Timing Issue - adjustable range does not allow proper timing to be set.

[JesseR]

So here is the skinny, I have a 76 620 with the original L20b. It has a new Weber 32/36 DGEV and is properly adjusted, choke works great, no vacuum leaks. All smog stuff has been eliminated. I have recently checked the valve adjustment and everything appears in range. Alternator, regulator, battery and coil tested and appear good. Plugs, wires, cap rotor all replaced within the last year. Points set properly.

 

About 6 months ago it started backfiring badly. After going through all checks I discovered the timing was way off. I had enough adjust-ability in the distributor to get the timing back to 12 deg with the vacuum advance off and the engine warm. I tightened the adjustment screw and went on my way.

 

So here is my issue. Once again it started backfiring badly again when the engine is at temperature. Starts and idles great. Once warm, the engine stalls, backfires and has no power to accelerate. I checked and the distributor had not moved from where i set it previously. Threw the timing light on, engine warm, vacuum advance removed and the timing was off again. it was off about the same amount it was the last time I adjusted it. The distributor needed to be turned clockwise (same direction it was corrected last time) but the timing adjustment would not allow the timing to be moved into range. I removed the adjustment bolt so I could get the timing correct but now i cannot lock it down. The distributor has not been removed since i have owned the truck so it has not been monkeyed with.

 

I need to understand what might be causing the timing to continue to move? And how do I correct the problem so my timing stays in the adjustable range and does not move.

 

Love my truck, and only want it running right.

[Rick-rat]

 

 

Make sure your vacuum advance is moving freely in the distributor

[JesseR]

I will check again, when i replaced the rotor a while back i gave a suck on the vacuum line and the advance was moving.

[Draker]

How lo ND have you owned this truck?

[Doctor510]

reset your points .020"

[distributorguy]

When the points close up, timing retards as you are seeing.  Open up the points and the timing advances.  

[banzai510(hainz)]

underside of the distributor is a 8mm bolt. loosen this and loosen the 10mm bolt that holds the dist to the timming plate

 

get your timming light and adjust. you shouls be able to go to 0-25 degs adjustablility Ezely unless dist /oil pump was installed wrong.

 

yes adjust the points and find a Electric ignition when you get around to it.

 

Do not buy new coils and suck as most are not needed and has to be the correct ohm value.

then adjust the carb if needed

 

 

olddatsuns.com tech section and has soem of my vids. dont be a lazy Datsun owner, watch them

 

 

ck the condensor wiring to make sure tight. and or new condensor. and ck the dist side to side play as this may cause points to open prematurly

 

 

buff that truck out. nice color

[distributorguy]

What Banzai is saying is that you may need to drop the oil pump to rotate the distributor driveshaft 1 tooth to shift your range of adjustability.  The gear has 20 teeth, so a 1 tooth change will rotate your distributor 18 degrees.  In case you have a bastard child truck, the other issue is that there are 2 different clamping plates, 1 rotated further than the other which would necessitate that 1-tooth shift.  

[JesseR]

I will get out there today and re-gap the points, the correlation between point contact and spark timing make sense.

 

Electronic ignition is next on my list. I have the PerTronix 1741 Ignitor in my Amazon cart as we speak waiting for my Datsun upgrade change jar to fill up. Can you guys recommend this unit or is there something else I should get?

 

As for the truck, it was a pay it forward....  It had been a farm truck that spent most of the 10 years before it was given to me under a tree on a farm growing moss. The paint is original and I have buffed out the front but I have left the bed raw. I call the look the reverse mullet, "party up front, business in the back" I have had it for about 2 years and it is my baby. It is a work in progress and has largely been small repairs and rewiring. I did the carb conversion and de-smog. I have lowered it slightly, 2 in the back, 2.5 up front. Did interior led lighting and a low wattage tripath based stereo with sub so the stock alternator would not get overworked. After the electronic ignition I will start saving for front disk brakes. It is not without flaws, and that is what makes it so great.

 

Thank you all for the advice, I will let you know how it goes!

[banzai510(hainz)]

the Pertronix will fit a single point dist. However on the l20 dist theres a ring above the point lobe that the magnic ring in pertronix kit wont fit over. YOu one has to pull the shaft and get it machned off.

Take photo of the distributor inside with rotor off.

[distributorguy]

Your truck will make more power with good points than it will ever make with a Pertronix installed.  Its a little more maintenance, but keeping points is more durable overall.  If you buy a Pertronix unit, you also need a 3 Ohm coil and to rewire the ignition or it won't last the 30 month warranty period.  

[G-Duax]

A buddy of mine thought Pertronix sounded like a cool set-up.

Another buddy thought they were FM (F-cking Mystery)

After the first buddy bought, install, and drove it till failure, we all decided they were Smoke & Mirrors.......

 

But I will stick to my electronic dizzy.

[banzai510(hainz)]

they will fail if one puts a EI coil and no ballast resisitor.

Mallory Unilites were another. Stupid kids would run the low ohm GO FASTER coils and pop the modules. Its in fine print to use the stock coil and ballast or resisitive wire

 

I got them cause I had single L16 distrutors around that were still good

I like them.

But if one can find a Matchbox thats good also. But hook it up right and use the correct coil(79 200sx/620 stock coil)

[JesseR]

That is all really good advice...

 

So i opened the distributor and the points were closed down. cleaned and set the points to .020. Started the motor and set timing to 12 deg advanced. Was able to lock down the distributor to within adjustable range. went for a test drive and it has never run better. Thank you all so much. I had to adjust the idle a little now that it is running correctly.

 

On another note there is an adjustment bolt on the bottom of the distributor that looks like a second adjustment. It was not necessary but i checked it for snug and left it alone.

 

I think i will live with the points if it continues to drive the way it is now. Now that I know how the points affect timing, it should not be a big deal. saves me $100 dollars that i can put towards brakes.

 

It is 70 degrees outside.. I think I will go drive my truck!

[Draker]

Lucky! It's shit weather up here.

[distributorguy]

Enjoy, while we look forward to -10 tomorrow morning.  Ughhh....

[Draker]

I guess I'll take our shit weather over your shit weather.

[JesseR]

Truck is clean and running great, thank you all! I washed it so of course it is going to rain! Murphys Law for ya.

 

Anyone know if there is a Datsun club in southern Oregon that gets together on a semi-regular basis. Somewhere between Grants Pass, Medford or Ashland.

[JesseR]

Bonzai510, here is a distributor shot....

 

 

 

[JesseR]

It did not take my images.. what is the trick to inserting them in a post?

[JesseR]

I found the guide, i guess i need to load photos elsewhere and link them...  for another day...

[john510]

A buddy of mine thought Pertronix sounded like a cool set-up.

Another buddy thought they were FM (F-cking Mystery)

After the first buddy bought, install, and drove it till failure, we all decided they were Smoke & Mirrors.......

 

But I will stick to my electronic dizzy.

A Pertronix setup that is properly wired up will work just fine.Definitely better than points.

[JesseR]

https://dl.dropboxusercontent.com/u/43418296/20140823_162308.jpg

 

https://dl.dropboxusercontent.com/u/43418296/20160212_132523_resized.jpg

 

https://dl.dropboxusercontent.com/u/43418296/20160212_132427_resized.jpg

[banzai510(hainz)]

Yeah Your Pertonix (if you bought it)will only fir if you machine the ring around the point lobe.

What I do is get another for about 1o-20 bucks as that's what they are worh to a guy whos done a KA motor(don't need them) pull the rubber cap on top of the dist shaft then theres a Phillips screw and you can pull this apart. but also the vaccum advands needs to be pulled ect. then you have have the ring machined off.

Unless a machine shop can chuck it up and machine it off w/o disassemble.

I have multiple distributors laying around. My last one the vaccum advance got stuck and would cut out. I tried getting the srew from the vaccum advance and could not get them out. I just grabbed another dist and ran with it.

 

you got a clean set up. get some GOJO hand cleaner and start cleaning the motor bay a little at a time . will look nice and clean.

 

paint them rims and find some hubcaps

[JesseR]

When I do disk brakes up front i am going to need rims which is why i sprayed the factory ones with primer just to get by. I will probably go with solid steel wheels and have them powder coated. As for the engine bay, I am slowly cleaning up wiring and i like the advice on the GOJO and will work on cleaning stuff up a little at a time. Put about 50 miles on the truck today and it drove great so i appreciate all the help. If anyone comes through Ashland, OR hit me up!!!