Club Triumph

hi all, I am now confused I have set my timing as per the Haynes manual 13 deg btdc and I checked my repro original (so to speak) service manual and at the back of the book it lists the specs for all versions of the car but under the mk3 gt6 it says timing should be only 6 deg btdc so now don't know what is right, please set me straight as to which is correct, many thanks Paul.

It's not 13. That's for a Mk1 on 100 octane 5* fuel. I think I set mine to 10 but 6 might be the more correct figure for 95RON.

(Actually mine was last set by Pete Baldwin on a rolling road to get optimum without knock, so I've no idea what it is)

oh getting abit deeper into this I am now more confused as ive read that having electronic ignition(sparkrite) using a timing strobe is no good, what a lot of people do is turn the dizzy until the tickover revs start to drop away then turn back slightly and that's about right, test drive and as long as there's no pinking that's it, um seems a bit hap hazard to me, any thoughts, paul.

Can't see what's wrong with using strobe as it triggers from the HT lead so why does it matter how the spark is produced? Works fine for me with Sparkrite, I set at recommended timing then retard as necessary.....

I'd be intrigued to know why they think electronic ignition makes the timing strobe no good. However, the usual "by ear" method is to find the position that gives the highest idle then back it off a bit.

In general, your ideal ignition advance at any operating point would be "MABT" (minimum advance for best torque). In reality, you won't be able to sustain that over much of the rev/load range because of knock. However, you will at idle. The factory designed the distributor curve to get reasonably close to that across the range, and that includes being "fairly close" at idle. So you want to find that, but since you don't have a torque meter available you use idle speed as a proxy. The more efficiently the engine is running, the more power (and hence higher speed) it can achieve for a given amount of air (i.e. throttle opening). So find the highest speed, retard until it just starts to drop. BUT... for various reasons, the factory would not actually have set MABT at idle (it's more load sensitive so the idle isn't as stable) and your correct idle ignition advance is a couple of degrees retarded from there.

Since the fuel you're using is not the same as what Triumph intended, many would argue that the above method is actually better than setting the book figure with a strobe.

thanks people for replies, I'm understanding more thanks to you, if I could just ask these final questions on this matter,  if I set by strobe do I need to disconnect the small vac advance pipe if so do I block it off some how, secondly the timing marks on the pulley show one heavier mark (which I believe is TDC) then I have graduations from there, one way upto 24, I have painted a line on the pulley at what I believe is about half way inbetween 13 deg BTDC am I correct, I am going to set this if i'm correct, but also I am going to try the alternative listening to tickover then backing off idea, thank in advance (or retard), Paul

I believe the book figure is supposed to be set with no vacuum advance, so yes, unplug the pipe. Best to remove it from the distributor and plug the pipe so that there's no air bleed into the carb. It probably won't make a big difference but it will increase idle speed and throw the mixture off a bit if you leave it open.

If I remember right, the GT6 has graduated markings on the vibration damper part of the pulley, and a single pointer on the timing case. Some engines (later Spitfire?) have a single mark on the pulley and a graduated scale on the timing case. The mark you need to add is on the opposite side between those options, of course.

As I said earlier, I don't think 13 is right for a Mk3. The PDF of the WSM quotes 6 for a (non-US) Mk3 as a "static" figure, which should be the same for idle with no vacuum advance.

many thanks Rob, yes the Mk3 does have a pointer and graduations on the damper as you describe I will do as you suggest and set at 6 Deg BTDC and see how it runs, I may also try the other method just out of interest, Paul

Don't forget that if it pinks excessively on that setting you can play around with different fuel grades and/or octane booster additives before retarding the ignition

Find a quiet road with an incline, advance the ignition until it pinks going uphill then back it off until it stops.

Don't forget though that as you retard it from the factory setting you're potentially losing power and fuel economy....

Not sure I'm worried that much that'll I'll mix my own additives though