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!

[GregAmy]

Never call out "Beetlejuice" unless you really want to talk to him... (IMG:style_emoticons/default/wink.gif)

Yes, I've laid out everything in the blog: philosophies, processes, tools, techniques, parts, wiring diagrams. So the general engineering is already there.

However, as I cautioned you via email, Jeff is spot-on that this is not a plug-n-play system (except for The DubShop's dual-TB setup) and this project does require a range of knowledge in terms of engineering/mounting the components, building a wiring harness, and subsequent tuning. I agree with his contention that fabbing something like this requires "...[skills] with custom fabrication, electronics and software and have significant hours available to...build a harness" (I have removed the "design" part, as I think I've done that for you.)

However, as Jeff implies, selecting and mounting the components was the easy part of the project. The most significant amount of time was spent designing and fabbing the wiring harness. I didn't keep track of hours, but I do recall wiring diagrams taped to all my cabinets around the garage pretty much all winter as I worked with the engine on the stand wiring it up, wire by wire, terminal by terminal, connector by connector. It being winter, with nothing else to do exept drink beer, helped a lot in my continuing the project to completion, and not having it become a garage queen (but there were moments...)

I will stray with Jeff that it requires "exceptional" skills, as I don't think I necessarily possess that, but it does require good skills. If we could find someone to fabricate wiring harnesses in bulk to my design, then this conversion would be dramatically easier (almost "easy"). But that's not something I'm interested in doing myself.

In the end, the Microsquirt is a good little system that, honestly, is only a few generations improvement from D-Jet. Both D-Jet and Microsquirt are "Speed Density" systems (L-Jet - "Luft" - is Mass Air Flow), both are batch injection (and MS does wasted spark), but what the MS offers is a better MAP sensor and finer-measurement TPS, wideband feedback, and user tunability.

But in the end, they're the same general technology...

Glad to help as I can...but you better really want to do it. - GA

[JeffBowlsby]

Hey Greg,

If the harness is the hardest part of the swap can you post a bit of information it, or links to previosu posts? Do you have a few photos depicting the overall layout and a few of the connections?