My Sanity Saver 521

[mrbigtanker]

Went to all throttle cable so don't have those problems. Very nice truck. Like it a lot.

[maxima_tyler]

Use this to get part numbers, many parts for a 521 are still available from Nissan.

http://www.carpartsmanual.com/datsun/pickup-1965-1972

 

Go down about halfway on this page, download the Nissan factory service manual for Datsun 521 trucks.

http://www.davidcmurphy.com/olddat/620tech.htm

 

Now, the questions you asked.

how can i tell if ive already caused some damage?

You have to just look at the gas pedal pivot, and try to move the bracket sideways, and while you are down there, push on the pedal and see if the bracket moves, it should not.

 

what can happen if the gas pivot pedal bends?

The pedal pivot moves around, weakens the bracket, and eventually, the pedal pivot comes disconnected from the cab sheet metal.  the the gas pedal does not work, and is just flopping around in the cab.

 

if im understanding this right its possible that all i need to do is adjust the pedal stop to higher than it is right now?

You have to see what damage has already been done.  The fact that you are having problems with the cable now, tells me you have a little more damage than you should.

 

You need to take the air cleaner off the carb,  That will give you access to the connection of the cable to the carb, and you can see what is going on.

 

This may seem totally unrelated, but it is not.  There should be a pigtail from the negative battery cable, engine end, that goes down to the frame of the alternator.  This electrically grounds the alternator to the engine, and the battery.  At the alternator, there should be a second black wire, that goes to the voltage regulator and is attached to the inner fender by one of the voltage regulator bolts.  This wire grounds the cab to the alternator, and battery.  If this wire is missing, or disconnected, the cab will try to ground to the engine by the throttle cable.  This over heats the inner metal throttle cable, and the plastic outer cable melts, and destroys the throttle cable.

 

The connection between the gas pedal and the carb is just a cable.  The cable is usually trouble free, but it is 45 years old.  It can wear out.  if the carb end of the inner cable is getting frayed, it could hang up on the outside cable, where it is attached to the carb. 

 

 

I took a couple pics and videos to try and show whats going on.

 

I have the ground at the voltage regulator. how can i tell if the ground is good?

 

 

First off, the bracket at the gas pedal. here's a video of the pedal. does this look normal? i couldnt find any broken welds, but it flexes a little. Does not feel like its loose though. Is that too much flex?

 

https://youtu.be/MErrKn2bOMY

 

I was able to recreate the issue. i was cruising at around 55mph pretty steadily and then the throttle issue started. the video is of the throttle issue. there's wind noise but you can hear it stuttering.

 

https://youtu.be/QmOn5pu4Lzo

 

I found that the carb was way out of adjustment, running super lean. i adjusted that to a good mixture, and its been running better, but hasnt stopped the throttle problem completely.

 

here are some pictures of my carb, and the throttle cable. i've been trying to compare to pictures on this site, but its tough to find the exact carb. please let me know if you see anything that doesnt look right. right off the bat, i know im missing the automatic choke plate. i have it, but one of the three bolts that holds it in place is sheared, so it wont stay in place. my drill wont fit between the car and the fire wall to drill it out, gonna get a compact drill from a friend to fix that.

 

 

There's a tube at the bottom of the carb in this pic, just above the exhaust manifold. its capped with what looks like a screw, but im nervous to take it out cause i dont know what it is. what is that tube for? is it supposed to be capped like that? i dont think it should be, so where should it lead to?

 

 

 

 

Pictures of the throttle cable. didnt look burned or frayed anywhere..

 

 

 

Anything else i should look for? thoughts on what the problem could be?

[mrbigtanker]

So looks like the weld from the base plate to the cab is broken. Now I am going to. Check mine tomorrow but unless it's a optical illusion the weld snapped under it.

[DanielC]

The 1972 521 had some significant differences from the 1971 521 trucks.  1971 521 trucks had a manual choke, the 1972 got an electric choke.  I have not had a 1972 521, I am not sure if you have the correct carb on the engine.  You probably do, but I do not know.

I would take the throttle cable off the carb, and move the throttle with your hand, and see if you can figure out if it is hanging up on something.

 

I think the short hose with the small screw in the end of it is to supply engine vacuum to a valve on the air cleaner base, that in turn operates a door in the snout of the air cleaner, that controls how much heated air goes into the air cleaner.

[maxima_tyler]

Can anyone with a 1972 521 get me a picture of the wiring to their electric choke? The wiring diagram DanielC posted here is for a manual choke, doesnt have what i need.

 

im not sure why, but my gut is telling me this has something to do with my problems here. even if it doesnt, it'll get one less thing off the "problems list" if i can get this truck wired right.

[maxima_tyler]

 

I've fixed my bogging accelerator and coughing/backfiring! i wasnt exactly sure what i needed to fix, so i went through a manual someone gave me (cant remember who) when i first got my truck called "Datsun Tune-up and Repair For Everyone" by Paul Doug. it explains in really simple terms how to do things like change oil, check and change spark plugs, and how to check and adjust your valves, points, condensers, timing idle and air/fuel mixture. I decided to go through it and check my valves and points, which were both way out. My valves were super tight, and the points were really worn out. i fixed the two of those (adjusted the valves and replaced the points), along with new spark plugs (just because) and the problems are fixed! it also fixed the issue i had in one of my first posts in this thread of oil coming out the exhaust. well, not completely fixed, but id say it reduced it by about 80%.

 

I took the truck out for a drive yesterday and was able to cruise at 60mph no problems at all. The only thing im noticing now is my idle sits a little high, but goes up and down randomly when im at a stand still. im going to try playing with the adjustment screw over the next few drives, and hopefully i can find the sweet spot.

 

I'm still looking to better weld the accelerator pedal plate as others have mentioned above, but it definitely was not the root cause of the problem.

[maxima_tyler]

i'd like to host a link to the document i used. I really think a lot of people newer to these engines and mechanical work in general, like i am, can use this (multiple datsun engines are covered in this book).

What is the best way to do that?

[Lockleaf]

Google docs is a decent option.

[banzai510(hainz)]

you can use a small thin wire and just solder on ove the broken  trace.  sometimes just reeating the VR can in back of the instrument panel will fix the gas gauge. most times its together fuel gauge and the Temp gauge will go out .It goes thru that CAN(Volt reg)

 

 

Oh if this is a 72 there is  wire that will have 12volt with key on ck back by the fisewayy for a 12volt key ON wire. this most likely went to the carb.  Looking at the photo the element was taking out.  really they make a cheap cover kit with plastic cans to convert this to a manual. so you can still use this choke.

 

summit has a Dorman conversion kit,55101

[DanielC]

On April 9, the question was asked, "How do you know if this ground is good?"

One way of checking a ground is to use a volt meter that reads low voltages, less that one volt, and measure the voltage from the negative battery terminal, to the ground connection on what ever you suspect has a poor ground.  If you use a analog meter for this, start with the meter in a 15 volt (or higher) range first, then switch to a lower voltage range.

Ideally, you will measure 0 volts, but in a real world, with the circuit turned on, a voltage reading less that .2 (two tenths) of a volt is OK, the lower the better.

 

With the voltage regulator ground pictured in post #52 above, take it apart, clean it with a wire brush, and put it back together.  If you suspect it was causing a problem, check the voltage between the negative battery post, and the regulator case, before and after cleaning the connection.

[maxima_tyler]

I've made some progress over the last month.

 

With some help from Banzai510 through PM's and the info above, i replaced the voltage regulator with a solid state voltage regulator. The brand new mechanical regulator i bought was over-volting my electrical system and causing problems. with the solid state VR that problem is gone. good.

 

Second, i finally gave in and installed a manual choke, just a universal one i bought at O'Rielly's. i've really been trying to find the parts i need to get my electric choke working, but so far its been to no avail. I'm still looking for an electric choke relay, and some pictures of 1972 datsun 521's with the electric choke still installed for reference... but for now, the manual choke has definitely been worth it. gone are the days where i have to play the throttle for 5 minutes as the truck warms up. now its a simple start up and let it idle on its own, which is nice.

 

Things are starting to come together slowly. now i can drive the truck confidently without it giving trouble, not that it gave much trouble before.

[maxima_tyler]

Time to tackle one problem at a time. I'm going to try and figure out my combo meter issues with the info you guys gave me on page 3, but for now i need opinions on a mechanical issue.

 

The truck is stalling as i come to a stop at stop signs and red lights. Some gas as i break will keep it alive as i break, but i want a proper fix, lol.

 

i've adjusted the idle as high as i can without the engine running frantically and the issue hasnt gone away.

I've read that the exhaust manifold gasket leaking could cause the problem, so i've replaced that but no change. Though im losing less oil now, which is nice haha.

The next thing im going to try is replacing all the vacuum lines. I've read a leaking line can cause this issue, so hopefully that will be my easy fix.

 

Any other things i should look for?

[banzai510(hainz)]

To me the idle jet is plugged.

521 the fuel line is in the wheelwell and water gets down in there and its just dirt and rust. I run 2 filters the stock one and another inline one before the fuel pump. Do this first so you don't clean out the carb and suck more in. As I have had them plug up right in front of me and I just cleaned it.

 

My 521 just had this proplem last week. Webers are EZ and I got some canned air and blew thru the idle circuit. I also blew the idle jet. But I also fucking lost one in the dirt but had a spare. So be leary where you do this.

Also since you have a stock carb I don't know what to tell you.

 

Since you screwing in the speed screw your just running off the main jet by bypassing..

 

Find a photo od the idle jet holder and see if you can clean w/o dropping anything

Good luck.

[maxima_tyler]

To me the idle jet is plugged.

521 the fuel line is in the weekwheel and water gets down in there and its just dirt and rust. I run 2 filters the stock one and another inline one before the fuel pump. Do this first so you don't clean out the carb and suck more in. As I have had them plug up right in front of me and I just cleaned it.

 

Just to be sure, the idle jet is the idle mixture screw itself, correct? The same screw i use to adjust the idle, i just unscrew that completely from the carb and spray something in the hole that it was in to get all the crap out (either canned air or WD-40 with the thin red nozzle). Would it be good to do the same thing with the air/fuel adjustment screw?

[banzai510(hainz)]

The mixture adjust for the air( i think)

 

on stock 521 I dont know where the idle jet is of how to take or clean it.

 

Once My stock carbs go bad I swapped them out and never look back.

 

There was a place selling stock 510 manual carbs for like 150$ . I do like them when they work as they are quiet and use the stock aircleaner. The weber 32/36 are Ezer to work on and trouble shoot but make more noise.

Datzen mike of Daniel or other will know more on these. As I dont mess with the stock carb.

 

 

do NOT   NOT use wd40. if anything carb cleaner

 

 

do mexican tuen up. Rev the motor and put a rag over it and maybe it will suck the dirt thru the jet

 

Waiting for a response!!!!!!!!!!!!!! or PM if fixed

[maxima_tyler]

Seems i made some good progress this weekend!

 

i cleaned out the idle jets and retuned the carb. I gave it a little more gas in the A/F mixture and adjusted the idle and it seems to have fixed the problem of cutting out when coming to a stop.

 

also fixed some more electrical issues! i used the link posted earlier on to do some diagnosis on my combo meter and found a few problems. http://community.ratsun.net/topic/30917-combination-meter-521/?hl=%2Bcombo+%2Bmeter. I had two broken traces which were causing the lights to not work, so i fixed those up and now the lights work! I also got the temp and gas gauge (almost) working. I originally thought there was only one voltage regulator in the truck (in the engine compartment), but there is a second one that is mounted to the back of the combo meter. I took that one off the back of the meter and it had a broken trace, which was an easy fix. That got the temp and gas working on the bench, but the gas still didnt work when installed in the truck. So i crawled under the truck and followed the wires leading from the fuel sending unit and found that the power wire was cut in two spots! i took out the broken section and spliced in some new wires and it almost works! The gauge works but only goes to 1/4 full. It reads accurately under 1/4 full but any more and it will only show up to 1/4 full and thats it. I'll see what i can find to fix it, but for now im content with a working temp gauge and a half working gas gauge.

 

Back of combo meter. took the photo after i fixed the traces:

 

 

fixed traces on combo meter. not the prettiest since i had trouble getting the solder to stick.. but it works, and i covered the ends with liquid electrical tape so it wont make contact with anything.

 

 

fixed trace on the voltage regulator:

 

Working lights! In person, you can see the fuel gauge a bit better, and you can see the entire speedo. stupid iphone

[maxima_tyler]

Next thing im working on is front suspension. Im pretty low in the front, and i'd like to keep it that way, but the KYB gas-a-justs cant handle it. i installed some new ones in march and they blew this weekend. I just bought some new shocks (same brand/type) but im going to go a little further with this and have some custom shock mounts made up that will be taller than the stock ones. i have a local fabricator through work that can make them up for me, so i need to put a CAD drawing together to make it happen. Then its a matter of cutting the old ones out and welding the new ones in. Not me of course, i cant weld like that yet, but friends with welders work just as well to get the job done.

 

I'll keep the updates on the progress on this, but im thinking of keeping something close to the original design, and just raising the top mounting point about 2" above stock to give the shock more space for travel. since its a bit taller and there will be more unbraced length, im thinking of making the metal about 1/16" to 1/8" thicker than stock. Even if it is overkill structurally, it will help in the event i blow shocks again so i dont punch through the mounts like it did before. I'm a civil engineer by trade, so im fairly comfortable with the concept, but if anyone has suggestions on a design, feel free to chime in!

[DanielC]

Glad my combo meter post helped you get another 521 working better.  I feel for you folks who are located far away from the west coast, where Datsun parts are easier to come up with.

[mklotz70]

Pull the tape off the back of the fuel gauge that's in your above pic.  You should find two holes with slot-like pieces inside.  You can turn those to adjust the physical limits of your gauge.

[maxima_tyler]

Glad my combo meter post helped you get another 521 working better.  I feel for you folks who are located far away from the west coast, where Datsun parts are easier to come up with.

 

When it turns out successful like this mini project did, i dont mind having limited options since i like trying to get the original stuff working again. when those projects go south though, its a pain in the ass!

 

Pull the tape off the back of the fuel gauge that's in your above pic.  You should find two holes with slot-like pieces inside.  You can turn those to adjust the physical limits of your gauge.

 

Is that really all there is to it? damn, i wish i had asked the question before i put the meter back in.. lol

[Charlie69]

Be sure and put tape back over the holes to help keep dust out.

[mklotz70]

I'd use a plastic screwdriver, but you can probably do it while it's still mounted.

[maxima_tyler]

BIG PROBLEMS!

 

I got everything all fixed up and the truck had been driving great for a while. Then on friday cruising down the highway i started hearing a rattle from the engine, then really shortly after there was a lound KACHUNK and rattling, and i had total loss of power, though the egnine was still running. Turned it off and checked the oil and was bone dry, which was weird cause my oil light didnt come on, and i know it works properly. I let the engine cool for about an hour while a friend brought be some oil. nothing was leaking or smoking so i figured i had avoided major damage, so i tried to limp the truck home. 3 miles down the road the same thing happened, this time with total loss of power and engine stall. I hadnt lost any oil, but checked the coolant, and i couldnt see anything through the top of the radiator. i didnt want to cause anymore damage, so i got the truck towed back to the house.

 

Yesterday i put a bottle of premixed coolant and tried to start the truck but it would crank and crank with no start. so i took off the valve cover and intake and it was full of this milky oil and coolant, like really full...

 

 

 

 

Oil flowing from the coolant pipe from the block to the bottom of the carb

 

 

i decided to pull the drain plug and all the coolant i had poured into the radiator poured out of the pan with the oil... i let it drain overnight to try and get it all out.

 

so with the little research ive done, im hoping its just a blown head gasket, but im really worried i've cracked something. im looking for info on how to properly remove the cylinder head so i dont mess up the timing chain. anyone have something like this happen to them?

[hobospyder]

Get the wedge off amazon first

[hobospyder]

This:

 

https://www.amazon.com/gp/aw/d/B0002Q8TV4/ref=mp_s_a_1_1?ie=UTF8&qid=1468782356&sr=8-1&pi=AC_SX236_SY340_FMwebp_QL65&keywords=datsun+timing+chain+tool