Jump to content

Interchangeable Parts - L16-L20B


yoloSun

Recommended Posts

Hey guys, looking at a local add - there's some parts available, an  L16 with some kind of cam installed, some factory 510 hubcaps and a Weber down draft carb.

 

Does the mechanical fuel pump interchange with the L20B? carb? caps? 

 

My 620 L20B has the emissions removed, would the manifold be usefull?

 

Edited by yoloSun
Link to post
  • yoloSun changed the title to Interchangeable Parts - L16-L20B
  • Replies 29
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Mechanical fuel pump will swap.

 

Unless new skip the Weber. You don't want someone else's problems.

 

Intake would swap but smaller diameter runners inside. Keep your '79 intake.

 

Hub caps or wheel covers. I think the 510 had wheel discs or covers and they would be 13" you have 14" rims

  • Thanks 1
Link to post
On 5/24/2018 at 7:35 PM, datzenmike said:

If on your L20B manifold then stock carb or with an adapter a Weber 32/36.

 

If you look you may find a manifold and set of L16 SSS or L18 SSS Hitachi SUs from Japan. Fit right on, simple, reliable (once adjusted) infinitely adjustable and some modest power that the stock carb can't provide. For one, the air goes straight and doesn't have to make a 90 degree bend under the carb.

 

1Upfvv6.jpg

 

Thanks dude, I've been looking for a while now, and I've decided to try my hand at locating these carbs you've suggested.

 

I've got lots of time, land & fabrication ability - And I'm not afraid of no used carburetor.

I've rebuilt motorbikes, mopeds, scooters, trail bikes, dirt bikes, mini bikes, trucks , tractors, mowers, cars, jeeps, vans & every kind of small engine 2 stroke and four.

 

What I don't have is knowledge of these carburetors and how to spot them under different names while hunting ebay or w/e

 

As an example this listing near me 

$150 · MG Midget Classic Mini Morris Minor Twin Carb

 

93537279_614.jpg

 

Looks like it.  

 

Link to post

Those would be British made Skinner's Union or SU type carburetors the same that Nissan used to copy the design from. Midget engines are only 1,100 to 1,500cc which is a little small for a 2,000cc truck engine. I think ideally you would want SUs with 38mm or 40mm throttle diameters for a 2 liter engine.

 

Here's a set of late 'flattop' SSSL16 or early SSSL18 Nissan SUs....

 

2nOFMQK.jpg

 

FQwMrHU.jpg

 

These were on the L18 engine so the intake is a perfect fit on an L20B. I think these are 38mm bore. These were never sold in North America, only in Japan, but did find their way here on imported engines.

  • Thanks 1
Link to post

MGB Sus were bigger, but adapting British SUs to a Nissan manifold may be difficult. There were multiple different mounting flange shapes and bolt patterns, the linkages are different too.

 

Best bet is to find a pair of 240Z Hitachis SUs and adapt them.

 

Or skip altogether in favor of a DGV Weber. Used Webers are ok, if you get them for cheap and you know how to rebuild and clean an old carburetor. I have an ultrasonic cleaner which does wonders for those small passages inside a carb.

  • Thanks 1
Link to post

I think the 240z were 46mm and quite possibly a little oversize for the 2 liter engine.

 

 

 

Have you thought of adapting motorcycle carburetors onto a home made manifold??

 

 

Almost 60 pages. Only thing I will add was that it's recommended to drill the jets out oversize L20Bs but this was 2008 and no one had wide band gauges. I did this and the engine ran below 9.6 (probably as low as the gauge would read) slowly worked my way up to near stock R-1 jetting. Made my own intake, always nice to make things. VERY happy with the results. These are a slide carburetor AKA a constant velocity carburetor similar to how an SU works. Unlike a regular carburetor there is no accelerator pump, the carburetor opens only as much as needed. Floor it at 1,500 RPMs in 5th and there is no lurch or bog it just makes more throaty noise and begins pulling smoothly. I don't do this but you can. Off the line is also smooth and without bog or hesitation. 

 

suiatH7.jpg

 

Even hammered my own 'velocity stacks' out of muffler pipe.

Axo32Ju.jpg

  • Thanks 1
Link to post
Posted (edited)

Aaaw sick stacks dude!

 

Man now I'm gettin' the itch to do it too...

 

I read the 1st of 57 pages, l like it.

 

Thanks the useful info guys! 😃

 

Now do those R1 carbs need individually tuned, and have you gotten any clogged jets very often?

 

Also are there any obvious markings or differences between the L16 & L18 SUs that I can use to identify the L18 SUs with?

 

Heres a set of I think L18 SU's on ebay.

 

https://www.ebay.com.au/itm/DATSUN-180B-SSS-TWIN-HITACHI-SU-CARBYS-INLET-MANIFOLD-L18-NISSAN-1600-L16-/324058145420

Edited by yoloSun
Link to post

They are all the same size so they all get the same jet.

 

The fuel filter cleans the gas of anything large enough to clog a jet. A 100 micron filter is fine for an inline filter before the pump. 100 microns is 0.1mm and the jets are 1.4mm so not worried.

 

Round top are the earlier ones (and look like the picture you posted) and flat top the later though an L16 might have the later flattop ones. They have 2 mounting bolts to the intake.

 

There are also Roadster round top SUs

 

The 240z car had round top SUs that will work, but I think slightly larger than you need. What ever you do don't buy Z car flattops! Z car SUs had 4 mounting bolts to the intake.

 

Here is a site that shows what went on what and probably how to ID what you find.....

 

https://www.ztherapy.com/

 

Check out the Spotters Guide on the left for 510 Z car Roadster and Volvo

  • Thanks 1
Link to post

R-1s are 1,000cc and rev 14,000 so my thinking is that a 2,000cc engine revving to 7,000 would need the same amount of air and carburetor.

 

Check around, Suzuki may also have used a similar carb set up.

 

 

Up to and including 2001, I looked it up. 2002 was the introduction of EFI.

 

I just run without any. I notice nothing different running without. Afraid to mess with it.

 

Vacuum for the brake booster I bought a GM electric booster vacuum pump but I think I will plumb lines into all 4 runners. Haven't figured out what to do about the PCV valve either.

 

 

  • Thanks 1
Link to post
Posted (edited)

Damn the going rate for these things ain't cheap, I saw people raving about the savings though.  🤔

Not gonna find any at the local pick and pull either...hmmmm....

Suppose I could be patient untill I find a good deal.

Edited by yoloSun
Link to post

For any performance engine, the distributor should be re-curved. There are a few shops that do it, and it only costs $150 or so. You can do it yourself if you know the philosophy behind what you're doing. I think the https://www.amazon.com/Modify-Your-Nissan-Datsun-Engine-ebook/dp/B0092WMDCK  book explains how to do it.

 

Stock timing curve with vacuum advance is good for efficiency, but not great for power.

Link to post
Posted (edited)

Yeah, I don't trust myself when I do it with the timing light. I will probably get the final tune done by some old school shop. Cool book, left out 620's though!

 

My project will end up something like lil red here, since I'll be making a rat box for the back. At the least it will have cool smoke stacks. I just really like smoke stacks. not ugly through the bed stacks, but elegant stacks like lil red here.

 

lil-red-truck-jpg.55192

Edited by yoloSun
  • Like 1
Link to post

Stock L series mechanical pump works just fine.

 

 

 

Wouldn't efficiency and power go hand in hand?

 

Would the headlong rush for power make this modification hard to live with at part throttle on the street?

 

 

I understand the need to mechanically advance the timing at WOT as the engine speed increases and there is less and less time for the gas to be fully burned and the hot expanding gasses to push down on the piston at the correct position ATDC.

 

Why do (all) engine makers delay the full mechanical advance to near 3K? 

Why is full advance 'all in" by 2K considered preferable?

 

     

Link to post

I believe the answer is economy.

But It's been a while since I read up on that subject.

The average driver is usually at city speed or highway speed and not brap speed.

 

Power and efficiency have a relation to time. If you want the most power in the least amount of time, it's gonna cost efficiency. 

That's where Engineer's come in. 

 

Efficiency is their currency

Link to post

How did you modification handle on the street?  Was it hard to live with at part throttle in traffic?

There's probably a way to to modify the pedal to throttle ratio to something livable

Link to post

In every way it was better than better, it is superb. Smooth even pull from start all the way up.... and as you near 3K it begins to make awesome noise that drowns out the exhaust. Warm restarts is barely a bump on the starter. Cold starts is a chore. There is an enrichment cable I plumbed into the dash. Pull it all the way out like a manual choke. Takes 5-8 starts before it fires up and idles at 600. Does not like to be driven for about one minute. There is also an idle speed adjustment, also on the dash that you can set a fast idle with. Engine will increase by itself as it warms. Once warm you then have to turn the idle back down. I tried a Windex bottle of gas. Squirt into each throttle and fires right up. Would be nice to have an electric pump with a push button to do this for me.   

 

The R-1s requires less pedal from idle to full WOT (wide open throttle) than the Hitachi down draft. In effect the pedal ended up closer to the floor and a small movement produced big throttle opening. It was hard to squeeze gently and get smooth applications of throttle. I modified the foot pedal by relocating the fulcrum point upwards in effect increasing the stroke and lessening the throttle opening. Now it's just like the Hitachi for feel with enough travel to smoothly adjust the throttle when driving in traffic.

Link to post
1 hour ago, banzai510(hainz) said:

stay with a weber downdraft since you cant time a motor. A worn out SU is only gonna cause you proplems

Oh, I can time a motor.  

 

I don't have the number one headband, but I do alright.

 

Fine tuning power bands with chalk?  Can't do that unless I drive it, and I'll never be sure every time I twist it.

If good enough isn't, then I'll use a better tool.

 

Maybe I'll even re-re-re-watch some of your videos

Link to post

Stick with simple. Set timing and valve lash to factory recommendations, replace old or worn stuff like ignition parts (NOT the coil) every 3-5 years. Cheap things like fuel filter change every 3 years weather needed or not. Change oil and filter regularly, again as needed. I change mine by time not mileage because I only drive a few months in the summer. Every other year, but before it's so dark you can't see the dip stick through it. Fix things right away. Keep full of oil and water and check at least once a week if driven daily. It's good insurance. Do this and you can safely assume that you are getting everything out of your engine.

 

Most want every fractional piece of horse power from their engines but no way to know for sure if you managed to get it when you modify or tune things. All we have is our ass dyno and it's not that sensitive. Our ear dyno is too sensitive, and louder exhaust (or intake) means huge power gain. (LOL) Unless you have a dyno that is impartial, there's no way to feel a few HP.  Be aware that a lot of after market stuff is bogus snake oil,  some can actually produce less output, and some no gain at all.  The one or two HP (usually at RPMs you never drive at) are $50 each!!!

Link to post
On 3/28/2021 at 12:28 PM, datzenmike said:

Stock L series mechanical pump works just fine.

 

 

 

Wouldn't efficiency and power go hand in hand?

 

Would the headlong rush for power make this modification hard to live with at part throttle on the street?

 

 

I understand the need to mechanically advance the timing at WOT as the engine speed increases and there is less and less time for the gas to be fully burned and the hot expanding gasses to push down on the piston at the correct position ATDC.

 

Why do (all) engine makers delay the full mechanical advance to near 3K? 

Why is full advance 'all in" by 2K considered preferable?

 

     

Theory vs practice

 

Have you ever re-curved a distributor?

 

The added timing brought in at low RPMs is where the benefits are felt, but if not limited at total advance, can be harmful.

Link to post
16 hours ago, yoloSun said:

Suppose I should throw on some Weber side drafts and call it good?

 

Curious how the throttle response and sound compare to a pair of those.

Matter of fact it would be good with a set of 40 mikunis.

Thats what I did on my L16 just throw a pair on that was rebuilt and it fucking worked I couldnt believe it. It went better when I cammed it but On a L20 it should already be better than my cammed L16/18s I been using.

My only regret is I never had L20 blocks laying around to build instead of L16 which were disposable motors. SIMPLE SIMPLE motors  all you need is power to the coil and thats pretty much it to run the thing. A Bushman in africa can keep this running. 

Newer computer FI motors I dont know shit

  • Like 1
Link to post

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.