Flywheel identification
Thread Starter
Instructor
Joined: Jun 2004
Posts: 125
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From: Copenhagen
Flywheel identification
Im getting ready to buy a aluminium flywheel, but im not sure if my clutch is a 10.5" or a 11"
On the original flywheel still sitting in the car is a number L 588, can anyone tell me if its possible to id the size 10,5 or 11 from this number. I have a 10.5" flywheel on my hand, but will it fit ?
Its a 4 speed muncie. (how can i tell if its a M20 or M21 ?)
Thomas
On the original flywheel still sitting in the car is a number L 588, can anyone tell me if its possible to id the size 10,5 or 11 from this number. I have a 10.5" flywheel on my hand, but will it fit ?
Its a 4 speed muncie. (how can i tell if its a M20 or M21 ?)
Thomas
Le Mans Master
Joined: Jan 2002
Posts: 8,913
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There has been recent discussion on fly wheels, Aluminum fly wheels may have some issues.
Read this.
http://forums.corvetteforum.com/show...565&forum_id=4
Read this.
http://forums.corvetteforum.com/show...565&forum_id=4
Le Mans Master
Joined: Jan 2002
Posts: 8,913
Likes: 283
I think you could run the numbers and find out, Post them.
I think you may need the 153 tooth gear though.
There are issues with re-surfacing aluminum flywheels, as they have a steel plate riveted to the clutch surface. In any event, my concern with the Aluminum fly wheel is it getting hot and warping. It may be a misplaced concern, but the General used Steel, even with the 18 pound L-88 fly wheel for a reason.
Mark
I think you may need the 153 tooth gear though.
There are issues with re-surfacing aluminum flywheels, as they have a steel plate riveted to the clutch surface. In any event, my concern with the Aluminum fly wheel is it getting hot and warping. It may be a misplaced concern, but the General used Steel, even with the 18 pound L-88 fly wheel for a reason.
Mark
Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
If your '66 is a small-block and has the original bellhousing (3858403), the Fidanza 168-tooth flywheel (for 11" clutch, 14" overall diameter) won't fit in the bellhousing, nor will the 11" clutch. That bellhousing will only accept a 153-tooth flywheel, 12-3/4" overall diameter, for a 10.5" clutch.
No way to tell M20 vs. M21 with it in the car by looking at it; if the rpm drop when shifting from 3rd to 4th is about the same as from 1-2 and 2-3, it's an M21 - if the rpm drop from 3rd to 4th is a lot more than it is from 1-2 or 2-3, it's an M20.
No way to tell M20 vs. M21 with it in the car by looking at it; if the rpm drop when shifting from 3rd to 4th is about the same as from 1-2 and 2-3, it's an M21 - if the rpm drop from 3rd to 4th is a lot more than it is from 1-2 or 2-3, it's an M20.
Thread Starter
Instructor
Joined: Jun 2004
Posts: 125
Likes: 0
From: Copenhagen
The bellhousing is for an 11" clutch, the starter i bought this spring is for a 168 toth flywheel i remember now.
Im taking the gearbox out this winther to put in new bearing where the tranmission Yoke goes in, so how can i tell when i have the gearbox out ?
Thomas
Im taking the gearbox out this winther to put in new bearing where the tranmission Yoke goes in, so how can i tell when i have the gearbox out ?
Thomas
Le Mans Master
Joined: Jan 2002
Posts: 8,913
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John, is there a difference in the input shaft splines, course and fine?
If I remember when I ordered a kit for my M-21 there may have been some options for the spline count on the input shaft. If I remember mine 65 M-21 was the course or (13 count).
Mark
If I remember when I ordered a kit for my M-21 there may have been some options for the spline count on the input shaft. If I remember mine 65 M-21 was the course or (13 count).
Mark
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Team Owner
Joined: Oct 2000
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From: Washington Michigan
Originally Posted by Danish Corvette Guy
The bellhousing is for an 11" clutch, the starter i bought this spring is for a 168 toth flywheel i remember now.
Im taking the gearbox out this winther to put in new bearing where the tranmission Yoke goes in, so how can i tell when i have the gearbox out ?
Thomas
Im taking the gearbox out this winther to put in new bearing where the tranmission Yoke goes in, so how can i tell when i have the gearbox out ?
Thomas
All Corvette M20/M21 Muncies through 1970 had 10-spline inputs and 27-spline outputs; changed to 26 and 32 in 1971.
