Newbie with first Datsun

[Wiser_Papa]

Totally new to Datsuns and vintage cars in general. Just picked up a ‘69 and learning a lot from all of you. Thanks to you I’ve redone most of the ignition and fixed a misfire. Coil, resistor, spark plugs, cap, rotor, point set (gapped properly), condenser, distributor ground leads. Then used a timing light to set it to 16 degrees from TDC. She runs like a top! Just a few electrical problems to address and I can start on the cosmetic work.

IMG_6879.jpeg

[drieseck]

Congratulations, very nice car!! Welcome to the addiction.

[GeoffM]

Welcome!

[Gregs672000]

Welcome to the family! Sounds like you got a good start and had success in your first efforts... that bodes well! Never hesitate to ask for help or suggestions. I recommend a read through of the online manuals just to familiarize yourself with the car etc in general. I do note you have a later model, but it sounds as though it has been "de-smogged" if you're setting timing at 16... you need to be sure however as setting a smogged engine ('68 and later) to 16 instead of 0 will over time the motor and cause damage (spark occurs too soon and makes the engine fight itself). Was it at 16 when you got it, or did the previous owner tell you anything?

[Stick]

Congrats ... great looking car!

[Wiser_Papa]

Welcome to the family! Sounds like you got a good start and had success in your first efforts... that bodes well! Never hesitate to ask for help or suggestions. I recommend a read through of the online manuals just to familiarize yourself with the car etc in general. I do note you have a later model, but it sounds as though it has been "de-smogged" if you're setting timing at 16... you need to be sure however as setting a smogged engine ('68 and later) to 16 instead of 0 will over time the motor and cause damage (spark occurs too soon and makes the engine fight itself). Was it at 16 when you got it, or did the previous owner tell you anything?

Well that’s really important and thank you for bringing it up! I assumed 16 from reading the forums but didn’t realize it was different for de-smogged vs smogged cars. Previous owner doesn’t know. How, may I ask can I tell if it needs to be 0 or 16? If it helps, I know that it doesn’t have a smog pump, as I was considering relocating the alternator to the other side of the engine where the smog pump usually goes. What should I look for? Can I supply a pic to help ascertain whether it’s de-smogged or not?

[Stick]

You'll need to disassemble the distributor slightly to insect the cam plate ....if the cam is stamped "7.5" it will be "desmogged" and timing should be at 16 degrees BTDC. If the plate is stamped with "17.5" the timing should be set to 0.

I went through the same process not long ago .... below is a link to the picture on the top of page 4.
viewtopic.php?start=45&t=37878&sid=fbe9 ... 997a224e94

[Gregs672000]

Another way to tell (and since you apparently have or have access to a timing light) is to check how far the mark on the crank is advancing when reved up. Harbor Freight sells an inexpensive "dial-back" timing light ($35?) that you can use that will tell you how much the distributor is adding. Or you can simply observe the mark and make sure it's not going waaaay beyond the last mark (marks are 0-20 degrees). Note the distance between marks (5 degrees each) and estimate how much further the mark advances. A non-smog distributor adds about 20 degrees, a smog one adds about 36 (to your already set timing advance of 16, making it over 50 degrees total!)... quite a bit more and should be observable (total should be about 36 degrees). The dial-back light will allow you to rev and hold the rpms while you actually turn a dial that will move the mark on the crank and tell you how much it is advancing by how much you have to turn the dial back to have it flash at your original idle timing position (16). It's hopeful that the PO did everything to de-smog the engine since the pump is already removed... did they remove the air injection nozzles in the head and install plugs into those ports? If so, that might suggest they did a more complete job vs just removing a bad air pump. Did YOU have to change the timing?

[Wiser_Papa]

Great tips, and I’ll be doing both. Looking for the stamping on the cam plate, and also using the timing light to determine how much the dizzy is adding with throttle. I do indeed have the Harbor Freight timing light you speak of, with the dial on the back. Great tool for $35. Yes, I had messed with the timing myself because upon checking it, it was actually negative (retarded?) relative to TDC. So my options were to set at TDC or 16.

[Gregs672000]

Check with the vacuum advance line disconnected from the distributor so you can see the mechanical (not mechanical and vacuum) advance that is being added. I'm gonna guess you may have a smog dizzy that adds all 36 degrees by itself. If that's the case, then your choices are 1) set to 0; 2) purchase a recurve kit (springs and slotted T); or 3) upgrade to an EI distributor that has the proper curve, a better spark and no points etc to ever wear out/change. Costs range accordingly!

[raylim]

@ Wiser_Papa
Where in the Los Angeles area are you in?
We have a bunch in the South Bay, San Gabriel Valley, San Fernando Valley...
There is a C&C this Sunday at Tireco (the old Nissan Building) if you're interested to meet at least two of us.
Ray

[Wiser_Papa]

Well I chickened out of taking the dizzy apart to look for the stampings for now. But I did do a couple things per advice. 1. Remove vacuum advance and attempt to get RPM to slightly below 1K (tach is not perfect and idle isn’t rock steady, but it’s close). Set timing light dial to 0 and confirm ignition timing is near 16 BTDC at idle. Turn dial on timing light to 16 and confirm timing mark on the pulley shifted back to the big fat TDC mark. Rev engine and confirm it doesn’t move way past the 3rd tick mark on the pulley. It did not appear to do so. My thought is that with the timing light dial set to 16, a further advance of another 3 tick marks would put ignition timing at about 31 degrees. It did not go very far past the 3rd tick mark. Come to think of it, couldn’t I have turned the dial further to 36 and make sure it doesn’t go too far past the fat tick mark while revving? This is all new to me and my amateur logic might be deceiving me here but I *think* that stands to reason. Anyway I put the vacuum line back, revved it a few times to enjoy the snappy throttle response and took it for a jaunt before getting glares from the neighbor. By that time the wife also complained of the smell of gas in the garage again so I left it there.

[Wiser_Papa]

@ Wiser_Papa
Where in the Los Angeles area are you in?
We have a bunch in the South Bay, San Gabriel Valley, San Fernando Valley...
There is a C&C this Sunday at Tireco (the old Nissan Building) if you're interested to meet at least two of us.
Ray

@raylim I’m probably less than 2 miles from you sir, in Temple City. I had lunch at Summer Roll and chatted with the owner Tony with the white ‘64. He said I needed to talk to you one day. I’d like to take it to a cars n coffee one day but TBH I’m a little scared it either might not make it there and back, or that the brakes are too weak to be safe on the fwy. I can’t tell if my brakes need work, or if that’s just how brakes were in the 60’s

[Wiser_Papa]

Oh one more thing. I think this photo shows that the intake was plugged as part of the desmogging work.

IMG_6975.jpeg

[Gregs672000]

I'll be honest in that I have not used the dial back feature in a while as my non-stock "wasted spark" ignition does not work well with it. However, your distributor does not sound like it is over advancing the timing (BTW, your moving of the dial does not change the actual timing of the engine, it simply gives you a means and scale to see how much timing is being added, or not). I believe that if you set the light dial to 0 it should be flashing at 16 on the crank (and if not, then adjust THE DISTRIBUTOR until it flashes at 16 on the crank when set to 0 on the dial), then as you rev and HOLD the rpms above 3500 rpms the flash will advance beyond the last mark (20 on a U20 engine, I'm not familiar with the R16 pully but likely similar), and while holding 3500rpms adjust the dial until the light is flashing at your initial 16 on the crank again, then look at the dial and it will show you how much advance is being added... should be around 16-20 degrees on the dial (16 degrees initial, then the distributor adds another 16-20 degrees for a total advance of 36 when you're at 3500rpms +... may have full advance at 3000rpm, but for sure at 3500). The DIAL tells you how much the distributor is advancing the timing at whatever rpm the engine is at when you adjust the DIAL until the mark is flashing at your starting point, in this case 16 degrees... make sense? For example, at 2500rpm it may require you to turn the dial 10 degrees to get "back" to 16 on the crank, so you know the distributor is currently adding 10 degrees to your initial 16 degrees for a total of 26 degrees of timing advance at 2500rpm.

Ignition timing and "advance" is required by an engine in order to give it more "time" to burn the fuel as engine (rpm) speeds increase. Too late and it will not burn all the fuel before the exhaust valve opens and the "charge" gets pushed out, wasting the energy from burning the fuel charge. Too early and the explosion is happening such that the explosion is pushing down against the piston as the piston is being forced upward mechanically, creating extremely high stress that can blow holes in piston rings. Timing is on a "curve" (progressively increases) based on how fast the engine is turning. The most power is found by optimizing exactly WHEN the explosion occurs, as just a degree or two can make a difference in how much power the engine makes from the fuel it explodes/burns, and this varies based on engine design and rpm. The manufacturer does their "best estimate" for their engine and creates a curve based on this, and how this is accomplished is determined by the weights, springs and amount of movement allowed inside the distributor. In my case and as on modern cars, on my modified (and more sensitive engine) I no longer have a distributor and instead a computer determines when to fire the plugs based on what I tell it to do. An aftermarket 123 distributor (available from JT68 and maybe other vendors) is fully programmable in the same way, but unless you're going to spend time on a dyno (as I STILL need to do) you will be guessing as to what the VERY best ignition timing will be for YOUR particular motor, and that's likely overkill for a stock engine unless you're trying to squeeze out every horse. I hope this helps you understand what you're trying to accomplish.

Whew... no more coffee for me!