3.9 - 4.0 Conversion

[Ranger_Ivan]

First of all, I'm new here. I'm also rather new to the wonderful world of Rovers. So, it's supposed to be a love/hate relationship, right?

On to business...

The 3.9 motor in my '95 Disco died a few months back. Considering some of my budgetary contraints, I was having problems tracking down a replacement 3.9, when somebody suggested converting to a 4.0. I talked to the techs at the local LR dealership, and they said it shouldn't be a problem. So, I bought a 4.0 motor...

Now I'm learning about some of the issues involved in this conversion, issues not mentioned when I asked what all would be required. I'm wondering if anybody else has done this conversion, and what sorts of things you've experienced.

Thanks,
Alex

 

[Tree Trimmer]

I have been looking to do a conversion, of some sort, so I have done lots of research and talked to lots of people. If I had been doing a conversion to another land rover engine, I would have upgraded to a 4.6. With basically the same problems you are going through now you could have had more power for the same price. I think the best people to deal with on the land rover engine upgrade is RPi enginering in the UK. If you haven't been to their site, check it out. rpiv8.com You might learn something that will help you on your swap. I hope you didn't buy your engine from the Land Rover Dealership!

 

[ptschram]

OMG, the only real issues are that you must replace the camshaft with one from a 3.9 and make/buy a spacer for the crankshaft.

Due to the 4.0 being a distributor-less (spawn of Satan) engine, there is no mechanism to drive the distributor. The 3.9 camshaft has the ability to drive the distributor. Also, the front of the crankshaft is slightly different requiring a spacer for correct orientation of the front pulley.

John Robison has the spacers for sale off-the-shelf and can provide more in-depth assistance.

There are very few and slight difference between the 3.9 and the 4.0. Slightly stronger bottom end from the cross bolted mains. But otherwise, very similar.

 

[casbro]

Hi everyone,
I,m Currently just about to take delivery of a 2000 4.0 here in Australia.
My 3.9 developed a crack in the block on the cylinder closest to the dip stick.
My current list of change over items are:
Cam shaft from the 3.9
Timing case cover and distributer from the 3.9
The entire fuel injection system from the 3.9 (the manifold up)
The flywheel ,clutch,alternator,starter etc..
I currently fuel this beast on LPG (liquid petrolium gas) and gasoline ,so I'm not able to use anything from the 4.0 fuel system.
I'll take some pics as i go and this my help!
cheers!

 

[robertf]

I did this swap in mine not too long ago

cut the dowel pin flush with the crankshaft flage on the back, I tried everything to remove it and it wouldn't budge

use a 3.9 cam as stated above. If you get an aftermarket one for a buick/rover application the retainer plate won't fit without some simple machining to the camshaft.
I think D&D does this machining and resells crower cams.

a spre timing chain lower gear works fine as a spacer once the teeth are removed. It is very hard material. If you are going to have it machined, grind as much of the teeth off as possible before taking it somewhere.

 

[ptschram]

Albany, eh? The only Stealership near you would have to be PDX.

Talk with either Dennis Simensen or Scott Lucas. They've both done it and can walk you through it.

Tell them I told you to call (and also to kick Pedro in the shins).

 

[robertf]

I don't know where PDX is, but I'll bet its not in Australia

 

[ptschram]

I don't know where PDX is, but I'll bet its not in Australia

You know Robert, I overlook the obvious occasionally. When I went back and looked at this, I found I'd already commented. To make matters worse when it originally came up, I was considering putting an engine from one of my parts trucks in my '95 DI and it wasn't until I had the engine out of the parts truck that I realized I didn't have a good camshaft.

I got quite a bit of ribbing from a friend of mine for having posted the process and shortly thereafter finding myself in a pickle for the oversight of what I had shortly before posted about the process.

In this case, my distaste for an employee of Land Rover PDX clouded my reading skills!

 

[Azdiscovery]

Dealer did my swap when I blew the head gasket at 75,000. (before I did any of my own wrenching on the drippy bastard myself)

 

[casbro]

I've got a local guy who wants to sell me all the gaskets and bits and pieces, i'm also going to renew the clutch.
He has offered to walk me through it and it should be ok.
I'm still waiting on the shipping of the motor so ,should be able to start soon!
The 3.9 motor has a crow cam in it and i definitley will use that.

OH i forgot to say the 3.9 engine had 290,000 klms on it before i killed it towing 5 metre long ski boat(cast 350 chev) with too much gear in it over the mountains.
Boiled and filled the engine with yogurt.(two head gaskets and a cracked block)
Replaced 1 head ,two head gaskets and put stop leak in the block.
Got another 30,000 klms.
Yep time to chuck it out and start again.

 

[casbro]

Well Its done,
But missing a few key things such as : oil leaks,boiling water,strange vacume sounds,misfiring etc...
Its purring and to all that have a reasonable amount of skill with a spanner , this should be a pretty straight forward conversion.
To add salt to the wound we purchased this 4.0 motor from a wrecker in Sydney Australia on Ebay for $1500.00 Aud....:rofl: Its was out of a 2000 model car that was dismantled in 2004 and sat on a shelf till now because nobody liked it!
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=160139763738&sspagename=ADME:L:RTQ:AU:1

So as not to hijack the thread i've kicked in another

 

[piper109]

I now have sitting in my garage a dismantled 4.0 that had been previously converted to a 3.9. The engine had issues. I bought a '95 5 speed Disco with a sick engine, knowing nothing about them. Rather than fix this engine's issues, I found a good running junk yard 3.9 and its installed and running.
It seems the issues were stuck oil rings and bad valve guide seals.

The engine can easily be repaired. The bottom end has bearing wear but crank is fine. Bores/pistons are very good. Heads are good apart from valve seals. Guides are not worn. Before dismantling, engine was quiet and compression was about 120-135. It just used a lot of oil as the control rings were stuck.

The crankshaft still has a dowel pin. I used the flywheel in the replacement 3.9 which was set up for an auto tranny.

Block has correct front cover, distributor drive and presumably a 3.9 cam shaft. All the lifters are still in place in the block and the crank shaft pulley is still installed and was in line with other pulleys for the serpentine belt. Oil pan and heads are off, otherwise still together.
These parts are for sale if anyone is interested. Located in South Carolina. I would like to make space in my garage.

Steve