Post 4943748)
I would check all my clutch adjustments first...I had the same issue and adjusted the cluth, no more problems!

G50 gearbox - no cable to adjust

mthomas58 10-09-2009 09:38 AM

Quote:

Originally Posted by ibeaudoin (Post 4943718)
According to your signature, your car is a 87, so a G50.
I always thought that you couldn't re-surface a G50 flywheel.

Correct - it is recommeded that they be replaced, not resurfaced. I got enough recommendations here from others who have had success and took the risk. Now I wish I hadn't.

88-diamondblue 10-09-2009 06:00 PM

Mark not sure what caused your problem. I have heard of the flywheels being warped and need to be checked before machining. Possiblity?
I had my G50 flywheel resurfaced as I was going to use a spring centered clutch. $30 at what is considered the best shop in town. Would not have it resurfaced if I was using the rubber centered clutch. Another thing my shop did that I didn't see on your flywheel is they took the same amount off the outside lip as they did on the main surface area. Take a look at the flywheel and you can see the two surfaces that they machined. Also the curved pattern of the machining is visible.

http://forums.pelicanparts.com/uploa...1255139077.jpg

The spring centered clutch has been great and no noticeable difference from the rubber centered clutch.

http://forums.pelicanparts.com/uploa...1255139391.jpg

Buzzard95 10-20-2020 11:08 AM

Related problem. Replaced my Clutch (Sachs) and flywheel (Sebro) on my 88 911, and now have a vibration/chatter at low RPM's (2000 - 2500) under load/acceleration progressively worse in higher gears. Also replaced axles (Leobro's) No problems of this type before engine drop. Ideas or links to other posts welcome.

reclino 10-20-2020 12:19 PM

Vibration under load sounds like a CV joint issue. Yes you said you replaced them, could be one of the new joints is too tight and binding.

Noah930 10-20-2020 01:06 PM

In my DD Honda, I had the dealer replace the clutch when they were rebuilding the motor due to a warranty issue. The flywheel was resurfaced. Afterwards, the clutch chattered horribly. The problem "wore out" after about 10 months. That was about 3 years ago, and no further problems. So maybe just give it a few more months?

911pcars 10-20-2020 08:47 PM

Quote:

Originally Posted by Buzzard95 (Post 11071596)
Related problem. Replaced my Clutch (Sachs) and flywheel (Sebro) on my 88 911, and now have a vibration/chatter at low RPM's (2000 - 2500) under load/acceleration progressively worse in higher gears. Also replaced axles (Leobro's) No problems of this type before engine drop. Ideas or links to other posts welcome.

Perhaps gear lube or lube oil is leaking/dripping into the clutch/flywheel contact area. Take a peek through the starter opening. Take it one step at a time.

Sherwood

proporsche 10-20-2020 11:39 PM

make sure you have the 15mm nuts tight on the trans. if look it will vibrate...
Ivan

rikaro 10-21-2020 12:34 AM

isn't chatter on a resurfaced flywheel pretty common? it's like getting a lightweight flywheel that makes the same noises

p557m 10-21-2020 05:26 AM

Check your engine mounts.


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