Flywheel Runout...?
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Flywheel Runout...?
Upgrading the stock clutch to a SPEC stage 2+......
Just bolted on my flywheel being careful to torque the bolts in stages (15-37-74 ft.lb.) Thought I'd just check the disc contact face for circular runout with the dial test indicator. What I found was .006" FIR (full indicator reading) when measured towards the outer rim just inboard of the pressure plate threaded holes.
Does anyone think this is excessive?
This is a stock steel flywheel that has just been resurfaced.
1999 Z28
Just bolted on my flywheel being careful to torque the bolts in stages (15-37-74 ft.lb.) Thought I'd just check the disc contact face for circular runout with the dial test indicator. What I found was .006" FIR (full indicator reading) when measured towards the outer rim just inboard of the pressure plate threaded holes.
Does anyone think this is excessive?
This is a stock steel flywheel that has just been resurfaced.
1999 Z28
#2
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i could be wrong but i don't think your getting a valid measurement due to other factors, i.e. crankshaft end play. I don't think you can accurately measure flywheel run out with it mounted to a crankshaft that has end play. I could be wrong, hopefully someone who is sure will chime in
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You're right, the crankshaft end play could potentially be a factor.
I turned the flywheel about 6 times by wrenching on the bolts that fasten it to the crankshaft after they had been torqued. I was pressing hard to keep the wrench on the bolt heads while overcoming the compression in the cylinders so I'm guessing I had the crank loaded forward in the bearings.
On each turn the DTI was consistently reading a gradual increase to .006" in the same area then falling steadily back to .000" at 180 degrees on the other side.
I turned the flywheel about 6 times by wrenching on the bolts that fasten it to the crankshaft after they had been torqued. I was pressing hard to keep the wrench on the bolt heads while overcoming the compression in the cylinders so I'm guessing I had the crank loaded forward in the bearings.
On each turn the DTI was consistently reading a gradual increase to .006" in the same area then falling steadily back to .000" at 180 degrees on the other side.
#5
If It were me, I'd get the flywheel on a surface plate and check it that way, similar to how one might tram a mill head to the table.
Mounting it to a face plate on a lathe would tell you if that runout is there or not also.
You might try indexing the wheel to the bolt holes/crank, rotate 180 deg, reinstall then recheck using your tried method to see if the runout follows the move or remains with the indexed start point.
Interesting issue though, might explain a lot of the shudder in these type systems.
Mounting it to a face plate on a lathe would tell you if that runout is there or not also.
You might try indexing the wheel to the bolt holes/crank, rotate 180 deg, reinstall then recheck using your tried method to see if the runout follows the move or remains with the indexed start point.
Interesting issue though, might explain a lot of the shudder in these type systems.
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I've checked it on a granite kitchen work top and I'm quite sure the friction disk side, which was the only side resurfaced, is extemely flat.
The problem I think, is the crank shaft mounting face of the flywheel, which was not resurfaced, is not quite parallel to the friction disk face!
Tboh: You talk like a fellow toolmaker/machinist! Anyway, I agree with you, any of your inspection methods would confirm this theory.
Also, I think I can prove how this happens during the grinding operation... I've drawn up a couple of CAD pictures which I need to post. Stay tuned...
A question: Does anyone get both faces of a flywheel resurfaced?
The problem I think, is the crank shaft mounting face of the flywheel, which was not resurfaced, is not quite parallel to the friction disk face!
Tboh: You talk like a fellow toolmaker/machinist! Anyway, I agree with you, any of your inspection methods would confirm this theory.
Also, I think I can prove how this happens during the grinding operation... I've drawn up a couple of CAD pictures which I need to post. Stay tuned...
A question: Does anyone get both faces of a flywheel resurfaced?
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Update - SPEC flywheel and Stage 2+ clutch
Rather than using my resurfaced cast steel flywheel I decided to buy a new one and went with the SPEC steel billet SC75S, which, I thought was extremely well manufactured Thank you SPEC!
Anyway, after torquing down the flywheel I thought I'd just check the circular run-out again on the friction face of the flywheel and to my surprise the same .006", as I saw on the resurfaced flywheel, was still there. I have to assume the error is related to the crankshaft mating face. I did clean the crankshaft mating surface well and even rubbed over it with some steel wool.
This was my inspection set-up with the magnetic DTI clamped to the catalytic converter:
Zooming in a little and zeroing the DTI:
Rotated the flywheel numerous times in case the end play in the crankshaft bearings was affecting the reading but the .006" persisted at 180 degrees to the .000" reading:
I can't fix this condition so I will just have to continue on. Also, other issues with the new slave are now come to light!
Anyway, after torquing down the flywheel I thought I'd just check the circular run-out again on the friction face of the flywheel and to my surprise the same .006", as I saw on the resurfaced flywheel, was still there. I have to assume the error is related to the crankshaft mating face. I did clean the crankshaft mating surface well and even rubbed over it with some steel wool.
This was my inspection set-up with the magnetic DTI clamped to the catalytic converter:
Zooming in a little and zeroing the DTI:
Rotated the flywheel numerous times in case the end play in the crankshaft bearings was affecting the reading but the .006" persisted at 180 degrees to the .000" reading:
I can't fix this condition so I will just have to continue on. Also, other issues with the new slave are now come to light!
#9
I would suspect you need to measure runout of FW on a lathe or other "non installed" fashion as the crank end play and the inconsistant rotation of motor under compression is a factor distorting the measurements.
#11
I've checked it on a granite kitchen work top and I'm quite sure the friction disk side, which was the only side resurfaced, is extemely flat.
The problem I think, is the crank shaft mounting face of the flywheel, which was not resurfaced, is not quite parallel to the friction disk face!
Tboh: You talk like a fellow toolmaker/machinist! Anyway, I agree with you, any of your inspection methods would confirm this theory.
Also, I think I can prove how this happens during the grinding operation... I've drawn up a couple of CAD pictures which I need to post. Stay tuned...
A question: Does anyone get both faces of a flywheel resurfaced?
The problem I think, is the crank shaft mounting face of the flywheel, which was not resurfaced, is not quite parallel to the friction disk face!
Tboh: You talk like a fellow toolmaker/machinist! Anyway, I agree with you, any of your inspection methods would confirm this theory.
Also, I think I can prove how this happens during the grinding operation... I've drawn up a couple of CAD pictures which I need to post. Stay tuned...
A question: Does anyone get both faces of a flywheel resurfaced?
PS. Did this flywheel turn out to be flat or was it a pringle potato chip?