Anyone had flywheel bolts back out?
07-13-2017, 10:18 PM
#16
Rennlist Member
"Shim" suggests it goes behind the flywheel for the reason I mentioned, but I'm not familiar with that shim so don't know. Seems like you'd be better off with shorter bolts if that's the only issue....
07-14-2017, 09:26 AM
#17
Quit Smokin'
Rennlist Member
Rennlist Member
Thread Starter
Tom,
I had assumed the shim went between the bolts and the flywheel to keep the heads from digging into the aluminum... But I notice that it has a hole for the roll pin, which would not be necessary unless it was supposed to go between the crank and the flywheel. I'm not sure the flyweel would center well on the hub of the crank if it was shimmed out very far.
I had assumed the shim went between the bolts and the flywheel to keep the heads from digging into the aluminum... But I notice that it has a hole for the roll pin, which would not be necessary unless it was supposed to go between the crank and the flywheel. I'm not sure the flyweel would center well on the hub of the crank if it was shimmed out very far.
07-14-2017, 01:38 PM
#18
Rennlist Member
Tom,
I had assumed the shim went between the bolts and the flywheel to keep the heads from digging into the aluminum... But I notice that it has a hole for the roll pin, which would not be necessary unless it was supposed to go between the crank and the flywheel. I'm not sure the flyweel would center well on the hub of the crank if it was shimmed out very far.
I had assumed the shim went between the bolts and the flywheel to keep the heads from digging into the aluminum... But I notice that it has a hole for the roll pin, which would not be necessary unless it was supposed to go between the crank and the flywheel. I'm not sure the flyweel would center well on the hub of the crank if it was shimmed out very far.
07-15-2017, 04:48 PM
#19
Rennlist Member
Keeping flywheels tight
A lot of good info in this thread. Here's some more that may be useful.
1. Flywheels coming loose are a common problem, particularly on the race track. I believe a frequent cause is Loctite bleeding between the mounting flange and the flywheel surface when installing bolts with Loctite on the bolt threads. (Think about this and the result.) The mating surface must be kept clean and dry. Clean both surfaces with red Scotchbrite, then spray some 'brake clean' (NOT carb cleaner) on both male and female threads and blow out with air. Now put ONE DROP of red Loctite in each of the crankshaft's female threaded holes. This way, when the bolt is installed, the mating surface will stay dry and happy. I've NEVER had a flywheel come loose using this method.
2. It's fine to reuse factory bolts. Clean off the old Loctite with a wire brush, spray threads with brake clean..... see above. BTW, the 'brake clean' is the same as Loctite primer which is recommended in Loctite's literature. Oh, and carb cleaner has petroleum in it, so it's a no-no for this and similar applications.
3. None of the aftermarket flywheel bolts are engineered for the specific job/application. The factory bolts are more than adequate, so why use something else with unknown stretch, clamping force, torque spec, etc.?
4. Often an aftermarket flywheel is not machined properly. If the crankshaft side ID of the center hole is not properly chamfered, it will interfere with the radius machined on the mating area of the crank. When this occurs, the FW will not seat properly on the flange and it will loosen. Further, the QC on many aftermarket flywheels is horrible; both balance and runout. There's definitely a performance advantage with light flywheel/clutch packages, but their dimensions and balance should be checked before throwing them on.
1. Flywheels coming loose are a common problem, particularly on the race track. I believe a frequent cause is Loctite bleeding between the mounting flange and the flywheel surface when installing bolts with Loctite on the bolt threads. (Think about this and the result.) The mating surface must be kept clean and dry. Clean both surfaces with red Scotchbrite, then spray some 'brake clean' (NOT carb cleaner) on both male and female threads and blow out with air. Now put ONE DROP of red Loctite in each of the crankshaft's female threaded holes. This way, when the bolt is installed, the mating surface will stay dry and happy. I've NEVER had a flywheel come loose using this method.
2. It's fine to reuse factory bolts. Clean off the old Loctite with a wire brush, spray threads with brake clean..... see above. BTW, the 'brake clean' is the same as Loctite primer which is recommended in Loctite's literature. Oh, and carb cleaner has petroleum in it, so it's a no-no for this and similar applications.
3. None of the aftermarket flywheel bolts are engineered for the specific job/application. The factory bolts are more than adequate, so why use something else with unknown stretch, clamping force, torque spec, etc.?
4. Often an aftermarket flywheel is not machined properly. If the crankshaft side ID of the center hole is not properly chamfered, it will interfere with the radius machined on the mating area of the crank. When this occurs, the FW will not seat properly on the flange and it will loosen. Further, the QC on many aftermarket flywheels is horrible; both balance and runout. There's definitely a performance advantage with light flywheel/clutch packages, but their dimensions and balance should be checked before throwing them on.
07-15-2017, 05:02 PM
#20
Rennlist Member
A lot of good info in this thread. Here's some more that may be useful.
1. Flywheels coming loose are a common problem, particularly on the race track. I believe a frequent cause is Loctite bleeding between the mounting flange and the flywheel surface when installing bolts with Loctite on the bolt threads. (Think about this and the result.) The mating surface must be kept clean and dry. Clean both surfaces with red Scotchbrite, then spray some 'brake clean' (NOT carb cleaner) on both male and female threads and blow out with air. Now put ONE DROP of red Loctite in each of the crankshaft's female threaded holes. This way, when the bolt is installed, the mating surface will stay dry and happy. I've NEVER had a flywheel come loose using this method.
2. It's fine to reuse factory bolts. Clean off the old Loctite with a wire brush, spray threads with brake clean..... see above. BTW, the 'brake clean' is the same as Loctite primer which is recommended in Loctite's literature. Oh, and carb cleaner has petroleum in it, so it's a no-no for this and similar applications.
3. None of the aftermarket flywheel bolts are engineered for the specific job/application. The factory bolts are more than adequate, so why use something else with unknown stretch, clamping force, torque spec, etc.?
4. Often an aftermarket flywheel is not machined properly. If the crankshaft side ID of the center hole is not properly chamfered, it will interfere with the radius machined on the mating area of the crank. When this occurs, the FW will not seat properly on the flange and it will loosen. Further, the QC on many aftermarket flywheels is horrible; both balance and runout. There's definitely a performance advantage with light flywheel/clutch packages, but their dimensions and balance should be checked before throwing them on.
1. Flywheels coming loose are a common problem, particularly on the race track. I believe a frequent cause is Loctite bleeding between the mounting flange and the flywheel surface when installing bolts with Loctite on the bolt threads. (Think about this and the result.) The mating surface must be kept clean and dry. Clean both surfaces with red Scotchbrite, then spray some 'brake clean' (NOT carb cleaner) on both male and female threads and blow out with air. Now put ONE DROP of red Loctite in each of the crankshaft's female threaded holes. This way, when the bolt is installed, the mating surface will stay dry and happy. I've NEVER had a flywheel come loose using this method.
2. It's fine to reuse factory bolts. Clean off the old Loctite with a wire brush, spray threads with brake clean..... see above. BTW, the 'brake clean' is the same as Loctite primer which is recommended in Loctite's literature. Oh, and carb cleaner has petroleum in it, so it's a no-no for this and similar applications.
3. None of the aftermarket flywheel bolts are engineered for the specific job/application. The factory bolts are more than adequate, so why use something else with unknown stretch, clamping force, torque spec, etc.?
4. Often an aftermarket flywheel is not machined properly. If the crankshaft side ID of the center hole is not properly chamfered, it will interfere with the radius machined on the mating area of the crank. When this occurs, the FW will not seat properly on the flange and it will loosen. Further, the QC on many aftermarket flywheels is horrible; both balance and runout. There's definitely a performance advantage with light flywheel/clutch packages, but their dimensions and balance should be checked before throwing them on.
I haven't had any problems in maybe half a dozen tries, though in almost every case I used a new factory flywheel and clean obsessively. I've never used Loctite though -- did I miss a factory recommendation for that, or is that just good advice based on experience?
07-15-2017, 05:49 PM
#21
Race Car
I DO use loctite but the blue and only because you can't recheck the bolts later for a pre-race prep. I use the blue because it's tagged as serviceable where the red 271 is considered permanent. While it can certainly be removed, especially on a race car, I'm going to remove them more often than an average user.
I got suckered for the Loctite primer too way back in the day when it was the recommended procedure for 640 sleeve retaining to avoid automatic front pump bushing movement until I figured out it was nothing special.
Chlorinated brake cleaner dries better than the nonC and you have to be careful since some manufacturers seem to just rebadge choke cleaner as brake cleaner.
T