Crankshaft dampers are to help with torsional vibration which can cause a lot of problems.I brought this question up on the Engineering Forum and got a lot of feedback from the pros. A 4 cylinder has inherent vibrations that a 6 doesn't have. But, they both have some vibrations [or harmonics/frequencies] in common. The 6 cyl. damper will help to cancel out those common vibrations but won't touch the 4's design specific vibrations. It may help, and apparently does, and won't do any harm, but it's not a fix-all.
As i recall DriversWanted uses the 6BT elastometric damper with good results, and lots cheaper. Don't know if the Fluid Damper would be more or less effective.
Do you think the passengers can notice torsional crankshaft vibration?This is something that has crossed my mind aswell. How about the 4BT probably doesn't need a dampener but it benefits the passengers?bounce bounce bounce bounce
I'd put money on it not being crankshaft torsional vibration for two reasons.One of the more irritating vibrations in mine is around 1,500-2,000+ or so, just guessing as no tach. I can feel it throughout the truck, all the way up into my steering wheel! It's like one of those beds they used to have in cheap motels many moons ago, with the coin slot where you added quarters for the 'Soothing Vibro-Massage', hah!
I'd guess it's a torsional vibration and don't know if either damper would help. It may last on up in the rpms's but not sure. I built everything too rigid I think, and obviously don't have the right isolators somewhere, or everywhere. I used some tired old Dodge 400-440 mounts at engine, and the tranny tailshaft is sitting on some more tired motor mounts, maybe Dodge 360's. I'm sure new ones would help, but may need something else all together. That, and some kind of harmonic damper? Maybe...
My engine runs really rough when the valve clearance is out. Obviously different amounts of air getting into each cylinder and making different size bangs.Don't know, Dougal, just don't know. I've already got a harmonic damper on my trans output slipyoke, and a custom driveshaft by the top shop, Tom Wood's Custom Driveshaft in Utah, USA. Everything but adapter and bell is new Dodge 6BT CTD stuff. Happens in any gear, too. I still have to adjust my valves, hopefully this weekend, and that may contribute I guess.
OOoohhh, now THAT's some GOOD NEWS Dougal! Sure hope that's it. Just got my new gaskets and went and picked up some paint today for the valve covers, so maybe tomorrow morning?My engine runs really rough when the valve clearance is out. Obviously different amounts of air getting into each cylinder and making different size bangs.