B18 Timing help

JohnMc said:

So if you goose the throttle, it keeps running?

What do the sparks look like?

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yea, it keeps running if I give it a quick rev every so often.

Haven't checked spark color or strength yet. The plugs are generally black no matter how much I lean it out.

With the timing light not going off and black plugs, I'm going to assume I have a pretty weak spark..but I'm also retarded so it could be something else.

I would suggest checking those plug wires. A resistance check will help you test them.

I'll check the plug wires tonight. They are Denso brand that are closed to two years.

Thanks for the suggestions!

Still, giving the throttle a goose every once in a while to keep it running makes me think something is up with the carbs, more so than the ignition.

Those look like HS6's, so they don't overflow into the carb throat, instead just onto the exhaust manifold. (lol).

But still, it more sounds like the engine is just loading up on gas a bit much on an extended idle, and dying from being over rich. Possibly the jets hanging down (in choke position), instead of sitting against the stops? Or the float bowl levels a bit too high so more fuel is going in than should (not overfilling the bowls, but perhaps dribbling into the carb throats?).

JohnMc said:

Still, giving the throttle a goose every once in a while to keep it running makes me think something is up with the carbs, more so than the ignition.

Those look like HS6's, so they don't overflow into the carb throat, instead just onto the exhaust manifold. (lol).

But still, it more sounds like the engine is just loading up on gas a bit much on an extended idle, and dying from being over rich. Possibly the jets hanging down (in choke position), instead of sitting against the stops? Of the float bowl levels a bit too high so more fuel is going in than should (not overfilling the bowls, but perhaps dribbling into the carb throats?).

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I've gone though just about everything in the carbs multiple times (minus changing the jets). I've verified the chokes aren't stuck in the down position while it runs. Floats are new along with the fuel bowl valves. I'll pop one of the covers again tonight and check levels when it dies. In the past I had an issue with them overflowing out of the vent hole and onto the exhaust (awesome design), but new valves fixed that.

I do know that the fuel pump on this thing FILLS the fuel filter to the brim. I have one of those inline mechanical fuel pressure limiters that came with the car. I can try reinstalling that to cut down on how much fuel is being fed to the bowls.

It's not the fuel pump overfilling them, or they'd be overfilling out the vents.

Have you tried backing the mixture adjusting nuts all the way up? Just to see if you can get it leaner.

I was figuring the pump was giving it enough gas, because the filter was sitting there visibly full of fuel, the assumption being that you'd see that empty out of the carbs weren't getting enough gas. But wet sooty plugs, and a rev or two keeping it going for a while longer just makes me think it's a rich mixture carb issue.

Are the carbs balanced front and rear (air flow)?

Also, maybe try the mixture check pins - they sit under the dome's edge and push the piston up a specific amount. Try those at idle and see what they have to say about the mixture.
Push the pin up and:
- if the idle slows down, that carb is too lean. Adjust the jet downward slightly to richen
- if the idle speeds up briefly, then slows back down, that's good
- if the idle speeds up and stays faster, that carb is too rich. Adjust the jet upward slightly to lean

So here's my notes. It took 10 minutes of cranking again but it finally started and idled like ****.

Plug Wire Resistances
Cyl#1 8.8
Cyl#2 14.7
Cyl#3 7.1
Cyl#4 6.75
Coil Wire 10.7

Both of the coils I have are oil filled, so I've placed them right side up for testing.

Coil w/ external resistor
Bat 12v
(+) on coil side (disconnected from coil) 12v
(+) on coil side connected to coil and ignition on 11.7v
(-) with ignition on 5.9v
(-) when cranking 7.5 to 7.6. When it hits 7.7v it attempts to fire.

Coil w/ internal resistor
Battery 12v
(+) side when disconnected from coil 12v
(+) side when connected to coil 11.7v
(-) with ignition on .13v
(-) when crankking 4.5-4.6v

Car was backfiring through the carbs when running at both 15 flats and 0 flats (carb jet level with the body or whatever its called).

When pressing on the mixture check pins it would almost instantly die (idle dipping down) at both 15 flats and 0 flats. I am running 15w50 in the dashpots. I've also tried ATF

Since it sounds like it's running lean with the idle dipping at 15 flats, I'll go try and add more. Each time the car dies I am pulling the plugs and they are black.

***EDIT***

I readjusted the carbs to both 17 flats each and it started.

Rear carb idled high in pressing in the the mixture pin. Changed it to 15 and it was fine.

Front carb idle did not change when pressing in the mixture pin, so I left it at 17.

Both carb air flow is balanced by using a hose and my ear. I don't have a gauge.

With the car idling, it is at about 1100-1200RPM. However the tach on my multimeter reads 3500 when placed on the (-) on the coil. If I attempt to lower it to around 800-900 it begins to stumbled every so often. I revved the piss out of it for 1 minute and pulled plug #1 and plug #4. Both were black. No black smoke out the tailpipe.

I figured I should also mention while it's idling at the 1100-1200 that the timing gear pulley reads well above 30 degrees. If I lower it to 30 it will die. Previously I was able to get it to idle around 20.

Have you checked the advance mechanism in the distributor? If the springs are broken the timing will be very erratic.

The springs are intact and pull back on the advancer plates when you move them with a screw driver.

Have you checked for an intake manifold gasket leak?
Or a warped intake manifold?

I know that doesn't affect timing and realize you have pulley issues also.

))<>(( said:

The springs are intact and pull back on the advancer plates when you move them with a screw driver.

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As long as you see the spark advance and retard as the revs climb and drop, it's probably OK. A little timing wobble is not unusual in an older 'well experienced' distributor running ignition points.

A balancing tool is a great multiple carb tuning shortcut, absent that you have to do a very iterative process of trying to balance them by ear. Basically, when you screw the idle screw in and out some small amount (like 1/4 turn), on each carb, it has the same effect on idle speed. Screw it in 1/4 turn on the back carb and idle rises some small number of rpm, then go back. Then try it on the front carb and see if it goes up more, same, or less rpm. If it goes up less, then the carb is flowing less air, and needs to be opened up slightly. If it's the same, leave it alone. If it goes up more, close it slightly. And vice versa.

This is (considerably) complicated by the fact that the carbs might not have the same jet tuning - one may be running richer or leaner, thus affecting the idle speed produced from that carb. So after you've gotten them roughly balanced via the idle adjuster screws, then start tuning the mixture on each carb using those lift pins (when lifted, idle goes up and stays up - too rich, goes up then returns - good, goes down - too lean). Then go back and rebalance them via the idle screws, and if it made a difference, go do the mixture again. Until you aren't doing any adjustments on either.

Of course, this is where you have to mention the throttle shaft leaks on a worn old set of SU's. They feature brass shafts rotating in a cast aluminum body with no rubber seals of any sort. When the shaft wears into the softer aluminum (perhaps due to unleaded fuel? Or just... cheap design) it can create an air leak. And at idle, where you adjust these carbs using the lift pins, the vacuum is largest, and the 'metered' air flow is the smallest, so the leaks have the larges effect on mixture, leading you to set them to account for the leaking air, and leaving them too rich at all the other throttle settings.

Back when my PV had SU's it seemed like I needed to do a tuning session on them more or less seasonally. They just tend to drift out of tune for some reason. In small ways.

[Without reading the whole thread over...] If you replaced the points, did you make sure you lubricated the piece that follows the distributor cam? If you don't lubricate it, it wears very fast and causes huge drivability problems within a couple hundred miles.

Replaced the ghetto coil with the blue Bosch coil. Read 12V on (+) with ignition on and connected, so that's a step above the **** coil. Fired up but idled like ****. Re-adjusted carbs again because fuel was spitting outside of the mouths while cranking, but wouldnt fire.

At this point I'm 99% sure it's a weak spark. I laid down spark plug #1 connected to distributor near a piece of metal. The spark was faint, white, and didn't fire every time.

As far as the lubing, yes, I lubed the distributor arm, ceramic or plastic thing that rubs on the cam in the distributor, oil filler, and the top part under the rotor.

What would cause this? Cap, rotor, plugs, wires, coil, points are all new.

This is the rotor/cap/plug combo I have on the car
https://www.ipdusa.com/products/8337/105824-tune-up-kit-for-breakerless-conversion

Interesting, no condenser in that tuneup kit...

gsellstr said:

Interesting, no condenser in that tuneup kit...

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Yea, I had to buy it separate.

https://www.ipdusa.com/products/6591/100227-distributor-condensor

P.S. just tested spark from coil to coil wire and its strong, but a yellowish color.

Also I think someone asked, the intake manifold gaskets are new. I replaced all intake side gaskets. I've also tested the condenser.

Here's what the cap and rotor look like:

It could be a couple of things causing weak spark.

The points come with some corrosion inhibitor on them which needs to be removed prior to installation. I use a flap torn from the box to clean them.

The new condensers are a little smaller than the original ones and the clamp doesn't fit tight enough. I use a piece of brass shim stock to tighten it up so it gets a good ground.

The post that connects the points and condenser needs to be centered where it goes through the body of the distributor. Also, the paper strip inside the distributor insulates the points spring and needs to be in place.

Ive taken apart the distributor to make sure everything has a good ground and the screw is centered through the body. The paper is still intact, but old. I used a piece of plastic/o ring to make sure the bolt is centered and doesn't move.

As of right now, the points/condenser assembly goes: Bolt head-points clip/holder-metal clip thing-paper-distributor housing-rubber o ring in hole-rubber grommet-metal washer-spade connector-points-metal washer-nut. The condenser I have is firmly grounded/held in place against the distributor housing.


Where can I buy a kit like that? Besides the distributor itself, that's the only thing I haven't replaced in the entire ignition system.

I also keep reading about B18s and "armored cables". I'm running some ****ty stranded 16awg wire with ****ty auotzone connectors on the end between the the (-) on the coil and the condenser.

The proper order is bolt head, rectangular metal washer, points spring, square phenolic washer, paper strip - distributor housing - small round phenolic washer (centered in recess in dist. housing), metal washer, condenser wire, metal washer, lock washer, nut. The spade connector wasn't used on these distributors from the factory but you can use it if you want. The original wire just had a ring connector. The other parts in the kit aren't used on this style distributor.

Double check that condenser. If you can move it in the clamp by pushing on it with your thumb, it's too loose.

I have the distributor post kits in stock. The price has gone up on the kits so I customize them by removing the unneeded parts to lower the cost.

I believe the "armored cable" you're reading about is the coil (+) wire that's shielded by a double thick flexible metal tube and attaches the coil to the ignition switch. It's a theft preventative measure because it prevents the car from easily being hot wired.

Let me pull the distributor and re-fit everything. It sounds like I'm missing some washers in there, so I'll round some up.