Jump to content
George44

4.6L V8 P38 engine into a Defender 90 HELP

Recommended Posts

Hi All,

Was looking for some advice... I recently took a gamble and purchased a cheap 4.6L V8 petrol engine which I believe came from a P38 Rangey. The question is will it go in my 1990 defender 90 and how much modification will be required. I also have no idea about gearboxes etc. My defender currently has a LT77 gearbox with a 200tdi disco engine in but im also concerned about propshaft sizes whether a standard one will fit or not. I basically need an exact list of all the items I need. Another obstacle I have is I have no idea if the engine actually runs or not and as I don't own/work in a garge I am not sure how I can find this out. As you can probably tell im a bit of a novice at this but there is only one way to learn! Any ideas/advice given would be greatly appreciated.

Share this post


Link to post
Share on other sites

Should answer a few of your questions. If you keep the transfer box in the same place you won't need to change the props. Gearbox is specific to the engine so you need a v8 r380 or auto box.

my build thread from 200tdi to 3.9. Should answer a few questions you have.

http://forums.lr4x4.com/index.php?showtopic=93802&page=1

Share this post


Link to post
Share on other sites

A quick way to assess the state of a V8 is whip the inlet manifold and rocker covers off. It'll let you have a look at cam wear and the general colour/state inside which can tell you a lot about how it's been treated and what you can expect from it. Heads off if you want to check for the dreaded liner slip/bore crack they can suffer from.

Inlet and rocker covers are easy and replacement gaskets are cheap, so that's not a bad place to start. Whip the sump off and see what's luring in the bottom too.

Some good pics and tips for assessing the state of a V8 buried here: http://www.v8engines.com/engine-4.htm

Worth bearing in mind that they want to sell you parts, though, so don't let it panic you!

Do you have the whole injection system with loom, ecu, fuel pipes, fuel pump etc? Always about a hundred little bits you end up needing when doing a conversion...

Share this post


Link to post
Share on other sites

You've dropped yourself in the deep end there - a P38 lump will be fuel injected & electronic ignition so without an ECU you have no way of making it run. There are a few options on that front but I would really really recommend a Megasquirt kit from Nigel (www.megasquirt-v8.co.uk) it going to be the best way of running it. Otherwise you'd have to convert the engine to old-style (3.5 / 3.9) front end+sump with all the old ancillaries to regain a distributor, then bolt carbs to it - and there's not really any brilliant options for carbs on a 4.6.

Gearbox wise it depends what you've got right now and what you want - if your 90 is a V8 it will bolt straight in. If it's not, you could bite the bullet and buy a V8 gearbox and it all becomes a standard V8 90 parts-bin job (std. exhaust, props, etc.) or you could use a Disco/RR gearbox and convert it (gearsticks in wrong place, there's a kit for that now I think) but then you've got a more bitsa kinda end result. Or you could use a 4cyl-to-V8 adapter ring onto your existing gearbox, suffer some farting about with clutch & exhaust etc...

You may/probably need to install a remote oil filter kit to avoid the filter clouting the front axle. You'll need to bypass (NOT blank) the 4.6's oil cooler connections (or fit an oil cooler), blank off the crank position sensor hole (opposite side to the starter motor), adapt the P38's power steering pipes to fit, re-plumb the heater, chop the air-con compressor bracket down, relocate the air filter, weld in a lambda sensor bung, fit high-pressure fuel lines & filter, electric cooling fans, buy a new throttle cable, and a load of other little bits I can't remember off the top of my head.

Buying Nige's full kit will cost you a packet but will include a load of little bits, like a drop-in replacement high-pressure fuel pump. Likewise, buying the "right" gearbox may cost more but makes life easier all down the line.

Our 4.6 V8 Megasquirt Defender install covers all of this: http://forums.lr4x4.com/index.php?showtopic=89916&page=7#entry827152

Doug's already posted his I see, that may be a good one to start with if you're converting a non-V8 Defender as we had it relatively easy!

  • Like 1

Share this post


Link to post
Share on other sites

I have a hotwire ecu with a rpi tornado chip fuelled for a 4.6 so that would be a simple way and cheaper option for you. make a offer on the ecu, I might even have a hot wire loom too if your stuck for one.

AL

Share this post


Link to post
Share on other sites

A hotwire ECU would need a distributor, so the front end & sump would need to be converted to early type.

Share this post


Link to post
Share on other sites

.... and if you are going to do that, it will be cheaper to Megasquirt it, and gain all the benefits that go with that!

  • Like 1

Share this post


Link to post
Share on other sites

Failing that, I have a 3.9 front end with a dizzy I would be happy to swap

Maybe he can shorten the crossbolt crankshaft with an angle grinder to suit your 3,9 front end... :-)

I would always go for Megasquirt.. or if you want it to keep it as simple as possible Megajolt ignition and a Holley carb ;-)

Share this post


Link to post
Share on other sites

Or for a more fuel efficient way of fuelling the engine without an ecu, a bucket with eight holes drilled in the bottom and sat on top of the inlet manifold...

Share this post


Link to post
Share on other sites

Maybe he can shorten the crossbolt crankshaft with an angle grinder to suit your 3,9 front end... :-)

Ah, diddnt think that was the case, thought it was all the same(ish) with a longer stroke crank.

Share this post


Link to post
Share on other sites

Ah, diddnt think that was the case, thought it was all the same(ish) with a longer stroke crank.

You can fit the 3.9 front end on a 4.6, you just need a spacer for the front pulley.

20151119_110800.jpg

4.6 crossbolted block with 3.9 RRC front end

Share this post


Link to post
Share on other sites

If you're in that deep, a camshaft change is the least of your worries :P:)

Just for lack of hassle I would MS it -I value my time...

  • Like 1

Share this post


Link to post
Share on other sites

Ah yes, I forgot I swapped cams the same time I reverted to the P38 front end.

In the name of all that's holy, don't fit a 4brl carb, at least SU's have the advantage of being relatively simple and reliable (as clockwork goes).

Share this post


Link to post
Share on other sites

If you're in that deep, a camshaft change is the least of your worries :P:)

Just for lack of hassle I would MS it -I value my time...

Not if you have put a dissy timing cover on a 4.6.

Share this post


Link to post
Share on other sites

Sorry, not clear what you mean Garry?

Share this post


Link to post
Share on other sites

You can fit the 3.9 front end on a 4.6, you just need a spacer for the front pulley.

20151119_110800.jpg

4.6 crossbolted block with 3.9 RRC front end

Allright! There is always a way! :-)

But I wouldnt fancy to go back to the ancient oilpump/distributor setup though...

Share this post


Link to post
Share on other sites

best way imho is megasquirt it, i did the same with a 4.0 gems into my 90 that was a 200tdi, fridge has basicly listed what needs to be done, i bolted a disco v8 lt77s with adapter to use defender gearchange to the original lt230( gearstick in correct pos), then bolted in engine and welded in new engine mounts, rest is all nuts and bolts work, megasquirt and it will go like stink

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy