crankshaft damper

Hello,

My father is restoring a Jaguar MK2 3.4 with automatic gearbox. He has allmost finalised this project. except for one thing:

During a very short test drive the crankshaft damper came off. Actually, the rubber ring which is attached to it came off, which caused the damper to detach.

My father thinks it doesn't harm to drive for a while without the damper.

  • What do you people think? and ...
  • can the original damper be reinstalled after we found a suitable rubber ring? (it seems the rubber ring was joined rigedly)
  • Is this a common defect?
  • Are these crankshaft dampers easy to obtain?
  • Does a "new" damper need new balancing/calibration?
  • Is there trouble to be expected with setting the timing? (It's okay now)

your opinions are most welcome. Questions for more details can also be send. Remove HATES SPAM from my address, when replying via electronic mail.

best regards, Tom

Reply to
Tom van Grootel
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I'm no expert at all but if the damper was fitted originally then the engine needs it. However no harm should be done by driving it at low revs while you get a new one. The damper extends the fatigue life of the crankshaft by reducing torsional vibration. The crankshaft will vibrate at particular speeds and the damper is tuned to be effective at those speeds, so don't use one from another type of engine. I don't think you can re-use the broken one as the rubber is bonded to the steel. There are lots of specialist suppliers you can find on the web, or join the appropriate car club if you haven't already. Ideally the damper should be balanced with the other moving parts, but that means another engine rebuild. Actually the benefits of dynamic balancing are often highly exagerrated - talk to a Jaguar expert about whether it's really necessary. It should not have any effect on the timing.

Reply to
Les Rose

Drive without it and risk a broken crankshaft at anything over 3,000 rpm , in line 6's especially Jag need the damper.

Reply to
AWM

You can drive it to the garage, but keep the revs down. A Jag _will_ break the crank if you rev it whilst undamped.

My Dad has a pre-war MG J2. If you want to worry about crankshafts and dampers, then get one of those. Two bearing crank (850 OHC 4-pot) and an absolute red-line of 4K rpm without it. We also have a spare engine with broken crank.

Reply to
Andy Dingley

As others have said, replace it ASAP. You can drive the car at low revs for short distances until then. Don't try repairing the damper yourself. They are bonded rubber construction. The rubber is an essential part of the component. It's stiffness/flexibility is important. If it's any interest, I have never heard of a crank damper failing before. Is it a common failure on some engines?

John

Reply to
John Manders

Thanks for all informative replies, but indeed I also like to know this is a common failure or something was installed wrongly. Which could mean we should take beter care in reinstalling the new one. Some extra info: We never found the rubber ring. I assumed it came off which cause the damper to detach. Maybe the ring is still in the pothole :)

gr. Tom

Reply to
Tom van Grootel

Tom van Grootel wrote: snip

The bonding between the rubber and metal will always break down over time because the two materials have such different mechanical properties.

Reply to
awm

Commonly caused by oil leaks. The rubber doesn't like it.

Reply to
Andy Dingley

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