Timing Catch 22 … have you ever encountered this?

[75 Westy FI noob]

Ive found through much trial and error that if I static time my engine it will start, but then run a but rough. The. I set the timing with a timing light.. advancing it a bit to about 8 degrees at idle. It idles and runs there.

But, next time I go to start it… it will not fire unless I redo the static timing task.

Vacuum leaks have been addressed via smoke test.

Really seems to be timing bc it wont fire at all after tiling light set to 8 at idle.

Any ideas?

Using an aftermarket dizzy w mech advance.
Has new points. Gap set, when installed but that was my first tile doing that.
Plugs, wires, coil are new.

[bsairhead]

[Wildthings]

Remove the cap, rotor, and dust plate and what the points while someone cranks the engine for you. You should be able to see the points opening and closing with a tiny spark.

If an engine has been running fine and the condenser doesn't look like it is 30+ years old I do not replace them. Why changing out a part that is working and likely has many years of service life left, with one that is unproven?

[75 Westy FI noob]

[/quote]What did you gap the points at?[/quote]

Perhaps slightly smaller than spec.
I will double check it. I dont think i had to correct feeler .. close by .001 or two

[75 Westy FI noob]

[Wildthings]

What are you working on anyway? Pictures are always nice.

[75 Westy FI noob]

Bay Bus ‘75 FI

Will send some pics.

[75 Westy FI noob]

Set to about 8 with timing light at idle.
Runs well as the mech advance is slightly engaged.

Now sitting at about 8 w engine off, and zero mechanical influence.. can see that the pad is on the farside/downside of the lobe and the gap is closing… closed.
(Also, discovered i have no dust cap so its dirty)

Maybe the answer is bigger gap. I bought a new set of small feeler guages.
Just not sure where to set the lob before adjusting.

Where it sits now ? That’s the ‘starting position’.
Or back it up to the lobe’s peak and gap it there?

[Wildthings]

It looks like your points are on the opening side of the lobe and quite far open, that would indicate to me your timing is too far advanced.

You set the gap when the wear block is centered on the top of the lobe. With new points you are looking for 0.018-0.020" of gap, the 0.016" assumes used points with a bit of pitting. I always remove the distributor to deal with the points, much easier to do when you aren't all cramped up and you can see what you are doing. Just set the cap aside with the wires (excepting the coil wire) still attached and remove the 13mm nut and washer that hold the clamp to the block, do not mess with the 10mm adjusting nut. When reinstalling make sure the cog on the bottom of the shaft engages with the slot in the drive and that the body fits down fully into the engine case. This way the timing should not change much. Be sure to get the green wire hooked back to the #1 terminal on the coil, if you hook it to the #15 (B+) side of the coil bad things will happen.

[75 Westy FI noob]

Thank you, WT. I’m so frustrated at this point. Getting it to fire is primarily a matter of luck. I managed once again after about an hour to get it to start, and then foolishly once again advance the timing slightly to make it idle better. And now, once again, I now cannot get it to start no matter what.

I’m beginning to think there’s too much lash in the distributor and the points are closed even when it’s set correctly.

I set my points to 16 maybe if I open them up to 18 or 20 that will help

Oh, and its now crawling w black widows after sitting thru the heat of the summer! 🔥

[75 Westy FI noob]

Pulled it out as prescribed… much much easier to do now.
Gapped to .019.

Will retry.

Note my 2nd ThermoII visible there

[busdaddy]

[75 Westy FI noob]

Can make out the black wire cap on the T2 …
It makes timing this one interesting bc cannot swing the condenser past it.

Anyhoo.. the extra gap got it running. Still think theres too much lash in this dist so i plan to replace it. It starts and runs rough… so i advance slightly.. runs well.. but then wont start. Ha

Gonna leave it rough.
Will shoot it w timing light later. Too hot.
Gonna take the W and have a cold one.

Thanks WT.
Never took my dist out before. Was scared to do that.
Made adj the points soo easy.

The dist is in no mans land. Hard to reach from hood or hatch

[75 Westy FI noob]

May have too few Amps from my battery.. cant close the lash on start, etc

When I say lash, I mean theres a few degrees of travel between all the way closed and the point where the spring comes into play.

[Starbucket]

Is the mechanical advance sticking, give the rotor a twist a couple of times and see if it's returning all the way. When was the last time you put a drop of oil on the felt pad in the shaft under the rotor it looks dry?

[75 Westy FI noob]

The mechanical advance that works against the spring load, seems to be smooth and free. But there’s a bit of space .. couple of degrees, where the rotor will turn before it encounters, the spring. And those couple of degrees seem to be what’s causing motor to fail to start (bc points closed).

Setting it at idle, the “lash” is gone.
Engine off, its 2-3 degrees off.

I havent ever oiled that spot under the rotor But its worth a try.

[raygreenwood]

A couple of things that may help in the long run:

First, these are your points from your posted picture

1. Notice that the gap on the left side of the points (red arrow) is way bigger than the gap on the right (yellow arrow). This means that it will fire on the narrow side only, eventually charrin that edge if it has not already.

2. Notice the blue arrow pointing to grease on the contact. Your points are dirty. Most greases are dielectric to some extent. Clean them and be careful of the grease.

3. The red circle shows the shagged out phillips screw which means you will likely never get your points tight enough to keep them from moving. Get a new screw.

4. The yellow circle shows a mushed out rubbing block. Get new and better points.

Item #1 and #4...as well as just looking at your points and the bushing material tells me these are likely Borg Warner points or similar.....which are junk.

They have all sorts of issues with the points contacts being straight and parallel. many are bent from production.

Get some SMP points from NAPA/Echlin. Ray

[75 Westy FI noob]

Ive oiled the felt as StarBucket suggested. It was dry. The oil may help with the rotor reset position.

Opened the Gap to .019 as suggested.. bigger gap definitely helping to get the spark in wider band.

Started it and readjusted the timing with a light to 8 at idle and 28 at high rpm.
Now starts and idles. Wish i could post video/audio.

Will adjust the valves one more time when weather gets out of the 90s.
Also found small exhaust leak at the elbow gasket. I may use JB Weld on that since its so small.

Thanks all for great advice!

[HarryFD]

Good tips above but to set points correctly, you need a Dwell Meter. Gap will get you close but the meter will make it right and also show if your points are drifting.

Something like this is what you need. https://www.amazon.com/DY2201-Digital-Multimeter-5...K831OC0S5G
_________________
1970 Deluxe Sunroof Bay Brilliant Blue/Cloud White
1973.5 911 Targa
2009 MB C300

[Wildthings]