Talk to me about flywheels

[NewArt]

So while transferring over the ancillaries from my dead Boxster engine to my reborn Boxster engine, I noticed that while the clutch, pressure plate, and flywheel looked good, the flywheel spring-back test failed. The last times that I drove the car, I didn’t notice any problems or vibrations with the clutch. I’m thinking that I need to replace the flywheel because of the spring-back test, but I’m not sure why. Any knowledgeable opinions?

[BYprodriver]

Originally Posted by NewArt

So while transferring over the ancillaries from my dead Boxster engine to my reborn Boxster engine, I noticed that while the clutch, pressure plate, and flywheel looked good, the flywheel spring-back test failed. The last times that I drove the car, I didn’t notice any problems or vibrations with the clutch. I’m thinking that I need to replace the flywheel because of the spring-back test, but I’m not sure why. Any knowledgeable opinions?

That is the only part that absorbs harmonic vibrations. Just think about how well it will perform 5,000 miles from now, do you want to do this same labor again this summer?

[The Radium King]

Originally Posted by NewArt

The last times that I drove the car, I didn’t notice any problems or vibrations with the clutch.

sure about that? your engine may have noticed a problem. did you ever determine why the engine popped? what did the crank look like?

[NewArt]

I haven’t had time to complete the teardown of the old engine. Mostly concentrating on getting the new one up and running. I suspect an oiling issue which may have been my own fault. I found some gasket material in the sump from when I installed the deep sump. This may have clogged some of the passages. We’ll see when the post mortem is complete.

[NewArt]

So I just received a new LuK flywheel. I opened the box and placed it on a bench. I tried the spring return test and guess what: exactly the same return (or lack there of) as my old flywheel. So WTF?! $500 poorer!

[JFP in PA]

Originally Posted by NewArt

So I just received a new LuK flywheel. I opened the box and placed it on a bench. I tried the spring return test and guess what: exactly the same return (or lack there of) as my old flywheel. So WTF?! $500 poorer!

[10/10ths]

....all of the folks I trust who know these cars inside and out tell me to stick to the factory flywheel.

That harmonic balancer built into that OEM flywheel is critical in keeping the crankshaft from grenading.

[NewArt]

JFP, thanks for the info. According to this procedure my DMF is fine after the first criterion, i.e. no abnormal transmission noises. However, continuing on to the next step, it doesn’t return to the original position. But then neither does the new one, fresh out of the box. The following criteria do not apply. So, what should one conclude?

[NewArt]

Originally Posted by 10/10ths

....all of the folks I trust who know these cars inside and out tell me to stick to the factory flywheel.

That harmonic balancer built into that OEM flywheel is critical in keeping the crankshaft from grenading.

AFAIK, LuK is the flywheel supplier for Porsche.

[10/10ths]

....just adding my .02 for the collective.


Good luck.

[JFP in PA]

Originally Posted by NewArt

JFP, thanks for the info. According to this procedure my DMF is fine after the first criterion, i.e. no abnormal transmission noises. However, continuing on to the next step, it doesn’t return to the original position. But then neither does the new one, fresh out of the box. The following criteria do not apply. So, what should one conclude?

If the new flywheel does not pass this simple test, it is bad. Defective parts right out of the box are not unknown.

[Eric G]

Yes you need a new one, yes you should go with the dual mass flywheel and yes it will keep your engine from going off like a grenade.