1975 620 Longbed "Shelley"

[Jskinny]

11 minutes ago, datzenmike said:

Needs a distributor and the PCV fixed.

Could I swap over my existing distributor and adjust if needed or is there more to it than that? 

 

Just thinking about how direct of a swap over another L20b would be for someone with next to no experience. Whether for this one or in the future.

[Jskinny]

Eets gone

[Jskinny]

Went to Wekfest in Seattle this past weekend and saw a few datsuns in the sea of Hondas. 

 

And I stole these photos from Instagram since apparently didn't get any more photos.

 

 

Corvette swapped Z on the left (I know, tsk tsk) and the first 510 again.

 

 

Edited July 1, 2025 by Jskinny

[ggzilla]

Yes, it's easy and straightforward to swap a working distributor from one L-series 4-cylinder engine to any another

On 6/26/2025 at 12:11 PM, Jskinny said:

Could I swap over my existing distributor and adjust if needed or is there more to it than that? 

 

Just thinking about how direct of a swap over another L20b would be for someone with next to no experience. Whether for this one or in the future.

 

Put your working distributor and its pedestal here:

 

PCV hose missing. Use the PCV valve and hose from your existing L20B

[Jskinny]

6 hours ago, ggzilla said:

Yes, it's easy and straightforward to swap a working distributor from one L-series 4-cylinder engine to any another

 

Put your working distributor and its pedestal here:

 

PCV hose missing. Use the PCV valve and hose from your existing L20B

So no adjustment of the points etc? Seems fairly plug and play, just connecting everything back up.

[ggzilla]

If your old engine has a running distributor, then after swapping, no adjustment of the points is needed. Only setting initial timing

1 hour ago, Jskinny said:

So no adjustment of the points etc? Seems fairly plug and play, just connecting everything back up.

However, since points distributors -- per the owners manual -- need adjustment of the points every 3month/3000 miles, it will have to be done sooner or later

[Jskinny]

1 hour ago, ggzilla said:

If your old engine has a running distributor, then after swapping, no adjustment of the points is needed. Only setting initial timing

However, since points distributors -- per the owners manual -- need adjustment of the points every 3month/3000 miles, it will have to be done sooner or later

3000 miles?? I'll have to find my manual again, but mine likely needs an adjustment then! No record of when it was done last.

 

At this point my plan is to drive it as is working on smaller parts until I find a good deal on another engine or something more happens. Pretty sure it already has burnt rings so just keeping it running in the meantime.

 

The "bite off more than he can chew" version of me is also open to a KA swap, but getting the experience doing a simpler l20b>l20b is probably a better route.

 

And I have a disc conversion kit to do before I think about engine swaps. 

Speaking of, still need to figure out what kind of proportioning valve to get. 

 

[Jskinny]

Something cool I just discovered recently is that Mike Klotz's 620 brake kit is now being made by Sin City Datsuns, so it's still available for people who wanted his kit but missed ordering one from the man himself. They also say they can help with any technical questions in regards to the kit.

 

https://www.sincitydatsuns.com/shop/p/product-4-9e76d-pr6ls-5tznn-n4da7

[ggzilla]

I get that disc brakes are cool, but they don't stop any faster than the drum brakes. So technically you don't need to do that before getting a more powerful engine

 

 

The need to periodically adjust the points is to keep performance at the maximum. The engine will still run for a long time without adjusting. I have gone a whole year in between adjustments, but the points gap keeps getting wider and so the timing changes out of spec after a while, not to mention a weakening spark. Eventually the points will carbon over or burn out and the engine won't start

 

This is the reason so many swap a matchbox distributor in. No more points adjustments, a stronger spark, and reliability that last decades. The matchbox virtually never goes bad, unlike some other brands of electronic ignition

1 hour ago, Jskinny said:

3000 miles?? I'll have to find my manual again, but mine likely needs an adjustment then! No record of when it was done last.

 

Agreed, the L20B is also less expensive. A great way to get some experience

1 hour ago, Jskinny said:

The "bite off more than he can chew" version of me is also open to a KA swap, but getting the experience doing a simpler l20b>l20b is probably a better route

 

[Jskinny]

Cool, thanks for the explanation. I'll be looking into this more and see how bad it is. 

 

Different question for the more experienced than I though, currently I'm running Castrol GTX classic 20w50, but realized I assumed the viscosity was because of the zinc additive. It's not the cheapest oil which is fine, but I recently looked up Shell Rotella T4 10w30 based on @datzenmike's recommendation on another thread, and saw it was substantially cheaper.

 

Any reason I shouldn't switch and start getting Rotella or am I just being slow? Main difference is the viscosity, I think the zinc content is a similar PPM. 

 Plus it'd match the stickers.

 

 

[datzenmike]

Oil viscosity and ZDDP have nothing to do with each other.

 

The oil weight is for cold weather starting. 30w oil (when its cold) flows faster onto the bearing surfaces than 50w. Once the oil is hot there's not much difference between them. The viscosity should be selected on the coldest weather you expect till the next oil change. 10w30 is good down to 0 F. 20w50 good down to 20F.

 

Rotella T4 also comes in 15w40. The ZDDP is 1,200 PPM. Most all other oils since '93? are formulated for today's gas engines and has slowly dropped to 500-650 PPM

 

 

[Jskinny]

Been a while. Nothing too much to update. Wiper linkage broke (the plastic brackets snapped and bound up the whole linkage). Found you can get replacement linkage on ebay so ill be looking into that as well as trying to design replacements for the brackets. Hopefully the wiper motor istelf didnt burn out, was pretty hot the one time i touched it. Been getting lots of rain here so the truck is probably hibernating for the winter again. 

[Jskinny]

Got the linkage mostly out today. Just have to remove 2 of the 6 studs that are being stubborn. 

Took a few photos but need to figure out how to upload from mobile.

Edited January 2 by Jskinny

[Jskinny]

Plastic brackets holding the wiper pivots on broke, and 2 of studs are rusted to the bolts so they just spin. Hopefuly slow and steady does the trick, and lots of penetrating oil.

Edited January 2 by Jskinny

[Jskinny]

Here are some photos of the wiper pivots from the inside. What's annoying is that the hardware used to bolt them on are studs, not actual bolts. Had to use vicegrips (and a lot of penetrating oil) to get enough grip to stop them from spinning with the nut on the outside. 


Finally got them all out with only one stud broken. 

 

 

Now, to find a replacement. I've been looking at these on ebay. They look like they could work, Thailand has a lot of these old nissans. Has anyone else tried this?

I'd like to avoid the NOS since its still (old) plastic. aside from the cost being more than an assembly itself. I am hoping the ones above are metal, but if they aren't I'd assume the plastic is at least in better condition than the NOS just fom being newer.

[Rustbin]

On 1/4/2026 at 3:04 PM, Jskinny said:

Finally got them all out with only one stud broken. 

 

 

You did real good, lately it seem I only get one not broken.

[Jskinny]

Ordered a linkage from ebay, should be delivered today. Came pretty quick so we'll see if it works out.

[Jskinny]

The new linkage looks great. The old wiper caps even thread on nicely. Now just have to get some new gaskets. Gives me a chance to use SendCutSend.

[iceman510]

I cut mine from some sheet rubber I bought from Amazon.  

[datzenmike]

The studs are splined just like wheel lugs. I've broken a few. Best was to gently tighten/loosen over and over and try to get them just moving and keep going letting the threads push the rust ahead of them. 

[Jskinny]

Got the new linkage in. Seems to fit and pivot smoothly, just need to figure out how to attach the Wiper Linkage Clip Retainer Cup Ball Grommet Bushing (available as of now on Zcardepot as part #200-1143) to the shaft of the wiper motor arm. 


I have the clip that held the original linkage, so I am thinking maybe I need to just drill a hole in the center of the plastic clip, slide the shaft through, and the clip can slide on and keep everything in place. Thats a problem for another day though.
 

Got some gasket material off amazon and made some new ones for the wiper pivots.

[Jskinny]

Also got a few photos since we have been getting some nice weather: