Ron1200's '79 KC 620

[DatMo]

Looks great man

[Ron1200]

Trying to banish the shift lever vibration when going 70+.  Took out the brass pieces I had in there and installed new stock plastic bushings (cup & pin).  Will see if this fixes it.  Took an opportunity to install a new shifter boot and folding cup holder.

 

 

New leather boot and Fischer folding cup holder (about $23 in eBay)

[Ron1200]

Besides the SUs, I have options...

A Weber 45DCOE & Canon manifold and an Offenhauser manifold (works with Downdraft Weber).

The 45DCOE is NOS.  It's an Italian and has the box.  It is recommended that the distributor be changed to full mechanical advance (though it appears there are ways around that). 

 

The Offenhauser is a 6178-DP specifically made for 76-80 Nissan 2000cc motors. This application retains the vacuum advance.

 

Decisions decisions... I like the look of the 45DCOE alot, however now that I've discovered that its valuable as it is new.  And with no provision for vacuum advance, I'm inclined to sell it. 

 

I'd consider rebuilding the SU's but have not been able to contact Z-Therapy (after trying 8 times and leaving 2 messages), I think I'll just move onto other options.

 

[Ron1200]

I'm pleased to report that the shift lever vibration is gone. Replacing the u-joints took care of most vibrations, the stock plastic bushings resolved the vibration that was left.

 

Nissan Part Numbers for the 5-speed:

32855-H1010 = Bush Control Lever (works with the pin, you need 2 of them)

32861-N4200 = Bush Control Lever Head (the plastic cup that pops onto the transmission end of the lever)

 

Initially, I was thinking that I had a transmission issue... I'm really pleased that the u-joints and the plastic bushes fixed it.  :thumbup:

[Ron1200]

On the SUs, I may be dealing with a coke linkage issue.  The jet on one carb does don't pop back up when the choke lever is released.  I need to clean and lube the linkage and see if this will fix my rich mixture problem.

 

I checked and I have a W58 head on this L20b motor.  Per The 620 Resource Head Info Page, "These heads don't flow well and are avoided for high-performance applications." I think this shoots my Weber 45DCOE plan full of holes.  The Weber side-draft is a performance carb and paired with a W58 head is kinda like lipstick on a pig. Well shit!  :no:

 

So stick with the Hitachi-SU's or use the Offy manifold and buy a DGV.  One nice thing is both options use vacuum advance so no distributor modifications are necessary. 

[Ron1200]

I reached Steven at Z-Therapy and found out a couple of things:

1. The air box fitted to the 620 when I purchased it blocked the vents and made the SUs run rich.

2. The jet nozzle can easily be removed (via one screw) out the bottom of the carb and cleaned with a wire brush to fix the sticking choke. (I used a rifle bore brush)

 

Here's a pic of the air box.  See the two extra holes for the vent I drilled.  I'm just about to drill the vents for the 2nd carb.

[Ron1200]

I got the SUs balanced and adjusted, not perfect, but close for a SU newbie... And all I can say is WOW!.  This truck drives sooooo much better.  Smooth acceleration from idle to redline and better MPG to boot.  I can see people here like them.  Woot!  :thumbup:

 

Took me a while but I finally got the linkage figured out.  I could not find adjustment info specific to these carbs... maybe it's obvious to some, but it wasn't for me.  Screws circled in red are the high speed balance screws, the screws circled in blue are the typical idle adjustment screws. 

[]2eDeYe]

 

 

 

Nice work! This has always been one of my favorite 620s. Still have that hood in my shed :D

[Ron1200]

Thanks Steve.   I was going to peel the vinyl off and paint the hood. Someone on Ratsun (I can't remember who) suggested that I offer it up for trade.  I'm glad you got it. 

[Ron1200]

... and better MPG to boot. 

So pre-airbox modification 14.6 MPG... post-airbox modification 24.2 MPG (includes city driving and some top speed runs).  :thumbup:

[]2eDeYe]

That is spectacular :D

[Ron1200]

Installed Harley Daymaker LED knock offs... At 20W Low / 30W High they are under the stock power consumption and easier on the old wiring.  Have only had a quick drive and they appear to be better than the Wagner sealed beam halogens I had in there.

They were a pain in the ass to install... 1.) the headlight tabs (four) don't align with the bucket tabs (three) and 2.) it didn't help that my 620 has two different styles of headlight buckets.  The right pair is different than the left pair.

 

 

[]2eDeYe]

Bright :cool: 

 

 

Do you have a link to those? 

[Ron1200]

These are the ones I used...

The Watts are different that what I posted earlier... 30W on low beam & 48W on high beam.

[]2eDeYe]

Thanks :cool: 

[Ron1200]

Here's a pic of the repo door window rubbers that come out of Thailand.  I don't think they are as good as originals.  But those aren't available any longer.  I had to trim them slightly as the lip would roll under when the window was lowered.  Better than nothing and should go a long way in keeping the fir needles out of the door.  You know that fir needles are acidic and when mixed with water make a 'witches brew' that dissolves sheet metal. .. Best to keep that to a minimum.  Much quieter without the window rattling FTW.  :thumbup:

[Charlie69]

Nice work Ron.  The window sqeegies look like 720s.

[]2eDeYe]

Yeah, I wasn't impressed with those either. 

[sebpv]

never thought about cutting the lip. Will do that. Btw is silicone spray something to try on the inside edge?

[Ron1200]

 Btw is silicone spray something to try on the inside edge?

 

Might work for a while and likely would require occasional reapplication. < Just a guess as I haven't tried it. :)

[Eagle_Adam]

Missed this thread somehow....

 

First time I met Skib he rolled up in this truck!

 

You've done great things with it so far, that rear bumper is prob my fav addition you've made so far!

[Ron1200]

Sometimes it's just the little things that make you smile... like having working dome light switches...

 

Thanks to Charlie for the info on these. 

[Ron1200]

Fixed my jumping tach needle... Turned out to be dirty or loose contacts.  Cleaned the slip-on connectors at the coil and tightened (pinched with pliers) the spade connectors at the matchbox on the distributor.  I don't know which actually corrected the issue as I did both at the same time. B)

[Ron1200]

New Tires! General Altimax RT43 195/70-14.  I like wide sidewalls on lowered trucks... They make for a smoother ride.  I went with the 195/70s as they are very close to the same tire height as the 185/75-14 that were mounted when I got the 620 and they keep speedo correct after all the effort to make it right. These are rated well by Consumer Reports and Tire Rack. Not a racing tire but one that matches up with my idea of a daily driver and hooks up well in the wet.  :thumbup:

 

 

Not 'Hella Flush'

 

Spare now works with stock under bed carrier. Wheel from Ted... Powdercoated by Jon

[Ron1200]

Well Shit! Cooling system problem stranded me in Centralia...