Been wanting to eliminate the squealing damper noise that sometimes occurs at startup due to the failed rubber between the crank portion and the pulley drive ring. First I started to build a form box to cast a plaster mold of the assembly for future reconstruction.

I blocked all tappings, roll-pin key and center hole to prevent entry of any materials.

I made the tray just deep enough to form up to the bottom edge of the accessory pulley.

After trying a fast setting plaster type of compound I was not satisfied with the results so a turned to using a two part epoxy.

The reason for the foam inside the form box was to reduce the amount of epoxy needed to make the mold. Here it is cast.

This is the finished casting for setting up the damper.

It is now ready to receive the parts and have the new rubber injected.

So, something that I have not been able to source through the ROMs for the Marrelli equipped cars is the clock position for the TDC mark. I know on the Lucas models that the mark is located straight down the bottom for timing the engine.

However the Marrelli doesn't have a timing mark, not one of the (3) 6.0L engines that I have has one. I also know that the timing on these cars is fully computer controlled and determined by the 3 point trigger wheel, so I suppose there is no need of a timing mark. But still, it would be nice to have it where it should be. If I were to go by US v8 standards, I would place the woodruff key straight up at 0 and going with the Lucas timing location put the TDC of 1A 180 from it at the bottom.
Perhaps someone can share whether keyway straight up is an indication of TDC or not and where the mark should be in relation to it.

Also, does anyone happen to know how the damper comes apart? I put it in a vice but with protection but it didn't budge very much.
One note is that the epoxy could only be poured in 1/2" lifts, so I used 4 screws set endwise in the bottom layer to help key the second pour of materials in case there was any tendency for them to separate. Shouldn't be but just in case.

 

Is this repair something you came up with on your own, or what?

I know that places that make, or rebuild dampers for US cars use very specialized equipment to get the correct durometer rubber ring into the damper, based on the RPM the damper needs to do its its harmonic cancellation at.

Doug

 

Have you looked at post 7 in this thread: https://www.jaguarforums.com/forum/x...ebuild-198145/

 

I know of two places, one on the west coast and one in NC. As far as damper dudes or damper boys, whatever they go by, I have not heard the best with regards to some of their work. Now this could be past history but when I was rodding my Nailhead Riviera the man responsible for the quickest naturally aspirated Nailhead on the planet, who also pioneered the first set of roller tip rockers for that engine knew of those rebuilt units coming apart /failing at a young age. As a result I held on to what I had hanging around in case I needed one. A naturally balanced or zero balanced engine is much easier on the damp as there is not as much vibration to counteract.
As far as the rubber goes, there are a number of different options. One as noted in the below mentioned post.

Yes, I did see that thread and was some of the inspiration to do one. He uses a two part urethane. Some polys' are harder than others. Superflex is a rather stiff one, which most suspension components are made with. However there are others that are more compliant such as windshield glass adhesive. Some have made poly bushings from it with good success providing more elastic properties closer to that of stock rubber. It also has very tenacious holding power, which if anyone has tried to remove a windshield with a manual draw knife, not a hot knife, then you know what I'm talking about. I have 2-3 of them to do, so I figure I have nothing to lose.

 

Sorry it's been a little slow in coming but like everyone I've been busy with too many things that get in the way. Here is an update on the damper rebuild. Finally got the two pieces apart and put them in the mold. Ended up going with a different urethane than I originally planned on but it's finally done.
Here are the results:

Here's the front.

Here is the back side.
The challenge with the 3M Windo-Weld is packing it down into the center portion as the space is not large enough to get the nozzle in between the center hub and the alternator drive ring. But with persistence it can be done. Working time is 10-20 minutes with the urethane. I chose this product as it has a higher shore hardness that what I was going to use but not as hard as poly bushings.

Here's the goods
Did the front side first and let it set over night and then pulled it from the mold to pack the back side.
May get it installed tomorrow

 

Just a quick update:
For those that may be wondering, the damper has been installed on the car and currently running fine. We'll see what the longevity of it will be but at this point is working well. It's been a while since this was finished as I was also installing a primary e-fan as well as a replacement for the factory auxiliary fan. Just now waiting for a new lower temp switch to replace the factory one with as it never comes on at the moment.
Also put new treads on the front. Never an end to things to do.

 

I think this is a superb fix, and a very useful thread. Congratulations!