So I have a tired 1.8 that's got some oil leaks, burns some oil, probably needs valve guides, but is running great on Ljet. I have a rebuilt 2.0 with the 2.0L heads, not sure if it is a 1911 0r 2056, and not sure if it is the stock cam or one with more lift and duration suitable for carbs. While I have some Italian 40 IDF Webers, tins, fuel pump, regulator, and everything needed to make it a dual Weber, I like the fact that the Bosch Ljet is all there and working beautifully. I can reach in with the key after the car has sat for days and it starts when the key is turned. I don't want to have to tear out the FI system, rewire and replumb the fuel pump, rebuild the webers, etc, etc.

My questions: Can I use 2.0 L intake manifolds and get them to line up with the 1.8 intake plenum and throttle? Are the 2.0 L manifolds the same diameter as the 1.8 and are they the same length? Can I use the standard cloth covered intake hoses or will they be short? Do I have to bend the 2.0 L manifold tubes to line up, or do I somehow rotate or clock the intake plenum? Will 1.8 injectors fit in the 2.0 manifolds, or should I get 912e injectors? I want to use a new rebuilt throttle that was bored to 47mm from Pbeslin. It solved my notorious 1.8 sticky throttle. I also plan to use 2,0 L tins for the 2.0 L heads and their spark plug orientation. Who thinks A/F ratio will go too lean above 3500 rpm?

Please chime in& #33;Click to view attachmentClick to view attachmentClick to view attachment[attachmentid
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bolt it all together! Will sort of be like a 912e engine, it will all fit and maybe not peak power but good enough Make sure that you use the 1.8 oil filler as well

The 2L intake runners will not line up with the 1.8 plenum without modification. The Ljet is more than capable of running the 2.0L. The stock 2.0 is 1971cc.

Never attempted this but considered it. Some good info here (page #6, post 117)

http://www.914world.com/bbs2/index.php?sho...lled&st=100

Thanks Brenz, great info there on adjusting AFM!

Yes thanks, 1911 is for 1.8 with new 96mm P&C, 1971 is the stock 2.0 with stock crank.

How best to modify the 2.0 L plenum tubes? Make them same length as the 1.8 and then bend if possible?

Thanks George. 1.8 oil filler to get the crankcase ventilation connected to the intake boot. I had heard that the 2.0 L plenum pipes are shorter and the 4 cloth hoses will be too short. I see you have used or powder coated 2.0L plenums available.

Yes on the 1.8 Ljet. Just drill and enlarge the holes in the 1.8 manifold to match the studs patterns on the 2.0 L heads. Everything else stays the same.
If you're worried about the cam, it's pretty easy to measure lift and duration with the engine out. There are plenty of posts about it.

I've done it.
If you have 914 2.0 heads use the 2.0 manifolds and longer manifold to plenum hose. The rest is stock Ljet.
Works good, I don't see any power difference between L-jet and D-jet.

I have done it too. I wouldn't suggest modifying the AFM. Just put in bigger injectors from the 912E (also known as Nissan 280ZX injectors) and an oversized bus throttle body.

Thanks Mark. Any recommendations on longer cloth manifold hose? Do I bend the 2.0 tubes at all to line up better to the 1.8 plenum?

Thanks Clay. I had heard about the bigger bus throttle body at 52 mm, but I wasn't sure if it would work or connect to the oem throttle switch from the 1.8. There is a brand new bus throttle body from Go Westy at 52mm with sealed ball bearings to eliminate the shaft wear resulting in a sticky throttle plate. But I had my 1.8 tb repaired with bearings and seals, and was bored out a little to 47mm. What would just an enlarged throttle bore do if using the same AFM on a 1.8 ? More (or less) response at low rpm, or just more air at high rpm and possible lean problems? Then what happens when coupled with bigger valves in 2.0 heads? Easier flow of air into engine, yet all through the very same AFM. One would think it wouldn't be much different, but hopefully slight improvement in performance and responsiveness. Possibly less velocity and mixing of air charge?.

Interesting, please keep us posted.

I have this combination on a 1.8 converted to 2056 with the 2.0 head stud pattern. It works great. You may also need to use the 2.0 liter top cooling tin sheet metal pieces (because of the different spark plug locations) along with the 2.0 liter intake runners. As others said, the 2.0 liter runners were too short to work with the braided hose connectors, but it was wasn't hard to find some nice looking rubber ones of a suitable length and diameter and use some German hose clamps on either side of those for a clean, if not quite stock look. The 1.8 manifold and 2.0 liter runners align closely enough to work well with the slightly longer rubber hoses (and probably seal better with the clamps than the original braided ones did - l-jet isn't very tolerant of air leaks). All the remaining FI parts are stock 1.8 L-Jet, including the injectors. It works well, idles smoothly and pulls very strongly up to the redline.

A side note that might interest other '74 1.8 owners -- I was able to find a replacement for the large (30mm) braided S-curve hose (NLA) that goes from the oil filler to the intake at italianautoparts.com. It doesn't have the molded S-curve but works and seals well enough and looks original. Ferrari pricing though...

Great info everyone. I’ll try the 2.0 three bolt manifold tubes-with 2.0 heads and tins. I’ll try my rebuilt 1.8 TB and plenum with 1.8 injectors to start, and then swap in 912e injectors and see how differently it really runs . May try an Ljet type 4 in a 1968 912 also if this runs nice!

I used some Gates rad hose from the local parts place. Nice, black, turned the label downwards and used hose clamps from a VW T1 intake manifold. The hose was a tight fit so the clamps were likely overkill.

I used rivnuts to bolt the L-jet air cleaner mount on. I did it first with self tapping screws, didn't like it and re-did it with the rivnuts, but the screw holes were nice for locating where to drill.



Do a search, there's a thread in the garage on this mod.

The ports on the 1.8 manifold don't match up to the ports on the 2.0 3 bolt head.
Likely it would work but it would kill the flow.

Thanks Mark Henry for responses and insight on this project. And thanks to all for the good ideas and discussion on the challenges in doing this mod.

Here's my plan moving forward:
The 2.0 heads with matching intake runners should give the best flow, 2.0 tin to allow spark plug wires to fit, and establish the mounts on the tin for the 1.8 Ljet air cleaner assembly. Some Gates radiator hose seems like the easiest way to connect the mismatch intake runners to the plenum with some inconspicuous hose clamps. I think the 1.8 plenum and an enlarged 1.8 or Westy throttle body, and maybe the 912e/280 zx injectors look to be the rest of the recipe I'll use. Now I know what additional parts that I need to get while I plan for a motor swap out.

Eye Candy is $249, but out of stock:Click to view attachment

My rebuilt and bored 1.8 TB from Phil (Whip618) member vendor here, may be better match for 2.0 Click to view attachment

Nice sir Mark that you are now planning to install your 2056 engine. Yes your Ljet system is in perfect condition with the original 1.8 engine in that car. I’m amazed how your existing Ljet parts are working well since the 1st time it run (after that car was seated for several years) I’m sure with the 2056 engine soon, the car will be running a lot lot better.

From experience...

The 1.8 throttle body is too small for your motor. Use the 2.0 bus throttle body conversion really woke up Betty's car. The difference in the way it pulls is noticeable.

The 1.8 throttle body will work, but the bus throttle body is 10mm bigger.

Just my $.02

Clay: Should I use the new GoWesty 52mm throttle body shown in the pictures with my existing throttle switch on it or do you mean a used part from a 2.0 or 2.1 L bus. Do you have more specifics or part numbers to suggest?

Here is the thread on Vanagon throttle body conversion.

Vanagon throttle body for L-Jet.

That is how I did it.

Clay

The go westy TB is not a bolt on as the throttle position and cabling is different. It will probably work but the throttle plate and shaft needs to be modified.



Clay, do you have part numbers for the 280zx injectors?

This is from O'Reilly Auto parts site.

BWD Fuel Injector
Part #: 57519P

Same as a 912E.

Thanks Clay!

Why is there a throttle spring pulling in the direction of rotating the throttle open?

Should be pulling against the throttle cable?!

Jim

I haven't read a manual on this, but I agree that echocanyon's spring looks to be connected to the wrong spot and as connected, serves little purpose.

My secondary spring travels in the opposite direction to the throttle cable. I was originally missing that spring, so I bought one from George. It seems like a pretty strong spring. From that point on, my car started developing sticky throttle syndrome, although remember it is 44 years old too, so the throttle body shaft and housing are worn too. I bought a spare TB and found the spare had a broken wound (torsion) spring on the TB plate shaft. This meant that there was no throttle return spring at all, an unsafe situation, in my opinion.

So what does the second spring do? in studying what it does, one sees that the main throttle bell crank, pulled by the throttle cable, pulls against the wound spring, but also moves the secondary bellcrank and pulls against the secondary spring when it is hooked to the engine tin to the left rear of the engine. It actually adds more return spring force against the throttle, and seems to be a secondary or backup throttle return spring. It certainly loads up the forces on the shaft bearings in the TB. Perhaps the national highway safety administration requires the extra spring for safety. I think the extra spring helps cause the wear that leads to the sticky throttle.

Camping onto this old thread, as it's related information.

In researching a replacement throttle body for my 2L D-Jet, I see that there were two versions, with and without integral/spiral return springs. Why the difference, and where is the cut off?

Does anyone have an idea on how big the hole in the plenum is (i.e., how big can you overbore the TB) and if it has shown any performance improvement?

Greg

They are 45mm and people bored them out to 50mm. I have one but went back to a stock one for damn if I can remember. Guess I should stick the 50mm back on just to see if I get a little more hp at 6000rpms

I'm looking to get Phil Eslin to rebuild my '74, but I want an integrated return spring. Was that a later thing or an earlier thing?

Does yours have return spring? I'm also giving thought to getting mine bored out, so if you decide yours is available, and it has a return spring, we might be able to horse-trade.

Its the later 75-76 TB that had the integrated secondary return spring. I prefer them as well as its an added piece of mind. If you dont mind changing your hose arrangement slightly the 75-76 plenum also has an addition for a 2nd external return spring giving yet another layer of redundancy on the throttle return.

FMVSS standards require two sources of throttle return force back in the mechanical cable days. The OEM's self certified that every new application could return to idle within one second even with one of the spring clipped. The test was run at -20 Deg F. Ask me how I know.

I am also running an L-Jet on a 2056. Wallmart (of all places) sells the FJ707 injector which is the one used on the 240Z and it works fine as indicated on my AFR meter.

https://www.walmart.com/ip/Standard-FJ707-F...cement/46073945

Several of these threads that discuss using the larger diameter Vanagon throttle body for L-jet systems have me curious if anyone has done the same with using the Vanagon TB on the D-jet system.

Vanagon TB for 1.8 L-jet

1.8 L-jet to 2.0 L-jet

http://www.914world.com/bbs2/index.php?showtopic=244849

http://www.914world.com/bbs2/index.php?showtopic=244471

I didn't readily find any threads discussing so wanted to ask the group if this was also common or not. Any pitfalls are problems with doing so?

Thanks for the insights.

Respectfully,
Sean

@74 sunflower 914 : Do you have their part number? Indeed, one of the parts I've never seen available.

The 240Z had carbs. The part you are talking about fits a 280ZX, vintage 1982. Same injector as the 912E.

Clay

My mistake. Thanks.
Ray

I figured it was a typo.

StarBear the hose for the L-jet oil breather is 22mm, not 30mm as I mistakenly remembered. It is available here:

https://italianautoparts.com/?product=braid...-per-foot-bah22

I just bought 3 feet and cut it to the same length as the original. Since it is not molded to match the original S curve I used inconspicuous hose clamps on either end to secure it after pushing it into an S shape like the original. My 40+ year old one still looked ok outside but was oil soaked and cracking at both ends and leaking air.

Thanks guys for the tip about the FJ707 injectors and over-bored throttle body.