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mad uncle cliff

Cliff's 720 project

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Hi all,

 

It's been 34 years since I owned a Datsun with an L series engine (first car was a 1600) but I am now back in familiar territory with a 1985 Datsun 720.

 

Reason I bought this is because it is probably the longest tub you can get for transporting motorcycles wit the tail gate up. 

 

And because I like Datsuns.

 

This one is in good running order,  it has 170,000 on the clock and is showing some rust which is fine by me. The stock interior is very clean and I will keep it that way.

 

I plan to push the rust look a little harder and get the front of the ute looking like it just drove through a rust storm, so some wire wheel work to do there.

 

Other than that, I will fit a Weber downdraft soon just to get it running smoother and then long term I will have some fun building up a new L20B from scratch for it.

 

Long long term I would ditch the tub and fit a custom wreckers tray on the back for taking the race bike to the track - but I might get an older Datsun ute for that project.

 

Hmm - I would add photos but it seems this forum only allows it by URL - is that right?

 

 

 

 

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ute, tray.... gotta be from below the equator. Our last L20B was in the '80 720, nice to see it kept going elsewhere. You'll need to start a free photo hosting site account and store any pictures there. Then copy the picture information, bring here and paste it here in your post.

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On 8/26/2019 at 6:21 AM, Jef-fro said:

🤯

 

YI4Sk5e.jpg?2

 

Okay, so this is how it looks now the paint is starting to take a vacation from the metal.

 

tTHP3oU.jpg?1

 

The money shot - over seven foot of tub, just right for race bikes.

 

YE78B2p.jpg?1

 

Clean and stock inside.

 

I have picked up an 80's AM/FM radio cassette player to replace the stock radio, and I got an original NOS 80's cassette holder unit to bolt under the dash.

 

Now all I need are some Aussie 80's cassettes.

 

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Looks like a real good base for an easy project. 

 

Mmmm, cassettes. I lived through the 8 tracks and went into the cassettes, and now too old for the new fads in music.

 

Don

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Adapter should bolt right on but use some form of thread sealer as they vibrate loose and a vacuum leak is hard to diagnose. I think the part that the throttle cable connects to on the Hitachi needs to be transferred onto the weber. In the kit should be a white plastic elbow that fits up into the underside of the air filter housing for the valve cover vent tube so it doesn't become smelly in the cab.

 

This is a progressive carb in that the secondary begins to open at around half throttle and it's easy to stuff in too much carb all at once and have a slight lag. You'll have to learn to step into it and go by engine sound as you add more throttle. The Hitachi opened the secondary by vacuum and only when it was needed and all automatically.

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I use red loctight.

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Quick question before I lash out on the carbie upgrade -

 

When I start the car it idles high on the auto choke and it spits out black sooty water from the tail pipe.

 

Once it warms up and the idle drops, all this goes away.

 

Is this just the normal carbon and condensation tailpipe spit when cold for an old engine or "is it a sign"???

 

I will upgrade the carbie and then in around a year or two drop in a rebuilt L series engine and transfer the upgraded carbie across.

 

Just wondering how long the current engine will last...

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The choke forces a fuel rich condition needed on a cold engine. This will soot up the exhaust pipe and it's inevitable that some will get spit out the back. As long as the choke shuts off in a reasonable time this is normal. I guess you could try adjusting the choke a touch leaner as long as it doesn't impair stariing cold.

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9 hours ago, datzenmike said:

The choke forces a fuel rich condition needed on a cold engine. This will soot up the exhaust pipe and it's inevitable that some will get spit out the back. As long as the choke shuts off in a reasonable time this is normal. I guess you could try adjusting the choke a touch leaner as long as it doesn't impair stariing cold.

 

Thanks!

 

Might get better with the Weber.

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The older I get the more I learn I don't know.

 

Can someone please explain this "hoodride" thing to me?

 

Only because I am planning to sand back my hood (although here in Oztralia we call them bonnets) and someone told me I was too old to be building a hoodride.

 

 

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15 minutes ago, mad uncle cliff said:

The older I get the more I learn I don't know.

 

 

The beginning of wisdom.

 

Hoodride would be a vehicle looking, or made to look it's true age (or older) with faded worn, missing paint, visible primer, (AKA patina) surface rust stains, small dents and scratches, mismatched fenders and/or doors, that proudly displays it's scars from a life well used. No attempt is made to restore it to show room quality and even the opposite. A hoodride places itself beyond comparison with more beautiful examples of itself and stands alone. They can be so plain that they become 'beautiful'.

 

 

 

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On 8/27/2019 at 3:17 AM, mad uncle cliff said:

 

YI4Sk5e.jpg?2

 

Okay, so this is how it looks now the paint is starting to take a vacation from the metal.

 

tTHP3oU.jpg?1

 

The money shot - over seven foot of tub, just right for race bikes.

 

YE78B2p.jpg?1

 

Clean and stock inside.

 

I have picked up an 80's AM/FM radio cassette player to replace the stock radio, and I got an original NOS 80's cassette holder unit to bolt under the dash.

 

Now all I need are some Aussie 80's cassettes.

 

This is awesome. 

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On 8/28/2019 at 5:50 AM, datzenmike said:

Adapter should bolt right on but use some form of thread sealer as they vibrate loose and a vacuum leak is hard to diagnose. I think the part that the throttle cable connects to on the Hitachi needs to be transferred onto the weber. In the kit should be a white plastic elbow that fits up into the underside of the air filter housing for the valve cover vent tube so it doesn't become smelly in the cab.

 

This is a progressive carb in that the secondary begins to open at around half throttle and it's easy to stuff in too much carb all at once and have a slight lag. You'll have to learn to step into it and go by engine sound as you add more throttle. The Hitachi opened the secondary by vacuum and only when it was needed and all automatically.

Not to steal the show here, but I've noticed my 32/36 on z24 cuts out when you punch the gas, or even when you roll in too much throttle too quickly. I'm convinced the cause of the engine falling on it's face momentarily is that secondary opening up suddenly. Any way to fix this (besides "adjusting" my driving style)?

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"I've noticed my 32/36 on z24 cuts out when you punch the gas, or even when you roll in too much throttle too quickly."

 

A modern or even a 30 year old fuel injection engine measures many factors, and decides how long to leave the fuel injectors open to allow the proper amount of fuel, usually squirted directly at the intake valve.  Air temperature, air pressure, engine temperature, amount of throttle opening, how fast the throttle was opened, engine RPM, load on the engine, and many other things I cannot recall.off the top of my head.

 

A carburetor knows the manifold vacuum, and the speed the air is going through it, that is all. 

Additionally, jamming the throttle wide open in a hurry allows air, which is very light to rush into the intake manifold.  Liquid gasoline is heavy, compared to air, and takes a long time to start moving through the carb passages.  To compensate for this, the primary on most two barrel progressive carburetors have an accelerator pump that pressurizes a little bit of gas, and squirts the gas directly down the venturi of the carburetor when the gas pedal is suddenly floored.  It also takes a little bit of time for the fuel squirted in the carburetor to go through the intake manifold and get to the cylinders.

 

So, if you mash the throttle on a carb engine, especially at a low RPM, the manifold vacuum drops to almost nothing, there is not much vacuum to draw gasoline in to the manifold.  The engine temporally goes way too lean, and bogs down.

 

The modern fuel injected engine has a computer to control the fuel into the engine.   The carburetor engine depends on the driver to know the limitations of a carb engine, and drive it accordingly.

Edited by DanielC
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It's in the nature of the 32/36 progressive carburetor. If driven too aggressively you can open the secondary way before the engine can use it.

 

 

On 8/28/2019 at 5:50 AM, datzenmike said:

 

This is a progressive carb in that the secondary begins to open at around half throttle and it's easy to stuff in too much carb all at once and have a slight lag. You'll have to learn to step into it and go by engine sound as you add more throttle. 

 

 

 

3 hours ago, DanielC said:

  The carburetor engine depends on the driver to know the limitations of a carb engine, and drive it accordingly.

 

 

The 32/36 would be an almost perfect carburetor if it had a vacuum operated secondary that openes only when the engine was revved up and in need of the secondary. Until then it's a perfect carburetor for those who like to be more involved in the driving process. In some ways it takes a learned skill to drive one at optimum.

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Cool - all very interesting stuff on "driving to your carbie".

 

So today I decided I had better have a look at my carbie to see what it is, I mean how silly would I look if I bought a Weber only to find I already had one?

 

This is my stock carbie.

 

5zdaOGl.jpg

 

Guessing this is the original unit for the engine then.

 

And I am guessing it has an electric choke, given the red wire and the green wire running to it.

 

 

 

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Meanwhile - the hoodride look continues.

 

zWOfT15.jpg

 

I have stripped the front edge of the hood/bonnet back to bare metal and blended it into the large area where the paint was missing.

 

Currently sitting parked up all wet and covered in salt.

 

Yes this is my midlife crisis emerging and you may think this destructive, but I have a repro bonnet and guards all wrapped up in storage for later use (they came with the car) so why not stuff around with the panels that will eventually go?

 

(hmm - might pop an air intake in that stripped back area - looks like the right spot for one).

 

 

 

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5zdaOGl.jpg

 

Hitachi

 

Red is for idle cut solenoid. This is on with the ignition and allows gas to the idle circuit. Off starves the engine of gas and prevents 'run on' or 'dieseling' when you turn the engine off. If you get a Weber try to include this function.

 

Green wire becomes Blue under that Black sheath. Blue is the electric choke heater. It's on a relay and should only be powered when the engine is running. This is a nice feature to have on a new Weber also.

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I oredered this from Pierce Manifolds in Gilroy California.   Call them and tell them what you want the Wber for.  Ask if they ship internationally.

 

DSC02890.jpg

 

DSC02891.jpg

 

Beautiful place you live!

 

 

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19 hours ago, Charlie69 said:

I oredered this from Pierce Manifolds in Gilroy California.   Call them and tell them what you want the Wber for.  Ask if they ship internationally.

 

DSC02890.jpg

 

DSC02891.jpg

 

Beautiful place you live!

 

 

Thanks - yeah I could get one from there, but I actually just bought one local second hand on eBay and it comes on a manifold too.

 

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u8akx9z.jpg

 

Bought this off eBay today, guy is only a 1/2hr drive from home so I will go and get it tomorrow.

 

Half the price of the same carbie new and it comes on a Lynx manifold too.

 

No choke, but I think for around $50 I can get the electric choke fro the Weber store here in Melbourne.

 

Talking to this guy on the phone , he has a lot of Datsun engine stuff lying about... 

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