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mainer311

Just bought a 521

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Hey Guys,

 

Just wanted to introduce myself. I'm 32, live in eastern Massachusetts, and I'm a bit of a Nissan/Datsun nut. My first car was a 1993 D21 2WD, lowered. I've also had a 1996 Maxima SE 5spd, 2008 Frontier 6 spd, and now a 2012 Xterra Pro-4x 6spd that I wheel.

 

I bought my first Datsun 6 years ago, a 1968 Roadster 1600 that I've been restomodding for a while. Rebuilt the R16 and trans, along with pretty much everything else. It has a "big brake" Altima/Volvo conversion on it, and dealer option Appliance mesh wheels. The body has been repaired before and is rough, but it looks good from 20 feet or so.

 

On Monday I picked up a 1971 521 and have been starting to go through it. A lot of the ball joints boots are melting (seems to be a common Datsun theme) and the king pins are a bit worn but not horrible. The body is in decent shape, aside from the rockers. For the time being, I'm going to redo the horrid brakes (they don't look like they've been touched in a while) and think about a disc upgrade in the future.

 

I ordered upper control arms bushings, new brake shoes, KYB gas-a-justs, and tension rod bushings to get me started. The king pins don't seem to be much of a safety concern, so I'll put them on the list for later.

 

Future plans: Hella e-code H4's w/relay re-wire, GM 1-wire alternator swap, front lip, lower it, and first gen Frontier 6-spoke wheels.

 

8GxpKlt.jpg

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Welcome to Ratsun. Nice survivor of the rust belt!

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Welcome to the party....

521's are coming out of the wood work lately.... looks pretty clean and straight....

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Nice truck!  Especially on the east coast.

 

Do not do a GM one wire alternator swap.  The alternator needs a wire for ground, obviously a hot wire, and wiring to check the system voltage at the battery, or fuse box.  The stock alternator and regulator does all this.  The only drawback of the stock charging system is the low alternator output.  I have used an alternator from a Nissan Pathfinder in a 521, and it lines up with the crank and water pump pulleys.  Later model L-16, L-18 and L-20-B engine use a cast lower alternator mount.  This mount holds the case of the alternator slightly lower, and may allow a bigger diameter alternator to fit.  Watch clearance to the steering idler arm.

Nissan (Datsun) electronics are very high quality.  The stock system works well with a stock truck. 

 

With the high output lights, you will need a higher output alternator.   The stock alternator is about 35 amps, and uses an external regulator.  If you can find an alternator for a 71 510, with air conditioning, they used a 50 amp alternator, that is compatible with the stock voltage regulator.  You can also swap a later model Nissan alternator, that has an internal regulator, and by adding two jumpers to the stock voltage regulator plug on the engine harness, make it work.  You must retain the ground wire on a voltage regulator screw to the inner fender, that goes back to the alternator frame.  This wire grounds cab sheet metal, if it is removed, or goes bad, the cab will ground through the throttle cable, overheat it and destroy it, and possibly leave the throttle stuck open.

 

The stock fuse box will, not handle the higher output headlights.  You must use relays for them, taking power directly from the battery.   The stock headlight relay is right by the battery, on the inner fender wall.  This relay has four wires.   Red with yellow stripe is power in to the relay, from the light switch.  Red with a black stripe goes to the low beam terminals on the headlights.  Red with a white stripe goes to the high beam terminals on all four headlights, and the thinner green wire, with a yellow stripe goes to the turn signal switch, and is grounded when the turn signal lever is pushed forward.

I use the KC 3300 relay for headlight wiring on my 521 trucks, is is a 40 amp relay, with two pin 87 terminals, and you can get it from Summit Racing.

 

I would use 12 gauge wires for the relay to headlight wires.  Using two of the KC 3300 relay, one can be high beam, the other low beam.  For the high beam relay, I would use 10 gauge wire to pin 30.  Trigger the KC relays with the output from the original stock headlight relay.  Put fuses in the headlight power wires.

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Dan, thanks for the headlight info.

 

I did a similar construction on my Roadster, using two relays for the high/low, but that car only has two housings, not four.

 

On these trucks, are only two bulbs on for lows, and all four on for highs? I haven't even noticed how they work yet.

 

I did some poking around with the alternator swaps and will have to weight the options. I have a 63A camaro alternator in my Roadster, but it takes a bit more finagling since the mounts are different. 

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Truck alternators don't have much room so a small diameter one is best. When the belt is tensioned they have very little room below and hit the idler arm. Above them there is the lower rad inlet and hose. If really set on a larger high amp alternator make a mount for the other side below the distributor. The block is drilled and threaded for an air pump. My '71 snapped the mount bolts off and a friend did the other side swap for me in the mid '70s.

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My smog pump is still there, but the belt is removed from mine, and the secondary outlet on the exhaust manifold is capped off. I'm assuming I can remove the whole thing and block all the lines that go to the carb/intake? I did a search and it's clear as mud.

 

Am I better off leaving the pump there with the hoses in tact?

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If your state does not require smog, you can take the smog pump off and the rest of the stuff that goes with it.

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The two outside lamps are high/low, the two inside lamps are high only.

 

You can remove the air pump, and the gulp valve.  The intake manifold large fitting that goes to the gulp valve is a British pipe thread size.  The little hose fitting on top of the three/four intake runner can be left in place, and a cap put on it.  This is a good place to hook a vacuum gauge, to tune the carb.

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My smog pump is still there, but the belt is removed from mine, and the secondary outlet on the exhaust manifold is capped off. I'm assuming I can remove the whole thing and block all the lines that go to the carb/intake? I did a search and it's clear as mud.

 

Am I better off leaving the pump there with the hoses in tact?

 

Yeah you can pull/plug all that crap. Did the same on my 71 521. Will post pics of what I removed.

 

Everything circled in RED I deleted/capped.

 

35546046425_dafbc2f59a.jpg

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Welcome to the party....

521's are coming out of the wood work lately.... looks pretty clean and straight....

 

Your neck of the woods too.

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Has anyone ever wired their headlights such that all 4 come on for low and highs? If I run (4) H4 bulbs, I could theoretically just plumb them all together, and run a separate relay for each. That's really only about 20A for each fuse. Use the factory relay to turn the two extra relays on and off like Dan mentioned.

 

Also, does anyone know the size of the bolt used on the upper outer control arm bushing? I'll be replacing those and the front shocks this weekend while I'm redoing the brakes. 

 

Does anyone have a link to the hitachi carb layout? I've tuned HS4 SU's before, so this carb seems a LOT easier since there's no balancing.

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I think the bolt is 1/2... I think there is a post about it... I'll try to see where it is...

And yes you can wire the lights any way you like.... fuses and relays...

I tried it once the wrong way.... the minute I turn the high beams on everything went out.... including low beam, on a back road with no street lights... oops....

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Actually about 5 posts down on this page... says control arm bushings in the title.... i dont know how to link it from my phone....

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Here is a wierd thing I figured out.... I believe the high/low bulb can only go in one of the headlight buckets.... I can check again...

But I have mine completely disassembled and was showing my son how it was all going together... there seemed to be different locking tabs on the back of the glass bulb the coincided with the metal bucket and they were different....

But who's to say you can't cut things up to make it work..

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I'm going to switch to Hella e-codes, so no worries about bulb fitment. They'll be H4 all the way across.

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if they H4(Hella e codes) you need to upgrade the wiring as they are 35amps on the outer lamps(stock)

Buy a H4 wiring harness. !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

GM altmight not fit believe me

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Maybe I should have specified in my introductory post: I'm a mech engineer by trade, with tons of car and electrical experience. No need to reiterate again that I have to redo the wiring. I don't need a harness, since what I want to do is not typical anyway. I'll just build my own.

 

I've decided that the 60A 510 w/AC alt will be a good fit.

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Lol...then what you need us for?  

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Maybe after hearing peo peoples opinions, he realize that he will do it his way.

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