Vitesse 2 liter - strobe timing / pulley markings query

[J Hobbs]

Hi all, so I recently acquired a 1966 Vitesse MK1 16/6 cabriolet converted to a 2 liter which I've got running great but have a query nonetheless...

Its had an unleaded conversion in the past and over here in France I'm running it on 98 octane. Using a strobe, engine at 1000rpm and vacuum disconnected I initially set the timing to 10° advanced, noticed as expected what I believe is some pinging under heavy load and have slowly reduced it over time. The pinging is now gone under any condition but the thing is it now reads a few degrees retarded from zero based on the pulley markings. Nonetheless it has run flawlessly like this for weeks (its my daily), does approx 26 mpg, temps are spot on and stable, starts perfectly and power is far from sluggish (although obviously is improved with advancing but at the expense of pinging).

So my question is just how trustworthy are the markings and if its possible to mount a pulley incorrectly ? I'm sure the previous owner did his best but I've had to rectify many other questionable things on the car.

Should I trust my instincts and leave as is or would this indicate an issue that should be investigated despite the car running so well ?

Cheers in advance

 

Edited 5 hours ago by J Hobbs

[JohnD]

J Hobbs,

What many do not know is that the crank pulley that carries the TDC marking does double duty, as a pulley to power water pump and alternator, AND a crank damper, to suppress torsional vibration.    This is entirely different from engine balance vibration, as the straight six has the best inherent balance of any other engine configuration.     Torsion vibration derives from the firing stroke that 'rings' the crank, and if it coincides with one of the resonant frequencies of the crank can lead to damage.      In four cylinder engines a damper  isn't necessary, as all the harmonics are too high for resonance, but like an organ pipe, the longer six cylinder crank vibrates at lower frequwencies, within the rev range.   So Triumph provided a damper in the pulley, by having a rubber ring between the metal hub and the outer ("inertia") ring which carries the timing marks.

This is a so-called 'viscous' damper, and works well, but when these were made the rubber was similar to tyre rubber.   Over the years the rubber has deteriorated, and may no longer have the viscosity to provide damping.  Worse, it can loose adhesion, and the ring turns on the hub.   Then the markings become nonsense!

I suggest that you use a piston stop method to determine exactly where TDC is.  If it is not where your pulley markings say then the pulley should be replaced.  The usual suppliers sell new ones.

This YouTube video shows someone checking TDC on a Triumph straight six,   He finds that the markings are wrong, but does not know the reason why! 

Good luck!

John
 

Edited 5 hours ago by JohnD

[J Hobbs]

John hi and thanks for the quick reply, ok had no idea about that either so in any case I'll investigate the pulley mech integrity and continue to trust my ears and instincts then regarding the timing, cheers

I realise it would be going off topic but I've always thought it sits lower than others I've seen and can't work out why, its recently MOT'd, bushings look ok and it has a Canley Classics spring. The car handles fine and I like the low look so dont wish to change it but curious nonetheless, any ideas ?

[johny]

Also as said many times before some pinging is acceptable. The recommendation is for setting the timing so pinging stops when reaching 2000rpm in 4th gear accelerating hard on a flat road - to avoid it below this limit you can change down a gear. As you say youre possibly loosing power and fuel economy (I can get quite a bit better than 26mpg) by retarding so much....

[J Hobbs]

Johny, interesting, yes I am being a "perfectionist" about it. If I accept pinging uphill in 4th between 2-3000rpm and very occasionally on the flat as you say I can easily run it at close to 10° advanced with better performance and economy but I've always thought pinging was to be avoided at all costs, hmmm...

 

Also thats 26 UK not US mpg, what can you get out of yours ?

Edited 4 hours ago by J Hobbs

[Steve P]

The car does look low at the back, you mentioned a Canleys spring, does it have a lowering block or maybe a swing spring from a Spit/GT6 which IMHO is no good on a Vitesse?.

Steve

[J Hobbs]

Steve hi, how would I identify a swing spring from a Spit/GT6 ? I attached a photo of the spring reference and there is no sign of a lowering block, it looks low all round to me but especially at the rear, strange huh

Edited 4 hours ago by J Hobbs

[Pete Lewis]

a search for the marked  305495 is unknown but from canley's  305945 is 1600/Mk1  a std.  rear spring 

may be the felt pen marker was dyslexic  ????

so not a swinger which will  give some low rides on a vitesse 

a carefull look for a drop plate seems a need to resolve this 

canley have a good reputation for spring suppliers 

if the ride height gets too low you can end up sitting on the bump stops inside the shocker.

(got that tee shirt from trying a swinger)

[J Hobbs]

Cheers Pete, yes have no doubt re the spring quality, whats a "drop plate" so I can look for it .) ? Also whats your take on acceptable levels of pinging ?

[Pete Lewis]

the drop plate or drop block fits under the spring and locates in the top of the diff 

they come in 1/2" 3/4"  and 1"  thicknesses .

to preserve you pistons you dont want any persistent  pinking    it can fail  a piston in time without any warning 

definitely  check the damper ring  we had this on our 1600  back in the early 2000's  makes for good head scratching  , you could turn our ring with your fingers , 

i would  not waste any funds on octane boosters   ,your 98 should be fine (providing thats what you actually got)

most of us run on 97/98 with factory setting and they are fine 

do you have a std distributor or some after market hopeless replacement ????

Pete

Pete

[J Hobbs]

Ok gotcha will look for a potential drop plate.

Re the pinging then it sounds like in this case being a perfectionist isn't the way to go and "some" pinging is a better compromise, especially as there is no way I have "persistent" pinging at factory setting, just some under extreme load so I think I'll go that route but will still verify as John suggested the accuracy of the timing marks

Distributor is stock but first rotor arm fire is at upper right not lower left so I believe 180° out...

Edited 3 hours ago by J Hobbs

[Pete Lewis]

180 doesnt matter a hoot  so long as the leads reach its fine 

what  spark plugs are you using dont want any with an R in the suffix 

Pete

 

[J Hobbs]

Good to know re the distributor

Busted... I have actually put in multi electrode NGK BUR6ET. I'm aware you and many others are anti them but since there are just as many who have nothing but positive experience with them it objectively seems one of those grey areas that perhaps only production quality / quality control can explain. Anyway for me at least they are a noticeable improvement over the BP6ES that were in it especially at idle, extremely easy starting and smoother running but if things deteriorate I will let you know

Edited 2 hours ago by J Hobbs

[johny]

2 hours ago, J Hobbs said:

Johny, interesting, yes I am being a "perfectionist" about it. If I accept pinging uphill in 4th between 2-3000rpm and very occasionally on the flat as you say I can easily run it at close to 10° advanced with better performance and economy but I've always thought pinging was to be avoided at all costs, hmmm...

Also thats 26 UK not US mpg, what can you get out of yours ?

As I say there should be no pinging above 2000rpm when on the flat. Mines a saloon with the 2L version of your engine and no overdrive so easy cruising at 50mph gives 33 - 34mpg(uk)...