Strobe light trouble

[SeaKayaker]

Maybe I am doing something wrong?
I want to check the ignition timing, as my new R4L (1979=1108 with ducellier & vacuum advance) pinks just slightly, if I use, say, half throttle (or more) when accelerating. New points, condenser, plugs, leads, airfilter, running on Sans Plomb 98 with lead substitute additive. I have a strobe light, I have marked the "notch" on the flywheel (which confirms the rotor arm pointing to spark plug lead No.1 ) with tippex. But, when I use the strobe light, it does not show the mark in the bellhouse window at any time. I can see the flywheel advancing, when I increase the engine revs, But, there is no sign of the flywheel mark. As a by the by, have just ordered a Boyer Bransden unit, which seems to be the best option, keeping the R4 Philosophy in mind, and will fit that next week.
All advice welcome.
Sea Kayaker, in the south of France

 

[iMacThere4iAm]

You have to disconnect the vacuum advance tube before using a strobe.

 

[mojobaby]

probably irrelevant to your problem, but I use Sans Plomb 95 with lead substitute additive. works perfectly for me and its a bit cheaper.
I have two marks on my flywheel. One is Top dead centre and the other 10 degrees before TDC. I usually set up half way between these two marks.
Perhaps you've marked the wrong notch on the fly wheel?

 

[jonigel]

Sans plomb 95 is right for your engine unless you have a CIE 14 and it does not really need additives,mine does 1000s of KMs per year no trouble..
As for timming it is probably easier to do it by ear, sounds like it needs a bit of advance,if your points gap is good ,54 degrees dwell + or - 1,or 16 thou,they are old engines and each one performes slightly differently,it is trial and error Bon Courage.

 

[DavidN]

Not seing the flywheel mark sounds odd.
Are you sure you picked the right Spark plug cable to time the strobe light?
You have to use the one that is close to the gear box.

 

[SeaKayaker]

Many thanks for the advice.
I am sure I have the correct (front) HT lead. I have been using SP98 to see if it stopped the engine pinking (which it seems to improve), But I will try SP95 again.

I will re-check the dwell angle...

I am beginning to wonder if the flywheel has been removed and refitted at some time in the past.... There is only one mark, which i highlighted with tippex. On my next day off, i will re-check all: and try to get a good picture to post.

many thanks,
SeaKayaker

 

[angel]

You may have too much spark advance, so that the mark goes out of sight (the window on the bellhousing is rather narrow). Set the timing with the static method, then check it dynamically with the strobo lamp. Make sure the vacuum advance pipe is diasconnected.
It's not possible to fit the flywheel in the wrong place on the 5 bearing engines.

 

[SeaKayaker]

Hello Angel! You were spot on! The timing mark HAD disappeared from view as there was so much advance. Thanks to all for the advice here.
I re-set the timing as per your advice, and the book, and immediately lost the pinking. However, I then found some uneven running, and a lot of "stumbling" when accelerating from low revs when trying to pull out from road junctions....
I have now advanced the ignition slightly, to the point that the flywheel mark is only just visible in the window with the strobe light when at idle (vacuum pipe removed). Much better performance.
I then fitted the new Boyer inductive discharge unit (just arrived in the post from Boyer in Maidstone, England).
Fitting was very easy. Starting is quicker, Tickover is smoother (the improved spark really is noticeable). Wow! the engine feels much crisper throughout the rev range!!! £35 well spent.
I went for a 3 hour drive this afternoon, warm, sunny, sunroof open, car running really well. Very happy!
Sea Kayaker