1971 Datsun 521

[Draven521]

Bought this 1971 Datsun 521 from facebook market place for a pretty low price. I was told it was running 3 years ago. DOT on the tires was from 2002 so I think I was lied to. I love the truck and always wanted one so I took a chance. I’m 24 years old and don’t know much about car mechanics but always enjoyed watching people go out and start cars that have been sitting for 10+ years. With that being said I knew what I was doing just a bit. Had the car for a month and changed out a few key components and got it to turn over and it was running for a solid 45 minutes. Engine cut off and now I’m no longer able to do it again. Upon it running I noticed a ticking coming from the engine. What could that be? I don’t like the sound of it. Mind you it did take a while before I finally got it to turn over. Killed my battery 3 times in the process and had some heavy backfires and a few flames shoot out the carb. It’s going to be my daily and in the future wanna build it up. How can I get it to turn over faster and more consistently as well as fix the tick? 

[datzenmike]

Hopefully just a tick and not a knock. Likely just the valve clearance needs checking/adjusting. Intake is 0.008" and exhaust valves are 0.010" This is the cold setting as your engine isn't running and this will be fine. You'll need a set of feeler gauges and some metric wrenches.

 

Recharge the battery, clean the battery terminal posts and the cable connections, clean and dry the spark plugs. Take distributor ap off and look at the points. Turn engine till points are fully open, gap should be 0.018" to 0.022". If they look bad, they are so replace them.

 

Take the air filter off and look down the carburetor... Is the choke closed?

[Draven521]

I replaced the distributor, now has the 2 point distributor. With that I replaced the starter, alternator, spark plugs and wires, cap and rotor, ignition coil and ballast resistor. The choke is adjusted i believe. So that’s where I’m not understanding the issue? How would I adjust the valves? I’m new to all this.

[Draven521]

Definitely just a tick, if it was a knock I would’ve cried.

[Draven521]

Also when I gave it gas in neutral it cut off

[datzenmike]

7 minutes ago, Draven521 said:

I replaced the distributor, now has the 2 point distributor. With that I replaced the starter, alternator, spark plugs and wires, cap and rotor, ignition coil and ballast resistor. The choke is adjusted i believe. So that’s where I’m not understanding the issue? How would I adjust the valves? I’m new to all this.

 

If points it needs a points coil 1.5 ohms and a 1.5 ohm ballast..... or a 3 ohm coil without the ballast.

 

 

 

 

 

[Draven521]

11 minutes ago, datzenmike said:

 

If points it needs a points coil 1.5 ohms and a 1.5 ohm ballast..... or a 3 ohm coil without the ballast.

 

 

 

 

 

I definitely look into that. It’s a new distributor, I don’t know how quickly points get worn out or if they can sometimes not be gapped properly. How would I go about resolving that 

[datzenmike]

1 hour ago, datzenmike said:

Hopefully just a tick and not a knock. Likely just the valve clearance needs checking/adjusting. Intake is 0.008" and exhaust valves are 0.010" This is the cold setting as your engine isn't running and this will be fine. You'll need a set of feeler gauges and some metric wrenches.

 

Recharge the battery, clean the battery terminal posts and the cable connections, clean and dry the spark plugs. Take distributor cap off and look at the points. Turn engine till points are fully open, gap should be 0.018" to 0.022". If they look bad, they are so replace them.

 

Take the air filter off and look down the carburetor... Is the choke closed?

 

[Draven521]

9 minutes ago, datzenmike said:

 

I’m not questioning you lol I know absolutely nothing. I’m just curious about the points. It’s a new distributor and was put in last week. Could the points be bad on a new distributor? What do I use to measure the gap?

[datzenmike]

The points simply close like a switch allowing power to flow through the coil. Inside the coil a strong magnetic field is formed. When the points open current instantly stops and the magnetic field collapses around a secondary coil inside the first. The collapsing magnetic field induces a voltage in the secondary, proportional to the number of winding of the coil. In the case of an ignition coil about 15-20 thousand volts, enough to jump the gap of the spark plug.

 

When the points open there will be some arcing and this slowly erodes the contact surfaces. At about every 5,000 miles you can file the points surfaces clean and re-gap them. By 10-15 thousand miles they may need replacing.

 

The gap is measured with a feeler gauge, same as the valve lash.

[Draven521]

4 minutes ago, datzenmike said:

The points simply close like a switch allowing power to flow through the coil. Inside the coil a strong magnetic field is formed. When the points open current instantly stops and the magnetic field collapses around a secondary coil inside the first. The collapsing magnetic field induces a voltage in the secondary, proportional to the number of winding of the coil. In the case of an ignition coil about 15-20 thousand volts, enough to jump the gap of the spark plug.

 

When the points open there will be some arcing and this slowly erodes the contact surfaces. At about every 5,000 miles you can file the points surfaces clean and re-gap them. By 10-15 thousand miles they may need replacing.

 

The gap is measured with a feeler gauge, same as the valve lash.

Thank you for the thorough explanation! I’ll definitely check all that and update you. As far as my engine cutting off when I give it gas, what causes that? 

[datzenmike]

There are four circuits in your carburetor.

 

1/ Idle which is separate and adjustable for air/fuel mixtures.

 

2/ Primary barrel which takes over above idle and for normal driving and fuel economy. It is non adjustable and set by the primary jet.

 

3/ Secondary barrel which is larger than the primary and is for heavy throttle driving where performance is more important over economy. The secondary is not connected to the throttle cable but is pulled open by a vacuum diaphragm when the engine reaches a sufficient speed to need more air and fuel. It also is not adjustable.

 

 

4/ When the throttle is opened the engine speed is at idle and not turning nearly fast enough to generate enough vacuum to draw fuel in for the added air. To transition from idle mixture to primary running there is a mechanical pump (called an accelerator pump) that squirts raw fuel into the primary to cancel this over lean condition while the engine begins to speed up. 

 

 

Your engine quitting when stepping on the gas could be the accelerator pump not delivering fuel. Or it could be that the primary jet is blocked and above idle it has no gas to run on. Try stepping on the gas slowly to get above idle and onto the primary. If done slowly and it revvs up then the primary jet is likely ok.

 

It could be a lot of things.

[Draven521]

6 hours ago, datzenmike said:

There are four circuits in your carburetor.

 

1/ Idle which is separate and adjustable for air/fuel mixtures.

 

2/ Primary barrel which takes over above idle and for normal driving and fuel economy. It is non adjustable and set by the primary jet.

 

3/ Secondary barrel which is larger than the primary and is for heavy throttle driving where performance is more important over economy. The secondary is not connected to the throttle cable but is pulled open by a vacuum diaphragm when the engine reaches a sufficient speed to need more air and fuel. It also is not adjustable.

 

 

4/ When the throttle is opened the engine speed is at idle and not turning nearly fast enough to generate enough vacuum to draw fuel in for the added air. To transition from idle mixture to primary running there is a mechanical pump (called an accelerator pump) that squirts raw fuel into the primary to cancel this over lean condition while the engine begins to speed up. 

 

 

Your engine quitting when stepping on the gas could be the accelerator pump not delivering fuel. Or it could be that the primary jet is blocked and above idle it has no gas to run on. Try stepping on the gas slowly to get above idle and onto the primary. If done slowly and it revvs up then the primary jet is likely ok.

 

It could be a lot of things.

 

You’re awesome! I appreciate all the information so much! I’m going to start with checking the accelerator pump and move onto the primary jet. I’ll keep you updated if I am able to get it up and going 

[datzenmike]

Engine off, look down the carburetor and have someone pump the gas pedal. What you should see is a strong spurt of gas into the primary barrel.

[Crashtd420]

Looks like mike has you going in the right direction.... I'm glad to see you're trying to get it running to enjoy it vs the immediate motor swap that seems to occur in most threads....

 

One thing I dont think mike touched on was timing....

How and/or did you reset the engine timing after you replaced the distributor?

Do you have a timing light to check the timing?

Improper timing will cause back fires both in the carburetor and exhaust if it's far off....

 

And yes these motors have a noisy valve train.... keep in spec and it's a smooth sound... out of spec might get a little extra ticky..... 

 

2 other bits of advice:

Did you do an oil change?

what oil and filter did you use?

Mike will definitely comment on this but he will recommend a diesel oil vs just regular oil... and not to use fram filters, not sure the preferred one now... I believe wix is still a good choice....

 

I am on the assumption your engine is the L16 with the 210 head I believe it has soft valve seats.... I'm not sure if still recommended to use a lead additive in the gas, but I know my 210 head gave me issues because of the valve seats... very worn and couldn't adjust anymore...

Again this will get mike to comment better... he seems to explain the why a lot better than me...

[datzenmike]

I left the timing for when the engine gets started again, though maybe you can time it just by spinning it with starter? It must be remembered that you did have it running for 45 min. so it must be close.

[Crashtd420]

1 hour ago, datzenmike said:

I left the timing for when the engine gets started again, though maybe you can time it just by spinning it with starter? It must be remembered that you did have it running for 45 min. so it must be close.

I know you can time it by just spinning the engine with the starter.. I got mine close that way when was setting up mine.... 

 

But you are right it was running so it has to be close....

 

When I first got my datsun we went through similar issues... we got it running but the timing was off seemed like it wasn't running on all cylinders but it was idling... once it was correctly set restarting was easier and the idle was smoother....

 

 

[Stoffregen Motorsports]

If sitting for ten years, the fuel system needs to be completely replaced. Remove the hoses and throw them away, blow out the hard lines and remove the tank and have a peek inside. If it is dirty, have it flushed at least. You'll be lucky to have the fuel pump work after ten years. It may for a bit, but the diaphragm will eventually fail, putting rubber pieces into the fuel line and probably plug up the carb.

 

Same goes for brakes and even cooling system. Remove and throw away all hoses and blow out hard lines. Have the radiator flushed and you'll probably need a new water pump. Brake calipers and wheel cylinders will likely need replacing/rebuilding too. Replace the thermostat while you have it apart.

 

Those videos that show a vehicle firing after sitting for so many years don't show how they fail minutes, hours or days after they get it running.

[banzai510(hainz)]

I would have dried to drain the tank.

put new fuel filter on incase lots of rust in tank.

 

Once you got running check for volage for the batter so you kow if your charging.

 

Out a dual pint dist in? mas thee a single point in there? or just one set of points was removed. Got photos of old dist? and new one put on?

Is the motor timed with a light?

 

does motor idle by its self?

 

The tick can just be a loose rocker arm. or your just not used to older vehicles as some L motors seem to be kinda noisey to newer vehicles.

 

sometimes changing out to many stuff at once you could introduce a proplem.  Most times when a datsun dont run  could be just points not working and just need adjustment.

 

I fixed a non running 521 once by just tightening the carb bolts and adjust the mixture

Edited October 20, 2023 by banzai510(hainz)

[Slow Loris]

@Draven521 don’t listen to me I’m a real idiot, but DO listen to these guys their advice on this forum helped me get my 521 running after it sat in someone’s yard for 10 years. They are brilliant. You will do it!
 

Also, hopefully just a thread tangent here but @Stoffregen Motorsports I did everything on your 10 year non-op list above EXCEPT I didn’t change my fuel pump or its diaphragm. Can you elaborate on that? Like, take it to the bank my fuel pump is going to croak any day and I might as well order a replacement? 
 

Also @banzai510(hainz) funny you mention that I JUST got around to tightening my carb bolts the other day and HOLY HELL did that make a huge difference!!

 

 

[Draven521]

1 hour ago, Slow Loris said:

@Draven521 don’t listen to me I’m a real idiot, but DO listen to these guys their advice on this forum helped me get my 521 running after it sat in someone’s yard for 10 years. They are brilliant. You will do it!
 

Also, hopefully just a thread tangent here but @Stoffregen Motorsports I did everything on your 10 year non-op list above EXCEPT I didn’t change my fuel pump or its diaphragm. Can you elaborate on that? Like, take it to the bank my fuel pump is going to croak any day and I might as well order a replacement? 
 

Also @banzai510(hainz) funny you mention that I JUST got around to tightening my carb bolts the other day and HOLY HELL did that make a huge difference!!

 

 

 

9 hours ago, banzai510(hainz) said:

I would have dried to drain the tank.

put new fuel filter on incase lots of rust in tank.

 

Once you got running check for volage for the batter so you kow if your charging.

 

Out a dual pint dist in? mas thee a single point in there? or just one set of points was removed. Got photos of old dist? and new one put on?

Is the motor timed with a light?

 

does motor idle by its self?

 

The tick can just be a loose rocker arm. or your just not used to older vehicles as some L motors seem to be kinda noisey to newer vehicles.

 

sometimes changing out to many stuff at once you could introduce a proplem.  Most times when a datsun dont run  could be just points not working and just need adjustment.

 

I fixed a non running 521 once by just tightening the carb bolts and adjust the mixture

 

11 hours ago, Stoffregen Motorsports said:

If sitting for ten years, the fuel system needs to be completely replaced. Remove the hoses and throw them away, blow out the hard lines and remove the tank and have a peek inside. If it is dirty, have it flushed at least. You'll be lucky to have the fuel pump work after ten years. It may for a bit, but the diaphragm will eventually fail, putting rubber pieces into the fuel line and probably plug up the carb.

 

Same goes for brakes and even cooling system. Remove and throw away all hoses and blow out hard lines. Have the radiator flushed and you'll probably need a new water pump. Brake calipers and wheel cylinders will likely need replacing/rebuilding too. Replace the thermostat while you have it apart.

 

Those videos that show a vehicle firing after sitting for so many years don't show how they fail minutes, hours or days after they get it running.

 

12 hours ago, Crashtd420 said:

I know you can time it by just spinning the engine with the starter.. I got mine close that way when was setting up mine.... 

 

But you are right it was running so it has to be close....

 

When I first got my datsun we went through similar issues... we got it running but the timing was off seemed like it wasn't running on all cylinders but it was idling... once it was correctly set restarting was easier and the idle was smoother....

 

 

 

14 hours ago, datzenmike said:

I left the timing for when the engine gets started again, though maybe you can time it just by spinning it with starter? It must be remembered that you did have it running for 45 min. so it must be close.

 

14 hours ago, Crashtd420 said:

Looks like mike has you going in the right direction.... I'm glad to see you're trying to get it running to enjoy it vs the immediate motor swap that seems to occur in most threads....

 

One thing I dont think mike touched on was timing....

How and/or did you reset the engine timing after you replaced the distributor?

Do you have a timing light to check the timing?

Improper timing will cause back fires both in the carburetor and exhaust if it's far off....

 

And yes these motors have a noisy valve train.... keep in spec and it's a smooth sound... out of spec might get a little extra ticky..... 

 

2 other bits of advice:

Did you do an oil change?

what oil and filter did you use?

Mike will definitely comment on this but he will recommend a diesel oil vs just regular oil... and not to use fram filters, not sure the preferred one now... I believe wix is still a good choice....

 

I am on the assumption your engine is the L16 with the 210 head I believe it has soft valve seats.... I'm not sure if still recommended to use a lead additive in the gas, but I know my 210 head gave me issues because of the valve seats... very worn and couldn't adjust anymore...

Again this will get mike to comment better... he seems to explain the why a lot better than me...

Hey guys sorry I been really busy with work. So thankfully I’m not to much of an idiot lol. I disconnected my sending unit immediately when I got the truck (probably didn’t need to). Disconnected my fuel line and put a new one on it and stuck it inside a 3 liter bottle filled with gas. I just did the oil change and I used abheavy duty oil (15w-40) as well as a motorcraft oil filter. Got all my brakes as well as a new master brake cylinder, clutch slave cylinder and clutch master cylinder (got it all when I got the truck)  Gonna get the wheel cylinders tomorrow. I don’t know if the fuel pump is bad. I went through 2 bottles of fuel when I was letting it run so my guess was that it was pulling just fine. I did check the timing the other day and it looks like everything is line up. I watched a really long video to understand all that last week. I did purchase a timing light and gonna put it to use here in a bit. Havent got to work on it just yet because of work but I’m gonna be up all night getting this thing going. I didn’t have a key for it so I learned a little bit of the electrical to install a flip switch panel and that’s what I been using to turn it over. My guess is the accelerator pump or jet is the answer to my problem so I’ll tackle that. As far as cooling, the first thing I did with the truck was flush the cooling system and got new hoses. I didn’t changed the thermostat just yet but I’ll definitely get that done. I appreciate all the replies and help. I want to enjoy this truck for the classic that it is and than maybe one day swap it with an SR20DET but that’ll be a couple years from now. 
 

it had a single point distributor. I kept all the parts I’ve replaced. I don’t know what to do with them if anyone is interested in them. I also purchased a key cylinder with key from Datsun Garage out in California. Got I’m patient because it took a month before I finally got it. By than I had the flip switch panel in. If anyone is interested in that too let me know

[Draven521]

9 minutes ago, Draven521 said:

 

 

 

 

 

Hey guys sorry I been really busy with work. So thankfully I’m not to much of an idiot lol. I disconnected my sending unit immediately when I got the truck (probably didn’t need to). Disconnected my fuel line and put a new one on it and stuck it inside a 3 liter bottle filled with gas. I just did the oil change and I used abheavy duty oil (15w-40) as well as a motorcraft oil filter. Got all my brakes as well as a new master brake cylinder, clutch slave cylinder and clutch master cylinder (got it all when I got the truck)  Gonna get the wheel cylinders tomorrow. I don’t know if the fuel pump is bad. I went through 2 bottles of fuel when I was letting it run so my guess was that it was pulling just fine. I did check the timing the other day and it looks like everything is line up. I watched a really long video to understand all that last week. I did purchase a timing light and gonna put it to use here in a bit. Havent got to work on it just yet because of work but I’m gonna be up all night getting this thing going. I didn’t have a key for it so I learned a little bit of the electrical to install a flip switch panel and that’s what I been using to turn it over. My guess is the accelerator pump or jet is the answer to my problem so I’ll tackle that. As far as cooling, the first thing I did with the truck was flush the cooling system and got new hoses. I didn’t changed the thermostat just yet but I’ll definitely get that done. I appreciate all the replies and help. I want to enjoy this truck for the classic that it is and than maybe one day swap it with an SR20DET but that’ll be a couple years from now. 
 

it had a single point distributor. I kept all the parts I’ve replaced. I don’t know what to do with them if anyone is interested in them. I also purchased a key cylinder with key from Datsun Garage out in California. Got I’m patient because it took a month before I finally got it. By than I had the flip switch panel in. If anyone is interested in that too let me know

I have vids and pics but don’t know how to upload them lol

[Draven521]

58 minutes ago, Draven521 said:

I have vids and pics but don’t know how to upload them lol

I completely forgot to mention. This isn’t the stock carb. It’s a Webber 32/36 I’m guessing the previous owner threw it on there. I’m the 3rd owner of this truck. I don’t know if the mileage has ever rolled over but I have high hopes that it hasn’t. The truck is sitting at 99k. That is if it didn’t roll over 

Edited October 21, 2023 by Draven521

[datzenmike]

Weber? well forget what I said about the carburetor, mostly.

 

99,999 could be 199,999 miles, the L series is certainly capable of that and much more if owner maintained it properly.

[Draven521]

1 hour ago, datzenmike said:

Weber? well forget what I said about the carburetor, mostly.

 

99,999 could be 199,999 miles, the L series is certainly capable of that and much more if owner maintained it properly.

Yes sir Weber, I should’ve mentioned that sooner but the information about the carb is noted and I really do appreciate it! Should I go back to an oem carb?