How NOT to have your flywheel machined
11-13-07, 06:49 PM
#1
How NOT to have your flywheel machined
I'm pretty pissed about this. I had my flywheel machined a while back when I built my engine by a local machine shop. I installed the engine, spent alot of time getting it tuned right, and saved up some money for a good clutch. I thought my old one was slipping badly since I built this motor and upgraded the suspension. It just needs a higher torque-handling capability, I told myself.
Wrong. Turns out, my new clutch slips too.
That can't be happening! So after pulling my hair out over it, I removed the transmission again to see if the flywheel had glazed or caught a case of the hotspots. That's when I figured it out. The place where the clutch mounts to the flywheel isn't part of the surface that got machined. They're on little cast studs that are above the face of the flywheel. So essentially what happened is that when he machined the flywheel, it made the friction surface farther away from the clutch.
I don't want to drop the money on a new flywheel, and a used one is too risky. On top of that, it's a convertible, so I don't want to sacrifice drivability for performance with a lightweight flywheel. So does anyone know what the spec is on the distance the face of the flywheel is from the mounting studs? I'm going to get it machined again, but this time I'm getting the studs machined down a little so the clutch can meet the face properly.
Wrong. Turns out, my new clutch slips too.
That can't be happening! So after pulling my hair out over it, I removed the transmission again to see if the flywheel had glazed or caught a case of the hotspots. That's when I figured it out. The place where the clutch mounts to the flywheel isn't part of the surface that got machined. They're on little cast studs that are above the face of the flywheel. So essentially what happened is that when he machined the flywheel, it made the friction surface farther away from the clutch.
I don't want to drop the money on a new flywheel, and a used one is too risky. On top of that, it's a convertible, so I don't want to sacrifice drivability for performance with a lightweight flywheel. So does anyone know what the spec is on the distance the face of the flywheel is from the mounting studs? I'm going to get it machined again, but this time I'm getting the studs machined down a little so the clutch can meet the face properly.
11-13-07, 07:39 PM
#2
Rotor Head
Join Date: Jan 2002
Location: British Columbia
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Why are used flywheels risky? Just get one that hasn't been machined. Also, you dont sacrifice driveability with a lightened one... I have one in my car and it drives great! Revs out really quick too! I think you'll like it! First gear takes about 1.5seconds to get through!
11-14-07, 03:42 AM
#3
Yeah man, just pick up a used flywheel, take your old one back to the shop and show him how he fucked up, and ask him to machine your replacement for free in return for it. It's the least he could do.
FWIW I have an s4 NA flywheel I am giving away free if you want it. Is useable as is but would be a good candidate for resurfacing as well. Just pay shipping of 15 bucks via paypal and its yours.
FWIW I have an s4 NA flywheel I am giving away free if you want it. Is useable as is but would be a good candidate for resurfacing as well. Just pay shipping of 15 bucks via paypal and its yours.
11-14-07, 07:53 AM
#5
Rotary Enthusiast
I'm pretty pissed about this. I had my flywheel machined a while back when I built my engine by a local machine shop. I installed the engine, spent alot of time getting it tuned right, and saved up some money for a good clutch. I thought my old one was slipping badly since I built this motor and upgraded the suspension. It just needs a higher torque-handling capability, I told myself.
Wrong. Turns out, my new clutch slips too.
That can't be happening! So after pulling my hair out over it, I removed the transmission again to see if the flywheel had glazed or caught a case of the hotspots. That's when I figured it out. The place where the clutch mounts to the flywheel isn't part of the surface that got machined. They're on little cast studs that are above the face of the flywheel. So essentially what happened is that when he machined the flywheel, it made the friction surface farther away from the clutch.
I don't want to drop the money on a new flywheel, and a used one is too risky. On top of that, it's a convertible, so I don't want to sacrifice drivability for performance with a lightweight flywheel. So does anyone know what the spec is on the distance the face of the flywheel is from the mounting studs? I'm going to get it machined again, but this time I'm getting the studs machined down a little so the clutch can meet the face properly.
Wrong. Turns out, my new clutch slips too.
That can't be happening! So after pulling my hair out over it, I removed the transmission again to see if the flywheel had glazed or caught a case of the hotspots. That's when I figured it out. The place where the clutch mounts to the flywheel isn't part of the surface that got machined. They're on little cast studs that are above the face of the flywheel. So essentially what happened is that when he machined the flywheel, it made the friction surface farther away from the clutch.
I don't want to drop the money on a new flywheel, and a used one is too risky. On top of that, it's a convertible, so I don't want to sacrifice drivability for performance with a lightweight flywheel. So does anyone know what the spec is on the distance the face of the flywheel is from the mounting studs? I'm going to get it machined again, but this time I'm getting the studs machined down a little so the clutch can meet the face properly.
Hot_Dog
90 RX7 GXL
11-14-07, 07:56 AM
#6
Yes, any machine shop who has done more then one flywheel in its career should know that you need to maintain the orignal step between the mating surface and the pressure plate mounting surface. Thats such a no brainer it hurts my brain 
Smack that guy.
Smack that guy.
11-14-07, 01:12 PM
#7
RotaryResurrection- I'll contact you tomorrow about that flywheel when I get paid. 15 bucks shipping is going to cost less than having the old one machined down to an unknown spec again.
Anyways, the guy found another way to screw me. He's now out of business, so I can't go throw it at him like I wanted to.
Reason I said a used one is risky was because I didn't want to grab one fom a junkyard that had the same thing happen to it. And I really don't want the lightweight because it is a convertible, which needs the extra stored "inertial torque" to get it going. Plus, this car's just a weekend driver, and I don't want to race it anymore. (nor do I feel like dropping the dough on the lightweight)
Anyways, the guy found another way to screw me. He's now out of business, so I can't go throw it at him like I wanted to.
Reason I said a used one is risky was because I didn't want to grab one fom a junkyard that had the same thing happen to it. And I really don't want the lightweight because it is a convertible, which needs the extra stored "inertial torque" to get it going. Plus, this car's just a weekend driver, and I don't want to race it anymore. (nor do I feel like dropping the dough on the lightweight)
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