sorry--vibration again

[david lewis]

hi all,

i recently had the rear u/j changed on my 13/60 and had really bad vibration afterwards so we i had the prop taken to feltham propshafts for balancing,the vibration is a a lot less and a different resonance and occurs between 45 and 55 mph.

if i take the car out of gear and coast at 55 the vibration stays the same so does this mean it is something else other than the prop as surely when coasting the prop should not cause any vibration.

the wheels have been balanced and there are no signs of any distortion.any ideas welcome.

cheers

 

 

[Darren Groves]

Engine mounts and/or gearbox mounts could be knackered. Try disconnecting the flanges and rotating each end of the propshaft a half turn, try every combination. Not sure why this would work on a newly balanced prop, but it can and did for me.

[Pete Lewis]

Make sure the prop and diff, geabox coupling flanges have no aged bruising and all have a very smooth flat location face

any runout will cause a prop vibration. Run a good flat file over the face

 

double check there is absolutely no lift in the drive shaft uj /yokes

Pete

[david lewis]

thanks for the advice guys,still interested to know if you take the car out of gear at 50mph or so does the prop continue spinning or just the drive shafts.-sorry if i am being thick!

cheers

[Peaks]

Hi David,

 

I battled with a vibration in my Vitesse for many years. Long story short, there was wear in the sliding joint (I think the 13/60 has the splined joint, not strap?). The wear was only slight, and the play in it was certainly within what was generally accepted as being acceptable. Never the less, that's what was causing the vibration, even as you describe, in a no load situation, although it was a lot worse when the car was in gear as the propshaft does indeed continue to spin whilst in neutral (it's still connected to the wheels via the diff).

 

 

 

I got a new propshaft from Dave Mac and ever since the car has been a pleasure to drive. The new shaft wasn't cheap, but wasn't as expensive as you may think. Dave Mac even arranged for collection of the old shaft and delivery of the new in the price, all I had to do was leave the old shaft outside my front door for collection while I was at work. Excellent service.

 

 

 

it may seem galling to spend more money when you have already paid for a replacement u/j, but in my case at least, it was well worth it to have a car that is nice to drive.

 

[mishmosh]

The prop , diff and driveshafts all spin when clutch depressed. The clutch disengages the engine from the gearbox.

[Pete Lewis]

And to add synchromesh in the gearbox is also prop driven, the prop turns the mainshaft

and the synchro has to spin up or slow down the clutch disc

many think its the otherway round in a blink the baulk ring has to grip, baulk and whiz the disc up

to speed once all is the same speed the ring lets go and you engage .

 

Pete

[jondhm]

I would support Peak's recommendation of a new propshaft from Dave Mac. I went down this route a couple of years ago and it has transformed my GT6.

[Henry Boler]

I would support Peak's recommendation of a new propshaft from Dave Mac. I went down this route a couple of years ago and it has transformed my GT6.

 

Me too! Dave Mac shaft on my GT6 MK3. Absolutely incredible now!

[Eddie]

Thinking outside the box, as they say - have you had the front wheel balancing checked?

 

I remember I had a vibration at 45mph in an Anglia that turned out to be a balance weight had come off one of the front wheels.

[peterhennell]

I'm new to this Forum lark, but having read these posts thought my experience might be relevant.

 

My 1969 13/60 convertible had exactly the same vibration when I bought it and I spent the first two years and loadsamoney trying to find the cause. Everyone said it would be the propshaft, but I had that balanced twice - each time we did something else it seemed to improve it a bit but didn't cure it until finally someone asked if I had the strap prop. I'd never heard of that, so he explained, we looked and it did have it. I bought a second hand solid one from the Spitfire Graveyard which cured it instantly! It was a little noisy, so when one of the U/Js needed replacing I bit the bullet and got a new sliding spline shaft from Canley Classics, by which time the price had gone up considerably of course. Apparently the strap shafts can be fine when on the balancing machine but once back on the car they presumably do what they're designed for and move so, in effect they can't be balanced.

 

I now have that, which anyone can have for nowt if it's any use, and the solid one, which anyone can have for what it cost me (£26 I think) or I'll keep it as a spare. Hope that's helpful. Peter

[Darren Groves]

Same here, had a strap type propshaft which I was balanced twice but still had vibration, changed to a solid type and all was fine.

 

My current propshaft if a sliding type from Dave Mac Propshafts, costs less money than you might think.