V-12 Flywheel Lock for Damper Bolt Removal

My 74 E Type V-12 is securely in a very solid engine stand, but I need to figure out the best approach to removal of the front damper bolt without rotating the engine. I will appreciate your thoughts on the best method/tool for locking the flywheel.



Do you have a pneumatic impact wrench?

If not, just fabbing up a flywheel lock that will bolt to one of the bellhousing holes will work.

Thanks, Paul. My stand has a frame that mounts off the regular motor mounts and goes around the entire engine. I am not sure i left enough room in front to fit the impact wrench but will try first.

After trying a little breaker bar wrenching I assumed that decades of corrosion on a bolt that was torqued to 150 lbs. would require extreme measures.

In my experience, very few crank bolts will be corroded in. Usually, an impact wrench will get them loose, but if you don’t have room, then you will have to come up with some kind of flywheel lock to do it.

If the fly wheel has already been removed, you could fab a bar that would bolt to the crank flange, and be long enough to interfere on one of the bell housing bolts.

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Even easier than that is just screwing in two flywheel bolts, partway, then inserting a flat bar of 1" x 1/4" steel across those bolts to interfere with one of the bell housing bolts, or the engine cradle.

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That’s a better idea!

Perfect. That should enable me to get it done and I appreciate the sharing of your wisdom on this subject.

Here’s another example of what’s offered in the market. This tool may be modified (holes drilled to match block tapping, etc.) and is very cost effective.

EMPI® 00-5003-0 - Flywheel Lock more details on - EMPI® 00-5003-0 - Flywheel Lock - about $13.

Once you remove the Dampner bolt it’s imperative to use a bottom tap to clean out the crankshaft threads. Since the Dampner bolt is NLA you’ll have to reuse the original so anything that increases the torque tension while installing the bolt isn’t good. Just be careful to clean both threads before installation. Don’t over torque the bolt either. Breaking on of those bolts it a B*TcH to remove from the crank!

Happy Trails,


Thanks for the cautionary advice. I am planning to use my gun cleaning tools to clean internal threads but will run the bottoming tap in as well to make sure it runs freely.

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Bottoming tap and a little Remington Rem Oil for cleaning, lubricating and protecting (more than just firearms). As a final note, check the Harmonic Dampner over real good. If it’s original you may consider sending it off to be rebuilt. The rubber ages, becomes hard and detaches from both parts. Painting a “slip” line is a minimum to insure it’s not going bad, causing timing marks to shift! Just a suggestion. Money well spent to overhaul a 50+ year old part IMHO.

Happy New Year and
Happy Trails,


The rubber does not look bad to the naked eye but agree that it will be wise to do that while the engine is out and apart since the rubber has not been stressed and had a chance to fail in 25 years. Is Dale Manufacturing still a recommended source? Other recommendations are welcome.

Happy New Year


The two I’ve used in the past, depending on your location, are Dale Manufacturing and the DampnerDoctor. The latter a bit more $$$$$.

Happy New Year,


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I am pulling mine this summer on my 88 XJS when i pull radiator, for same reason, preventative.

Will a big screwdriver wedged into flywheel teeth be enough? Especially for torquing back to 150 ftlbs?

If you have another person to hold the flywheel, and the engine is supported, and held tightly, yes.

Engine mounts enough?

I just completed removing my Series III V-12 ring gear (automatic transmission) with a cheap flywheel lock## Empi 5003 Flywheel Lock Tool

that did not fit the flywheel teeth real well, but was good enough to withstand a combination of air wrench and breaker bar. About 5 of mine were so tight my air wrench gave up, but the breaker bar worked after a couple of PB Blaster applications. On the automatic transmission plate the metal sheeting within the ring gear perimeter is not heavy enough to withstand the force mine required. I tried that approach until the metal around one of the holes started deforming, and then I bought the flywheel lock.

I will cross the bridge to getting 150ftlbs of torque on reassembly somewhere down the road, but I think it should work since I was putting more than 150ftlbs of effort into getting the bolts out.

Good luck


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Yes, that should suffice.