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521 Dual carbs- Still learning!


fisch

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Trying to educate myself in this new world of Datsun's. Thinking about these carbs.

 

First question- What are they? They say 'Japan 210' on them. Owner says they fit a 521 L16.

 

Second question- Does the picture show everything I would need to bolt these puppies up to a L16 (currently with stock carb set up)?

 

Third question- Is this setup any better than a weber 32/36 DVG conversion?

 

Thanks, all hail Ratsun!

 

DualCarbs.jpg

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Trying to educate myself in this new world of Datsun's. Thinking about these carbs.

 

First question- What are they? They say 'Japan 210' on them. Owner says they fit a 521 L16.

 

Second question- Does the picture show everything I would need to bolt these puppies up to a L16 (currently with stock carb set up)?

 

Third question- Is this setup any better than a weber 32/36 DVG conversion?

 

Thanks, all hail Ratsun!

 

DualCarbs.jpg

 

From Datsun Z Garage:

The "good" SU's were from 1969-1973 and will have 4 or 3 screws holding down the domed piston depending on which year it was made. The year makes no difference for performance, as the nozzles and needles from different years interchange. If you have carbs with the square choke flap in the inlet or flat tops then you have porly performing emission carbs. Exchange them for earlier SU models.

 

These look like the infamous flat to carbs to me. Read the second last line.

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From Datsun Z Garage:

 

These look like the infamous flat to carbs to me. Read the second last line.

 

So Mike, are these any better? Thanks for dropping some knowledge on me!

 

Dual2.jpg

 

Dual1.jpg

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I'll second that...

 

If you have carbs with the square choke flap in the inlet or flat tops then you have porly performing emission carbs. Exchange them for earlier SU models.

 

These look like the infamous flat to carbs to me. Read the second last line.

 

When de-smogged the flat-top SUs work just as well as the round-top, and they are a few years newer too (may be in better shape when comparing used to used).

 

Also will second that they work WAY better than a 32/36. Better mileage, better torque and mid-range, what's not to like? I'm actually looking for a good set right now for the beater 510.

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doesn't everything in the engine bay of a 521 say japan 210 on it? i know the block does and i think the head does as well...

 

Well, the SU intake says JAPAN 220. ;)

 

And the answer is because the parts are based off the same casting number, the casting number for the L16 stuff is usually casting 210. Alot of the L18 stuff is casting A87, the L20b stuff casting U67.

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How hard would these be to stick in 521? Is there a difference between the linkage on the carb, and the cabled throttle?

 

These are a couple of points the owner brought up. Seems like a nice guy.

 

"they will bolt up to your motor with absolutely no problem, you will need to do some modifications on your choke cable it won't be long enough. Also your truck uses a cable instead of linkage if I remember correctly, you need to look to be sure it's been a few years since I've seen a 521 if it does have a cable it would require a little bit of fabrication the hook it up."

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How hard would these be to stick in 521? Is there a difference between the linkage on the carb, and the cabled throttle?

 

Yes, there's a difference. There will be some fab work involved. The linkage shown is for a 510 only.

 

Converting it to a cable isn't too tough if you've been working on these for awhile. If your new to it, it may be frustating.

 

And FWIW, the choke cable should really be replaced with a proper dual cable choke set-up. These can be robbed off a Roadster, a 240Z, or bought new from a shop specialing in old Brit stuff. Victoria British sells them new for around $20 to suit an MGB.

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Yes, there's a difference. There will be some fab work involved. The linkage shown is for a 510 only.

 

Converting it to a cable isn't too tough if you've been working on these for awhile. If your new to it, it may be frustating.

 

And FWIW, the choke cable should really be replaced with a proper dual cable choke set-up. These can be robbed off a Roadster, a 240Z, or bought new from a shop specialing in old Brit stuff. Victoria British sells them new for around $20 to suit an MGB.

 

Dual cable... Oh because there are two carbs, gotcha.

 

By fabrication are we talking 'welding'?

 

I am totally new to this! To be perfectly honest I've owned 4 vehicles over the last 20 years. The last time I touched a carb was on a 1985 Dodge charger 2.2.

 

Sad, I know...

 

I got this truck with the hope of learning all the stuff I've neglected over the years. Did a lot of research on older trucks, fell in love with Datsuns (always love my brother's 81 210SL), and here I am with a 521 in the garage.

 

Hope my lack of experience doesn't scare y'all away. I am a quick learner!

 

And it doesn't really relate, but I do some kick ass artwork, so I am good with my hands. Check it out!

 

http://www.fischart.com

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wow... you are damn good fisch. and i'm glad that you are cause i can't stand it when people say something about how great their art is and it sucks. i've been doing "art" for a long time. i still don't call myself an artist for various reasons, mainly i'm lazy and don't persue furthering my abilities, whatever. have you ever done any vehicle renderings? i would love to be able to do it myself but realistic anything has never worked with my style. i could do a charicature of my ideas, but i kinda want something realistic, and i'm terrible at any kind of lighting.

 

anyway, props on being an amazing artist. and what did you do alot of artwork for magic or just the ones you have on your site or what? as soon as i saw the first images i was like... hmm looks like the same style as the magic artists.

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Thanks man! Yeah I've been around! I've been an illustrator for about 15 years. I am well over 100 magic cards. I never have done car renderings ala chip foose, but want to try it. And I love super distorted car illustrations. That is a whole other skill set I've not explored. It is almost like when doctors pick a specialty. My specialty is humanoids, creatures, basically anything that breathes. I've followed the aesthetics of cars and truck design for years, just never spent much time under the hood.

 

I love my job, it is the best, but the trade off is I've spent all my time with my hands in oil paint and making art, and not enough time with my hands inside an engine!

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I would personally stay away from SU carbs try to find a set of mikuni carbs they are a bit pricy but work so much better than SU's and better than webers in my opinion and I have used a three types. OHH and by the way your artwork is F'n sweet I'm not so much into fantasy stuff but I respect good art, you should definitely try your hand at doing some automotive stuff by the looks of your other stuff I'm sure it would look just as good

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As far as casting numbers that seems to make sense.I have torn apart a few and have seen the a87 in the L18 and u67 in the L20 not on the head.

I cant believe you guys are still running 210 heads.They suck.No offense they just do.I suppose,theoretically,they would provide more torque on a small displacement L16.But offer nothing for performance pep.Smaller valves and tiny uneven intake ports.

I have a set of flat tops from a 240z.They seem kinda huge.I cant remember but I think they are like 48mm each.Are all su's the same body size?Do thine eyes decieve?I have no mani but ocasionally bid on them on ebay.

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I cant believe you guys are still running 210 heads.They suck.No offense they just do.

 

Some of us have them because we won't tear open a perfectly good running engine. ;)

 

If I was after maximum horsepower I wouldn't be wasting time with anything L-based anyway.

 

I suppose,theoretically,they would provide more torque on a small displacement L16.But offer nothing for performance pep.Smaller valves and tiny uneven intake ports.

 

Well, the 210 head was engineered for the L13 so that should explain a bit. Everywhere else in the world the L16 usually got the 219 head.

 

I have a set of flat tops from a 240z.They seem kinda huge.I cant remember but I think they are like 48mm each.Are all su's the same body size?Do thine eyes decieve?I have no mani but ocasionally bid on them on ebay.

 

4-cyl carbs are 38mm (1.5"), Z (and 2000 Roadster) carbs are 44mm (1.75"). No, the bodies are definitely not all the same size. Basically nothing swaps between the bigger and smaller SUs. Even their mounting flange is different (but big carbs can be modified to work on the small carb intake)

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Dual cable... Oh because there are two carbs, gotcha.

 

By fabrication are we talking 'welding'?

 

Maybe... :D

 

In this case there's more than one way to skin a cat. Easiest trick is usually to remove the stock 510 linkage on top of the intake and re-use the rod that actuates the carbs, then weld a cable "wheel" to it. Then you can make a stanchion/clevis to hold the cable sheath still either at the carb mounting flange or air cleaner base.

 

This is WAY easier to show than tell, I'm afraid. I'll see if I can dig up a pic of the way I did mine. I wouldn't let this keep you from doing it though. What's life without a little adventure?

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So Mike, are these any better? Thanks for dropping some knowledge on me!

 

Dual2.jpg

 

Dual1.jpg

 

Yes, they look like the Hitachi SUs used by Datsun. Never heard much good about the flat top ones. They were performance limited by the smog/emissions controls on them. They can be re worked but I would start with something better first.

 

BTW the SU British carb that Hitachi built under license stands for Skinners Union.

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I would personally stay away from SU carbs try to find a set of mikuni carbs they are a bit pricy but work so much better than SU's and better than webers

 

I must respectfully disagree. There's no way dual Mikunis "work better" than SUs. The SUs will have more torque, be easier to tune, and easier to set-up. And less than half the price. SUs are basically the closest thing you can get to fuel injection in a carburetor.

 

Don't get me wrong, Mikunis are REALLY nice, but they are getting to be too expensive, are a bit harder to tune, and are really built for top-end performance, not daily drive-ability. They are race carbs. SUs are proper street carbs.

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I must respectfully disagree. There's no way dual Mikunis "work better" than SUs. The SUs will have more torque, be easier to tune, and easier to set-up. And less than half the price. SUs are basically the closest thing you can get to fuel injection in a carburetor.

 

Don't get me wrong, Mikunis are REALLY nice, but they are getting to be too expensive, are a bit harder to tune, and are really built for top-end performance, not daily drive-ability. They are race carbs. SUs are proper street carbs.

 

For all out top rev performance might agree that Minukis might have an edge over the venerable SUs. But for driveability (idle, off idle and low speed) and power with good fuel economy, would have to go with the SUs.

 

Constant velocity/variable venturi wins every time.

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I must respectfully disagree. There's no way dual Mikunis "work better" than SUs. The SUs will have more torque, be easier to tune, and easier to set-up. And less than half the price. SUs are basically the closest thing you can get to fuel injection in a carburetor.

 

Don't get me wrong, Mikunis are REALLY nice, but they are getting to be too expensive, are a bit harder to tune, and are really built for top-end performance, not daily drive-ability. They are race carbs. SUs are proper street carbs.

 

I also respectfully disagree no offense but if you think SU's would make more torque and work better, are easier to set up and tune than a mikuni set up I would pay to have your car dynoed with both set ups and let the numbers speak for themselves I have commuted in my wagon 80 miles round trip and not had a bit of problems with the mikunis and depending how they are jetted and what size chokes you have off idle and over all drive-ability is not an issue I have alot of people that commute over 80-100 miles round trip everyday and have no problems but if you like the so called performance of SU's...? and dont forget some Datsun roadsters came stock with mikuni's so I have been told. I have had all three types of carbs and have never looked back after mikuni's. I just think more people should try more options.

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I also respectfully disagree no offense but if you think SU's would make more torque and work better, are easier to set up and tune than a mikuni set up I would pay to have your car dynoed with both set ups and let the numbers speak for themselves

 

Huh? I just told you the Mikunis would make more power... :confused:

 

Dyno readings cannot show drive-ability or throttle response. Or how easy to tune they are...

 

I have commuted in my wagon 80 miles round trip and not had a bit of problems with the mikunis and depending how they are jetted and what size chokes you have off idle and over all drive-ability is not an issue

 

Again, proving my point. No need to worry about right size chokes and jets with SUs. Tune 'em once and forget it.

 

and dont forget some Datsun roadsters came stock with mikuni's so I have been told.

 

Yes, the high strung "race" model. The other 98% came with SUs. If the dual Mikunis were the best all-around set-up, don't you think they would have all come that way?

 

I just think more people should try more options.

 

As do I. But the guy asked for opinions on SUs, and if they were better than a 32/36 (which we'll probably all agree they are).

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stick with a weber 32/36 if you want a daily trouble free car

 

find a used one for under 100 dollars hopefully w/adapter

 

I have ridden a car with SUs and was impressed . But i would never buy over tthe internet or mail(could be used old junk)

maybe local and off a running car.

 

I have Mikunis and they are very dependable even for a daily driver. recommend 40s for a daily driver

but best to have all parts otherwise you could have nothing.

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