can anyone help, i have just rebuilt my engine consisting of new head,tappets.oil pump.waterpump and all gaskets and seals including rear main so flywheel off. i have not touched the bottem end as it was rebored and re-shelled only 10,000 miles ago. the engine had no vibration before the the build, but when i started it yesterday there is a huge vibration at 4,000 you can feel it right through the car and even through the gearstick. the engine mounts are fine and there is nothing touching the bodywork. I had the same vibration about a year ago and was told it was a distorted flywheel which was 'blue' both sides, i replaced it with a brand new one and it has been fine ever since until now. the flywheel can only go on one way so i can eliminate that, but i did not mark the clutch cover could it be that, or will the whole crank assembly need rebalancing? any advice much appreciated

 

Did you remove the propshaft when you took the engine out at all?

I have been told the prop neds to be marked in relation to the diff and refitted back the same way...so they are balanced. Just a though.

Mart

 

no, i left the box in. the vibration is when the car is stationary when revving up, only comes in at 3,500 - 4,000rpm so must be a balance problem?

 

IMO it's clutch cover defective.

Regards

Claude

 

My Cossie was the same after my rebuild last year, loud resonance/vibration at 3000-4000rpm, went after a few hundred miles.

 

The vibration is so sevre the actuator rod vibrates up and down and the alternater blades distort in and out. I am going to take the engine out on the weekend, all I can think of is to get the complete bottom end balanced, crank, pulley, flywheel and cover, opefully this will solve the problem. thanks

 

I had the vibes in my car shuddered the whole car but only in fifth gear at 50 mph!!
Cured it but took some head scratching, done all the usual, was DIZZI in the end, the bush had seized to the shaft in the top of the dizzy, and had spun in the housing, the phase gap ranged from ZERO to 2.9mm, and yes it still ran almost perfect, just a misfire when hot below 1500 and very light load.
Fixed dizzy with NEW BUSH(bronze), machined shaft for Ł35 all in.
Just a thought might be worth a look as only a few minutes ?
tabetha

 

Hi tabetha, I checked the dizzy appears fine. It is hard to say how sevre it is without seeing it for yourself, I think it is a balance problem because it only comes in between 3500 and 4000 then starts to fade away. I am experienced in the tyre trade, at it is like an out of balance fornt wheel, no vibration below 60mph, but starts to come in above 60mph - 75mph, then you can drive through it, sounds familier to my vibration. thanks Tabetha.

 

the flywheels are balanced reasonably well at factory to each crankshaft..
It's possible the flywheel is out of balance but it would have to be majorly bad to cause that vibration.. I had a resonance vibration at 3.5 to 4k and it was my alternator tensioner bar was completely loose. Does the vibration do it with the clutch cable pushed down,, worse or better with it down.
Im not talkign about the release bearing but Just maybe the clutch isn't aligned properly.. When you drive the car is it smooth or not?
Do the simple things before u commit to an engine out..
could be something simple... but to feeel it through the whole car !!!!
yikess

 

It makes no difference wether clucth is up or down, the alernator is new and bolts are tight. If you drive the car you still feel it at the same rpm. I am taking it to grove garage tomorrow so Ahmed can have a look at it as it is hard to explain without hearing it and feeling it for yourself. I hope it is something simple but knowing my luck it's probly engine out again!!!!

 

good luck mate,, let us know how you get on

 

My cossie has stopped vibrating !! I took it to grove garage and they said it was most probably the turbo damper, I had a bailey one on there and apparently it was tp rigid and not damping the vibration the 2wd turbo/manifold causes. I replaced it with a new RS500 item and now is fine, What a relief!!! Car is now being mapped by ahmed.