620 regulator thread

[Steroid]

So after extensive research (NOT by My choice though ! ! ) I found out that 620s had three different regulator plugs. I needed one (center) for a 1974. There is some luck in having so many trucks and parts but what really helped was that years ago I purchased all 620 service manuals. If You don't have one for the year of Your truck I strongly suggest it. So what happened??? If You remember the build thread for My black chopped truck, Choptana, You will remember that the cab came bare. I installed a dash and wiring loom from a truck that I couldn't remember the year. My first issue was with the front turnsignal lamp plugs. My second issue was with the alternator plug. Finally I had to check the voltage regulator to see why the truck would not charge. The charge light in the dash would not go out and the truck would die if the red positive battery cable was removed. Here is what I found:

 

 

From left to right, the rectangular plug was used on 620s up to October 1973. The black "V" shaped round plug in the center was used in 1974. The white round plug was used in 1975, 76 and 77 620s. Luckilly I had two '74 regulators other than the one in Choptana. The first one failed but the second one I tried made the dash charge light go out and also when I pulled the red positive battery cable, the truck kept running. Now for the bad part of this story........ six phone calls were made and I only tracked down 2 in Virginia that I purchased. Price each:  $90.00 ! !

I am hoping that some of You on Ratsun know of a cheaper place to purchase a 1974 regulator ! !  One question I have is were the 3 different plugs relative to the engine displacement? IE: 1600, 1800 and 2000 ? Why would it matter ? Can anyone solve this mystery ?   

[datzenmike]

Mike that '74.... you sure it's not an after market solid state regulator????

 

Nissan changed the plug shape, but an alternator is an alternator is an alternator and any regulator should work. All it does is increase or decrease the field (magnetic) strength and this increases or decreases the amount of power generated.

[Kirden]

I just bought a voltage regulator les than a month ago from O'reilys. It was ~$35 after tax and has that limited lifetime warranty. I have since switched to a 200sx alternator due to my 35amp dying on me, but I don't think that was related to the voltage regulator. I had a coolant leak above the alt from the lower water neck and the 35amp was pretty well gunked up.

 

One thing about the O'reily VR, it has a board on the bottem where it mounts to the firewall with a long spring peice. This spring quickly heats up and burns the board, causing some smoke. Both the old VR and the new VR burned in the same pattern, so these may not be quality parts.

[Steroid]

That center (1974) regulator is a solid state unit. I have two other 1974 regulators that are identical to the other two, one on Choptana right now. It came off of My orange propane truck. I was just using what was off of vehicles at the time to show the different plugs.

[sedition88]

I've got a '74 with the L18 and I have the the regulator on the left

[datsunaholic]

My '74 was built in March, 1974 and has the regulator on the left.  Same went for my parts '74.  The '75 I used to have, built in Nov '74, used the one on the right, as have all my '76s.

 

I've never seen the one in the middle.

[sedition88]

Greengoon gave me one that had the same connector as the one in the middle that came out of his 510 wagon, but is ws a alittle bigger

[banzai510(hainz)]

left the square one is a 510 type. or maybe very early 73 truck.

middle one is a solid state unite

right looks like a typical 620.

 

Vatozone varries the Wells Brand solid state units. I have had good luck with them.  YOu can ck Rockauto also. I think they should be under 30$ for whats really in them.

The Jap mechaicals are OK  but the USA NAPA branded Echlin ones suck bad. and are more expensive.

 

 

steroid I would monitor your voltage with a meter. Most ties it the alternator getting weak  most I see is the reg just makes sure it dont over 14 and cook your battery. if the vooltage drops the alternator is loading down. The Idiot light on the dash doesnt really cath this untill its alost too late.

[datsunaholic]

I should mention that I've seen that middle connector somewhere, just not in a 620.  There's a 4th type too- a rectangular-ish connector with 6 round terminals inside.  I have no freaking clue what that particular one goes to, might be a freaking Chevy LUV for all I know. 

 

I have a box full of brand new oddball regulators I got from the crackhead I bought my truck from.  I'm pretty sure several are not even for Japanese cars.  The regulators themselves pretty much are alike in function.

[Steroid]

Here is a photo of what I have and what I purchased. All of these have the 1974 only plug:

 

 

From left to right, The solid state unit that was on Funtana, the one I purchased 2 weeks ago (with the box above it) and, far right, the regulator that was on My orange propane powered 620. I am finding a little better price online now that I know the part number (VR 148).