Timing light help/timing help

jestlurnin

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Good morning folks.

Been going down the timing/distributor rabbit hole on mud and I’m currently second guessing my timing light procedure 😳. My goal is to tune the 2F properly after getting rid of a Webber carb in favor of the city racer aftermarket unit. See image below for said light and current set up. Not the most expensive timing light in the world but I believe it’s served me well over the last 8ish years with my old 60, old 40, and current 45.

Background: 78’ FJ55, 2F engine (I believe original), city racer aftermarket carb, Davis unified ignition distributor (see image below).

I understand the line on the flywheel is TDC and the BB is 7 degrees BTDC. The “pointer” in my window is present and easy to see. Both TDC line and BB have been painted for better viewing.

My 1st question: when attempting to set my timing at 7 degrees BTDC (window pointer on BB) should I set my timing light to 7 degrees of advance or set my timing light to 0 degrees of advance?

My guesss: if my timing light is set at 0 degrees of advance the window pointer should line up with the TDC line on flywheel and if I set my timing light at 7 degrees of advance the BB should line up with the window pointer which is the starting point I’m looking to achieve.

If I turn the distributor clockwise after lining up the BB with the pointer and my timing light at 7 degrees of advance it will move the BB “down” in the window or father towards the passenger side of the rig. and by turning the distributor clockwise I will be advancing my timing further.

Can someone confirm or deny my timing light/timing procedure pretty please.

2nd question: do I want to disconnect the vacuum line on the distributor prior to setting timing? The vacuum line goes from the distributor to the base of the carb next to the idle mixture screw.

Thanks in advance for any help!

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Let me see if I can get this right myself. It's been a while since I used my dial back timing light.

With MY timing light set at zero and turning the distributor so it flashes to show 7 degrees lined up, it's 7 degrees.

If I set it to 7 degrees on the light, the pointer would be at 0 (TDC)

Yes you disconnect the vacuum advance and plug the line so you don't have a vacuum leak at the carb. This is for initial timing at idle. Just the mechanical advance.

The dial back feature of the timing light is great for checking your timing curve at different RPM's. For example, when it's set at zero and you're showing the timing mark at TDC , when you start revving the engine the timing marks start changing. So if you decide to see what the timing is at 3000 RPM, you dial back the timing light until the pointer is at TDC again and then read the degrees on the timing light. So if it says 20 degrees on the light, you have 20 degrees of advance at 3000 RPM.

You can check your entire timing curve this way. If the vacuum advance is disconnected, it's your mechanical advance curve.

Once you reconnect the vacuum advance can, you can see how much it works. If it's adjustable, your timing light is the way to check it.

I hope this helps.
 

jestlurnin

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Thank you @aztoyman !

So if I’m understanding your post correctly I need to set my timing light to ZERO

(in my picture above I was tuning carb so it is set to RPMS)

and when the window pointer is on the BB I’m at 7 degrees advanced. And the farther I go clockwise the more advanced my timing will go? So say the BB is just about to exit the window towards the passenger side my advance would be at 10-12 degrees advanced?
 

Pighead

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and when the window pointer is on the BB I’m at 7 degrees advanced. And the farther I go clockwise the more advanced my timing will go? So say the BB is just about to exit the window towards the passenger side my advance would be at 10-12 degrees advanced?
IIRC, the dizzy rotor moves in a clockwise direction when running. So, rotating the dizzy body in a clockwise direction will retard the timing.
 

jestlurnin

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And yes your post did absolutely help and I believe confirmed I’ve been using my timing light incorrectly for 8ish years 😂
 
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I didn't see a pic of your balancer or timing pointer so I don't know if you are advancing or retarding it.

You should be able to tell which way it advances when you rev it and see which way it goes to advance. Or if it has higher numbers on the damper.

Or like @Pighead said. Look at the rotation of the distributor. Turning the housing toward or opposite rotation is advancing it.
 
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That HEI distributor should work great. Was it setup with an advance curve for YOUR application when you bought it?

If not, it's an easy one to tune. Look up whatever the recommended advance curve is for your truck, plot out what you have with your timing light and adjust it as needed. You can tune your vacuum advance as well IF it's adjustable.
 

jestlurnin

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Ok I got it now. Thank you everyone.

The D.U.I. dizzy was on the rig when I bought her. I’ll jump on there website and see if there is tuning info. If not maybe I’ll shoot them an email. Or search the interwebs.

To be honest I’d like to go back to a stock NOS dizzy if I can find one. Working on taking Marge (that’s what my boys named her) back to OEM.
 

thorslc1977

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The City Racer distributor ( OEM Toyota) that is for 1977 is a plug and play with ignitor or you can use the capacitor (comes with distributor) and not use ignitor. I dropped one in my 1977 and use my original ignitor and coil. It runs great. My old distributor had worn the bushing so much that the shaft wobbled so badly I had to use .012 gap to get it too run and eventually even that wouldn't work.
 

jestlurnin

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@thorslc1977 thanks for the city racer OEM dizzy plug. I’ve had my eye on that one. I’ll see what ends up shaking out with this D.U.I and if it’s no bueno I’ll probably go that direction. I’ve heard tails of these aftermarket dizzys walking up outa the hole causing engine failure. Plus it would be another cruiser electrical lesson to learn as I’m no electron wizard and don’t really understand the ignitor/coil/dizzy relationship as of now.
 
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@thorslc1977 I’ve heard tails of these aftermarket dizzys walking up outa the hole causing engine failure.

Or the shaft/armature can get sucked down into the engine and grind against the pick-up coil. Not pretty. At least you don't lose oil pressure before the spark begins to scatter making the vehicle undriveable.
 

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