Ignition timing question

[martin]

Hi martin thanks for that.
Whats this party in norfolk then

Hiya, have a look in the mag, they throw a weekend party in a hotel, we've been before and it's magic. Martin. PS, I can't keep calling you Bunny ?

[bunny]

Hi
Sorry Martin its vince not bunny lol will have a look in the mag, was hoping to get to the telford pub day out on new years day.
But we aren't going to make it now due to not enough time to get the old girl back on the road, but can make the norfolk one lol

[Westfaling]

I can confirm on re-building my engine that the TDC timing mark was off by 4 Deg. I elongated the mounting holes in the timing plate to correct the issue.
Nick

[wilf]

So - do I infer from this thread that the TV8 will take a bit more ignition advance than standard without issues, and benefit from it?

This is the exact same situation with the RV8, where to get best output, you advance until it pinks, then back off a bit. They run better with advance figures way above what the books say.

[Bob Heritage]

The Mk 1 distributor has a bigger advance curve, so be careful if you overadvance a Mk1.

[404ROD]

Was not the original Stag timing setting, recommended in the manual at 12deg. BTDC, was when leaded petrol was in common use? When unleaded came in the recommendations were to retard the timing by a few degrees. Perhaps the best was is to have the engine checked on an electronic analyser.

Rod

[Lingen]

Steve. A small point, but there is no need to disconnect the vacuum pipe and block it off, as it isn't doing anything at tick-over. It might be worth checking that the mechanical advance hasn't stuck in an "Advanced" position, as oiling it occasionally under the rotor arm is often forgotten. You should be able turn the rotor arm in an anti- clockwise direction against a spring, and it should return on its own. If it has siezed, it may free off with some lubrication, but if not, you will have a small stripping-down job to do. 12 degrees btdc is the usual setting with unleaded. If you find the bonding has failed on the crankshaft damper, and the scribe mark is no longer in the right place, I can tell you that there is a project in hand to have them reconditioned. It will be some weeks off yet, but should you decide to replace it, don't throw the old one away! Mike.

[martin]

Was not the original Stag timing setting, recommended in the manual at 12deg. BTDC, was when leaded petrol was in common use? When unleaded came in the recommendations were to retard the timing by a few degrees. Perhaps the best was is to have the engine checked on an electronic analyser.

Rod

Hi Rod, the original recommendation was 14deg. huge difference

[V Mad]

Was not the original Stag timing setting, recommended in the manual at 12deg. BTDC, was when leaded petrol was in common use? When unleaded came in the recommendations were to retard the timing by a few degrees. Perhaps the best was is to have the engine checked on an electronic analyser.
Rod

There are not many engines on the road which will match the originals now. Heads have been skimmed, gaskets changed for thicker/thinner, pistons changed from domed to flat top etc etc. So even if you were using the original leaded fuel, you would probably need a different static advance setting.

The same applies to the dynamic advance (centrifugal and vacuum) ie engines have changed and may work best with a different advance curve. I suspect many Mk2 stags are still running the standard Mk2 dissy, but if you are running at a lower compression (eg flat top pistons) you may benefit from using more dynamic advance such as that on the Mk1 distributors.

An engine analyser will not help much. To find out what is the 'best' advance for your engine (based on power/torque) you need a good rolling road session. They should be able to plot the best curve for your engine, then you can go and get a dissy set up to your own special curve. At the same time they will see if your carbs are set up correctly too.

[martin]

There are not many engines on the road which will match the originals now. Heads have been skimmed, gaskets changed for thicker/thinner, pistons changed from domed to flat top etc etc. So even if you were using the original leaded fuel, you would probably need a different static advance setting.

The same applies to the dynamic advance (centrifugal and vacuum) ie engines have changed and may work best with a different advance curve. I suspect many Mk2 stags are still running the standard Mk2 dissy, but if you are running at a lower compression (eg flat top pistons) you may benefit from using more dynamic advance such as that on the Mk1 distributors.

An engine analyser will not help much. To find out what is the 'best' advance for your engine (based on power/torque) you need a good rolling road session. They should be able to plot the best curve for your engine, then you can go and get a dissy set up to your own special curve. At the same time they will see if your carbs are set up correctly too.

Naughty boy !

[404ROD]

Hi Martin,
You are right to a degree(pun intended). My Stag handbook states static ignition timing as 12deg. BTDC on page 73.. The manual states static timing as 14deg. BTDC up to engine No. LF 20000 and 12deg. BTDC from engine No. LF 20001, page 05-1.

Rod