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Project Lucas, Plot Twist.

Well heck, it’s been a real rollercoaster recently, and things have been moving quickly…

So, lots has happened since my last update.

First, Lucas is hanging around long-term.

Secondly, Lucas is getting an engine upgrade

Yup, most will know already, but it’s happening; Lucas is getting a 3.9L upgrade.

How did we get to this point?

Well, even before the last update went live, Lucas for advertised for sale. The engine is trash, I had had enough, and just wanted to move on.

I had a couple of people contact me regarding the car, but they wanted guarantees such as that the current engine wasn’t terminal (it is) and that the original engine is savable (who knows). In the end one got back to me and declined to proceed further, and the other just never replied again.

In the meantime, the overwhelming support online from various forums and social media has made me think twice, and start looking at my options. I quickly discounted fixing the current engine, as it’s just not worth spending money on; it’s the wrong engine, it’s low compression, has low oil pressure, and an unknown mileage and history.

So that left me with two options. Upgrade, or rebuild the original.

I put out on a couple of places that I was looking for a 3.9 engine but didn’t have a huge amount of luck, so I proceeded with pricing up parts to rebuild the original engine.

What I concluded was that parts aren’t too badly priced, but shipping was going to absolutely cripple me. Most parts had to come from the UK and we are talking things like $200 freight for just a gasket set alone. That’s super hard to justify.

I then remembered I was a member of a local Land Rover buy/sell Facebook group, so I jumped on there and asked if anyone had a good 3.9 engine for sale locally. Within minutes, I had a response that yes, there was one available and it was local to me.

The next day, the engine was in my garage.

It’s a high compression 9.35:1 3.9L from a Discovery. Other than the manifolds and cut loom, it was complete. The seller claimed it was out of a truck that had 160,000km on the clock, ran and drove well, and made no unusual noises. Good enough for me. It was the right price too.

The high compression 3.9 should make the SD1 move quite nicely.

Vitesse 9.75:1Carb 9.35:1 (fitted)Disco 3.9 9.35:1
Power (HP@rpm)190@5280155@5250182@4750
Torque (NM@rpm)258@4000268@2500312@3100

The engine is, as the British say, minging. Clearly keeping on top of maintenance wasn’t exactly top of their spending list, as both valve cover gaskets had been haemorrhaging oil for a very long time. It was down all sides of the block, top to bottom

As you can see above, I started by removing all the ancillaries from the front of the engine.

The engine is the desired “intermediate” serpentine 3.9, which runs the crank-driven oil pump (vs the earlier distributor-driven pump) and has the correct shape to mate with the SD1 sump (later engines have a different shape to the front of the sump, and front cover). Unlike the SD1 which runs a pair of V belts to drive the ancillaries, this engine runs a single big multi-V serpentine belt.

I looked into using the newer parts and keeping the crank drive pump and serpentine drive, but in the end, it is easier to swap the SD1 front cover, sump, alternator and power steering pump onto this engine. It’s more or less a bolt-on affair. To use the serpentine front I would have had to look into whether the cooling fan height matches (apparently it’s higher on the 4X4 engines and the water pump is very different), and I would have to find a way to make the power steering pump work as it has completely different fittings. I will keep the components anyway, just in case I want to look further into converting to serp again.

Removing all the components off the front really reduces the length of the engine

Over the past couple of days I have set about trying to clean the engine up a bit, as it was filthy. I have spent hours now, with a brush, degreaser, and brake clean, scrubbing the heck out of it. It was very thick, and stuck well.

It’s not perfect, but after today’s effort it’s about as good as I am going to bother with. I haven’t cleaned the front cover, valve covers or sump, as I won’t be reusing them.

I removed one of the valve covers, just to see how it was inside. The screws for the cover were all finger-tight, and the gasket wasn’t even trying to seal. It’s pretty dark in there, so obviously it’s been on long interval servicing, but it’s burnt on and not sludgy, which is a bonus. Hopefully a few oil changes in quick succession will help this.

I did find this tucked up in the head though. No signs of it being bashed about, so I suspect it hasn’t moved much. It was so “weathered” from being in there, it must have been in there for thousands of Ks.

Old mate who serviced it at some point (probably the one that did the valve cover gaskets and didn’t tighten them up) just dropped it in there, closed it up and didn’t give two thoughts as to where his missing clamp went.

I also pulled the original SD1 EFI valve covers out of storage and gave them a degrease and clean ready for paint. You can tell the LH cover is the proper EFI one because it has the large round flat raised platform on the end for the breather filter, which the current carb covers (and 3.9) don’t have.

I’ve been trying to source another SD1 sump and front cover to make the swap easier, but it’s proving more difficult than expected, so I may have to just swap the ones from the current engine over.

In the meantime, I have ordered a bunch of parts; mainly gaskets and seals, to refresh a few things on the engine, and make the swap possible. They should be here within a week, and then I’ll start planning the actual swap.

The goal is to have the car up and running again for a work Xmas “car day” on the 21st Dec…. Time is ticking!

To help meet this goal I am going to initially run the engine on the “flapper” Lucas injection system from the 3.5. It does work, but isn’t ideal as it will be running at the upper limits of what the factory tuning can handle for the extra capacity. Once the engine has been shaken down a bit, I will then start working towards another Speeduino install. I have 95% of what I need already, and know where to get the other 5% I don’t have, it just takes money.

I’m also looking at using the new 3.9 fuel rail with the Speeduino, which would eliminate both the old injectors with the hose tails, and the resistor pack, so I could drive the injectors straight from the ECU in semi-sequential instead of batch firing like I did last time. All things to look into when the time comes.

So there we have it, Lucas is hanging around, and I’m finally getting the 3.9L auto SD1 I have wanted.

Stay tuned for more updates.

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1 year ago

Excellent news!

Rob Murray
1 year ago

Great news, saw on Piston Heads, but checked in here to make sure it was happening.
You will have to keep this one now you’ve invested so much time and money.