B20B Ignition issue

[lelshaddai]

Ok, replaced the valve stem seals yesterday. More or less went as planned. Now the car will not start. I download Ron's ignition writeup and am going through the manual. Cannot seem to diagnose what is wrong. Here is what has been tested. It turns other but cannot get a spark. It briefly tried to start but now just turns over. Could be cap and rotor but car started fine before I changed the seals. I did take cap off to change the seals.

With ignition on: Coil wire has 13 volts and wire to points has 13 volts. Center of cap has 13 volts. When I place the rotor in the upside down cap and connect it with the #1 wire on the cap I get 13 volts at the end of the plug wire.
Points on arm side have 13 volts. When points are closed the volts drop to .2 volts at the coil wire port in the coil and points wire at coil.

When I turn it over I do not seem to get a spark. I have tested other coils. from different cars that have threes wires on top for resistance but this coil is different.

I am prepared to get a new cap and rotor just wanted to troubleshoot and make sure that is it. The cap I have right now just sits on the dizzy with no tabs that go into slots to keep it in place. Is that normal?

Thoughts?

The engine is a B20B from a 68-69 P1800

[lelshaddai]

Using more of Ron's article I do have it running. It is timed to 18btdc, 750rpm idle, 35 btdc at 2500 rpm, Weber 32/36 carb dialed in. Lash are correct at .022-.025, points at .016. I still have a couple of issues. No matter where the timing is at or carb adjusted it still stutters every 3 to 4 seconds. It will do this at 65 mph also. You are cruising and it stutters like a miss.

[lelshaddai]

I have been thinking about the stutter further. The timing marks on the crank under the light tend to jump around. Could the distributor shaft area be worn to where it is changing the timing?

[arcturus]

Could be worn, easy to pull out and check the shaft. I think that 18 btdc is a bit much. Ten would be nearer the mark at 6000 to 8000 rpm in my opinion and according to book. I suspect that you might have an issue with the coil. It sounds similar to that which I experienced recently.Also check the insulating washers where the condenser wire attaches to the dizy body. That can be a source of problems.

[mocambique-amazone]

QUOTE=mocambique-amazone;2407040]George, you did mentioned 600-800 rpm ;-)
Lelshaddai, this dizzy should finish advance at 2550rpm. I would check max advance at 3000rpm to be on the safe side.
If this dizzy is doing only 18° mechanical advance at the crank something is wrong. It should do 24-26° at crank.
Remove the cap and check if it's possible to turn the rotor clockwise (back, against rotation) if there is play one spring maybe broken. Have a closer look with a torch. You should see two springs, a thinner and a thicker one. It would be the spring of the first step flight weight.
Hickup maybe a fault of the condenser too. You will check this on a dizzy-bench, which you won't have access to, or with a clear cap! People with bugs love them. The clear caps aren't good while driving, still good to do a test!
If you see a strong spark between the contact's the condensator is dead. Don't swap against a new one if yours is working. The new ones are garbage. Even NOS parts will fail, they get rotten inside sometimes.
Drive with a theft coil. If the hickup disappear the ignition switch is the fault. Or a electric contact to the switch.
Good luck, Kay[/QUOTE]Vx

[swedishandgerman]

As above, it seems that your mech advance isn't right; you should be getting a much wider range than just 18 to 35. It could be jammed up and just needing oil, but you can just check by grabbing the rotor arm, twisting it and checking that it has good springy tension and "clinks" back into position. If it's stiff, oil it. If it's floppy - that could suggest why it's jumping about with your timing light - you'll be lucky to find some springs and you're probably better off replacing the whole lot.

One thing - what are the numbers on the side of the distributor? For a B20B it shoudl be 078.

If it's an 078, use the timing light with the vac hose disconnected. It's a stupid vacuum retard thing and best left disconnected.

[Ron Kwas]

lel;

An occasional "miss" is often exasperating to locate, and simplest and best found by Kay's substitution method...

...regarding Centrifugal Advance Curve... I'm in the process of compiling curves for the various B18/20 Distributors to add to the Ignition page...this is not yet finished and ready for presentation, but see this thread on Volvoniacs for some good raw data which hopefully includes your fitted Dist: http://www.networksvolvoniacs.org/in...66/#post_56132

Good Hunting!

[arcturus]

Originally Posted by arcturus

Could be worn, easy to pull out and check the shaft. I think that 18 btdc is a bit much. Ten would be nearer the mark at 6000 to 8000 rpm in my opinion and according to book. I suspect that you might have an issue with the coil. It sounds similar to that which I experienced recently.Also check the insulating washers where the condenser wire attaches to the dizy body. That can be a source of problems.

Should read 600/800. Finger must have got stuck on the 0 key or maybe Parkinsons.
Theft coil. Please explain

[swedishandgerman]

Originally Posted by Ron Kwas

lel;

An occasional "miss" is often exasperating to locate, and simplest and best found by Kay's substitution method...

...regarding Centrifugal Advance Curve... I'm in the process of compiling curves for the various B18/20 Distributors to add to the Ignition page...this is not yet finished and ready for presentation, but see this thread on Volvoniacs for some good raw data which hopefully includes your fitted Dist: http://www.networksvolvoniacs.org/in...66/#post_56132

Good Hunting!

Oh wow! WOW! Where did that man get that information from? I hope it can be followed up with data for 026, 003/009, 077 and 078 distributors.

Those graphs are really useful compared to the data I have which gives info on start and finish, but nothing in between.

In fact, if lelshaddai has a very late b20a 085 distributor (never seen one of those before) then it looks like it doesn't have a very wide band. So saying it's set up at say 8 degs at idle, perhaps just under 30 degs is max at under 2,000 rpm is all it goes up to. I wonder if that is a distributor out of a very early 240 B20 or something; don't recognise it. Despite the engine coming from a b20b P1800. It shoudl be a 078

[lelshaddai]

Here is a pic of the dizzy. If anyone has a correct or better one for sale please contact me.