Engine damping on 500
Discussion
Just got the Griff back from its 24k service. Shed loads of other work too (unforunately NONE covered under Warranty Holdings!) One observation was vibration at 1500-2000 rpm, suspected misfire but no, that was all fine so then on to engine damper/pulley assembly. Apparently that is the only damping used in the 5 litre and a replacement was suggested.
How serious is this? Should I get it sorted ASAP or "do quite a few do that". If I could swing it in my WH policy no sweat, but they seem to have a rule that says "Ah, if it's a TVR policy and the part is being fitted to a TVR it isn't covered". I doubt I'll be renewing it.
Ta
Dave
How serious is this? Should I get it sorted ASAP or "do quite a few do that". If I could swing it in my WH policy no sweat, but they seem to have a rule that says "Ah, if it's a TVR policy and the part is being fitted to a TVR it isn't covered". I doubt I'll be renewing it.
Ta
Dave
How serious is this? Should I get it sorted ASAP or "do quite a few do that". If I could swing it in my WH policy no sweat, but they seem to have a rule that says "Ah, if it's a TVR policy and the part is being fitted to a TVR it isn't covered". I doubt I'll be renewing it.
Ta
Dave
Potentially serious, I wound't even consider not replacing it, without that damper your crank could suffer fatigue stress that will eventually kill it. Also if the damper is shifting on the crank it will soon damage the keyway on the crank to the extent that you can't replace it without replacing the whole crank.
Engine Tortional Vibration Damper, or Engine Damper for short. Usually a small flywheel type thing on the free end of the crankshaft opposite the load (clutch), so near the fanbelt pulley!
IPAddis said: There's an engine damper?
Ian A.
As Pete says to stop the crank vibrating, and as a small flywheel not good if not attached!
And yes I read the Griff has one. You can also get them on camshafts on OHC engines! (One difference between 20's and 1930's 12/50 Alvis cars (see profile)is the damper!)
Just got the Griff back from its 24k service. Shed loads of other work too (unforunately NONE covered under Warranty Holdings!) One observation was vibration at 1500-2000 rpm, suspected misfire but no, that was all fine so then on to engine damper/pulley assembly. Apparently that is the only damping used in the 5 litre and a replacement was suggested.
They should have insisted otherwise there is a great risk of the crankshaft snapping. BTW these are not a fit and forget replacement as the engine is balanced with them on and so just fitting a new one may make a balance problem even worse. Mine went (the rubber sheared) and Tower View ended up having to get the new one balanced to match the original one before it was fitted.
Steve
www.tvrbooks.co.uk
Take a look at the lower pulley, the one on the crank. You will see that the inner part is pressed onto the crank and held on by an interferance fit (I think the torque setting is 150 lb/ft or more). The outer part of the pulley is bonded to the inner part by a circular rubber ring maybe 4-5mm thick. That rubber gets stretched and eventually may fatigue causing vibration. If you paint a white marker line across the front of the pulley and across the rubber bond you can test it with a strobe light and see if the line stays in one piece. All the above assumes the Griff still has a rover lower pulley on it.
They should have insisted otherwise there is a great risk of the crankshaft snapping. BTW these are not a fit and forget replacement as the engine is balanced with them on and so just fitting a new one may make a balance problem even worse. Mine went (the rubber sheared) and Tower View ended up having to get the new one balanced to match the original one before it was fitted.
I think that makers already know the characteristics of the internal balancing before the engine is built and have the crank balanced after machining the journals. Then the engine is assembled. Then when the engines assembled the damper is fitted and Rover do the final balancing on 2 huge machines which rotate the engine at speed. I don't know if tvr have access to this type of machinery. Maybe they fit pre-balanced dampers and this would depend on there balancing margins. Because you don't know what the margins are and because your engine is a tvr you can't take a chance and just fit another damper from another rover. I agree with the above. It wouldn't do you any harm to have your new balancer balanced to match the existing balancer. I would check it's your damper at fault though, maybe it's not been tightened up enough. Few people tighten them to the 150 lb/ft.
I think that makers already know the characteristics of the internal balancing before the engine is built and have the crank balanced after machining the journals. Then the engine is assembled. Then when the engines assembled the damper is fitted and Rover do the final balancing on 2 huge machines which rotate the engine at speed. I don't know if tvr have access to this type of machinery. Maybe they fit pre-balanced dampers and this would depend on there balancing margins. Because you don't know what the margins are and because your engine is a tvr you can't take a chance and just fit another damper from another rover. I agree with the above. It wouldn't do you any harm to have your new balancer balanced to match the existing balancer. I would check it's your damper at fault though, maybe it's not been tightened up enough. Few people tighten them to the 150 lb/ft.
boosted ls1 said: Take a look at the lower pulley, the one on the crank. You will see that the inner part is pressed onto the crank and held on by an interferance fit (I think the torque setting is 150 lb/ft or more). The outer part of the pulley is bonded to the inner part by a circular rubber ring maybe 4-5mm thick. That rubber gets stretched and eventually may fatigue causing vibration. If you paint a white marker line across the front of the pulley and across the rubber bond you can test it with a strobe light and see if the line stays in one piece. All the above assumes the Griff still has a rover lower pulley on it.
It has just the one poly vee drive belt as far as I know. It's a later Serpentine engine and no air con
It is a Rover pulley but the balancing is done as a complete unit so any replacement must be matched to the original or the engine rebuilt and balanced from scratch. Any problems talk to Tower View as they sorted mine out a treat. It was the cause of a lot of issues like moving timing marks!
Steve
Steve
shpub said: It is a Rover pulley but the balancing is done as a complete unit so any replacement must be matched to the original or the engine rebuilt and balanced from scratch. Any problems talk to Tower View as they sorted mine out a treat. It was the cause of a lot of issues like moving timing marks!
Steve
Like Steve says if the timing marks move then it's definately shot so I would check it with a strobe. There must be a place where engines can be externally balanced without the need for a strip down. You see, the internal stuff can be balanced before it's assembled. The balancing on the nose/tail is external stuff like on some yank v8's where there isn't enough mass in the crank. I've seen stroker rovers which couldn't be balanced internally have material added to the nose and they have been balanced externally. The flywheels are left on and the whole engine or maybe just the bottom end is fitted to a machine and spun up. My friend has 3 tvr engines in pieces. Just out of interest I shall ask him to see how they were balanced, internally or externally. The basic LS1 is balanced internally whilst the vette LS1 has additional balancing via pins added to the flywheel and crank pulley.
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