Did my crank damper slip?

For a 92 5.3 Marelli XJS, shouldn’t the A1 mark be relatively close to the woodruff key? See video of mine… the A1 is around 1 o’clock but I think it should be at 6 based on how I’m holding the damper.

Not sure where the relative position of the mark is and can’t check mine. What l can find in online images does indicate a shift.
It should be of no immediate concern anyway since the timing trigger is attached firmly to the hub itself and cannot move. Were you having any alternator problems as this is the drive for that.

Sorry but I can’t answer your question about the relative position of the woodruff key. However, I did remove and replace a slipping damper in my wife’s 1990 XJ-S convertible (5.3L V12 with Marelli ignition) several years ago due a very annoying squeal on cold start. I used the chalk method described in Kirby’s book to confirm that the damper had failed and it was slipping. What a joy it was to no longer hear that squeal right after start.


Perhaps worth remembering that the earlier cars had a split cone that fit between the crank and the damper, so there was a key between crank and cone and another key between cone and damper. I think those two keys were 180 degrees apart. When the later cars did away with the split cone and simply fit the damper directly to the crank, presumably they located the key the same as it would have been on the ID of the split cone so the keyway in the crank was unchanged.

I found a picture showing A1 marking near the CPS trigger, so I think mine slipped. For some reason I thought I’d see if it was loose, and in the press it seemed to be. So figured I’d take it apart and look for an indexing mark I might have missed… cuz I’m bored I guess… lesson of the story is don’t press it out cockeyed. Luckily new are only $50 more then rebuilt… $200 on eBay shipped.

Don’t mean to revive a zombie thread but. I too have this problem. it looks like my damper has slipped. did yours end up being slipped too? This pic is taken when my engine is at TDC of cylinder #1A. The heads are off so i am sure as can be its at TDC.
Edit: changer 4 to 1A

Another 120 degrees will bring 1A to TDC and damper marking will be close.
Why are you referencing to #4.
Not near a car or motor so relying on memory here, could be way off base myself.

Sorry that was a typo I have the engine at 1A TDC

Could be the damper failed, or it could be the keys in the split cone.

I just managed to find a picture of where the mark is supposed to be in relation to the keyway, and mine has 100% slipped but they rubber looks in ok shape so I might be able to get away with running it as i don’t think it is slipping constantly.

Where should the mark be relative to the keyway?

It should be about 30 degrees ish away from the keyway. mine was close to 160 degrees off.
managed to find a good picture of one where it is supposed to be. don’t mind how thrashed it is. i checked it against new rebuilt units. https://www.limora.com/en/british-cars/jaguar/jaguar-xjs-1975-1996/engine/cylinder-block-and-crankshaft-12-cylinder-models/harmonic-balancer-27143.html

Here is an aftermarket new one. its harder to see the mark but look at the bottom left of the second pic.