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 May 17, 2021 10:57 pm

All times are UTC




Post new topic Reply to topic  [10 posts ] 
Author Message
 Post subject: Cam Bolt Material
PostPosted:Sat Feb 20, 2021 12:32 pm 
Offline
TDC Member
User avatar

Joined:Tue Oct 03, 2006 4:48 pm
Posts:8224
Location:Winscombe, North Somerset, England
I can't remember but what material are the cam bolts made from? The two 1/4"-28 x ½ that hold the sprocket on.

_________________
Sprintless for the first time in 35+ years. :boggle2:

2007 Porsche Boxster S


Image

You can't start a sentence with 'And'.

Grammar:
The difference between knowing your sh#t and knowing you're sh#t.

Schedule: Pronounced "Shedule" not "Skedule"!


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Sat Feb 20, 2021 12:56 pm 
Offline
TDC Member

Joined:Tue Oct 15, 2019 8:00 pm
Posts:219
They are just a standard high tensile steel setscrew, nothing special. Part No. HU704. The originals were unplated.

_________________
1975 Sprint Man O/D in Honeysuckle Yellow
1971 Stag Auto White

Too many cars, too little time!


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Sun Feb 21, 2021 7:03 pm 
Offline
TDC Member
User avatar

Joined:Tue Oct 03, 2006 4:48 pm
Posts:8224
Location:Winscombe, North Somerset, England
Thank you. :D

_________________
Sprintless for the first time in 35+ years. :boggle2:

2007 Porsche Boxster S


Image

You can't start a sentence with 'And'.

Grammar:
The difference between knowing your sh#t and knowing you're sh#t.

Schedule: Pronounced "Shedule" not "Skedule"!


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Sun Feb 21, 2021 9:34 pm 
Offline
TDC Member
User avatar

Joined:Sat Oct 07, 2006 7:23 pm
Posts:1180
Location:Staines Upon Thames
Someone put mild steel in mine many years ago. It wasn’t a pretty ending ☹️.

_________________
Mike

1980 Vermillion Sprint - 174bhp


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Mon Feb 22, 2021 12:53 am 
Offline
TDC Member
User avatar

Joined:Tue Oct 03, 2006 4:48 pm
Posts:8224
Location:Winscombe, North Somerset, England
Quote:
Someone put mild steel in mine many years ago. It wasn’t a pretty ending ☹️.
I can imagine. :roll:

_________________
Sprintless for the first time in 35+ years. :boggle2:

2007 Porsche Boxster S


Image

You can't start a sentence with 'And'.

Grammar:
The difference between knowing your sh#t and knowing you're sh#t.

Schedule: Pronounced "Shedule" not "Skedule"!


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Mon Feb 22, 2021 11:16 am 
Offline
TDC Member
User avatar

Joined:Sun Sep 08, 2013 2:35 pm
Posts:1569
Location:St Annes on Sea, Lancs.
I had a similar experience once. I bought a TR7 with a Sprint engine cheap (couple of hundred as I remember), cos it was making a "horrible banging noise" from the front of the engine when I bought it. I wasn't bothered, as I had a good engine to transplant into it. Anyway, S&S transported it via their workshops and, as part of their being interested, tried to do a compression test, during which it stopped banging and they found no compression at all.

When I got it, I took the rocker cover off to find that the sprocket was spinning on the cam. One of the two bolts was just missing and the stub of the other was still in the cam end. I think the banging had been the sprocket slapping the end of the cam after the first bolt had fallen out or failed. That had fatigue failed the other after a bit, which is when it lost compression.

For the cost of two bolts and some gaskets (they were probably from SprintSpares) and a bit of work, I thought it was worth trying to fix it. I was able to get the stub of the sheared bolt out through the back just with mole-grips. And believe it or not, it was fine. No bent valves or damage to the pistons. It may not have been the best Sprint engine I ever had. But it was a perfectly good engine for a daily driver. I never found the bits of the bolts or the keeper and I wasn't gonna take the sump off to look. I just drained the oil and re-filled.

I ran it for something like 6 months and probably eight or nine thousand miles before I lost the car on a pile of wet horse apples and went backwards into a ditch.

Graham

_________________
The 16v Slant 4 engine is more fun than the 3.5 V8, because you mostly drive it on the upslope of the torque curve.

Factory 1977 TR7 Sprint FHC VVC 697S (Now all of, but still needs putting together)
B&Y 73 Dolomite Sprint UVB 274M (kids!)
1970 Maroon 13/60 Herald Convertable (wife's fun car).


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Mon Feb 22, 2021 7:12 pm 
Offline
TDC Notts,Derby & Leics Area Organiser
User avatar

Joined:Sat Jun 14, 2008 10:15 pm
Posts:231
It's been on my mind (and my to do list) for a while now to change these bolts for something more substantial.
I bought an engine which had 5/16 UNF setscrews fitted to the sprocket/cam,so was thinking of doing similar to my current engine. Possibly even fit another two screws,so that there are four that are ninety degrees apart.
Anyone done similar or have any recommendations please?
James


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Thu Feb 25, 2021 8:52 am 
Offline
Future Club member hopefully!
Future Club member hopefully!
User avatar

Joined:Fri Nov 23, 2007 11:33 pm
Posts:4848
Location:hampshire
When I rebuild a Sprint engine I add two more bolts to the cam (if requested) for this I have a drill jig because due to the existing notch on the cam there is no room for error. I once dismantled an engine that someone had used stainless bolts and were lucky that they had not sheared as stainless is weaker than original. To avoid incorrect cam timing these extra bolts are 6 mm and a 1/4 UNF won't fit.
The other thing is the correct torque to tighten these bolts is vital and I reckon some people do them up too tight because there are only two and it seems not enough for such an important part.

_________________
track action maniac.

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


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Thu Feb 25, 2021 10:22 am 
Offline
TDC Notts,Derby & Leics Area Organiser
User avatar

Joined:Sat Jun 14, 2008 10:15 pm
Posts:231
Thanks for the reply Jon.
I should have known it wouldn't be easy.
I may have a go at it later this year,and possibly fit a vernier sprocket at the same time.

James


Top
   
 Post subject: Re: Cam Bolt Material
PostPosted:Thu Feb 25, 2021 5:49 pm 
Offline
TDC Member

Joined:Sun Mar 16, 2008 2:52 pm
Posts:2197
On the same subject, section 12.13.02 of the Workshop manual has a note that the tab-washer should not be hammered over as there is a danger of it losing it's torque.
Tony.


Top
   
Display posts from previous: Sort by 
Post new topic Reply to topic  [10 posts ] 

All times are UTC


Who is online

Users browsing this forum: Bing [Bot] and 1 guest


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