My Ratsun Datsun 521, now with L-20-B and a five speed

[DanielC]

I am suspecting I did not need to replace the master cylinder.    After replacing the master cylinder, my brakes got bad again, and after a few, or several times bleeding the brakes when they got bad, each time a shorter time between needing to bleed the brakes again, my brake lights started staying on.  At first, I thought it was a master cylinder problem, with brake fluid pressure holding the brake light switch on.   Yesterday, I took the brake light switch out of the truck, and it was always on.  I blew compressed air into it, and it still stayed on. 

 

You can not have the brakes light always on, people behind you do not know it you are really stopping, and since the brake lights do not need the ignition on to work, it will and it did drain the battery.

 

Today, I got a new hydraulic brake light switch.

I am lucky to have a good auto parts store nearby, Clackamas auto parts in Oregon City.   I called a local Nissan dealer this morning, to see if a brake light switch was available, it was not from Nissan.

 

Body parts on a 521 are measured using the imperial system, you know, inches.  I knew the flare nuts on a stock  521 are 3/8-24, and I was hoping that the brake line junction block hole for the brake light switch was just a standard 1/8 pipe.  It was.

 

This is the old brake light switch screwed into a 1/8 pipe "T"

 

The OEM brake light switch needed a 1" socket to remove it.

 

It needed a fair amount of torque to remove it, so I clamped the lower part of the brake line junction block in a pair of Vice grips.  I held the Vice grips in one hand, while unscrewing the old brake light switch with the other.

 

After removing the old brake light switch, I used a oil pressure switch socket to install the new switch.

 

This is the new brake light switch, installed.

 

Then I put the wires back on.

 

Brake lights on.

 

Brake lights off.

 

I did a very short test drive.  The brakes seemed OK.  It was late this evening, and traffic is basically gone, so I took Ratsun down to a local gas station, and got gas in it.  The brakes still seem to work normally.

 

It will take a few days of driving to see if I really got the brake hydraulic problem fixed.  i am now suspecting the old brake light switch was defective, and somehow letting air into the brake junction block, but not letting fluid leak out.

 

This is the second time I took Ratsun to a gas station, and filled the tank, since I put the L-20-B engine in it.  So finally, I could check the gas mileage on the truck with that engine.

221.9 miles on 9.738 gallons of gas, 22.787 MPG.  This is with the stock 5211 four speed transmission, and rear axle ratio, 4.375, mostly non freeway driving, and getting two loads of hay. and not really trying to get good gas mileage.

 

 

Edited August 16, 2018 by DanielC
grammer

[mklotz70]

You do great write ups Daniel! :)

 

[datzenmike]

Mileages sounds about right for L20B x 4.375 x truck weight. On cross Canada trips I got low 30s (per US gallon) but at home low 20s in my 620. I had an L20B 521 but don't remember ever keeping track of the mileage.

[DanielC]

Mike K, king of the you tube videos, thanks for the complement!  Do you have video, or a complete parts list of what I need besides your disk brake brackets to disk brake a kingpin truck?

Datzenmike, I am happy, with the mileage, because I was not trying to maximize it,  I am thinking there is room for improvement with a five speed and possibility a slightly higher (lower numerically) rear end ratio.

 

[mklotz70]

Did you get one of the aluminum versions.....or the steel brackets?

[mklotz70]

....not to sure about the king of YT vids. LOL!!  If you have the steel ones, I have vids done with those brackets.  If you have the aluminum ones, then the vids are still really close, but I don't have any with the new AL versions.

[DanielC]

MikeK, I got the aluminium brackets.

 

[mklotz70]

All the info you need should be on this page.... http://www.bluehandsinc.com/truck-kit-install.html  Make sure to check the other links, too.  If you have any other questions, just let me know. :)

 

[DanielC]

Mike, Tnanks.

   I think I have looked at that page before.  I will review it again.

Dan

[Charlie69]

The best parts in Mike's disc kits besides the brackets are the bearing adapters.  These allow you to use the very common 720 bearings. IMHO

 

 

 

 

Edited August 17, 2018 by Charlie69

[mklotz70]

That is such an old pic!!! LOL

[Charlie69]

It is a good one!!!

[DanielC]

I have driven Ratsun about 50 miles, mostly not freeway, and the brakes seem to be fixed.

Today, I went to Sherwood Pick-n-Pull, they have a 1974 620 truck, with a tool box, not a normal bed.  i was hoping the 620 truck had a speedometer pinion I need for the five speed transmission I have in Dragon, one of my other 521 trucks.  I pulled the speedometer pinion out of that transmission, and it is a red, 20 tooth pinion.  My Datsun competition catalog says that red 20 tooth pinion is for a 4.11 rear axle ratio rear axle.  If it is, I think I would like to put that rear axle ratio differential in Ratsun.

The stuff I got at Pick-n-Pull today.

 

I am using a stock manual hot air valve 521 air cleaner on Ratsun.  I would like to use this air cleaner, because of the automatic mixing of hot air off the exhaust manifold.  Winter is coming.

 

L-16 exhaust manifold.  The second L-20-B engine I got has a square port cylinder head, but it came with out either manifold.  I have spare intake manifolds, needed an exhaust manifold.

 

This is the fan I got today.  The L-20-B engine in Ratsun has not ran hot at all, I had put a 7 blade should use with a fan clutch on it.  i am going to swap this fan on to the L-20-B engine, because it should reduce fan noise.

 

The instrument cluster was out of the 620 truck at Pick-n-Pull, and I had disconnected the transmission end of the speedometer cable from the speedo pinion so I could remove that part.  I also took the cable.  It is longer than a 521 cable, reaches the right side of the transmission. 

[datzenmike]

Daniel you can use the square port L16 exhaust on a square port head L20B. If you drill two coolant holes in the U67 head the coolant intake from any L16/18 or L20B after 77 will work.

 

I swapped the 71B 5 speed into my car that also had the same basic 4 speed as ratsun. I un-clipped the original short speedometer cable from the body and fed it down behind the head over top of the transmission and plugged it in no problem. Been on and working for 7-8 years.

[DanielC]

 

This morning, I cleaned up the air cleaner I got from Pick-n-Pull yesterday.

Inside of the lid.

Outside of the lid.  This needs a little attention.

These are the vacuum hoses for the vacuum motor in the air cleaner snout.  The two black hoses on the right go to a "T" with another hose that were not connected to anything when I found the air cleaner at the junkyard.

There are the two controls for the vacuum motor.

i have an idea of how they work, and does this system also use the two port valve on the thermostat housing?  Air cleaner is off a 1974 620 truck.

Edited August 25, 2018 by DanielC

[mklotz70]

Are you running a stock carb or a weber?

 

[DanielC]

I am running a stock L-16 carb on the L-20-B engine.

[datzenmike]

I guess I forgot to hit the submit button this morning.....

 

 

The valve in the air horn is normally open with no vacuum signal.

 

The air horn valve has warmed exhaust manifold, cool outside air and can mix both together.

 

Vacuum from the intake passes through the larger black temperature sensor which has a small air bleed and a bi-metallic strip. When air filter temperatures are below 86F the valve is closed and the vacuum servo motor in the air horn is pulled closed against a spring. From 86F to 129F the air bleed is opening and the servo motor is partly open. Above 130F the temperature sensor is full open removing the vacuum signal to the servo motor in the air horn which closes off the warmed air and only outside air is drawn in.

 

Thus the air entering the engine is tightly controlled during warm up and in operation. Under heavy load conditions the vacuum is so low the servo motor will be pulled closed by it's spring regardless of how cold the air is to give maximum performance.

 

 

The other valve (altitude compensator) is also a bi metallic strip the opens an air bleed to the intake to lean out an over rich condition caused by higher altitude. Is this air filter from California??? They had this but federal trucks didn't.  There is another type of air bleed (idle compensator) that has two by metallic strips (yours has one so I think an altitude compensator) that leans out an over rich mixture caused by excessive under hood temperatures. 

[DanielC]

Thanks!

On the two L-20-B engines I have, there is a two port valve on the lower thermostat housing. 

What was it used for?

[datzenmike]

 The carb has a separate ported vacuum line (other than the vacuum advance) for the EGR. It goes to the thermostat housing valve. The Thermal Vacuum Valve TVV opens above 40-50F coolant temperature and allows EGR to take place, depending on the ported vacuum signal. None at idle and none or almost none at full throttle (low intake vacuum) Later trucks also have a Back Pressure Transducer BPT that allows more EGR is relation to exhaust pressure or load. Well, subject to not being full throttle

[Charlie69]

On 8/17/2018 at 6:59 AM, mklotz70 said:

That is such an old pic!!! LOL

Send me some new ones!!!  LOL

[DanielC]

Thanks again on the explanation on the carb heat and EGR controls on the engine and air cleaner, Mike!

This is what the air cleaner lid looked like when I brought it home, last week.  I hope to use it on Ratsun pretty soon. 

In Oregon, a Datsun runs pretty good in the summer, but in the winter, they really like heated air going into the carb.  I have actually had a 521/L16 Hitachi ice up before, because most 521 trucks had a manual air heat control valve on the air cleaner.

I still have some paint I had mixed up that is very close to the stock air cleaner color.  1968 or 1969 VW Chrome Blue is very close, and I had a auto paint store either tint, or shade the paint to match an air cleaner lid I had.

I stripped the old paint off the 1974 620 air air cleaner I got last week.  I started with the 3M Clean and Strip disk on an air sander.

 

The 3M Clean and Strip disk cuts right through the old decal.

More paint removal.

 

I also cleaned the air cleaner body.

 

I also used a small orbital sander to clean more old paint off the air cleaner body and lid.

 

These are Nylox brushes.  They are at Ace Hardware, in the USA.  They are made of Nylon, I think, with an abrasive embedded in the nylon bristles.   The bristles will go down into shallow pits pretty good, and will remove rust too.  You have to keep than moving, if you stay in one place, at too high of a speed, the metal will heat up, and melt the nylon. Keeping the speed slow also helps reduce metal heating
 

 
The Nylox brush goes in a drill.  The majority of the paint removal was done with this.   The brush is flexible enough to get into the depressions in the air cleaner lid, and into tight places on the air cleaner body.

Sorry, I messed pictures of the almost all of the paint removed from the air cleaner parts. 

 

After cleaning the old paint and some rust off the air cleaner parts, I primed them.  I had some other air cleaners, and I primed those two other lids as well.

I primed the air cleaner body.

 

The next day, I painted the air cleaner parts.

The air cleaner body painted.

 

This is how I painted both the top and bottom of the air cleaner.  You first prime or paint the bottom of the part, and then you can paint the top, after turning it part over. 

 

After letting the paint cure for two days, I reassembled the air cleaner.

 

This is a  picture I took of the hoses on the bottom of the air cleaner, before I took it apart.  This picture came in very handy when I put the air cleaner back together.

 

Edited September 1, 2018 by DanielC

[DanielC]

A few day ago, I took advantage of a early season sale on wood pellets I use to heat my home with.  I just started to unload the pellets.

 

Just another picture of the pellets in Ratsun.  Fifty 40 pound sacks, a ton of wood pellets.   With the L-20-B engine, it does not take as long to get up to speed on the freeway.

 

The brake hydraulic problem seems of be fixed. 

I also got another full tank of gas yesterday, and calculated the fuel mileage on the last tank full of gas.  24.72 MPG.

 

Edited September 1, 2018 by DanielC

[Charlie69]

Love to see you working your 521s!!!

[Charlie69]

On 8/17/2018 at 6:59 AM, mklotz70 said:

That is such an old pic!!! LOL

Here are Mike's Gen II Disc Brake Kit pictures.

 

 

 

 

 

Sure do shine!