The Triumph Dolomite Club - Discussion Forum

The Number One Club for owners of Triumph's range of small saloons from the 1960s and 1970s.
It is currently Sun May 16, 2021 9:12 pm

All times are UTC




Post new topic Reply to topic  [11 posts ] 
Author Message
 Post subject: Prop Shaft
PostPosted:Sun Apr 11, 2021 2:09 pm 
Offline
TDC Member

Joined:Mon Dec 12, 2016 9:53 pm
Posts:1185
Location:Harrow Middlesex
The centre mount brackets that are bolted to the floor,how is the centre bearing mount fitted to it,from above or below,what i mean is are the bolt heads pointing upwards or down wards

or does it not make any difference ?

Thanks Dave


Top
   
 Post subject: Re: Prop Shaft
PostPosted:Sun Apr 11, 2021 3:48 pm 
Offline
TDC Member

Joined:Thu Sep 28, 2006 9:06 pm
Posts:1037
Location:Bristol
It depends on the model.

A. For Dolomite manual change gearbox and automatic gearbox models.

Both lugs on the prop shaft centre bearing housing are located on the upper face of their respective mounting brackets.


B Sprint manual gearboxes and automatic gearboxes.

LHS mounting bracket is secured as per A above but the RHS lug of the central bearing housing is fitted below the mounting bracket with one washer spacing it from the bracket.


I am now confused as the document that I am reading states Dolomite automatic gearbox model only and goes onto state this model uses a different mounting bracket which moves the prop shaft centre line 0.375 inches to the right compared to the centre line of other models. The LHS mounting arrangements stay the same as in A above but on the RHS washers are fitted between the bracket and the car body and the lug of the central bearing housing is fitted below the mounting bracket.

The document states the various installations are to avoid possible noise and vibration. I think I may have a play and see if changing my installation will reduce the vibration I get at approx 1800 rpms.


Top
   
 Post subject: Re: Prop Shaft
PostPosted:Sun Apr 11, 2021 7:39 pm 
Offline
TDC Member

Joined:Thu Nov 09, 2017 7:55 pm
Posts:364
Location:Maidstone
If I remember rightly Dave I bolted mine from above because that’s the only way I could get it to work. I looked at the manual, and as Richard suggests, there are different methods listed but I couldn’t get mine to fit either way. So just bolted it up with the bolts coming down and the plates level. Hope that makes sense?

I’ve had no vibration issues so far 🤞


Top
   
 Post subject: Re: Prop Shaft
PostPosted:Mon Apr 12, 2021 11:43 am 
Offline
TDC Member
User avatar

Joined:Wed Oct 04, 2006 8:49 pm
Posts:839
Location:Sutton,Surrey.
Does this help.


http://www.dolomitesprint.com/prop.htm


I don’t have this problem.
Single piece custom Propshaft.

_________________
2005 Mercedes C Class V6 Diesel Turbo Daily Driver.
1980 Dolomite Sprint with a touch of BLTS
Balanced Lightened and Tweaked 13B Rotary and SuperCharged.
Rebuilding the Sprint time taken so far, 111Hrs@15/12/2020

Member TDC no 0471

Project 13B Sprint now back on. 121 @ 15/04/2021


Top
   
 Post subject: Re: Prop Shaft
PostPosted:Mon Apr 12, 2021 7:24 pm 
Offline
TDC Member

Joined:Mon Dec 12, 2016 9:53 pm
Posts:1185
Location:Harrow Middlesex
Thanks for the reply guys,when i took mine off it had one bolt pointing up and the other pointing down,i thought that was the previous owner,getting the bolts in from above was a pain,would be even harder now,ive run my fuel and brake lines under the tunnel :oops: :oops: :D

Dave


Top
   
 Post subject: Re: Prop Shaft
PostPosted:Mon Apr 12, 2021 10:24 pm 
Offline
TDC Member

Joined:Mon Dec 12, 2016 9:53 pm
Posts:1185
Location:Harrow Middlesex
Quote:
Does this help.


http://www.dolomitesprint.com/prop.htm


I don’t have this problem.
Single piece custom Propshaft.
Why did the Sprint have a two piece propshaft in the first place ?


Top
   
 Post subject: Okay........
PostPosted:Wed Apr 14, 2021 7:35 pm 
Offline
TDC Member
User avatar

Joined:Thu Aug 09, 2007 12:22 pm
Posts:6703
Location:Caithness, Scotland
Quote:
Why did the Sprint have a two piece propshaft in the first place ?
That is a good question Dave.

I cannot explain the theory, it is way beyond me,
however I understand that if a single piece propshaft was employed it would have to be a much greater diameter
and therefore heavier.

(Triumph 2000s had single piece props and these caused vibration problems.
Many attempts were made to cure this but the problem persisted.)


Ian

_________________
TDC Forum moderator
PLEASE help us to maintain a friendly forum,
either PM or use Report Post if you see anything you are unhappy with. Thanks.


Top
   
 Post subject: Re: Prop Shaft
PostPosted:Wed Apr 14, 2021 9:21 pm 
Offline
TDC West Mids Area Organiser
User avatar

Joined:Thu Sep 28, 2006 12:13 pm
Posts:12901
Location:Over here...can't you see me?
The two piece propshaft is designed to avoid harmonic frequencies which occur in tubes and cause resonation. I forget the exact criteria from my O and A level physics, but length and diameter come into play.


Top
   
 Post subject: Re: Okay........
PostPosted:Thu Apr 15, 2021 7:22 pm 
Offline
TDC Member

Joined:Mon Dec 12, 2016 9:53 pm
Posts:1185
Location:Harrow Middlesex
Quote:
Quote:
Why did the Sprint have a two piece propshaft in the first place ?
That is a good question Dave.

I cannot explain the theory, it is way beyond me,
however I understand that if a single piece propshaft was employed it would have to be a much greater diameter
and therefore heavier.

(Triumph 2000s had single piece props and these caused vibration problems.
Many attempts were made to cure this but the problem persisted.)


Ian
The Stag uses a single piece propshaft,but its a thicker diameter than the Dolomite one


Top
   
 Post subject: Re: Prop Shaft
PostPosted:Tue Apr 20, 2021 11:15 pm 
Online
TDC Shropshire Area Organiser

Joined:Sun Aug 21, 2011 4:12 pm
Posts:6127
Location:Highley, Shropshire
I asked the guy at Proptech, who built the custom props for the Carledo and Dolomega, whether i'd be better off going for a one piece and he said no way! As others have mentioned, the longer it gets,the bigger diameter it needs to be and the heavier it gets the more chance of unwanted harmonics developing. You run into the law of diminishing returns. I've been totally happy with his advice, the Carledo's split prop has done many thousands of hard miles (and lots of linelock burnouts) with no bad vibes at all - EVER!

A Stag prop is considerably shorter than a Dolomite split prop, despite the longer wheelbase on the Stag, go figure! EDIT, probably down to the Stag/2000 diff nose carrier being about 18" long!

Steve

_________________
'73 2 door Toledo with Vauxhall Carlton 2.0 8v engine (The Carledo)
'78 Sprint Auto with Vauxhall Omega 2.2 16v engine (The Dolomega)
'72 Triumph 1500FWD in Slate Grey

Maverick Triumph, Servicing, Repairs, Electrical, Recomissioning, MOT prep, Trackerjack brake fitting service.
Apprentice served Triumph Specialist for 50 years. PM for more info or quotes.


Top
   
 Post subject: Re: Prop Shaft
PostPosted:Wed Apr 21, 2021 8:57 am 
Offline
TDC Member
User avatar

Joined:Wed Oct 04, 2006 8:49 pm
Posts:839
Location:Sutton,Surrey.
The Carbon Fibre RX8 prop was actually longer than the Sprint.
So I went for a single piece prop, and from the advice from Dave Mac Prop-shafts.
3” diameter with 27mm UJs (As found on Stags and 2/2500) which are bigger than the Sprint.

Overkill more than likely but should take more horse power than I can throw at it.


You could always go thicker wall tube but keep the smaller diameter.

I’ve since learnt I could of had the Carbon Prop shortened with new diff joint/UJ
No mention at cost at this stage.

_________________
2005 Mercedes C Class V6 Diesel Turbo Daily Driver.
1980 Dolomite Sprint with a touch of BLTS
Balanced Lightened and Tweaked 13B Rotary and SuperCharged.
Rebuilding the Sprint time taken so far, 111Hrs@15/12/2020

Member TDC no 0471

Project 13B Sprint now back on. 121 @ 15/04/2021


Top
   
Display posts from previous: Sort by 
Post new topic Reply to topic  [11 posts ] 

All times are UTC


Who is online

Users browsing this forum: Bing [Bot], Google [Bot], MegaIndex [Bot], PetalBot [Bot] and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Limited