Navigator ignition timing

I think thatâs right as I recall.

Hello Nick,

The book figure is 24 deg but I too think this figure is too retarded. I run noticeably more advance and found that this gives much improved engine response. Start from 24 deg and experiment in small steps and back off if you get any 'pinking'. These engines have a reputation of damaging pistons if the timing is over advanced but the Electra runs the same cams and that is listed at 30 deg. I never did check for sure what advance I am running but it blued the exhaust pipes when set at the 24. so I simply retuned by ear. But be cautious.

Patrick

The problem I found was that 24` full advance gives a static timing of 2` which makes the bike noisy and hot an bothered at low revs. Opening up the points at tickover improves the navigator but high revs and full advance is when damage to pistons is going to occur. Patricks observations are spot on. The problem as I see it is the advance and retard unit being 11` camshaft advance, for all the lightweights, navigator and jubillee. The best thing for navigators could be an advance and retard of 8` of camsaft rotation advancing static timing but limiting full advance to nearer to 24`. Electronic ignition I think does away with the advance and retard unit, but I have not got there yet.

GRAHAM

I havenât got my Navigator running yet, but my jubilee has Boyer ignition set at 32 degrees max adv and runs and ticks over nicely, although I havenât put many miles on it yet. I think the Boyer is £100 well spent but will need to switch to 12volts. The pistons seem to be the same design as the navigator.

I still have a cracked piston from my old jubilee, I donât think it has much to do with timing, no signs of over heating I thought it was considered to be a design fault?

Dan

Actually reading from the later Norton Maintenance Manual for the Jubilee 250 - which includes the Navigator (1961-63) - this gives the ignition timing as 32 deg btdc fully advanced and 10 degs fully retarded. It does not give a different figure for the Navigator but the 24 deg figure is the one commonly quoted elsewhere. So make of that what you will. It quotes the plugs as Champion N3 but in practice I use Champion N9Y - purely because I have a stock of these for the MGB. I don't know of any source for the advance/retard springs.

Somehow 10 degrees static sounds about right - the standard Mk1 MGB is 8.8 compression same as the Jubilee/Navigator and this is listed as 10 degrees static.

Hi Dan,

That cracked piston is a bit odd as the crack seems to run from the gudgeon pin to the oil ring. Probably as you say just down to a manufacturing defect. Pre-ignition usually in my experience seems to result in the piston crown becoming detached and you get serious bore and head damage.

The crack is the same Is on both sides but I think the cracking is well reported, the bike ran fine until hot when it seized up, then freed when cold!

Hello All,

The first time I have any time to address the Navigator timing.  Looking at all this I was unsure  what to do 24 degrees when a a 250 and 400 both had figures in the 30s--like all my Triumphs 33 I think.  I have found the instructions for a Pazon electronic ignition which gives 32 for all the lightweights.  I think I shall try this but it may be a while until I get a chance to start it up.  I have never seen a Piston height figure--has anyone else?

Lots of fun today--I was putting a back wheel in an oil in frame |triumph and the bike slipped on the jack leaving me trying to hold it up like the bus on the Italian Job.  I got to keep strill but while reaching for something on a shelf I knocked a bit of bronze bar off which hit my hand and the tank taking chunks from both.

Cheers

JPA

Another lolly stick job.