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 Mon Aug 26, 2019 9:28 am

All times are UTC




Post new topic  Reply to topic  [ 4 posts ] 
Author Message
PostPosted: Tue Jan 29, 2019 5:37 pm 
Offline
TDC Member

Joined: Mon Dec 03, 2012 6:04 pm
Posts: 975
Does anybody know the correct strength rating for these? I can't find the bolts for sale anywhere and since I would prefer them not to shear; I would like to buy bolts that are strong enough for the job.


Top
   
PostPosted: Tue Jan 29, 2019 7:37 pm 
Offline
TDC Member
User avatar

Joined: Thu Oct 06, 2011 12:13 am
Posts: 2706
Location: The continent
These two aren't up for the job anyway, even in a stronger variant. They would be 10.9 or 12.9.

You can drill two extra holes to have 4 in total but better would be using 4x 5/16 bolt.

Jeroen

_________________
Classic Kabelboom Company. For all your wiring needs. http://www.classickabelboomcompany.com


Top
   
PostPosted: Sat Feb 02, 2019 12:12 am 
Offline
TDC Member

Joined: Mon Dec 03, 2012 6:04 pm
Posts: 975
Quote:
These two aren't up for the job anyway, even in a stronger variant. They would be 10.9 or 12.9.

You can drill two extra holes to have 4 in total but better would be using 4x 5/16 bolt.

Jeroen
Are you sure about those strength ratings? The bolts supplies are selling for the camshafts on a Stag are only grade 5 (three lines on the bolt).

If the bolt is too hard, isn't it going to be brittle and be in danger of fracturing?


Top
   
PostPosted: Sat Feb 02, 2019 9:42 am 
Offline
Future Club member hopefully!
Future Club member hopefully!
User avatar

Joined: Fri Nov 23, 2007 11:33 pm
Posts: 4836
Location: hampshire
Well this has to be a first for me as on this one 12.9 would perhaps be too high a tensile strength for this application. 8.8 (grade 5) 1/4 UNF would be the correct to absorb the shock and I agree with Jeroen that 4 off bolts are better and I have a drill jig that I use to drill both the cam and the sprocket and I tap the holes 6 mm on the extra 2 holes so that the timing cannot be done wrong.

When visiting Thruxton race meeting a few years ago a dolomite sprint had wrecked its engine when the cam sprocket broke free which prompted me to add 2 more bolts. When I build an engine for someone I offer this mod.

_________________
track action maniac.

The lunatic is out................heres Jonny!


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 4 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users and 7 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