Dave McDonald Posted July 5, 2020 Report Share Posted July 5, 2020 I'm stripping the engine of my early 1968 TR5 as part of a complete car restoration. See photos of the crank damper which must be 52/53 years old. The rubber does not look well, being obviously cracked. My question is this. Is that ok to reuse without causing possible future failure? Cue Mr Crank Damper - John Davies?? Dave McD Quote Link to post Share on other sites
peejay4A Posted July 5, 2020 Report Share Posted July 5, 2020 I wouldn’t use it Dave. Quote Link to post Share on other sites
ntc Posted July 5, 2020 Report Share Posted July 5, 2020 30 minutes ago, peejay4A said: I wouldn’t use it Dave. Why not it maybe only the outside part that has perished Quote Link to post Share on other sites
Dave McDonald Posted July 5, 2020 Author Report Share Posted July 5, 2020 1 hour ago, ntc said: Why not it maybe only the outside part that has perished That might be right Neil, but how do you know what the inner hidden part is like? 1 hour ago, peejay4A said: I wouldn’t use it Dave. I know appearance wise it don't look good. Does anyone know anything about the quality of replacements listed by the usual suppliers. When I checked it with the cylinder head off and a dial gauge to determine TDC on piston No 1 the damper TDC mark was spot on the marker on the front of the timing cover, so the outer hasn't slipped relative to the inner. More comments welcome. Dave McD Quote Link to post Share on other sites
ntc Posted July 5, 2020 Report Share Posted July 5, 2020 You have answered your own question Dave Quote Link to post Share on other sites
john.r.davies Posted July 5, 2020 Report Share Posted July 5, 2020 Thanks for the namecheck, Dave! I've found that the appearance of the rubber in a damper pulley is a very bad guide to its function as a damper. Only testing will tell. If you would like a test, Dave, contact me by PM? Quote Link to post Share on other sites
peejay4A Posted July 5, 2020 Report Share Posted July 5, 2020 Well, I still wouldn’t use it. Quote Link to post Share on other sites
ed_h Posted July 5, 2020 Report Share Posted July 5, 2020 Rubber is vulnerable to the elements. Fuel and oil exposure, ozone, moisture, and maybe even some occasional UV light all can cause damage. These are all surface effects, though, and a rubber surface of much age will usually show some degradation. These elements dont normally have a way to reach the internal working material, so if there is no evidence that the rim has spun on the hub, the damper is likely still fully functional. I often wonder how well some of these generic replacement dampers are tuned to the specific application. Ed Quote Link to post Share on other sites
john.r.davies Posted July 6, 2020 Report Share Posted July 6, 2020 "You've Got To Ask Yourself One Question: 'Do I Feel Lucky?' Well, Do Ya, Punk?" Quote Link to post Share on other sites
roy53 Posted July 6, 2020 Report Share Posted July 6, 2020 14 hours ago, ntc said: Why not it maybe only the outside part that has perished i'm with Neil on this one Dave. Roy Quote Link to post Share on other sites
Tom Fremont Posted July 6, 2020 Report Share Posted July 6, 2020 14 hours ago, ed_h said: I often wonder how well some of these generic replacement dampers are tuned to the specific application. Same here. Richard Good offers a viscous damper claimed to enable another 600-800 rpm. Even at its bracing price I would consider it if I were certain of it lasting indefinitely ( I'm not ). Tom Quote Link to post Share on other sites
Waldi Posted July 6, 2020 Report Share Posted July 6, 2020 It could well be the outside (exposed) rubber is perished. If you want to know remove 1-2 mm of it and see what appears. If the cracks stop, I would not hesitate to use it. The “fresh” rubber may need longer to degrade that most of us will need (including myself) Waldi Quote Link to post Share on other sites
RobinTR Posted July 6, 2020 Report Share Posted July 6, 2020 I will be facing the same dilemma soon. One thing I had planned was to mount the damper, rotate the crank and check the circumference with a dial test gauge to see if there is any run out. My engine was static for a long time, so I could imagine inconsistent swelling of the rubber if oil leaked to the low point. Would appreciate any suggestions for a reliable replacement item Quote Link to post Share on other sites
Dave McDonald Posted July 7, 2020 Author Report Share Posted July 7, 2020 On 7/5/2020 at 10:03 PM, john.r.davies said: Thanks for the namecheck, Dave! I've found that the appearance of the rubber in a damper pulley is a very bad guide to its function as a damper. Only testing will tell. If you would like a test, Dave, contact me by PM? John, You have a PM. Dave Quote Link to post Share on other sites
john.r.davies Posted July 7, 2020 Report Share Posted July 7, 2020 Dave, Nothing has come through, either here or via email. Try again? JOhn Quote Link to post Share on other sites
Dave McDonald Posted July 7, 2020 Author Report Share Posted July 7, 2020 1 hour ago, john.r.davies said: Dave, Nothing has come through, either here or via email. Try again? JOhn Sorry John. Sent now. Dave Quote Link to post Share on other sites
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