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TommyKnocker

19J to 3.9efi conversion

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Hi Guys, I’m relatively new to the LR scene. I have been working on my 1990 110 for the past  year and it’s getting to the engine swap stage. There is currently an 19J in her and I have a 3.9EFI ready to pop into her, so any advise is most welcome. I know I will need an LT85 box but will my LT230 transfer box be ok with setup? Also, will I need to change or reposition the engine mounts? Is there anything else you think I may come up against with the transplant?

Thank you in Advance 

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The engine mounts on the chassis are different and will need to be changed for the V8 90/110/Disco/RR classic type. Other than that, its just a different recipe of standard parts.

You don't NEED an LT85. They also came with LT77, LT77S, and R380 boxes. Must be the V8 type to get the right bellhousing, and all will bolt up to your transfer box. Check the gearbox output splines though, as this is a common problem. You may find your existing transfer box ratio a bit low though, but it depends on what wheels and tyres you have fitted.

With this setup, it will all fit your new chassis mounts and use standard exhausts etc.

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As smallfry says, the V8 went in front of many gearboxes, the late R380 being preferable all else being equal.

If you leave the LT230 where it is and work forward, you'll need to fabricate or buy new engine mounts & position accordingly.

1.4:1 LT230 is liveable with a V8 but it'll be revving higher than needed if you're on normal size tyres, a 1.2:1 ratio (Disco/RR) might be better.

It may be stating the obvious but you'll need a high-pressure fuel pump for the EFI as well as a bit of wiring etc. depending on what you're doing.

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Posted (edited)

Still a lot to think about then.. I have 33x12.5x15 tyres on her.. will this help with the LT230 or be worse 🙈

Edited by TommyKnocker
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The 3.9 will probably have the pipework for an oil cooler if it came from a Disco or similar. This can be a bit of a fiddle to sort out depending on what radiator you use as the thread guage on the pipework may not match (although it may look similar) - I blanked the external feeds from the oil pump off eventually which was fine for UK use temp wise. 

Good luck with the conversion, it certainly makes a fun vehicle - very thirsty though. I Megasquirted mine which might have helped a little with economy but made a massive difference to reliability and probably power.

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10 hours ago, smallfry said:

The engine mounts on the chassis are different and will need to be changed for the V8 90/110/Disco/RR classic type. Other than that, its just a different recipe of standard parts.

You don't NEED an LT85. They also came with LT77, LT77S, and R380 boxes. Must be the V8 type to get the right bellhousing, and all will bolt up to your transfer box. Check the gearbox output splines though, as this is a common problem. You may find your existing transfer box ratio a bit low though, but it depends on what wheels and tyres you have fitted.

With this setup, it will all fit your new chassis mounts and use standard exhausts etc.

You don't necessarily need a V8 specific gearbox, there are companies that make an adapter ring.

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12 hours ago, TommyKnocker said:

Still a lot to think about then.. I have 33x12.5x15 tyres on her.. will this help with the LT230 or be worse 🙈

Ashcrofts have a gear ratio calculator on their website, but there's every chance a 3.9 will pull 33's with a 1.2 transfer box quite happily - it depends what you're doing though, if you want relaxed motorway cruising or more torque off the line towing heavy loads etc.

I'd run it and see what you feel like - if it feels like it's revving too high on the motorway then it's an easy & cheap swap.

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I find 33's, 3.54 diffs, and a 1.4 transfer box just right on the road, pulling a ~2.3t truck.

Spritely, but gets close to 20mpg on runs.

 

Nothing worse than an over-labouring engine in a car IMHO.

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I run 255/85R16s on my V8 110, so circa 33" diameter. 1.4:1 transfer is optimal for a 110, especially if you tow anything remotely heavy.

My previous V8 90 was on a 1.2:1 and same size tyres. This gearing was OK with a manual box, but when I changed to auto it was so overgeared it rarely made it into top gear on normal roads, and when a hill appeared it wouldn't pull top, but revved its nuts off in 3rd. Changing to 1.4:1 made a world of improvement.

As others have said, work forward from the LT230 for positioning.

I have a spare LT85, should you be interested....

 

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On 10/6/2019 at 10:46 PM, TommyKnocker said:

Still a lot to think about then.. I have 33x12.5x15 tyres on her.. will this help with the LT230 or be worse 🙈

Hi I ran this exact set up (but on a factory V8) with 33x12.50x15" and a 3.9 but on a four barrel carb, I found as others have said that the 1.4:1 TX box ran fine and sat about 3100 RPM at 60 mph ish, it had no problems towing and you didn't have to stir the box when faced with a sharp hill on a fast a road and gave about 13mpg (on a basic LPG draw through system). I don't tow much so swapped the Tx box for a disco 1.2:1 the RPM at 60 mph is down round 2300 ish, the cabin is a lot quieter and fuel economy is up round the 16mpg mark (again on LPG) it can labor on hills but doesn't give up. Low box driving is unchanged and I've stuck with the higher ratio as it suits my needs. 

If you change the Tx box over from a disco change the speedo drive gear to to give the correct speed readout (couple of quid for part).

whilst you have the gear box and transfer box split as alluded to by some one else look at the output drive spline wear and tx box input gear. It is worth replacing the input gear with a later cross drilled variant (easy to do with the box on the bench) and this will halt any wear that is taking place. I remember it was £36 for the gear many years ago.

I have a LT85 split case fitted to mine and whilst they are reputedly a strong box, they are noisy, the r380 is far more refined to drive with.

When I did a swap the same as yours on a mates 19J 110 we cut the v8 engine mounts out of the doner rangerover and welded them into the 110 with a plate between them and the chassis to spread the load. also be prepared to either fabricate a new gear box tunnel or at least carry out some surgery on yours, how much will really depend on which box you choose to fit.

On the subject of cooling the I changed my factory original 3.5 for a 3.9 and noticed in the summer it was getting uncomfortably hot sat in traffic, a defender v8 rad with a oil cooler sorted that out. If the doner engine is from a range rover it likely has a sandwich plate in between the filter and pump  from which to tap a oil cooler off.

stick with the conversion its well worth it and on completion sit back and enjoy that v8 sound! good luck.

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