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Driveline angles


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Booked my Vitesse in to Hardy Eng Leatherhead for this Monday to investigate a diff oil leak and general look see. Hopefully it's just the pinion seal but while it's there I'm sure something else will need correcting! One thing I want to check is the driveline angles ie gb output to prop to diff angles. I'm sure when I last grovelled under the car both gb (T9) and diff were pointing down which is far from ideal as they should be 0.5-3* from parallel. The car has a new bailey morris prop and drives fine but under acceleration at higher revs in any gear the driveline is not as smooth as I would wish given the engine is fully balanced. If it was a prop issue it would be speed related but it seems right foot and load related. I can't lower the engine mounts and raising the GB would probably result in the prop hitting the tunnel therefore if required is it possible to raise the front of the diff? It will pivot on the rear mounts but the front carrier and bushes are set. Anyone else come across this issue with a solution other than cut and weld the carrier.

Iain 

PS.  There's a good app for your phone called Tremec Toolbox that you use by measuring with your phone. Also one from Spicer but it needs a separate angle finder.

 

download (8).jpeg

Edited by Iain T
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I went through this s while ago. My Vitesse is modified, engine gearbox moved back, J type overdrive etc. I tried all sorts, to cure a rumble, vibration. I do have a shortened prop which i had made in a smaller diameter, but thicker tube due too very little clearance between prop and hand brake/tunnel, as soon as you start trying to alter engine gearbox layout and prop angles.  Much better now, but not perfect.

https://sideways-technologies.co.uk/forums/index.php?/topic/8997-play-in-vitesse-diff/&do=findComment&comment=124312

 

Edited by Mark B
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Had a problem in my Vitesse with a balance weight on front of prop shaft clipping the tunnel, fitting the rear gearbox mount upside down cured it.

Problem started when I fitted a J type overdrive gearbox.

Regards

Paul.

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14 hours ago, Mark B said:

went through this s while ago.

Thanks for that Mark, very interesting. I looked at my Bailey invoice and it says 1140mm long with obviously a spline front for the T9 gb. The car drives fine and is smooth up to (and over) 70mph. It's the harshness under load at higher revs say 3500/4000+ that is annoying as the engine is now very willing! I have 2 shims and the offside engine mount so the Phoenix manifold misses the steering column shaft (even then I had to put a small dent in the pipe) and one on the nearside to give clearance for the sump to rack. I can't remove those to alter the nose down gb angle. I'll have another look at raising the gb but it's already might close to the tunnel. Raising the diff nose is the 'easy' option to minimise the problem but as you say there is only so far you can go. My wishbone has the 1" shim so I could machine a calculated angle on that to compensate for altering the diff angle. I don't know what the distance is from the rear diff mounts to the carrier to calculate. All I can do is work within current constraints as although I'll ask I don't think I can fit a cv joint prop. I'll also get the prop checked. I'd like to be there at Hardy's when the checks prior to stripping are done as this final step is bugging me and stopping me from using all that lovely straight 6 power.

I'll keep a running commentary of the results!

Iain 

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4 minutes ago, trigolf said:

Hence why I took the car to Vibration Free, Iain!

Yes I can see a visit looming. Still it would give me a chance to clear the soot from the plugs!

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I too had pondered from time to time about changed driveline angles causing vibration. It's been a very long time since I fitted the car with a J type o/d and I can't honestly remember whether the vibration only became noticeable after the conversion. Trouble is, back then, I just wanted to use the car all the time! What would be interesting is if we could compare a standard D type installation rear mounting height, compared to the J type fit?🤔

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6 hours ago, trigolf said:

I too had pondered from time to time about changed driveline angles causing vibratio

It's a nightmare but fun of sorts. Sorting out the carbs on my modified engine was a challenge so I now need something else to keep me awake at night🛌

Iain

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2 hours ago, PeteH said:

See the old "two worm drive clip" balance system is still the go to?. Proves the old addage "If it ain`t broke why fix it?".

There is a distinct difference between balancing as an individual item and as assembled. I had my wheels balanced on the car by Vibration Free and it made a noticeable difference even though the wheels were balanced when I changed the tyres. The same applies to the prop shaft. The issue is when I have a car with a problem I feel compelled to fix it even if it is minor!

I hope they open the M25 at 6am tomorrow as I have to get off at J9🤞

Iain 

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As far as I can acertain the gb if pointing down about 4 degrees. As to the diff according to the diagram I found the distance between the front and rear mounts is 272mm which means 1 degree is 4.7mm so perhaps 1-1.5 degrees is all I will be able to raise the nose.

I will phone Bailey Morris before I set off tomorrow to get their advice on a cv joint prop and the smallest dimensions 

Iain

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At least live axle cars have a relatively constant distance and angle for the propshaft to accomodate. Unlike cars with sprung axles. The choice here is a long Prop with no overdrive, or a shorter one with overdrive. Long prop will have less of an angle to cope with, but may vibrate more if the sliding spline begins to wear and throw out.

Many later cars use a two piece propshaft and the angles are even more extreme. Maybe you are worrying too much.

 

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On 16/03/2024 at 13:54, trigolf said:

Hence why I took the car to Vibration Free, Iain!

20231016_145210.jpg

The sliding spline should be at the front (gearbox) end. Is this the case with the picture shown?

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My sliding joint was at the front but I found this in the manual (see NOTE:) and reversing it certainly improved the smoothness although I subsequently had the prop straightened and balanced. Certainly easier to grease the splines with it at the rear....

image.png.6b139466b3c874c69036ceb56da584df.png

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1 hour ago, Wagger said:

The sliding spline should be at the front (gearbox) end. Is this the case with the picture shown?

Most older car manuals state that a sliding joint should be fitted at GB end. I did try fitting the prop that way,but it made no difference to vibration and prevents you from being able to grease the slider easily, so I refitted it at diff end. All Truimph manuals state it should be fitted at diff end ( probably just for greasing)🤔

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2 hours ago, trigolf said:

Most older car manuals state that a sliding joint should be fitted at GB end. I did try fitting the prop that way,but it made no difference to vibration and prevents you from being able to grease the slider easily, so I refitted it at diff end. All Truimph manuals state it should be fitted at diff end ( probably just for greasing)🤔

No grease access on my prop. Not even a plug. The front end has more rubber mounts to absorb vibration. I inherited a Vitesse with the prop wrong way round. It vibrated less when I reversed it.

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Had a look at Hardy's and my diff nose is pointing up ! The front mounts have already been cut down. The diff has to come out as there is excessive backlash and the rear bushes look shot. Should know more next week.

Iain 

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10 minutes ago, johny said:

Wow you are looking for work Iain😁

More like paying for it. The diff was supposed to have been refurbished by the POs restoration company but yet again this may not be the case. This is hopefully the last whirly bit to sort out then just enjoy driving it until........

Iain 

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