Timing/AC DELCO Dizzy Help

[Judger]

Good Morning (barely),

I recently installed a THC and am trying to get everything running a bit better on the 73 F engine. That said, I have never timed an engine before. The 73 came with an AC DELCO dizzy, I believe it's an HEI I believe. When I unlatched the top, it can't twist as it is keyed to only a specific location. Any help will be greatly appreciated.

When available I am debating swapping the whole setup for a Troll Hole Dizzy, although I would need a coil to go along with that I believe.

Is there any disadvantage to the Trollhole vs. OEM?

Also, is there any advantage to the AC DELCO that's currently on there?

VERY NEW to everything Land Cruiser and I appreciate any and all help.

Thanks,

Judge

 

[Curt]

To time the dizzy you have to move the whole assembly with the cap on, This means loosening off the bolt that secures the dizzy to the block. The rotor stays put and the signal generator moves back and forth, that's why you cant move the rotor. I have no experience with that sort of dizzy so not sure what the base looks like.

 

[ryanwk628]

To expand on what Curt said, here are two relevant pages from the FSM I grabbed off Coolerman's website.
The outer housing moves around the inner shaft which is connected to your engine by the cam gear. The timing process should be the same, moving the outer housing and cap relitave to the orientation of the inside shaft (which should be fixed if the engine is not running.) A timing light flashes where the rotor passes the #1 wire and strobes to show where a mark is at that given position. Im not sure what position an HEI should be set at idle but my distributor Im told should be at 10 degrees.

 

[Judger]

Okay so I was able to adjust the timing, there was a bolt down by the block. The FSM refers to the "ball mark". Is that the dot with the circle surrounding it. There's also a white line about a 1/2 inch down from that. I'm confused about what degrees advanced mean. I've tried YouTube with little success as most of the timing there is for Chevy's.

Also, it REEKS! like to the point where I have to shower after I've driven or work on it while running. I haven't done valves yet, it's an exhaust smell, not gasoline and doesn't smell sweet at all.

The engine isn't smoking, but when the air cleaner wasn't hooked up I did see puffs of blackish smoke exiting the vent in the top of the valve cover.

Thanks!

 

[ryanwk628]

Okay so I was able to adjust the timing, there was a bolt down by the block. The FSM refers to the "ball mark". Is that the dot with the circle surrounding it. There's also a white line about a 1/2 inch down from that. I'm confused about what degrees advanced mean. I've tried YouTube with little success as most of the timing there is for Chevy's.

Also, it REEKS! like to the point where I have to shower after I've driven or work on it while running. I haven't done valves yet, it's an exhaust smell, not gasoline and doesn't smell sweet at all.

The engine isn't smoking, but when the air cleaner wasn't hooked up I did see puffs of blackish smoke exiting the vent in the top of the valve cover.

Thanks!

I dont claim to be an expert but think I understand the basic concept. You have to send the spark before the piston reaches the top of its compression stroke because it takes a little bit for the energy to get there and the gasses to ignite. 10 degrees would mean it fires ten degrees before top dead center, so the cap has to be lined up with the rotor before the rotor is in the top dead center position. Advancing it means firing it earlier, retarding it means later. As the engine spins faster it usually needs to fire earlier (more advance.) This article explains it better than I can.

With the engine at top dead center, if the cap is line up right over the rotor, the timing should be at zero. Turning the distributor CCW from there would give you the initial advance because the rotor would pass under some amount before the zero point. The camshaft drives the dizzy (and valves) and spins at half the RPM of the Crank so that it only passes each point once every two strokes (compression and exhaust) so knowing that you could get it close to start (1/2 a degree ccw on the dizzy would be 1 degree on the crank) then dial it in.

Perhaps someone with an HEI can chime in on what the initial timing is. Probably somewhere between 10 and 14 would be my guess.

 

[65swb45]

Check your spark plugs for oil fouling. Sounds like you have blowby issues.

Best

Mark

 

[Judger]

Thanks to all. I think I'm getting it a bit. I have a vacuum gauge on the way, as I think there's a leak somewhere. The idle mixture screw isn't doing anything when I adjust at idle.

So the "bb" mark is the small ball marking I see while timing? The whole advanced thing is that I'm on the other side (above?) of the "bb" mark? How do you know how many degrees you are? I couldn't make out any other marks on the flywheel.

I will check for blowby (once I use the search feature and figure out what that is).

As always thank you!

 

[ryanwk628]

Full disclosure, I have not timed my 40 yet but will be shortly once I get it back together. If you cant see timing marks, as long as you can find top dead center you can calculate where they would go if they were on the balancer based on the diameter and use a paint marker to mark them off. Then use the timing light to set its position relitave to a mark on the block. Ive seen this done on vehicles that had timing stickers and the stickers fell off, where they couldn't trust to balancer zero or where the marks are just not clear.

 

[Judger]

Makes sense, thank you for the help.

 

[Cruiser Corps]

To set the timing, you have to have a timing light with an advance dial on it. On the distributor, the vacuum line for the advance should be disconnected and capped. Hook up the timing light, start the engine, then use the dial to find the BB. once the BB is lined up with the pointer, whatever the dial is set to is what your initial advance is. I set it to 7 degrees initial timing. Vacuum source should be manifold. With the vacuum connected, you should see around 22 degrees total timing at idle. That can be checked with the dial on your timing light as well.

- Josh

 

[Judger]

Okay, so then I bought the wrong timing light. I'll get one with a dial on it.

Thank you I will follow this! Really helpful!