Flywheel question.

Getting the Flywheel grinded is part of the procedure when renewing the Clutch. The actual thickness of the Flywheel is irrelevant BUT free play between the Pressure Plate and the Throw out Bearing must be around 1,5mm (cold) hence the Throw out Bearing must be shimmed correctly to achieve that play when the Throw out Bearing is fully retracted. Using the CORRECT parts is essential (Pantera specific) as well as correct adjustment. No shortcuts here and your Clutch will become very "friendly"

Btw you need to remove the Bell Housing from the transaxle and mount it on the Block with your Flywheel and Clutch assembly fitted. Then use a Steel Ruler across and measure with a Sliding Caliper the distance from the flange on the Bell Housing to the highest point on the Pressure Plate where the Throw out Bearing is ment to touch. Then measure the same on the Transaxle with the Trow out Bearing fully retracted and shim the Bearing so the measurements are the same minus the 1,5mm. That is essential to get that right. Once its tripple checked you can remove the Bell Housing from the Block and reattach it to the Transaxle. Dont forget to renew the Pilot Bearing/Bushing as well

Hope this is helping you to get that Clutch back to a "friendly" state.

Flywheel Inspection

If the ring gear is chewed-up then it will need replacement. If the flywheel’s clutch surface is flat but has the typical grooves and ridges, and can be cleaned up by removal of no more than 0.045” material, then a simple resurfacing may suffice, especially if the motor will only be used in a typical transportation application.

By my calculation 0.5mm is equivalent to 0.02", so the amount of material your mechanic feels is necessary to remove is within tolerance, its about 44% of what is allowable.

However, if the flywheel shows signs of stress cracking or heat checking, if it would require the removal of more than 0.045” material to clean it up, if it is warped or has excessive run-out, then the flywheel shall need to be replaced. A high mileage flywheel should be replaced if it shall be mated to a motor with increased output or installed in a car that shall be driven vigorously because a 40 year old cast iron flywheel should not be trusted to endure higher power output or vigorous usage.

The OEM flywheel is manufactured from cast iron, which is fine for typical transportation applications. However, a better choice for high performance applications is a lightened steel flywheel, which shall be tougher than the OEM cast iron flywheel, and the lighter weight will give the motor a little more pep too. At 26.4 pounds the Yella Terra #YT9902 is lightest steel flywheel known to me. Although an aluminum flywheel would be even lighter, the durability of the steel flywheel is more important than the light weight of an aluminum flywheel for a street car or sports car application. The Yella Terra flywheel is made of billet steel, it is designed for 11 inch clutches, it has a 164 tooth ring gear, and it is SFI approved. It is drilled for long style pressure plates identical to the OEM factory pressure plate, this is a durable and trouble free type of clutch. The flywheel is also configured for external balance applications (28 oz. imbalance).

Correct, I dont know why but I assumed he had a Steel Flywheel already

Good morning,
I'm "that other Pantera owner" Peter was mentioning. Thanks for all the very useful information. It was new to me that I have to shim the Throw out Bearing (ToB). I thought that the freeplay between the pressure plate and ToB is adjusted by the stop screw of the slave cylinder mechanism!
Another question I have is related to the installed clutch. It is a gold color one from Centerforce. I was told that Centerforce has a hole pattern of 11 inch. I found 287mm which is 11.3 inch (photo). Did I do a stupid measurement or do I have an exotic configuration on my car?
Greetings from South of France
Hartwig

Hartwig, this is a complex subject. There are generally three different types of throwout bearings that may be found, depending on what kind of clutch you are using. The first is a flat-face bearing used for stock Long 3-finger and aftermarket bent-finger diaphragm clutches. The second is a crowned-face bearing used for GM-style flat-finger diaphragm clutches. And both types can sometimes be had as 'constant-contact' throwout bearings, in which the clutch fingers are in constant light contact with the bearing face. With these bearings, no free-play distance is needed. This is helpful with non-stock clutches since it saves space and gives slightly more disengagement distance, which also extends the life of your ZF synchros!

Note also that non-stock clutches often use non-stock bolt patterns and/or bolt sizes, so an aftermarket flywheel that has multiple bolt patterns pre-drilled in it can be a useful addition. Redrilling a stock flywheel is not recommended since its hard to do it right but very easy to do it wrong. Both aluminum and steel aftermarket flywheels may also be a little (or a lot!) lighter than stock, freeing up some power and changing the way the engine revs and drives. If you do change flywheels, be sure the assembly you get is balanced to 28.2 inch-ounces; late Ford flywheels can also be balanced to 50 inch-ounces, and will fit a 351-C but will shake your car apart when running!

The ToB I got when I bought my McLeod Clutch came with a combination of Shims that made me able to set the correct play. The play is just enough so ensure the ToB does not ride on the Pressure Plate when Engine is Hot (or cold) and at the same time ensures maximum travel (disengagement) I dont remember where I found the data for the correct setting, but it must be in some of the Pantera specific literature somewhere.