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'72 521 L20B Swap Denver


biggaryT78

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I highly doubt it is of the OEM nature of anything on this truck but I have a Nissan alternator from another engine,  I will check this all out tonight when I get home from work and post any pictures I find. That sounds like a bad when I start melting stuff.

 

If this is an S&L alternator, what do I remove?  While keeping the black ground wire? 

 

Thank yoU!

g

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I see your alternator But cant tell what it is.

 

Just use the old alternator from the L18. if the bolt size is correct.

 

don't rev up? vacuum adv?   NO and not the wire cap rotor ect what you mentioned. I never changed them once I buy a new set they last 8 years EZ.

 

what can happen is set to TDC Zero on crank and see where the rotor is pointing when you lift the dist cap. if it points between 1 & 3 then your off a tooth and you got it set at idle OK but once it revs up it goes out of time. that's why vid shows the 11.28 position on oil spindal.

there were 2 dist mounts and if 1 is wrong for the dist then it will put it off between 1&3

however I assume this moto came with everything and have to assume its OK

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I see your alternator But cant tell what it is.

 

Just use the old alternator from the L18. if the bolt size is correct.

 

don't rev up? vacuum adv?   NO and not the wire cap rotor ect what you mentioned. I never changed them once I buy a new set they last 8 years EZ.

 

what can happen is set to TDC Zero on crank and see where the rotor is pointing when you lift the dist cap. if it points between 1 & 3 then your off a tooth and you got it set at idle OK but once it revs up it goes out of time. that's why vid shows the 11.28 position on oil spindal.

there were 2 dist mounts and if 1 is wrong for the dist then it will put it off between 1&3

however I assume this moto came with everything and have to assume its OK

I could not find any markings at all on the Alternator but it looks new, and it was the one that came off the L18 so should be working how it did. When I got the car, neither oil or ignition light would go off when the key was OUT! and it would drain battery.  I moved the ignition wire to a different post on the ignition switch and that fixed the problem... Maybe that is why it stays on now and it is my fault.

 

This motor came with everything on it and was clearly taken out of a vehicle and prepped for sending by a pro.  When I got it it was still metal strapped to the Pallet.  Should be timed okay now at 13.5 BTDC.  I messed with it a little bit last night and it seems to run much better right after I PLUGGED IN  #3 SPARK PLUG!!!  it was loose and i was running on 3 Cylinders, like a newbie. 

 

I took a closer look at the water pump from the L18 that I have the fan for... and it will work okay for now. I really wanted to get the right fan for the fan clutch style but I will switch these water pumps out for now since I have the fan, and order one from the interwebs for the newer style fan. Keep it simple right?

 

Tomorrow I will be trying to take this into a guy to get a little exhaust made (will take pictures I promise and I haven't been because have been working at night after work and its so damned dark they all suck) 

 

Falling in love with this little truck. Thank you everyone

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Updates,  I cannot really get this thing tuned well enough to drive. I searched the forum in depth and mostly it points towards my Hitachi carb. needing a rebuild or a sledge hammer tool then buy a weber apparently.

 

EngineBay_zpsd8rgn8lp.jpg

 

SO here are the symptoms maybe someone can help me out.

 

  Truck starts right up, cold or hot. Sometimes it wants one pump of the gas but otherwise it just works....  With idle set to 2k!

 

  Ignition light still stays on (haven't looked into regulator or alternator etc yet from above  just putting here in case it's related^^) 

 

  Wont idle below (1750RPM - 2000RPM)  Hot or cold it just dies. 

 

  Electric Choke is working correctly and starts out almost fully closed with a little slit in it and opens all the way when warmed up.

 

  Truck dies and will not idle at all when coming to a stop from moving it trys to die.  This truck does not have a booster connected at all and brakes should have zero effect on idle as far as I understand what is going on here?

 

  Looks like the second barrel never ever opens ever... and just keeps filling up with fuel... is this normal? I have never seen the second barrel open up ever on this carb. I cannot even make it work with my fingers trying to mess with levers etc.  Not sure If I am dumb by why would they have this if it never opens up when you step on it!  My old '73 BMW 2002 had a similar progressive two barrel and it worked AWESOME and I never had any issue with it. 

 

Help always appreciated you have all been super helpful already.

 

 

TruckSideOpen_zpsjgzn2pfj.jpg

TruckFrontHood_zpsyrcehdeh.jpg

 

TO DO:

Weber Carb. 

Find a fan that fits my fan clutch fan water-pump. 

New radiator

Custom exhaust. Modest and pretty quiet would be nice.

Steering wheel - endless options but I want something Datsun, and pretty big. 

Wiring issues - Headlights are not turning on but they used too. Ignition light stays on while car is on. (alternator IR issue)

Lower rear of truck with 3"blocks to match the re-indexing done on front. Modest drop is enough for me and Colorado weather.

Spit and polish and a bit of light sanding. I thought this was original paint, but upon closer sunny inspection it is rattle-canned blue over the original blue (close match) all over the entire car leaving the original white lines etc but not much more. 

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if motor revs up then rev it up higher then place your hand ove rthe main side of the carb then the 2nd barrel butterlfy should open up for a second or so . Or one can do this then place your finger in there to open the butterfly to keep it going.

 

1700rpm???????  is the speed screw on the carb linkage screwed in to much  making it run on the main barrel. CK this 1st.

 

take alternator out and have it cked. Untill then no more questions!!!!!!!!!! possible volt reg also but I alwasy have a spare for trouble shooting and 9 out of 10 times its not the volt reg.

 

 

 

lights is just a corrossion issue as they were working before. most like fuse box area. DanelC on here is familiar with these trucks more

 

 

I time my 521 to 7-10 deg but 13 might be OK also

 

 

sure no vaccum leaks???

 

time for a weber as the motor is OK

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"Truck starts right up, cold or hot. Sometimes it wants one pump of the gas but otherwise it just works....  With idle set to 2k!"

        Check for vacuum leaks.  A small leak is a huge percentage of the air needed at idle, makes the mixture too lean to run, however, opening the throttle allows enough air and fuel through the carb to make a vacuum leak a smaller percentage of the overall mixture. 

 

"Ignition light still stays on (haven't looked into regulator or alternator etc yet from above  just putting here in case it's related^^) "

We really need to determine if your alternator is Internally regulated, or externally regulated.  Get a volt meter, check the battery voltage with a running engine, even a check at 2000 RPM will do.  13.5 to 14.5 volts is a working alternator.   If the voltage is in the above range, with the engine running, unplug the small "T" plug from the alternator.  An internally regulated alternator will generally hold the above voltage range, an externally regulated alternator will not.

 

"Wont idle below (1750RPM - 2000RPM)  Hot or cold it just dies. 

  Electric Choke is working correctly and starts out almost fully closed with a little slit in it and opens all the way when warmed up.

  Truck dies and will not idle at all when coming to a stop from moving it trys to die.  This truck does not have a booster connected at all and brakes should have zero effect on idle as far as I understand what is going on here?"

All this makes me suspect a vacuum leak even more.

 

"Looks like the second barrel never ever opens ever... and just keeps filling up with fuel... is this normal? I have never seen the second barrel open up ever on this carb. I cannot even make it work with my fingers trying to mess with levers etc."

A stock Hitachi carb holds the secondary closed until the primary is open at least 70 degrees.  Even then, if there is not enough air flow into the engine (high enough RPM), the secondary will not open.  It is almost impossible to get the secondary to open without a load on the engine.

 

"Custom exhaust. Modest and pretty quiet would be nice."
See this thread: http://community.ratsun.net/topic/61167-how-i-replaced-a-521-exhaust-system/?hl=exhaust

 

"Find a fan that fits my fan clutch fan water-pump.  New radiator.  Steering wheel - endless options but I want something Datsun, and pretty big."  

Look in a junk yard, some yards now have websites that you can track new arrivals.   A good radiator shop should be able to repair your radiator.  Many 521 owners are looking for a better steering wheel.

 

"Wiring issues - Headlights are not turning on but they used too. Ignition light stays on while car is on. (alternator IR issue)"

For the headlights, refer back to the wiring diagram I put in post three of your thread.   Follow me, from the battery.  A wire from the battery goes to the fuse box.  Three or four fuses are always hot, check with a test light in the side of the fuse away from the battery, or better check the terminal on the cab side of the fuse box.  The headlight power to the light switch is a thick red wire, on the cab side of the fuse box.  This wire goes into the cab, through a connector by the glove box, and to the light switch connector.  If the headlight switch is on, power from the headlight switch in on a red with a yellow stripe wire.  This wire goes back through the glove box area connectors, and to the headlight relay, on the inner fender, by the battery.  This relay will have four wires. Red W/ yellow stripe, Red W/ stripe wire, Red W/ black stripe wire, and a green wire.   Red W/ yellow, should be hot with headlights on.  Red W/ white gore to the four high beams.  Red W/ black goes to the two low beams.  the green wire grounds the headlight relay coil, and switches from low to high beams.   There is a black wire connected to the headlight lamp plug, that goes back to the voltage regulator, and is grounded there.

 

13 Degrees BTDC might be OK in Denver.

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DanielC

 

I suspected a vacuum leak is causing these issues too but I cannot find it so far so kept thinking carb.  With these symptoms(especially the stalling out while braking) where do you think its coming from most likely? What vacuum hose connected or not connected would cause this?

 

I will post pictures of current locations of vacuum connection.  My engine has all the emissions junk on it but my truck does not have any of it to plug into so high probability of a vacuum leak or 5. 

 

Denver Junkyards are completely barren of all classic nissans/datsuns and parts it seems. They all kind of laugh at me when I ask them, but yes I am keeping an eye open mostly on Clist, as I need that fan really bad. I cannot even find a correct part number for this type of fan?

 

banzai510(hainz)

 

Parts:

Brand new Weber - 32/36 is on the way from www.webercarbsdirect.com I wanted to get one anyway, and its pretty cheep so why the heck not, I hear they are pretty nice little carbs.

 

I took a Fuel pressure regulator off of an L24 I have laying around. Going to stick this into the L20B fuel line.

 

I want to find the proper sized Nissan radiator. The one I have now is taller and goes down way lower than it should.  It wraps the exit hose under the alternator in a wonky like way and then goes back up to the engine block. If sourcing parts was not such a pain in the ass I would already have purchased this and installed it along with the fan. A new aluminum one is $340 plus shipping, which I think is steep.

 

I will be working on this at night this week, hoping to start driving this as a daily driver by next week and with how far I have gotten I think it is doable. 

 

Thank you!

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I am not really familiar with the different manifold setups used on the different years of L-20-B engines.  I know more about the manifolds that came with L-16 engines, and L-18 engines, and the L-18 engines I came across may have had L-16 manifolds put on.  Remember, L-16 engines are 45 years old, L-20-B engines are about 35 years old.  Pretty good chance somebody has changed something.

 

It is critical that the mating surfaces on the head, and the intake manifold are flat, and clean.  The extra emissions equipment on a L-20-B engine might be a source of the vacuum leak.  I noticed you have a vacuum diaphragm motor on your air cleaner snout.  Maybe the hoses that go to that, and any valves that control that are a problem.  Personally, if your engine has EGR, I would eliminate that.   I believe the EGR is also controlled by the engine vacuum.  If your intake, and exhaust manifold are mated, or one piece, I would look to change that.   Some Datsun L-engines use cooling water to heat the intake manifold, others use exhaust gas.  I prefer using the cooling water.  The manifold needs heat, the cooling water needs to lose heat.  Seems like a good match to me.   In my experience, Datsun engines are cold blooded, they need intake manifold heat, and also carb heat, to prevent the carb from icing up.  I have had the carb in my 521 truck ice up going into the mountains.   The 521 has a manual valve on the air cleaner snout that has to be manually changed,

 

Classified ads in Ratsun might be one place to source parts.  

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My guess is that the vacuum adv unit was NFG, disconnect it and plug the line at the carb

 

I am going to try this. I think my vacuum advance is not working at all right now. Everything else is plugged up at this point. I put map gas around the base of the carb. and manifolds while engine was running and it never skipped a beat.  Something is definitely off with this thing it just isn't running right.   Stalling out at braking makes for a crappy commute. 

 

I am going to post a video up of it running to help nail down some of my issues here. Oh and I am planning to delete all the EGR and anything else I can off this engine it all seems pretty useless like chasing your own tail.

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my vaccum advance is bad on my 521 last week. But I could still idle . But not hard to disconnect it and plug the hose line to the carb.

also see if the vacuume advance plte moves also. Mine was stuck and would not advance.

 

if true why dont you use the old distributor or the newer one if you have combatible coil set up.

 

 

This is why I run the old set up that I have on a rig. anything on your motor thats there you dont know if its all good. Distributor ,carb. One would think its good.

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Could you possibly have a vacuum leak in you brake booster? Seems like you've checked pretty much everything else.

 

Also, another member recently had a vacuum issue he was trying to diagnose. He had used an unlit propane torch and found nothing. He went back a week later with starter fluid and found the leak. Might be worth the effort to try that.

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Lockleaf

 

Good idea with the starting fluid as beefier interruption on engine. I will try that when its cold so I don't burn it all down.

 

My truck does not have a brake booster it is a '72 and the Manifold port to it I have plugged up I will be checking them all again tonight. 

 

I noticed on some other forums that A Low Coolant Level could cause this symptom? Not sure how that would be possible, but I filled it this morning to make sure and the truck still did the same thing, I have to reach down with my hand and rev the engine when I am coming to a stop so it wont die. 

 

I ordered a weber and maybe when I get that bolted down my problem goes away but I would much rather and really want to find out WHY this is happening.

 

Here is a nice list with all the Nissan Cooling Fans.  http://www.kopex.com.tw/autoparts/fanblades/nissan2.htm#

 

I think I need this one but it is hard to accurately measure that thing. 

 

 

na1781-2.gif

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never heard the low coolant level thing before unless its a water heater type choke.

 

With all that emmssions stuff that weber might be harder to get on there all the stuff is crammed up in there. then youll have to get rid of the stock aircleaner and the weber usualy has a taller air cleaner and youll need to get the shorter air cleaner so it dont hit the hood. Depends on the carb adapter thickness.

 

You never said it you cheaked the speed screw and see if set right.

 

the fans. One was for a car and one was a truck both L 20s but dont know which is which the spacing is different . I have spares for myself.if needed 

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This is expensive wheel? or no? $175

 

280Z OEM stearing wheel

 

00606_jTYMNKJBxls_600x450.jpg

http://denver.craigslist.org/pts/5274332861.html

 

Then I found this about the DISH of the wheel. http://community.ratsun.net/topic/55836-240z-steering-wheel-to-521-swap-question/

 

 

Seems expensive...  Probably could get one cheaper shipped from the WTB section... aka classifieds.

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never heard the low coolant level thing before unless its a water heater type choke.

 

With all that emmssions stuff that weber might be harder to get on there all the stuff is crammed up in there. then youll have to get rid of the stock aircleaner and the weber usualy has a taller air cleaner and youll need to get the shorter air cleaner so it dont hit the hood. Depends on the carb adapter thickness.

 

You never said it you cheaked the speed screw and see if set right.

 

the fans. One was for a car and one was a truck both L 20s but dont know which is which the spacing is different . I have spares for myself.if needed 

 

I checked the speed Speed screw (A) but I have little reference as to how it is supposed to function.  It looks like this picture touching cam, and when the Choke opens up it is on the last Notch.

 

 

(B) seems to control the idle speed,

© seems to do just about nothing, all the way in, car runs all the way out the car runs. middle car runs. Eh. 

 

Not my carb just something I found for reference. 

 

101_0100_zps2d6ebkny.jpg

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"C" screw sets idle speed, engine fully warm, choke fully open. 

"B" screw sets idle mixture, engine fully warm, choke fully open, vacuum advance plugged, idle speed at normal speed.    (700?)

"A" screw set fast idle RPM, on a cold engine.

 

Carb adjustment are the last thing you do on an engine tune up.  Adjust the valves. Set ignition timing.  Warm the engine up, fully.

 

If the idle speed is too high, the distributor starts adding mechanical ( centrifugal) advance.  Too high idle speed, you cannot set the ignition timing accurately.   Also, if the idle speed is set too high, the throttle plate in the carb uncovers some ports that are there to help the transition off idle.   In many cases, you can get better throttle response with a too low idle speed, than a too fast idle speed.

 

The best way to set idle speed and mixture is to get a vacuum gauge, and hook it up to intake manifold vacuum, and also a dwell tachometer, that accurately shows low engine RPM.   Get the warm engine idling below 700.   There should be a gap between the "A" screw, and the fast idle cam.   Once the idle speed is around 700 RPM, turn the idle mixture screw "B" to the fastest idle speed.  If the idle speed goes above 750 RPM, turn the idle speed screw ("C") out, to slow the idle down to about 700.

When you get close to the right mixture, you will not hear a change in the engine speed, but you will see a change in the vacuum.  Tune the mixture ("A" screw) to the highest vacuum.  Make sure the idle speed stays below 750 RPM.

Now, with the best idle mixture set, turn the mixture screw ("B") in, to get about a 25 RPM drop in engine RPM.  Go drive the truck, and see how it runs.  If you can find accurate information on the tune up specifications, for your engine, use those number for idle RPM, ignition timing, and other specifications.

Recheck the ignition timing.

 

You live in Denver.  Your engine may like more ignition timing than somebody living in San Diego, Portland, OR, or Vancouver BC.   If you have a quiet exhaust, on a warm day, advance the timing a degree or two, and drive the truck, and listen for a knocking sound from the engine.  If you hear a knocking sound, you have advanced the timing too far.  Back the timing off.

 

If you end up changing the timing, because of your altitude, and the engine will tolerate more advance, you need to go back, and readjust the carb.  

 

Once you get all this set, it will be much easier to tune your truck the next time.

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DanielC

THanks man! I need this info that's for sure. 

 

Okay well I found a vacuum leak using the starting fluid method.  When I spray it onto the throttle shaft of carb. it shudders and freaks out as expected from a vacuum leak.  At first I thought it was at the base of the carb on the cab side... but it seemed higher than that, so I grabbed a hold of the throttle shaft and wiggled it back and forth and there is probably about 1mm play side to side and almost 7mm of play in and out. Which seemed like a lot... so I went to the computer. 

 

I did a few searches and found this Carb inspection thread which brought some wisdom I think I should have already known.

 

http://datsun1200.com/modules/mediawiki/index.php?title=Carburetor_Adjustment

 

Check the Play on the Throttle Shaft

With old carbs, this is also a critical wear spot. When buying a used carb, this is the most important thing to look for.

Wiggle the throttle shaft from side to side (90 degrees to the shaft). Wear is common with old carbs. It should feel tight with no discernible play. A worn shaft makes a vacuum leak: the engine idle rough, even to the point of killing the engine at stops and it can not be tuned to idle correctly.

  • It should be tight, and if so no worries
  • If it's loose, it needs to be drilled and bushings put in. See Carburetor Repair 2.

 

 

 

Thinking this might be my problem and having already suspected carb problems,but I have learned that your conclusions are not always correct soooo.... to make sure I go back out to the truck and spray the starting fluid right on the shaft being sure not to get any on the carb mounting plate and sure enough it shudders and almost dies...  and to make double sure, I went inside took a big bong rip and blew smoke down in there and sure enough it sucks it in and runs better for one second* I turn the truck off and laugh an evil laugh and go grab a beer satisfied with this issue being (hopefully) resolved soon because The Weber comes this week. 

 

Maybe this truck will actually be driving on the roads of Denver again soon. 

 

Thanks to Ratsun!

 

*Trucks may not run better with marijuana blown into their vacuum leaks and could have been a placebo effect. 

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