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 Wed Sep 18, 2019 2:45 am

All times are UTC




Post new topic  Reply to topic  [ 7 posts ] 
Author Message
 Post subject: Cam Timing
PostPosted: Wed Jan 19, 2011 1:40 pm 
Offline
TDC Member
User avatar

Joined: Tue Oct 03, 2006 4:48 pm
Posts: 8025
Location: Winscombe, North Somerset, England
For years now I haven't been able to get my Sprint to rev much past 6000rpm, maybe up to 6250rpm. Not that it's worth going past that figure as the engine has passed it's peak BHP by 6000rpm. In that time I've swapped blocks, chokes, replaced the uprated valve springs for standard ones & fitted a Megajolt system. I would expect this engine to rev to 7000rpm quite easily.

So I am wondering how much difference would be made by changing the valve timing by a couple of degrees?


The engine:-

Standard bottom end with Mahle pistons.
TT10106 equivalent camshaft by Newman cams.
Weber DCOE 45s with 40 or 42 chokes.
Head has been ported & polished.
Sports exhaust including larger bore stainless downpipe.

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

2007 Porsche Boxster S


Image

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

Schedule: Pronounced "Shedule" not "Scedule"!


Top
   
 Post subject: Re: Cam Timing
PostPosted: Wed Jan 19, 2011 7:18 pm 
My yellow sprint revs to 7300rpm and has max power on the wheel of 139hp. Hans can state this but he still doesn't know why :roll: Maybe i will tell him once the secret of a good STD engine :woohoo:

STD mahle pistons.
STD hs6 carbs
STD airfilterbox
STD camshaft
BELL sport exhaust
Ported head
Lightened std flywheel
Lightened std rods

All std and not new but good enough to had it re used.

I think in your case it's the ignitiontiming and it's importand to have all balanced very well. All rods the same weight and the rotating and translating weight also in balance. There are also lots of different clutch covers from aftermarket suppliers and these like the LUK or Valeo are much (1,5kg!!!) lighter than the original heavy ones.

Jeroen


Top
   
 Post subject: Re: Cam Timing
PostPosted: Wed Jan 19, 2011 7:52 pm 
Offline
Future Club member hopefully!
Future Club member hopefully!

Joined: Wed Dec 13, 2006 11:04 am
Posts: 277
Location: Leicestershire
Have either of you had your Tacho's calibrated?

_________________
Dolly Sprint racer 33
81 Dolly Sprint.
TWR Group A Rover Ch no 002 Hepolite.
4 other Sprints mostly for spares
Rover Tomcat race car.
Lotus Elan + 2S
Mitsubishi Legnum.
BMW E46 M3 convertible.
Rover Vitesse SD1 4500 Twin plenum.
Rover Vitesse SD1 twin plenum
Rover Vitesse SD1 twin plenum.
Rover SD1 2000
Rover Vitesse 820 turbo coupe.
Rover SD1 4200 pick up.
MG TF 160 VVC.
MG Express van 160 VVC.
BMW E30 325i Touring.
BMW E12 M535i.
Lotus Cortina Convertible.
E type Jaguar series 1.
Triumph Stag.
MGB Roadster.
VW Transporter Kombi Sportline.
VW Touareg R line
Capri 3.0 Ghia.
Cortina Savage estate.
Chevrolet 28ft camper.
Morris Minor Traveller.
Nissan Navara.
Mercedes 814.
Suzuki 125 Van Van.
+ many more.


Top
   
 Post subject: Re: Cam Timing
PostPosted: Wed Jan 19, 2011 7:56 pm 
Offline
TDC Member
User avatar

Joined: Tue Oct 03, 2006 4:48 pm
Posts: 8025
Location: Winscombe, North Somerset, England
Good point Ken, but I got similar rpm readings on the dyno so I hadn't looked at that.

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

2007 Porsche Boxster S


Image

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

Schedule: Pronounced "Shedule" not "Scedule"!


Top
   
 Post subject: Re: Cam Timing
PostPosted: Wed Jan 19, 2011 10:51 pm 
Quote:
Good point Ken, but I got similar rpm readings on the dyno so I hadn't looked at that.
idem.

Jeroen


Top
   
 Post subject: Re: Cam Timing
PostPosted: Wed Jan 19, 2011 11:27 pm 
Offline
Future Club member hopefully!
Future Club member hopefully!
User avatar

Joined: Wed Aug 29, 2007 7:12 pm
Posts: 334
Location: solihull
Cam timing will make a difference. A couple of deg advance (much more than 5 deg adv and the valves/ pistons get a bit close) won't but say 10 deg retarded will cause it not to rev. Also what is your ING map like. My engine was making best power at 27 deg advance. If you want I can email you a copy of my ING map.

_________________
In for a penny, in for a pound!


Top
   
 Post subject: Re: Cam Timing
PostPosted: Wed Jan 19, 2011 11:44 pm 
Offline
Future Club member hopefully!
Future Club member hopefully!
User avatar

Joined: Wed Aug 29, 2007 7:12 pm
Posts: 334
Location: solihull
You can check the tacho by plugging the laptop into the megajolt. The rpm on there is 100% right. On the rolling road was the furling right at 6000rpm or was it leaning off

_________________
In for a penny, in for a pound!


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 7 posts ] 

All times are UTC


Who is online

Users browsing this forum: No registered users 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