Timing

[Leo92335]

Hello fellow datsun enthusiast, can someone help about how to time my 1973 datsun pickup truck L16  ,it's been about a year and a half project and it's almost ready to go out but it keeps overheating so any body that would like to share the proper way to time my truck, I would appreciate it very much, thanks in advance fellas. 

[DanielC]

does your distributor have points, a mechanical switch that opens and closes as the engine turns?

[Leo92335]

Thank you for replying, I have electric points from petronix 

[DanielC]

Do you have a timing light?  What does the timing pointer on the engine look like?  Is there a single pointer on the front cover of the engine, and several notches in the pulley  or one notch in the pulley and a sawtooth segment by the pulley?

[Leo92335]

Hello Daniel, I do have a timing ligth and I have a saw tooth segment on the engine block starting at 20,15,10,5,0,5 from left to right and on my pulley I have 5 empty lines and one separate that was highlighted white 

[DanielC]

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.

 

 

 

Edited June 18, 2020 by DanielC

[Leo92335]

I'm new to this forum and I don't know how to load the pictures, when I try to load pictures it asks for the url address and I can't seem to find the upload from my phone option 

[Leo92335]

I don't have a loud exhaust, it has the stock exhaust,

[Leo92335]

Well I'm going to find tdc than set it at 10 degrees btdc and I'll take it from there, thanks for everything Daniel, ill let you know 

[datzenmike]

On 6/5/2020 at 7:30 PM, Leo92335 said:

Hello fellow datsun enthusiast, can someone help about how to time my 1973 datsun pickup truck L16  ,it's been about a year and a half project and it's almost ready to go out but it keeps overheating so any body that would like to share the proper way to time my truck, I would appreciate it very much, thanks in advance fellas. 

 

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

 

 

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

 

[Leo92335]

Thanks I'll double check everything, The previous owners crashed and they eliminated the engine fan for an electric fan on the front of the truck but I drove it for about an hour at night and it didn't overheat so not sure if it has to do with the air flow 

[datzenmike]

55 minutes ago, Leo92335 said:

Thanks I'll double check everything, The previous owners crashed and they eliminated the engine fan for an electric fan on the front of the truck but I drove it for about an hour at night and it didn't overheat so not sure if it has to do with the air flow 

 

If it's not the original then start there. The fan may be too small. It's cooler at night.

[Leo92335]

I will do that, also I've noticed the heater core hose is  leaking, I'll check it out,thank you, you are awesome 

[banzai510(hainz)]

make sure to buy the 50;50 mix at Walmart or your favorite store. never use tap water.

 

Over heat at the stop light or while driving?  once driving the fan don't do that much anyways

[DanielC]

In the 1970's, I used s 521 to pull a two horse trailer all over the Pacific Northwest.  If I was towing up a 6% grade, in 90 degree plus temperature, if the temperature started to climb, I would turn on the heater.

I am currently driving a 521, with a L-20-B engine, and I still have the L-16 radiator in the truck.  It does not run warm, or over heat either.

If your 521 overheats, there is something wrong.  It could be as simple as low coolant, or a bad thermostat.  It could also be a worn out engine, with low compression, or retarded timing.  

Overheating means energy from the burning gasoline is going into the cooling system, and not being used to move the truck.

 

[datzenmike]

Heater: auxiliary cooling.

 

I've done this to take a needle's width off the gauge climbing a long hill to get to a pull off. A bloody hot day, a hill and only a single electric fan showed me I needed more cooling.

[Leo92335]

1 hour ago, banzai510(hainz) said:

make sure to buy the 50;50 mix at Walmart or your favorite store. never use tap water.

 

Over heat at the stop light or while driving?  once driving the fan don't do that much anyways

Hello and thanks for the help, its rare because when it's stop in my garage and warmed up the needle at the gauge reaches little more than half but as soon as I start driving it moves all the way to the right to overheating in a matter of a minute or 2,any thoughts?

[Leo92335]

1 hour ago, DanielC said:

In the 1970's, I used s 521 to pull a two horse trailer all over the Pacific Northwest.  If I was towing up a 6% grade, in 90 degree plus temperature, if the temperature started to climb, I would turn on the heater.

I am currently driving a 521, with a L-20-B engine, and I still have the L-16 radiator in the truck.  It does not run warm, or over heat either.

If your 521 overheats, there is something wrong.  It could be as simple as low coolant, or a bad thermostat.  It could also be a worn out engine, with low compression, or retarded timing.  

Overheating means energy from the burning gasoline is going into the cooling system, and not being used to move the truck.

 

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 

[banzai510(hainz)]

maybe he put the 3 core in there and the fan cause it was overheating and fuck it and sold it to you.

Could be the system is over pressurizing just enough till you start driving. Meaning a had gasket is possibly going to go out

 

I don't get the Crashed part???? If nothing was hit inside it wouldnt matter I would think.

 

I assume he has the fan sucking in air from front to back. Outside to In.

 

Fan on thermo couple switch    or just ON all the time???????

Edited June 19, 2020 by banzai510(hainz)

[Leo92335]

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 

[Crashtd420]

13 hours ago, Leo92335 said:

 I drove it for about an hour at night and it didn't overheat so not sure if it has to do with the air flow 

Just saw this.... kind of rules out the head gasket.... it would happen all the time.....

[Leo92335]

Thanks anyway buddy 

[Crashtd420]

Here is a question.... 

Did you verify which way is the fan blowing?

 

If it's out front it should be a pusher style fan.... blowing air across the radiator...  

 

My thought on that is if the previous owner got the wrong fan and made it spin the opposite way, that the fan blades would be oriented wrong.... 

Not even sure if a pull style fan could be wired backwards to making it push but it's something to verify..... 

 

[banzai510(hainz)]

if its a new 3 core radiator and if don't leak they should keep it a lot cooler.

 

suck outside air IN across the rad then on to the motor. Is how it should be.

 

My dad had a Toyota Cressida that would reach half way on the temp then lower and did this over and over.  It was the head gasket

 

you never mentions when the fan comes ON all the time. once up to speed the fan usually shuts off.

[Leo92335]

It's a pusher fan