Timing

[Leo92335]

It's a pusher fan its blows air from the front of the truck thru the radiator and it was installed properly and  it has a switch on the dash that is controlled manually so when it's warm I turn on the fan, when I've bought the truck the guy had it running and I drove home for like an hour at night and it arrived good ,all I changed was the carburetor for a Webber than I changed to electronic points but I did move the distributor and I've bought a timing ligth and I've been trying to time it,I've put it on the same spot and to the same settings but it keeps overheating 

[banzai510(hainz)]

If you put a Petronix in there you don't really have to change anything just time it

Now if you bought a whole new HOTSPART distributor that is another thing you really needed to point out.

However if you can say get to 10deg BTDC with the timing and still have lots of movement on the dist slot to move it up and down say from 0 to +25 BTDC I say you got the distributor spindal installed correctly.

 

the plus red wire of the dist will go to the Positive side of the ballast resisitor like the instructions say

 

if dist timing really off the faster you go the more it would cut out

Edited June 19, 2020 by banzai510(hainz)

[datzenmike]

15 hours ago, datzenmike said:

 

You make it sound like the timing is the cause of over heating and setting it properly will fix it? Fix the over heating first, an overly hot engine will ping sooner that a cooler engine. 

 

Over heating can be narrowed down to (mostly) two major factors

 

Coolant flow...

Thermostat stuck and not opening fully.

Soft lower rad hose that collapses from water pump suction 

Low coolant level

Rad core inside plugged with hard water scale

Heater hoses joined together to by pass leaky heater core.... make sure you block the flow if you do this

 

 

Air flow...

Missing fan shroud

Rad core plugged on the outside with bug, dirt and debris

Fog lights, bush bar obstructing air flow through rad

Fan belt slipping

 

Runner up....

Blown head gasket

 

 

3 hours ago, Leo92335 said:

Hello Daniel, when I bought it they had crashed and installed an after market aluminum radiator with an electric fan on the front of the truck so I'm not sure if that's the problem because the guy said it was his daily vehicle,,,,I already took off the thermostat and that's not the problem, the heating hose is leaking in the cab so today I'm going to flush the heating core and fix the leak and ill take it from there ,thanks 

 

I wouldn't run without the thermostat. Put a 180F in there. Thermostats set and adjust the engine's minimum temperature, they don't cause over heating. If over heating it's something else.

 

An electric fan on all the time is a wasted effort as the previous owner may as well have kept the belt driven fan. A switch on the dash is subject to human error, constant attention or it's 

on or off more than it needs to be. Better to have a temperature sensor in the lower return hose and a relay and fuse to the battery. Comes on only when needed which is mainly idling at lights on stop and go traffic. The rest of the time like warm up it isn't needed and above 30 vehicle motion pushes air through rad and blows away the hot air under the hood.

 

 

Sensor from a SR20 rad, threaded bung and length of pipe, a few hose clamps, 720 relay and an in line fuse. Comes on automatically only when needed which is almost never. Even comes on during heat soak after shut down when it tries to over heat when parked.

 

 

 

So 2 things, rad and or fan too small.

[Crashtd420]

1 hour ago, Leo92335 said:

It's a pusher fan its blows air from the front of the truck thru the radiator and it was installed properly and  it has a switch on the dash that is controlled manually so when it's warm I turn on the fan, when I've bought the truck the guy had it running and I drove home for like an hour at night and it arrived good ,all I changed was the carburetor for a Webber than I changed to electronic points but I did move the distributor and I've bought a timing ligth and I've been trying to time it,I've put it on the same spot and to the same settings but it keeps overheating 

 

I know you said you drove it home , but have you been able to drive it since the carburetor and distributor upgrades? 

Even at night, like the drive home,  when it is a little cooler?

 

I just dont see how those 2 things would be causing it to over heat.... but I could be wrong.... 

 

How far past half way does the needle go? 

Where is it when the truck is off and during initial start up?

 

Another thing is do you have or can you borrow a ir temperature gun?

Maybe check the upper and lower radiator hose to make sure the temp gauge is reading properly....

I have an L16 also with the 3row aluminum radiator and dual 10" fans...

my needle stays just a hair above halfway all the time ....

I'd be happy to take some temp reading from different locations if that would help.....

 

Mainly I'm just back tracking to make sure it's not something simple like the temp sender or gauge....

 

 

 

[jagman]

Just curious.  Have you checked the water pump?  On one of my cars I had a water pump fail because the impeller vanes got et somehow and it wasn't pushing enough through the radiator.

[datzenmike]

Ive had 521/510, 2 710s, 620 and a 720... all had stock 180F thermostats and the needle  ran at, or just a C hair, above half way on the indicated 'run range'.  An infra red gun isn't a bad idea. Shoot the thermostat housing, that will be the hottest point. Confirm that it's at or about 185F

 

Run the engine without the fan until it's definitely above normal and is where you would put the fan on. Use a garden hose to thoroughly wet down the rad to cool it. If the gauge drops right away then it's circulating.

[Leo92335]

6 hours ago, Crashtd420 said:

 

I know you said you drove it home , but have you been able to drive it since the carburetor and distributor upgrades? 

Even at night, like the drive home,  when it is a little cooler?

 

I just dont see how those 2 things would be causing it to over heat.... but I could be wrong.... 

 

How far past half way does the needle go? 

Where is it when the truck is off and during initial start up?

 

Another thing is do you have or can you borrow a ir temperature gun?

Maybe check the upper and lower radiator hose to make sure the temp gauge is reading properly....

I have an L16 also with the 3row aluminum radiator and dual 10" fans...

my needle stays just a hair above halfway all the time ....

I'd be happy to take some temp reading from different locations if that would help.....

 

Mainly I'm just back tracking to make sure it's not something simple like the temp sender or gauge....

 

 

 

Do you have your fans all the time or you have a temperature relay 

[datzenmike]

10 hours ago, Leo92335 said:

When I've bought the truck the hood was different color and the grill from another vehicle and the front bumper is bent a little so yes that confirms that they crashed and damaged the radiator and replaced it with an aluminum one which is thicker and they had to remove the engine fan and install an electric fan on the front of the truck between the grill and the radiator and they or he put a switch on the dashboard to turn it on manually so as u can see is hard to figure it out 

 

[Leo92335]

Hello I would like to thank everyone that tried to help me I found some of the problem, I did a rookie mistake and bought champion spark plugs trusting it would be compatible and as soon as I replaced them with the old ones I've noticed the needle would not pass the 1/4 mark but I'm still having carburetor issues now it has that breathing noise and choking problem I tried adjusting it but it keeps choking and the needle sometimes goes to the 3/4 mark when I'm driving fast but when I park it goes to the middle as normal but I think it hasto do with the 2 8 inch fans that I tried to upgrade instead of 1 12 inch one that had when I acquired it,it felt great going to the gas station for the first time in almost two years of hard work of upgrades and trying to revive this piece of crap,,,I'm going to order new spark plugs the recomended ones and I'll take it from there, thank you guys you really made me feel like I'm not alone in this restoration, I really appreciate it and I would do the same for any of you.i will post my carburetor problem as soon as I install my new spark plugs and I will take it from there, god bless this site and all of you. 

7 hours ago, Crashtd420 said:

 

I know you said you drove it home , but have you been able to drive it since the carburetor and distributor upgrades? 

Even at night, like the drive home,  when it is a little cooler?

 

I just dont see how those 2 things would be causing it to over heat.... but I could be wrong.... 

 

How far past half way does the needle go? 

Where is it when the truck is off and during initial start up?

 

Another thing is do you have or can you borrow a ir temperature gun?

Maybe check the upper and lower radiator hose to make sure the temp gauge is reading properly....

I have an L16 also with the 3row aluminum radiator and dual 10" fans...

my needle stays just a hair above halfway all the time ....

I'd be happy to take some temp reading from different locations if that would help.....

 

Mainly I'm just back tracking to make sure it's not something simple like the temp sender or 

 

[datzenmike]

Not passing  the 1/4 mark is because you don't have a thermostat in it. Get one. It runs best where it was designed to run around 185-190F.

 

Champion plugs will not make the engine over heat, just maybe run crappy. Always run NGK.

 

 

What carburetor do you have on it? Most are electric choke heater The choke is either on or it's not. They don't come on while driving. I don't understand "it keeps choking" comment.

[Leo92335]

I changed the spark plugs to the old  denso pw20tt that it had when I bought the truck and now it's better so I timed the engine but now the engine is running crapy  ,I changed the original carburetor to a Webber and now it feels like is choking when I'm driving ,I hear that whistling sound and it struggles to advance ,any thoughts?

[Crashtd420]

9 hours ago, Leo92335 said:

Do you have your fans all the time or you have a temperature relay 

I am running a temp sensor and relays for the fans... they come on once the truck is at temperature and will stay on for a little when I shut the truck off till the truck cools down .... 

[Crashtd420]

6 hours ago, Leo92335 said:

I changed the spark plugs to the old  denso pw20tt that it had when I bought the truck and now it's better so I timed the engine but now the engine is running crapy  ,I changed the original carburetor to a Webber and now it feels like is choking when I'm driving ,I hear that whistling sound and it struggles to advance ,any thoughts?

 

Kind of sounds like a vacuum leak.... check the base gasket of the carburetor...

Easy test is get the motor running and spray some carburetor clean around the base ... if the engine revs up on it's own that's your leak.... 

[Leo92335]

On 6/18/2020 at 3:46 PM, DanielC said:

Usually there is a single pointer, and a pulley with several notches, one notch bigger.  With the saw tooth segment, the pulley has one notch. 

If you have the saw tooth segment, and a notched pulley, parts from different engines may have been mixed up, and on your engine.

 

You need to determine what timing marks on your engine are for finding Top Dead Center, or TDC

Take the cam cover off the top of the engine.  Turn the engine clockwise, viewed from the front, and watch the two front cam lobes.   The very front cam lobe, the exhaust valve lobe will be about a 2:00 o' clock position, and the next lobe back will be about 10:00 o' clock as you get close to TDC.    If you are careful, and you turn the crankshaft pulley by hand, you may be able to feel TDC, because at that point all four pistons are not moving,

 

My guess is that you may find TDC with the white highlight mark on the pulley at 0 on the saw tooth.  

 

Initial timing on a L-16 is 10 degrees before TDC.  The vacuum line to the distributor need to be removed from the distributor, and plugged so there is not a vacuum leak.  The idle speed needs to be below 800 RPM.

 

Do you have a loud exhaust?  Do you know what an engine with spark knock, or detonation, or preignition sounds like?  If you are confident you can identify spark knock, or detonation, or preignition, you might be able to gain some performance by advancing the ignition timing 2 or 3 degrees.   Advancing the timing too much and having the engine spark knock will damage the engine, and you will have less power.   If you do not know for sure what spark knock sounds like, leave the timing at 10 degrees.

 

Pictures of your timing marks would be a huge help.

 

 

 

I have the service manual for the 1973 620 and it mentions to set the timing at 5 degrees but you mentioned and other fellas to set it at 10 degrees would you mind to explain for educational purpose why at 10 if the sm reads at 5 btdc?

[datzenmike]

 I wonder if that's because it's given in distributor degrees on some early manuals and on crankshaft degrees on newer ones. Five distributor degrees is 10 crankshaft degrees. My '76 L20BB is rated 110 hp (gross) but this was changed and my 620 L20B is 93 (net) hp which can be confusing.

[DanielC]

In the mid to late 1960's more emission controls were added to cars and light trucks.   Near the end of that decade, car manufactures just started to figure how to reduce emissions produced from the actual combustion in the operation of the engine.   A retarded ignition timing at idle is one of the strategies that reduced idling emissions.  One change for example was to change vacuum advance at the distributor from manifold vacuum to ported vacuum, that came in only after the throttle was opened slightly.

 

If all the parts that affect emissions on your L-16 are factory original, then follow the 1973 service manual for advise.  Does your truck have the original carburetor?  The original distributor?  Are all the parts in the distributor that control mechanical and vacuum advance working freely, and lubricated?   If any of that has changed, you are on your own.

 

In your original post in this thread, you asked about ignition timing, and you also mentioned overheating.   One of the causes of overheating is retarded ignition timing, spark timing that is too late.   Here is why.   There is an ideal spot in every piston engine that to efficiently make power you want maximum pressure in the cylinder from the burned fuel air mixture.  If the ignition timing is later than ideal, the piston is farther down in the cylinder.  This exposes more of the cylinder wall to the hot gasses, and the heat then goes into the cooling system, and the heat energy is not used to move the piston.

 

Modern engine have a computer to control ignition timing.  They have  knock sensor that tells the computer the ignition timing is too advanced.   The engine computer has input from many variables, and adjusts ignition timing accordingly.

 

Our old Datsuns have only three things to control the ignition timing.  Static timing, where we clock, or set the distributor, mechanical advance, sometimes called centrifugal advance, that adds more advance as the engine RPM goes up, and vacuum advance, that adds additional advance as the manifold vacuum goes up (throttle closes).

 

Almost all engines will start and run with 10 degrees initial timing.  It is a good safe place to start.  However I do not know exactly how the distributor advance curve is on your truck.  It may be best to set it at 5 degrees BTDC.  

 

If you know what too much ignition advance sound like, (spark knock, detonation) one of the ways to set ignition timing is to advance the timing until the engine knocks, full throttle, heavy load, hot day and then retard the timing from the point you first have spark knock about 2 1/2 degrees.

 

One more detail, you live in California.  Do you have to get emission checks on your truck to register it, or is it exempt from inspection?

 

 

 

 

[Leo92335]

Thanks for all that knowledge Daniel, I don't have the original carburetor I changed it to a Webber and I plugged all vacuum lines except the advance from distributor to bottom of carburetor, the distributor looks old so I'm gonna assume is the original,,luckily I live in California so I don't have to do smog check,,,,I left the timing at 5 degrees and now my carburetor started to struggle to advance ,do you think its because of the distributor at 5?,,,and another issue I encountered my timing ligth stopped working on cylinder one but when I try on another cylinder cable it works so I haven't been able to set it at 10,do you think my timing ligth its defective or something is affecting it ?

[datzenmike]

 

 

There has to be a spark through the wire for the timing light to work. I assume that the number one cylinder is not working. Running on 3 cylinders could be a problem.

 

Swap the 1 and 2 wires and see if the problem has moved to the second cylinder.  If it does, the number 1 wire is bad.

If no change check the distributor cap/rotor for damage preventing the spark not getting through. Pull the # 1 spark plug and examine for damage

[DanielC]

You can also hook the timing light to the number 4 cylinder plug wire.  TDC number 4 is the same as TDC number 1, as far as the crankshaft.  It is the camshaft that decides if the cylinder is on fire, or exhausting burnt gas.

[datzenmike]

Yup

 

Bur find out if #1 is not firing.

[Leo92335]

On 6/19/2020 at 12:33 PM, Crashtd420 said:

 

I know you said you drove it home , but have you been able to drive it since the carburetor and distributor upgrades? 

Even at night, like the drive home,  when it is a little cooler?

 

I just dont see how those 2 things would be causing it to over heat.... but I could be wrong.... 

 

How far past half way does the needle go? 

Where is it when the truck is off and during initial start up?

 

Another thing is do you have or can you borrow a ir temperature gun?

Maybe check the upper and lower radiator hose to make sure the temp gauge is reading properly....

I have an L16 also with the 3row aluminum radiator and dual 10" fans...

my needle stays just a hair above halfway all the time ....

I'd be happy to take some temp reading from different locations if that would help.....

 

Mainly I'm just back tracking to make sure it's not something simple like the temp sender or gauge....

 

 

 

Hey buddy can I take you up on your offer to do some normal temperature readings on your L16 I think my gauge is faulty, I would really appreciate your help, thanks in advance 

[Leo92335]

On 6/20/2020 at 8:34 PM, datzenmike said:

Yup

 

Bur find out if #1 is not firing.

All my cylinders are firing good and I was able to time it at 10 degrees but my dash gauge is acting crazy  ,I installed an aftermarket temperature sensor before the thermostat and it has a digital screen and is reading about 80c and it's on the green area, do any of you know the normal temperature of the 1973 620 L16 engine?

[Leo92335]

Just now, Leo92335 said:

All my cylinders are firing good and I was able to time it at 10 degrees but my dash gauge is acting crazy  ,I installed an aftermarket temperature sensor before the thermostat and it has a digital screen and is reading about 80c and it's on the green area, do any of you know the normal temperature of the 1973 620 L16 engine?

The aftermarket is separate from my dashboard gauge and the one acting crazy is the dashboard gauge the electronic display seems pretty good 

[Crashtd420]

11 hours ago, Leo92335 said:

Hey buddy can I take you up on your offer to do some normal temperature readings on your L16 I think my gauge is faulty, I would really appreciate your help, thanks in advance 

Sure I can this afternoon....

I know the top of the thermostat housing was 185 but I'm not sure what thermostat I have in there..... 170/180

Also I said earlier I had dual 10".... that was wrong apparently I have dual 7"s...

I did just upgrade 1 to 9".... 

 

Where would you like readings from?

Top and bottom of thermostat housing?

Upper and lower radiator hose?

Will Anywhere else help?

[Crashtd420]

11 hours ago, Leo92335 said:

The aftermarket is separate from my dashboard gauge and the one acting crazy is the dashboard gauge the electronic display seems pretty good 

This might be a good thing....

Where is the electronic gauge getting a signal from? Where is the sensor located? 

 

Your issue might just be the stock sensor failing...