Amazon: Newbie question - TDC issue

[Faust]

Originally Posted by Derek UK

Is the firing order correct? It needs to be 1, 3, 4, 2 (no.1 lead needs to goes at the 5 o clock position on your dizzy cap as you look at it from above – no. 1 cylinder is at the front of the engine). To set the static timing, no 1 needs to be at TDC with the rotor arm pointing towards no 1 plug lead. Both valves need to be closed on no. 1. "
Wrong.........
See Ron's picture - Plug lead #1 is at about 10 o'clock not 5 o'clock. With the cap off and at TDC the rotor should point at the notch in the edge of the dizzy case at 11 o'clock. Moving the dizzy body about 5º anticlockwise (10º of timing) should get you a start. Note TDC at #1 is with both rockers "rocking" i.e. both valves closed.

Strange one this: my no.1 DOES point to 5 o' clock. If I try swapping leads around/adjusting the dizzy (it’s fitted with the notch in the correct location to the best of my recollection) the car will not run… as it is car runs very well.

I've got the Bosh 078 on mine with the vacuum advance disconnected & capped.

Forget what the timing is set at - it might be 10 degrees BTDC at idle.

Of course with cars the age of ours, who knows what mysteries lurk?

Anyway, don’t want to derail this thread as it’s not about my car.

Ed: if the system is supposed to be set up the way described by Ron & Derek, then I’d certainly go with that!

[Ron Kwas]

Faust;

What is critical is the order of wires on Dist Cap when going CCW, and that whatever station Rotor points to when Crankshaft is at TDC, is going off to Cyl 1.

This means that if Dist Driveshaft has been changed from the standard position, Rotor WILL be pointing to some other clock position, but as long as the Ign Wire coming from that station on Dist Cap goes to Cyl 1, its no issue!

Also, as has been discussed here before, sometimes the Vacuum Pot on Dist Housing fouls the Engine Block as one is turning it in the course of adjusting timing...the remedy for this is turning the Dist Housing 90Deg in a direction (either) to eliminate this fouling, AND repositioning the wires in the opposite direction by 1 station (also 90Deg). Ref: http://www.sw-em.com/Volvo%20Ignitio...ional_Position

Bottom Line: Wires may wind up almost anywhere...but as long as they go to their respective Spark Plugs and in the right order, no problemo!

Cheers

[SE10 Amazon]

Originally Posted by Ron Kwas

Faust;

What is critical is the order of wires on Dist Cap when going CCW, and that whatever station Rotor points to when Crankshaft is at TDC, is going off to Cyl 1.

This means that if Dist Driveshaft has been changed from the standard position, Rotor WILL be pointing to some other clock position, but as long as the Ign Wire coming from that station on Dist Cap goes to Cyl 1, its no issue!

Also, as has been discussed here before, sometimes the Vacuum Pot on Dist Housing fouls the Engine Block as one is turning it in the course of adjusting timing...the remedy for this is turning the Dist Housing 90Deg in a direction (either) to eliminate this fouling, AND repositioning the wires in the opposite direction by 1 station (also 90Deg). Ref: http://www.sw-em.com/Volvo%20Ignitio...ional_Position

Bottom Line: Wires may wind up almost anywhere...but as long as they go to their respective Spark Plugs and in the right order, no problemo!

Cheers

does this count with the 123 Distributor as well?

cheers

Ed

[Ron Kwas]

Ed;

I'm not intimately familiar with the 123 Dist, but I can't believe it wouldn't follow the same rules in this respect...what is different on those is the manner Spark is generated, so that happens on the Ign Coil Primary side...the Secondary (Hi-Voltage) side is essentially similar to the OE Dist, and still must play functionally and mechanically in the same manner as the stock Dist, and route (Distribute!) the Hi-V to the correct Plug.

Someone with a 123Dist may want to chime in here and confirm this...

Cheers

[v8250]

Originally Posted by Ron Kwas

but I can't believe it wouldn't follow the same rules in this respect...Cheers

This+1, an ignition distributor of any/all types is simply transferring an electrical discharge to the right cylinder at the right time[from rotor to cap to sparking plug lead to spark plug], even contactless. As long as the distributor leads are in the right order and is set up near enough to run at idle[no matter how roughly] the BTDC, TDC and advance/retard can be found and set up. Though, naturally, one should be setting up ignition using dwell angle as opposed to just sparking gap.

https://www.howacarworks.com/ignitio...he-dwell-angle

this is a great reference for setting up and getting the best from distributor based ignition systems

https://www.veloce.co.uk/shop/produc...spip8edhbfakt6

[swedishandgerman]

Originally Posted by SE10 Amazon

does this count with the 123 Distributor as well?

Ed

The 123 Distributor is a great bit of kit to replace each type of B18 or B20 distributor seeing as it has all those different settings. It is a solution to the problem that each type of OE distributor is no longer available.

However - and I have in the past upset a good few people who have bought into the 123 thingamer at some expense - there is very little difference in what the thing offers in comparison to OE:

• The advance curves are copies of the OE curves. The B18A setting matches the original B18A curve, the B20B setting matches the B20B (078) distributor and so on,
• There is a feature that changes the advance at idle to give smooth idling. But I have no problem with idling on either of my OE cars,
• There's another feature that alters the advance at very high engine speeds if you're the kind of person who is prepared to rev the tits off your poor old Volvo.

A couple other benefits include elimination of points bounce at high engine speeds (never experienced that myself) and maintenance free, So if you're incapable of setting your points, that's great.

Setting up the distributor to begin with is a doddle with the little green light having chosen which setting as most appropriate for your engine, IE B18A setting for B18A and so on. However, I would still recommend setting it all up at full advance with a strobe light. That is setting it at say 34 - 36 degs at about 2,500 rpm, then checking it goes back to the correct advance it idle, what ever that should be in the book or thereabouts. I would still carry out incremental adjustments to make sure it is set with the most amount of advance with no trace at all of pinking. Efficiency is highest at just before pinking, but drops off massively when pinking. I recommend this method for any distributor, regardless of OE or 123 or anything. That's how they should adjust the timing on a rolling road - set it where it develops the most amount of power at the wheels.

There's one exception here which our man Faust has mentioned and is particularly pertinent seeing as SE10 Amazon's car is a B20B. The original B20B distributor (078 type) had a vacuum canister which was worse than absolutely useless - it's a vacuum retard thing and serves no purpose to the running of the engine. In fact, when there's massive vacuum in the manifold, like changing gear or going down hill, it retards the timing to burn up a load of hydro-carbons. It's best to disconnect the vacuum and plug it: it runs much, MUCH better.

As such, Ed (SE10 Amazon) seeing as you're replacing a B20B distributor you should do the same. However, and I think Arcturus did this on his B20B with great results, the B18B distributor has a fantastic curve for twin SU's with full mechanical advance and no vacuum advance. I well, WELL recommend using that setting and don't connect up the vacuum can.

For an engine with big modifications, the 123 Tune is something completely different where none of the settings on the standard 123 give the optimum curves.

[Ron Kwas]

Ed;

I've just completed a new section which explains and demonstrates this, and added it to the SW-EM Ignition Page...no news to the experienced vintage Volvo mechanics around here, but maybe of some help to those a bit less experienced. See: http://www.sw-em.com/Volvo%20Ignitio...ire_Variations

Cheers

[SE10 Amazon]

Just to update..........

Found the timing marks after some searching, so thanks for the help!

Green light is on on the 123 dizzy

I thought the leads and spark plugs had turned up, but they were for another car of mini (Classic Mini) but they arrived last week

Weather has hampered any efforts this weekend as there isnt any heat source in my garage!

but once I find some warmer layers i will get round to trying to start her!

Thanks again for the replies

Ed

[SE10 Amazon]

SHE RUNS!!!

Not for long, but she runs on all cylinders!

Thank you for your help on this forum members.

Think we have a fuel issue which is probably caused by the car sitting still for 14 years!

but we can get that working soon enough by clearing pipes and rebuiidng the carbs to make sure everything is moving properly.

Ill post some photos when i take some!

Ed