That's why it is suggested that you highlight the marks with white paint.

  {quote]55blacktie (11/6/2020)

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54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

I didn't realize that the timing marks are on the outer edge of the back pulley on my 55 Tbird. I was looking for marks on the damper, not the pulleys. I had to look at a close-up photo of a 55-57 Tbird pulley before I could find the timing marks. They are very easy to overlook, if you don't know where they are. 

55Blacktie. As I remember they said they were leaving as is. It was alright by me. It was an extra one I had as I knew mine had moved. I’d marked many in the past a my dad’s machine shop.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

The gripe I have with damper doctor , on a TBird damper, is that they didn't make the marks more visible, even when I specifically asked them to.  Otherwise, it seems to be ok


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Did Damper Dudes offer the option of making the timing marks more visible?

Damper Dudes did mine and since I’m in Ca. I got it back in 2 days. The timing marks were very feint so I carefully file tdc back in and marked with white paint. They called and told me they were leaving it as is. Additional lines were made by me at 12 and 32 and also marked with white. I can figure anything from those 2.

56 Vic, B'Ville 200 MPH Club Member, So Cal.

OK, just got off the phone with Damper Dude and they seem very eager to rebuild my damper.  Won't be sent off until salt hits the streets in Michigan but I'll report the results when able.  To me, anyways, this is really interesting stuff and a little bit over my head. It always amazed me how aircraft engines employed tuned movable weights on the crankshaft to dampen propeller harmonics and other resonant frequencies.  I knew there was a certain amount of crankshaft twist but never realized it is possible for a damper to "move" on the snout. Thanks to all for the information....................


64F100 57FAIRLANE500

I'm sending mine to Damper Dudes.

Seems to me at one time I remember hearing some rumbles about there being some sort of falling out at Damper Doctors, and some of the flock forming Damper Dudes. Anyway those are the two best known firms that do this kind of thing.

It's interesting (to me at least) to note that the crankshaft can flex or twist up to +/- 2° back and forth, the balancer weight tends to lead and lag and absorb this. The situation to be avoided is what's known as resonance, there is a certain specific RPM where this tends to occur. The engineers try to design around this point and ensure this happens somewhere outside "normal" driving conditions. But this is where the "harmonic" part too comes in. There are also resonance points at multiples of that RPM. A crankshaft can crack, or even break, due to a failed balancer. I would have to think it would also beat the hell out of the mains bearings, and probably main seal oil leaks.

Greetings to all:  This very informative thread reminds me of the need to finally do something about my 60 year old damper. Other than the rock hard selastome material, it's in good shape so I would prefer to have it rebuilt.  I may be wrong but I thought Ted has mentioned Damper Doctor on occasion. I have found others but would like to send it off to a very good and reliable place for this service. The enine a 312 built to specs of 1957. Any input would be greatly appreciated, thanks, JEFF..............     BTW, I purchased threaded rod, cut a section long enough to thread into the crankshaft until it reaches the bottom of the hole, place a heavy washer against the damper and use a well lubed nut to install the damper on the snout.  Thais method has always worked well for me and saves the threads in the crank. 


64F100 57FAIRLANE500