Replacing Ljet with 1.7L Djet on ‘74 1.8L, Ljet in pieces (literally) and have full djet Options

[CSoso]

Hey everyone!

Please don’t roast me if this has been asked before. I spent several hours searching the site… But if it has, a link(s) to any thread(s) would be appreciated…

I have a ‘74 1.8L barn find - sitting 10-ish years due to FI issues. The flapper box is definitely tango uniform and literally in 4+ pieces. Other parts have been removed and am sorting through the rats nest of hoses and pieces. The entire system is in question and I really don’t want to try to find hard to find parts.

The engine was only a quart low and amazingly had very few leaks. The odometer shows 15k miles (115k according to PO). After pulling the engine, I put a ratchet on it (after oiling, etc) and compression “feels” good with no grinding, squealing or grit feel. Will be checking compression officially shortly. The engine’s rebuild history is unknown, so am doing a thorough check. If there’s any hint that it needs rebuilt, it will become a 2056 with microsquirt. If it’s useable as is, I’d like to use parts I have to get her on the road - namely a djet FI system. I would then run her (her name’s Saphira) with the 1.8L until I get a 2056 built. As it’s been said many times here - a 914 going down the road is always faster than one on jack stands!

I have a full ‘73 1.7L djet system and most (missing mps) of a 76 2.0L djet system. I would get a new harness for either djet and rebuild the mps. Assuming I get whichever djet system refurbished, is it a simple remove ljet and replace with djet (distributor too)? Or will the different compression/displacement of the 1.8L cause issues? Any electrical connection issues to the rest of the car? I really appreciate this community and everyone’s helpfulness! Any hints, tips or suggestions are appreciated!

Cheers!

[Van B]

They are completely different systems from the oil cap to the ECU. I’m not sure you’ll be able to mount all the D-Jet parts without the appropriate manifold and intake as well.

Also, I don’t recognize the stamp on your engine tin… @wonkipop

If you decide to press, I’d like a shot at your L-Jet parts please.

[wonkipop]

They are completely different systems from the oil cap to the ECU. I’m not sure you’ll be able to mount all the D-Jet parts without the appropriate manifold and intake as well.

Also, I don’t recognize the stamp on your engine tin… @wonkipop

If you decide to press, I’d like a shot at your L-Jet parts please.

well spotted Van B
some of them got that engine stamp EA370
@JeffBowlsby has documented a few.
they seem to appear on the early cars in production runs.
i did come across one on a early 74 and also one on an early 75.

it will have the other number as well.
@CSoso
can you have a look at your engine and tell us what the stamped painted number on it is.
maybe take a photo and post.
will be a 604, or 605, or 606 or 607. (IMG:style_emoticons/default/beerchug.gif)

sell all your bits to Van for sure.
he will want them and is a worthy recipient.
with a bit of luck StarBear and I will be able to beg bits out of him after he establishes his evil L jet empire. (IMG:style_emoticons/default/smile.gif) but yeah. do not throw them on the dump.

and Van is hinting at something.
which is you will want to do a complete swap over and its all the anciliary bits.
D jet guys can come in because i don't know sh$t about D jet.

but here is my guess.
the relay board set up for D Jet with all the relays.
as Van says, probably the oil cap and PCV valve. replace that with D Jet set up because its different. also L =jet did not run with the vented heads. again D Jet guys can give knowledgable comment on that. maybe the dizzy is different too but i am not absolutely sure on that. different plenum. different throttle valve. different aux air valve.
what else. same decel valve. ummm.
its not something i have heard of anyone doing. but i see no reason it can't be done.
but you need absolutely all the D jet bits i would think and entirely remove all the L jet bits. the works.

[Geezer914]

Easier to sell the D jet parts and buy the Ljet parts you need. Fuel Injection Corp in CA can rebuild your AFM.

[ClayPerrine]

(IMG:style_emoticons/default/agree.gif)

D-Jet is the very first production EFI built. It is the most primitive system out there. Yes, it works well, the Bosch engineers did an amazing job creating it.

The L-Jet system is the next generation. Bosch took all they learned with the D-Jet and made improvements on the system. No special distributor with trigger points, no multi-wire throttle switch, no MPS with it's diapharam issues, etc. What they built in the L-Jet system was licensed to Nippondenso and put on millions of Nissan, Toyota, and other Japanese car maker's vehicles. It is by far a better system. It even evolved into the Motronic system still in use on current production cars.

I would suggest you fix the L-Jet system. I have kept one running on Betty's 914 for 37 years now. It is robust and very reliable.


Clay

[emerygt350]

Although I think you could do it if you had the plenum and all the bits, I think it would be easier to fix the 1.8.

[StarBear]

Will chime in with the others to replenish the LJet system. @Van B and @wonkipop have identified several alternate parts for use. Injectors are different, too. Be sure to have your dual relay and capacitor pack. Very reliable and works even with multiple system errors ( @Van B knows) but sensitive to vacuum leaks. Lots of LJet help here.

[JeffBowlsby]

Both the DJet and L-Jet are plug N play as long as the systems are complete and functional. If using the 1.7L DJet, you may need to tweak it for a 1.8L displacement application - such as increase fuel pressure slightly

LJet is a solid and reliable FI system as has been described. It is the original FI system for a 1974 1.8L 914 and I would consider it a primitive FI system. Parts are available though not 100% cerain about Fuel Injection Corp anymore - one of their main techs passed away recently and you should check with them for specific items. It delivers fuel as needed, where needed - well manintained, its great. Every part is available or substitues such as the 123 dizzy can be used. The 1.8L FI harness is $908. because it is much more complicated than a D-Jet FI harness.

DJet is a solid and reliable FI system and one generation more primitive than LJet - a fact yes, but is that important no. Original FI to all 914s, except the 74-75 1.8L cars. It delivers fuel as needed, where needed - well manintained, its great. Every part is available or substitues such as the 123 dizzy can be used. The 1.7L DJet FI harness is $556. and only fits a 1.7L 914 (same price for a 2.0L 914 DJet harness). If you were to source a complete 2.0L FI system, hardware, new harness and everything, it can be used on your future 2056. Cannot say that for the 1.7L or 1.8L setup.

Not a microsquirt fan for the everyday 914 owner, because it is not a plug N play FI solution. Unless you are exceptionally skilled with custom fabrication, electronics and software and have significant hours available to design and build a harness, and adapt the system to your car, we will look for your car for sale in about 10 years after it being on jackstands all that time, after numeous unsuccessful frustrating attempts to make the MS work.

[emerygt350]

If it were me, I would go with the ljet but be very smart about it. isolate everything you need to make it work, figure out what you need to replace (perhaps the afm) and figure out the price/time factors (that is, if you care). If the cost and time just don't justify it I would consider a lame carb solution for fun. I have an article from the 80s in VW magazine that describes how to just slap a 2 barrel on that plenum and call it a day.

[BeatNavy]

Not a microsquirt fan for the everyday 914 owner, because it is not a plug N play FI solution. Unless you are exceptionally skilled with custom fabrication, electronics and software and have significant hours available to design and build a harness, and adapt the system to your car, we will look for your car for sale in about 10 years after it being on jackstands all that time, after numeous unsuccessful frustrating attempts to make the MS work.

Jeff, I hate it when you beat around da' bush. Please tell us how you really feel (IMG:style_emoticons/default/smile.gif)

To the OP, there are a number of us here running MS. I think Jeff overstates the difficulty given that there is a large knowledge base, both in general as well as with a type IV, and there are plug and play components for sale from the Dub Shop and others. It's not for everyone, and stock FI is a great option, but some us also LIKE the process of figuring this stuff out.

Just wanted to give another perspective.

[SirAndy]

I have a full ‘73 1.7L djet system and most (missing mps) of a 76 2.0L djet system. I would get a new harness for either djet and rebuild the mps. Assuming I get whichever djet system refurbished, is it a simple remove ljet and replace with djet (distributor too)? Or will the different compression/displacement of the 1.8L cause issues? Any electrical connection issues to the rest of the car? I really appreciate this community and everyone’s helpfulness! Any hints, tips or suggestions are appreciated!

When i bought my car it had a 1.8L engine with a 1.7L D-Jet system on it.
It ran just fine.

Just make sure you have the complete d-jet system, you can't mix the l/d parts.
(IMG:style_emoticons/default/shades.gif)

[914_teener]

You have the motor out. Put 96 barrells on it stock cam is fine....the 1.8 heads are great heads.

Use the L-jet system the components are still relatively easy to find and that FI system is easier to tune than the D-jet stock FI. IMHO.

MS is not for the light of heart and it's NOT cheap to do.

Nowdays...if it's a barn find...I'd keep most everything stock as possible.


With the above combo you will be able to smoke the tires.... and drive like you stole it.

[emerygt350]

Yeah smoke the 50 year old 165s maybe...

[wonkipop]

I have a full ‘73 1.7L djet system and most (missing mps) of a 76 2.0L djet system. I would get a new harness for either djet and rebuild the mps. Assuming I get whichever djet system refurbished, is it a simple remove ljet and replace with djet (distributor too)? Or will the different compression/displacement of the 1.8L cause issues? Any electrical connection issues to the rest of the car? I really appreciate this community and everyone’s helpfulness! Any hints, tips or suggestions are appreciated!

When i bought my car it had a 1.8L engine with a 1.7L D-Jet system on it.
It ran just fine.

Just make sure you have the complete d-jet system, you can't mix the l/d parts.
(IMG:style_emoticons/default/shades.gif)

@CSoso there is your answer.

if you have a complete 1.7 djet system i'd probably go with it.
even the harnesses you win with. if the 1.8 harness is shot (being a barn find) as Jeff B says its more expensive anyway than the 1.7

re displacement/compression. the californian 73 1.7 also had the same lowered compression as 74 1.8 - ran on unleaded fuel. i don't think there was anything special to the d jet system for those cars.

if you change your mind and want to use the L jet plenty of help around here.
same goes for the D jet.

(IMG:style_emoticons/default/beerchug.gif)

[Geezer914]

Fuel Injection Corp. is still rebuilding AFM's but no longer doing ECU's. Their ECU specialist passed away from Covid.

[wonkipop]

Fuel Injection Corp. is still rebuilding AFM's but no longer doing ECU's. Their ECU specialist passed away from Covid.

thats so sad.

it happened here too with one of the top machinists in town who did a lot of old air cooled head work.

[CSoso]

Good evening!

Thank you, everyone for the replies and information! I have been following GregAmy’s blog and Microsquirt build and been in contact with him. (Thank you @GregAmy for all the info and questions answered- super nice guy who deserves to be bought lots of beer!) While it is not a plug and play system, he has done all the heavy lifting and I would shamelessly plagiarize (permission was given) what he has done. I like the idea of being able to tune and have a more modern system. He reports that it starts easily, runs super smoothly and he has confidence in it to run several long (7 hours iirc) trips with it.

My Denver cousin (who will be rejoining 914World soon - I hope), really knows and likes the D-Jet system(s) and has been trying to convince me to “slap the D-jet on and go”. At this point, I think that any of the options are going to take a similar amount of time. I will be refurbishing either the D-Jet or L-Jet components to like new condition with new hoses and harness, or building up the Microsquirt with new parts and fabricating some brackets and the harness. Price-wise, the Microsquirt is pretty much known to be around $1700 give or take depending on tools and part fabrication costs. The known D-Jet and L-Jet replacement parts I need are at least $1500 and that doesn’t count any other issues or parts that pop up or new hoses.

The other, very real, consideration is keeping it stock with the L-Jet. A new development is that I found a complete airbox in the bottom of a box. As I posted previously, I only had found pieces (4+) of one. And to be honest, I had not done a lot of research into the L-Jet.

I did find a “606” on the driver’s side engine tin and a “I.0” on the passenger side front. (I have pics but can only load one due to size). That makes sense as this was originally a California car and wandered to Michigan approximately 15-20 years ago, spending the last 12-ish in storage with the FI torn into. Sticker on driver’s side engine compartment shows it being an “A” engine (verses the later “B” version).

So… Next steps…
1) Inventory all pieces/parts and determine what exactly is needed to have a complete one each refurbished 1.7L D-Jet, 2.0L D-jet and 1.8L L-Jet systems. I may be closer than I think to a good L-Jet system.
2) Compression test (starter gets here Tuesday)
A) If the compression is bad, then will rebuild to 2056 (have all hardware and would rebuild the 1.8L heads) and go Microsquirt with 2.0L intake manifold per GregAmy’s set up.
B) If the compression is good then it will be a little tougher decision. I will make a fact-based decision based on research from #1 above and weighted for all the factors (cost, time, availability, originality, etc. - all the great considerations everyone has weighed in with!).

With this being Springtime in Michigan (snowed this morning) and my garage unheated, I have about a week to research and get my ducks lined up. I definitely don’t want to sell Saphira (that’s her name) to Mr Bowlsby (or anyone else) because she’s sat on jack stands for years! The goal is to have her running by July and on the road a few weeks later. There’s some front turn signal and bumper work to do as well, and more than likely a fuel tank to flush/clean.

Thank you everyone for the great information! This truly is an awesome community! Will keep everyone posted on progress.

[r_towle]

Dual Webers FTW

[Van B]

Something strange about that intake boot. Doesn’t look the same as a ‘74 or ‘75 9141.8L intake boot.

[wonkipop]

@CSoso

thanks very much for taking the trouble to record those numbers and post up image.

(IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beerchug.gif) (IMG:style_emoticons/default/beerchug.gif)

according to material we have found you have a california spec 74 1.8
if it still has its original throttle body it will only have one port for vac connection.
low down on front facing side (front of car side).
but it might have a different throttle body on it now.

all your maths on the $ numbers sound right.
i was going to say after jeff bowlsby posted up cost of 1.8 harness that d jet sounds better way to go $ wise if you got enough good components.

if you have a good afm, good harness, good injectors and ecu the L jet might be ok to use for a bit of low investment rolling fun. but all those things need to be good or $ stack up. and its only got 76 horses. fun horses, but minimal horses.

i got one so i am not putting them down. i really like it. but if it was a kaput barn find i'd be going full modern. mine isn't kaput barn find so i persevere.

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