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I have a TR4 which is a deep dish spring rear axle type and has standard steel rear wheels and a set of Verdestien tyres. Ever since it was restored by myself approx 5 years ago it has suffered from vibration / resonance at various motorway speeds. Since then I replaced the propshaft which made a massive difference.

 

The wheels are balanced only yesterday.

 

The car still suffers from reasonances and is only smooth at an indicated 58mph and another above that. I am not expected new car standards but a moderately easy drive like my sidescreen TR.

 

Any ideas as to what it could be causing the vibrations and / or how to test various bits ?

 

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Paul,

the lump was a TR4A thing. I don;t think they were fitted to TR4. However it may have an interesting result.

 

John, Have you tried running it without the mechanical fan - it could be out of balance.

 

Roger

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Hi John,

 

I note that your TR4 has an engine from a TR6, so my suggestions may not apply.

 

Have you got the strap plate that fixes between the gearbox top cover and the nearside gearbox mounting bolt.

 

This is part number 131711 - illustration 84, page 28 in the Moss Catalogue.

 

Also what gearbox have you got fitted? - early gearboxes had thinner bellhousing flanges to bolt onto the engine, these did suffer vibration problems, but I believe these vibrations emanated from the 4 cylinder crankshaft.

 

The initial step that Triumph took to counter the vibrations was to add a balancing weight strapped to the rear underside of the gearbox tail.

 

As a more permanent solution, during the late TR4 production period - April 1964 - Triumph produced a stronger gearbox casing with a thicker flange to bolt to the engine - about 15mm thick I think.

 

However none of this may help with your current problem having a TR6 engine in place??????

 

Regards, Richard

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So the vibration follows road speed not rpm, - its not gear dependent ? And only goes away at a narrow critical road speed 58mph?

( and assuming all wheels+tyres have been balanced !!)

 

As you have a solid axle not drive shafts then I think it points to the prop shaft.

Is the prop shaft shorter than standard - to accomodate the longer TR6 engine? Its a one-off?

If so the angle it runs at might be excessive.

More on prop shaft balancing and UJ angles here:

http://www2.dana.com/pdf/J3311-1-HVTSS.PDF

-check out their 'rules' see if your prop shaft complies. p8 of pdf

The 'massive difference' from eliminating wear in the old one after just 5 years also points to a misaligned prop shaft. On my 6 the UJs lasted 'forever'.

 

Peter

Edited by Peter Cobbold
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Simple to see if it's drive related I.e.transmission including the prop or speed related, get to the 'Worst' vibration speed and slip the car into neutral.

 

If the vibration disappears or even changes markedly then you have a transmission problem, take it from there.

 

Mt TR 4 had the gearbox 'Lump'

 

John.

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Thanks for the ideas.

 

To clear a few things up and possibly of interest to others thinking of the mod to their cars, fitting the TR6 engine to a TR4 keeps the gearbox in exactly the same place, the engine extends futher forwards requiring the TR6 rack, rack mounts and lower column to be fitted.

 

In answer to the questions: the TR6 engine and 'box is fitted complete with larger thickness flange but no strap or weights, the prop length is standard as the gearbox is in the correct position, I think that the original prop was wrecked when I put it back on during my restoration, I changed the UJ's but ignored the spline.

 

I spent most of the weekend getting the exhaust to pass through the chassis without touching and raising the gearbox 3mm so it is not resting on the removeable cross member.

 

So I will be checking out the dampers, the front ones were new 3000 miles ago, the rears are recon standard lever arms.

 

Any more ideas ?

 

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Hi John,

do as a previous post suggests - get up to 60mph and then select neutral - What happens to the vibrations.

If still there then not engine.

If gone then engine.

 

Is it from the front, or the rear.

 

Roger

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Are the flanges on the geabox and diff nose within 1 degree of one another?

read the pdf:

"RULE 2: UNIVERSAL JOINT OPERATING ANGLES ON EACH END OF A DRIVESHAFT SHOULD ALWAYS BE EQUAL WITHIN 1 DEGREE
OF EACH OTHER"

You have vibration and extremely rapid prop shaft wear......

Edited by Peter Cobbold
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I have checked all the shockers and the fronts were very stiff and the rears quite easy to move but the same side to side, these rears lever arms were never very stiff I understand.

 

The only potential I found was the rubber bush at the top of one of the fronts was not compressed dispite the nut being tight to the stop. I inserted a thick washer to tighten it all up.

 

Tomorrow night I will hopefully fit in a test drive and try the out of gear / overdrive variances to see if the engine has any effect. (after its rebuild and balancing I should hope not !)

 

Thank you for the advice, the prop shaft wear is a red herring I think as it was the original from a car which was 40 years old and did not have its original engine and gearbox indicating a hard life.

 

I'll tell you the result of my test drive, John

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The test drive showed an improvement, it still shakes a little but is much reduced.

 

To confirm I did 2 things, tightened the top bush of a front damper and also removed a hubcap from the back which had a 'fair bit' of material added by the chrome platers when they improved the surface to enable a successful plating operation.

 

Thank you all for your ideas. John

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This may not be relevant BUT when I rebuilt the 2 many years ago I could not get rid of a vibration (like an off balance wheel), I had the wheels rechecked etc. and even changed the wheels!

It turned out to be an off balance 'repro' brake drum. I made up a jig from a spare hub and could not believe how out of balance it was, I got some weights from our local tyre depot and attached them with JB weld. The amount needed can be seen on the photo. Never had a problem since.

This cropped up many years ago on the forum and I think the consensus was that there is no way a drum can be out of balance causing vibration, believe me it can be and it was.

It was only in your thread that you stated removing the hubcap improved matters. Have the drums been replaced at any time?

 

Nigel

post-795-0-98032000-1404305764_thumb.jpg

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Love it, TR Coarse engineering fix number 37, related to the Binford 6100 series lol.

 

Mick Richards

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From memory (ho ho) there were some rubber mounts round my gearbox that had turned to mush, later replaced with new ones from Moss.

On mine these would have allowed things to rattle round and imitate the drive shaft being out of balance. (inter alia)

Edited by littlejim
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I've never seen a hub with a grease nipple on the side before !

 

Bob.

Look closely, thats not a mod.

Stuart.

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I had realised that the nipple was meant to be there, but on my early TR3 front drums (before recent re-build & change to discs) the nipple was in the centre of the steel domed cap.

 

Bob.

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The hub in the photo is original and as Stuart say's the nipple is was a standard fitment but as Roger stated not really needed. According to the owners handbook they should be given 'five strokes of the grease gun every 5000 miles'. Obviously a total loss system!

 

Nigel (with TS952)

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