1978 Datsun 620 - "Sendy"

[G FORCE]

Looks like a great find and you're off to a great start! Congrats on the purchase.

[bxadook]

Thank you G Force!

 

My starting woes continued despite the earlier cleaning.

 

So tonight I tested the starter solenoid(Yellow-Black) wire, and I found the voltage to be 0.3V no matter what I did. I confirmed that my multimeter was working by testing on the battery and it came out to 12.4V. For some reason I do not trust this value of 0.3V. Is this enough to get the starter solenoid to even engage the starter? Based off what datzen said, he had 7V going to the starter solenoid wire and he was having starter issues. If it isn't, the truck shouldn't have been starting at all. 

 

My black lead was attached to the negative terminal(ground) on the battery, and red lead was attached to the yellow-black starter solenoid wire which was disconnected per datzen's instructions. 

 

I will try again tomorrow to get better readings, maybe with leaving the solenoid wire attached to the starter. 

 

Ben

[datzenmike]

1/3 volt can't be right. Try the black meter wire grounded on the starter or transmission case rather than the battery post. My 7 v would normally be even lower if the starter was turning the engine. It tended to chatter sometimes as the starter loaded down the voltage causing the solenoid to disengage the starter whereupon the voltage would jump back up to 7v and the solenoid would engage once more.  Other times it would simply click 3-4 times in a row finally catching and turning the engine and starting. I have about a dozen old starters so I swapped it only to have the problem remain.

 

The fix was to use the 7v signal to power a small relay that was connected to the positive battery 12v. Something like this...

 

 

[banzai510(hainz)]

You can make that drwg simpler

Now if you put the black wire on the minus side of the battery or chassis ground the positive red wire of the voltmeter to the yellow selinoid wire but remove it from the selinoid.Put the key to start and see what the volt meter reads.

If you are getting .3volts then key switch is fucked or real bad connections.I would go to the back of the key switch and reseat the plug first

[bxadook]

My light problems are all fixed with the OEM light assembly! What I thought was one problem turned out to be four. What a start to this journey 🙂

 

Here’s my tests:

 

1st test: Ground lead was battery. I attached the yellow/black wire to a male connector to confirm that I was actually getting a connection with my test circuit and ran the same test. Turned the ignition switch to start and got 0.3V.

 

2nd test:  I switched the ground to the transmission bell housing and kept the male connector, turned ignition and got 12.4V. 

 

Assuming there isn’t a voltage drop between battery and starter solenoid, the issue is the starter or starter solenoid? 

 

My battery isn't grounded? Will look into this in a few hours. I only had time to diagnose my starter issue. 

 

Ben

[datzenmike]

The battery negative cable is bolted to the head behind the fuel pump. If getting 12v on the transmission case it muct be connected. Perhaps where you touched the test lead was corroded and you didn't make good connection.

 

I guess the last thing to check is to use the starter case as ground and check the yellow/black wire for 12v. The starter must be grounded to the transmission case.... and it probably is, but just in case check it. If still 12v when using the starter case as ground I would say the solenoid is bad or perhaps the starter is damaged inside.

[vicdat]

I don't know if this will help, but once on my '79 King Cab. the main factory ground wire from the battery to the block (which has super clean at the terminal and looked OK) had, over time, developed an internal greenish-oxidation that manifested as a hit an' miss "no-start" issue. It got worse.... Once I changed out the cable - problem solved...

 

Vicdat 610

[Stoffregen Motorsports]

Grounds should make a complete round trip -  battery to body, battery to frame,  frame to engine, from engine to body. The layout doesn't need to be exactly as I described, but all of the major food groups need to be grounded.

[]2eDeYe]

Not going to speak on the electrical, just kinda skimmed for now but I wanted to post up. 

 

Nice truck! 

 

If you click on the pic in the album it opens it. You can then right click on it and copy image. 

Then you just paste into the reply window. 

 

 

 

Again, great looking truck. B)

[bxadook]

Confirmed 12.2V using starter case as ground. 

 

Been googling how how to determine if it’s the solenoid vs starter and I’m thinking I’ll just go ahead and replace both to not delay anything. 

 

I’ve searched the ratsun forums and you guys recommend original starters as replacement but my end goal here is a motor swap when my L20b dies(which may be never) 🤠. 

 

So so any particular brands you recommend? I know I’m going for the gear reduction starter. 

 

Can’t wait to open up the original starter and learn about/potentially fix it!

 

Ben

[datzenmike]

If replacing the engine get an original used starter rather than getting on that guaranteed for life re-manufactured windmill ride. I have a Canadian Maxima starter, they were a 6 cylinder L series engine. A 280 zx would be another. I turns slightly slower but is geared for torque, good when the weather gets cold or if you have a higher compression engine. It's longer that the 4 cylinder gear reduction starter and is a snug fit between oil sender and engine mount.

 

 

Usually the solenoid, then perhaps the starter brushes wear out.

[bxadook]

any of the L series motor starters are cross compatible with the L20b?

 

I have discovered that my starter issues are likely worse than the previous owner's because of the change in oil from synthetic to the thicker Delo 400, which is why it only bothered him on cold mornings. 

 

Ben

[datzenmike]

They all interchange but an L16 starter on a 280zx is likely not the best. Try Rotella T4 in 10W30. Delo 400 may have the same. I use 15w40 because I only drive my Datsun in the spring-fall

[bxadook]

Duly noted. 

 

I am still going to replace the starter because he was having the same issues but with less frequency than me even with his synthetic. 

 

If the starter is still giving issues after replacement will likely change to Rotella. 

 

Ben

[david lo pan]

Clean truck!

[bxadook]

Okay so the starter is pulled. Oil around the mating points. 

 

'

 

There is a lot of carbon build up. 

 

I noticed that there is a lot of carbon build up and oil around the contact surface with the bell housing/case. 

 

 

I am not convinced that there is a leak from the rear main seal from what I am seeing, as the oil could have come from the leak I haven't looked for yet and it might be contributing to my starting issues. 

 

 

Fresh oil in the case with lots of carbon build up. 

 

Will be taking the starter to Autozone to have it tested and cleaned. 

 

Ben

[bxadook]

Confirmed starter works on testing. Likely the solenoid. 
 

I’m not going to lie, already ordered my replacement starter. 
 

gonna keep the old one and if the replacement breaks I’ll replace the solenoid and use this one. 

[datzenmike]

NEVER throw old parts away. There is always something you can use on them still. Some parts don't even exist anymore and that would be a shame if someone else needed it to keep their Datsun on the road. The 'carbon build up' is likely oil that has worked it's way down from a leaking valve cover gasket that has collected clutch disc dust.

[Stoffregen Motorsports]

Old parts are also valuable for reference, even if they will never get re-used.

 

You never know what will be valuable in the future either. I recently put a box of '67 Corvette leftover parts on Craigslist, not knowing what to ask for the parts. The date coded jack got the most phone calls and sold for over $600.

[banzai510(hainz)]

http://tsimportedautomotive.com/gearreductionstarters.html  sells NEW starters  202 is the part number I think.  Even though its sold from Ohio the starter come from Hi Torq in calif.  Was told new Denso motor.  I haven't tried mine yet still in the box but these are the same ones Troy Ermish (the 510 outlet)sells for 240$

 

Be honest once I added a HOT start relay I got longer life out of my  O riley and Vatozone starters, Many could have been low voltage on the Key switch making it look like a bad selinoid.

[bxadook]

Interesting. I saw the Troy Ermish starters when googling everything and it was pretty enticing. The price tag was steep! It's pretty tough to justify really nice stuff right now given this is my first car that will need maintenance and its highly likely that I will mess something up.

 

I bought an AC Delco reman and so far 5/5 starts, including multiple cold starts in 30 degree weather. Thanks for everyone's help!

 

Next projects in no particular order are chasing down the oil leak, floor pan replacement, full suspension rebuild and D21 disc brake conversion in the front and rear. 

 

On a tough ICU and inpatient month so time is limited. 

 

Ben

 

[banzai510(hainz)]

what I do is start a note book and write when you bought the starter and record it everytime you change something then you can figure out what parts go bad and how often.

I cant even count howmany starters and alternators I have gone thru. my book got full in just 5 yyrs

[Stoffregen Motorsports]

21 hours ago, banzai510(hainz) said:

 

Be honest once I added a HOT start relay I got longer life out of my  O riley and Vatozone starters, Many could have been low voltage on the Key switch making it look like a bad selinoid.

Yep, good idea. I use generic continuous duty solenoids, like from a Ford truck. https://www.google.com/search?q=continuous+duty+solenoid&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjW-83ryoPnAhWRQc0KHbtYDYIQ_AUoAnoECA0QBA&biw=1680&bih=908

 

You can wire the whole car off the solenoid so that nothing touches the battery until you turn the key.

[banzai510(hainz)]

thats what I got on my 521, a Ford starter relay

[bxadook]

So I found a leak in the valve cover, where mike was expecting it and I have a valve cover gasket that is arriving today. Will see if this is the solitary leak! Is there anything I should check in the engine head when I pull the valve cover off? 

 

Ben