The Triumph Dolomite Club - Discussion Forum

Morning all,

Yes…it’s prop time !! Hoping I did my measurements correctly and my PropTech prop is the right length !!

Question please - does the prop hang underneath the brackets as per the parts manual ? Seems a little counter-intuitive ?!

Also odd that part 153106 has 2 bolts which stops it turning round when tightening from underneath, whereas part 153108 has one bolt and will spin round without a friend holding it tight inside the car !!

Thanks, Richard

How the centre bearing is mounted depends on the type of bearing....
Here's something on the subject I posted on another forum:
https://sideways-technologies.co.uk/for ... -mounting/

And a direct link to the appropriate technical bulletin: https://cdn.triumphowners.com/wp-conten ... pshaft.pdf

NORMALLY the centre bearing mounts both go above the tag brackets. Except on manual Sprints which run 1 above and 1 below to counter driveline vibes. The idea is to prevent the prop front section being exactly in line with the gearbox output shaft as this leads to unpleasant harmonic vibrations and accelerated wear in the front UJ.

But it's something you may have to experiment with, i'd start with both above and if it drives ok without vibration, leave well alone. If not then experiment with one above, one below etc till the vibe is eradicated.

Yes, the single bolt bracket is a PITA, but it's correct! I tend to drop a couple of tack welds on the plate whilst the carpets/seats are out, makes life easier in the long run!

Steve

Thanks for the technical info. I noticed that was note number 47. Have you got the other 46 ?!

Mines from a 1500 auto, right Steve ?!

Carledo wrote: ↑Tue Nov 02, 2021 3:37 pm NORMALLY the centre bearing mounts both go above the tag brackets. Except on manual Sprints which run 1 above and 1 below to counter driveline vibes. The idea is to prevent the prop front section being exactly in line with the gearbox output shaft as this leads to unpleasant harmonic vibrations and accelerated wear in the front UJ.

But it's something you may have to experiment with, i'd start with both above and if it drives ok without vibration, leave well alone. If not then experiment with one above, one below etc till the vibe is eradicated.

Yes, the single bolt bracket is a PITA, but it's correct! I tend to drop a couple of tack welds on the plate whilst the carpets/seats are out, makes life easier in the long run!

Steve

I did the same thing weld the bracket with one bolt hole while i had the carpet out

RichardHyde wrote: ↑Tue Nov 02, 2021 6:49 pm Thanks for the technical info. I noticed that was note number 47. Have you got the other 46 ?!

Mines from a 1500 auto, right Steve ?!

Pretty sure the prop you had is from a Sprint auto. If (as I suspect) it has a CV joint in the centre instead of a UJ, it's a Sprint one.

But the origin of the prop is almost irrelevant, it's how it lines up with the crank/gearbox mainshaft line that's critical. Both my modified cars work fine with both centre bearing mounts above the tags.

But that's my cars, your's with the Nissan lump may sit more tail down as the Sprint one does and need an extra angle introducing. It's probably POSSIBLE to measure angular deflection, but you are looking at a variation of less than 5 degrees and probably approaching zero. The level of my measuring equipment (and probably human error too) isn't up to that sort of accuracy, so I rely on the tried and trusted road test method. At least if I get a vibe, I know what to blame, how to fix it and don't go cussing the guy who built the prop!

Steve