7 replies to this topic

[BaronVonchesto]

just fitted back the head, and installed a new Minispares C-27H001 distributor while at it.

Installed the dizzy exactly as instructed in the haynes manual (with the no. 1 cylinder at TDC).

 

Engine started up right away and seems to be running well, however with my timing light its showing the ignition advance at about 40 deg BTDC at about 1000 rpm which is weird. Plus when I rotate the dizzy anti clockwise, the rpms start dropping off right away and rapidly. So right now i have it turned as clockwise as it can go. Vac advance has been blanked off with a screw and some masking tape.

 

Have I perhaps gotten the HT leads mixed up? I'm thinking I should try shifting each of the leads one step clockwise?

 

PS: I have an additional mark on my cam pully at 20 deg BTDC so thats how I know how many degrees it is even though the A+ only has teeth to 24 degrees.

Edited by BaronVonchesto, 27 May 2023 - 10:13 AM.

[weef]

Normally a good starting off point is a static setting of 5-6 dec BTDC. This usually gets the engine started and allows it to warm up to operating temperature.

Once wamed up blank off the advance/retard pipe and up the idle speed using the idle adjust screw on the carb to about 1500-2000 rpm, it is good if you can measure this but not essential. Now advance the ignition, turning the distributor clockwise, until the revs peek then retard the ignition, turning the distributor anticlockwise, until the revs drop slightly, maybe 300 RPM, you will have to guese this if you cannot measure the RPM, now nip up the distributor and reset the idle speed.

Road test time now to see if there is any pre ignition ,"pinking", and if there is back off the timing slightly till this stops.

Turning the distributor anticlockwise, retarding the ignition, will cause the RPM to drop as you describe and this low RPM setting can be a good starting point to do the adjustments I suggest. 

If the engine is now running sweetly and you are happy fit on your timing light and check the reading, using this setting for futher reference.

[Lplus]

just fitted back the head, and installed a new Minispares C-27H001 distributor while at it.

Installed the dizzy exactly as instructed in the haynes manual (with the no. 1 cylinder at TDC).

 

Engine started up right away and seems to be running well, however with my timing light its showing the ignition advance at about 40 deg BTDC at about 1000 rpm which is weird. Plus when I rotate the dizzy anti clockwise, the rpms start dropping off right away and rapidly. So right now i have it turned as clockwise as it can go. Vac advance has been blanked off with a screw and some masking tape.

 

Have I perhaps gotten the HT leads mixed up? I'm thinking I should try shifting each of the leads one step clockwise?

 

PS: I have an additional mark on my cam pully at 20 deg BTDC so thats how I know how many degrees it is even though the A+ only has teeth to 24 degrees.

I'd be surprised it ran at all at 40 deg at idle.  You don't have one of those clever timing lights that can be set for a preset advance, do you?  There was someone on here a few weeks ago  who had oneof those and it wasn't set for straight timing so he was having all sorts of problems.

[BaronVonchesto]

 

just fitted back the head, and installed a new Minispares C-27H001 distributor while at it.

Installed the dizzy exactly as instructed in the haynes manual (with the no. 1 cylinder at TDC).

 

Engine started up right away and seems to be running well, however with my timing light its showing the ignition advance at about 40 deg BTDC at about 1000 rpm which is weird. Plus when I rotate the dizzy anti clockwise, the rpms start dropping off right away and rapidly. So right now i have it turned as clockwise as it can go. Vac advance has been blanked off with a screw and some masking tape.

 

Have I perhaps gotten the HT leads mixed up? I'm thinking I should try shifting each of the leads one step clockwise?

 

PS: I have an additional mark on my cam pully at 20 deg BTDC so thats how I know how many degrees it is even though the A+ only has teeth to 24 degrees.

I'd be surprised it ran at all at 40 deg at idle.  You don't have one of those clever timing lights that can be set for a preset advance, do you?  There was someone on here a few weeks ago  who had oneof those and it wasn't set for straight timing so he was having all sorts of problems.

 

 

no i dont its just a simple cheapy timing light that lights up when it picks up a spark off the number 1 HT lead.

It definitely isn't at 40 deg btdc. as you say, that's just not possible. what's more likely is that the light is somehow firing at the wrong moment which is why i think the leads are placed in the wrong position.

[Lplus]

 

 

just fitted back the head, and installed a new Minispares C-27H001 distributor while at it.

Installed the dizzy exactly as instructed in the haynes manual (with the no. 1 cylinder at TDC).

 

Engine started up right away and seems to be running well, however with my timing light its showing the ignition advance at about 40 deg BTDC at about 1000 rpm which is weird. Plus when I rotate the dizzy anti clockwise, the rpms start dropping off right away and rapidly. So right now i have it turned as clockwise as it can go. Vac advance has been blanked off with a screw and some masking tape.

 

Have I perhaps gotten the HT leads mixed up? I'm thinking I should try shifting each of the leads one step clockwise?

 

PS: I have an additional mark on my cam pully at 20 deg BTDC so thats how I know how many degrees it is even though the A+ only has teeth to 24 degrees.

I'd be surprised it ran at all at 40 deg at idle.  You don't have one of those clever timing lights that can be set for a preset advance, do you?  There was someone on here a few weeks ago  who had oneof those and it wasn't set for straight timing so he was having all sorts of problems.

 

 

no i dont its just a simple cheapy timing light that lights up when it picks up a spark off the number 1 HT lead.

It definitely isn't at 40 deg btdc. as you say, that's just not possible. what's more likely is that the light is somehow firing at the wrong moment which is why i think the leads are placed in the wrong position.

 

If the leads were out of position the spark would be out by more than 40 deg.  I think your timing light might be on the fritz

[Spider]

I'd suspect the Harmonic Damper is on the way out and should be replaced ASAP.

At 1000 RPM, it won't run with 40⁰ Advance. I'm sure you have a bum reading here from the mark on the damper being in the wrong place.

[Lplus]

I'd suspect the Harmonic Damper is on the way out and should be replaced ASAP.

At 1000 RPM, it won't run with 40⁰ Advance. I'm sure you have a bum reading here from the mark on the damper being in the wrong place.

I never thougth of that, though wouldn't the timing mark have been out when the OP set the static timing?  Even if he'd checked tdc through the plug hole it would have been obvious that the timing mark on the pulley was off.  Still I suppose it could have just happened.

[Spider]

I never thougth of that, though wouldn't the timing mark have been out when the OP set the static timing?  Even if he'd checked tdc through the plug hole it would have been obvious that the timing mark on the pulley was off.  Still I suppose it could have just happened.

 

If the outer rim of the Damper is floating but still having some bonding, it'll may end up close to right when stationary, but end up anywhere when running.

Looking through a plug hole, even with something in there to feel the piston, it isn't hard to be out +/- 20⁰.