timing on a 510?

[ricky]

ok quick question that i have not been able to find a topic on. i have a l16 in my 510, and a matchbox dizzy. should the timing be set differently then the stock dizzy with points. and if so what is the recommended timing for an electronic dizzy on the l16. thanks

[izzo]

should be the same, i set mine at about 10-12 degrees advanced.

[ricky]

ok thanks, and do you know if i need to remove vacuum advance while i set the timing like i would do on a chevy v8

[izzo]

Not sure about that sorry, i don't remove mine.

 

Timing should be set to your liking and what makes the car run well.

[ricky]

yea im looking for a starting point so i can adjust carb.

[datsunaholic]

Changing to EI doesn't change the timing, but if you change spark plug heat range to take advantage of a higher-output EI coil, then it changes a little. But at that point there's no real "cookbook" on where it should be, you have to fine-tune it.

[ricky]

ok i know this is a dumb question but i couldn't find the answer in the book on my car. what side dose the timing tab go on. if you looking under the hood on my datsun 510 it is on the left side where you can barly see it. i think it goes on the right side but i dont know for sure. if anyone has a picture of where theres is that would be vary helpful thank you

[datzenmike]

The higher output allow you to run a wider gap than the points. 0.038" to 0.042" is typical. The wider gap produces a wider spark to ignite the fuel.

[bredatto510]

as of the vacuum advance yes disconnect it while timing to achieve static timing... open up the plugs to 44 gap set it to 12 degrees btdc and reconnect ur vacuum advance

[datzenmike]

All carbs since the late '60 use ported vacuum advance. Certainly all Hitachi's do. For emission purposes there is no vacuum advance at idle so there is no need to disconnect it when setting the static timing. Off idle, the throttle plate rises above the vacuum port and exposes it to intake vacuum and the distributor advances. But at idle, the port is open to atmospheric air pressure.

 

It was common in motors before this to run with manifold vacuum advance at all times as motors run much better, smoother and cooler with lots of advance at idle. Running so much advance at idle produces lots of pollution so it was decided by (those above us) that removing the vacuum advance at idle (effectively retarding) the timing reduced the pollution but at a loss of power and the fuel air was still burning as it went out the exhaust valve which transferred extra heat to the cooling system. Cars ran cleaner (at idle only) but ran poorly and hotter. To set the static timing you have to disconnect the vacuum advance on these engines.

[bredatto510]

All carbs since the late '60 use ported vacuum advance. Certainly all Hitachi's do. For emission purposes there is no vacuum advance at idle so there is no need to disconnect it when setting the static timing. Off idle, the throttle plate rises above the vacuum port and exposes it to intake vacuum and the distributor advances. But at idle, the port is open to atmospheric air pressure.

 

It was common in motors before this to run with manifold vacuum advance at all times as motors run much better, smoother and cooler with lots of advance at idle. Running so much advance at idle produces lots of pollution so it was decided by (those above us) that removing the vacuum advance at idle (effectively retarding) the timing reduced the pollution but at a loss of power and the fuel air was still burning as it went out the exhaust valve which transferred extra heat to the cooling system. Cars ran cleaner (at idle only) but ran poorly and hotter. To set the static timing you have to disconnect the vacuum advance on these engines.

 

hainz told me that i shouldnt have my vacuum advance connected to the manifold is this correct?

[datzenmike]

Manifold vacuum is highest at idle and lowers as the throttle is opened.

 

Ported vacuum is zero at idle and slowly increases as the throttle is opened (at first) but then quickly reaches maximum and then drops off much like as in the first sentence. Remember this is a pollution reducing technique, to reduce fast advance at low speeds. In reality, engines like lots of advance when there is very little gas and air mix in the cylinders (like idle or light throttle)

 

Your dizzy has a vacuum advance curve designed to work with a reduced amount of ported vacuum so running full manifold vacuum will max the advance right from the start. If you add in the 12 degrees static timing this may be too much and it may not run well at just above idle speeds. The cure is to reduce the static timing 4-5 degrees. The problem with this is that at high speed heavy throttle (where vacuum is low and no vacuum advance is present) your mechanical advance plus the static advance combined will now be 4-5 degrees short of the ideal 32 ish degrees ?? for a Nissan???

 

It's complicated, yet simple once you know what's going on I guess. I'm probably not doing a very good job either.

[bredatto510]

ok thanks so because of my situation with flattops and such its a good idea to just cap it all together so it wont advance my timing and cause pinging... ever since i capped it i have not pinged so thats good...

[ricky]

thanks for all the input it has been very help full. Ive been trying to adjust the timing by ear. now the car stays running a little after i shut it off. dose this mean its too advanced or to retarded

[izzo]

I think it means its slightly advanced, but! Mine did that when i first put my weber on, it quit after i adjusted it a little. Be sure car is warmed up for a while before you adjust the carb. If you dont know how to do that, ask. its pretty easy actually

 

be nice if you had a timing light, so you could set correct timing then adjust carb.

[ricky]

i have a timing light and an rpm gauge i can put on the spark plug wire while adjusting timing or carb. my issue is i dont think my timing tab is in the right spot no matter how much i adjust my dizzy the balancer mark never gets close to timing tab

[banzai510(hainz)]

L16s use a pointer on the front cover and the 5 marks on the pulley.

 

the most left groove is Zero and every grove is 5 deg up to 20deg.

 

Late model L motors that use a Sawtooth timmng plate will only have 1 notch on Pulley.

This can be either on the left or right off front cover.(so pulley must match also. Since this is a L16 I assume it has the 5 nothes on pulley and a pointer on front cover

 

there can be a number of issues which are all simple to fix.

oilpump /dist spinal off

wrong pedastal for the matchbox dizzy

wrong pulley installed and not match to timming plate/or pointer.

 

I would dial motor up to Zero TDC on crank and look at the dizzy spindal and see what it look like.hopefully in the 11.28 position.

 

 

it has to be close enough as its running right now.

 

this will help you figure it out.

http://www.guba.com/watch/3000024223/Hainz-Datsun-L-Series-Engine-01-Timing-Tare-down-and-Rebuild

[ricky]

ok i seen the marks i was useing the largest mark and trying to line it up with the timing tab. so there shouldn't be a timing tab like whats on a chevy?