Outer Limits 4x4 Board

I finally blew up the old 3.5 carby motor on the weekend. Put a conrod through the side of the block.

So now I need a new motor and while I am at it will put in an auto.

My first thought is I think the easiest, which is to put in a 3.9l EFI engine with ZF auto. It all a straight fit and will cost about $4000 for the lot.

First, are there any problems I should look for in the 3.9?

Second, any other recommendation?

I know someone will say 4.6 but money is the main concern at the moment. I was not expecting to have to replace the motor till next year and I don't want to spend anymore than $4k all up.

If you are willing to spend 4K on an old dunger then i dont think money is a problem !
I really dont think its worth the hassle to fit a 3.9 efi and the zf to what is a bush basher, i would just get a good short motor with a new cam and a little porting and leave it manual, auto's are good if you get one cheap enough but the efi part is asking for headaches, if you dont mind it being off the road for all of summer!

Main reason for the EFI is that I want MORE POWER! The 35" tyres suck a lot of power and I still think it is cheaper to put in a bigger engine than change the diff ratios. I am also sick of not having any idle on hills etc.

The auto will go in no matter what. For the sort of hills & rocks we do the auto is the way to go for sure, plus the clutch is also on the way out.

You wont get more powere necesserily with efi, but it will be smoother and more efficient, bigger cubes is the only way for more power, gearing would be a better option. toyo 4.3/4.5/4.88 conversion will give you rock crawling ability - look at Craigs with the 3.5 and 4.5 toyo centers.

A poke in the trading post found this...

Range Rover Vogue se 1989 4WD blue, 3.9ltr automatic, Needs a clean up but good nwc101 $4000ono call after 5pm (03)95890246 (0425)747861 beaumaris More

Just swap your tyres

The prophecy of David Danks may yet come true.. $$$$$

Tim

Have you driven a 3.9 auto lately - they are still a slug box. the 3.9 is unlikely to power your enthusiansm and your 35's comfortably - trust me!

with 4.11 rover gears you come back to about standard gearing when running 35's. I think a C&P is about $700.

*cough* 4.4 *cough*

Ok, Timbot, I had that Rangie all lined up but before I could go out & look at it today it was sold.

4.11 C&P is about $1400 supply only for pair. Will get it one day but not yet.

Have thought about Toyo centres but with maxi-drive lockers already in it is not economically viable.

As a bush basher only I can live with lower power but just wanted to comensate for the power I will lose putting in an auto, I thought a 3.9 would be the cheapest way to do this.

Maybe I should keep the carby's and get a 4.6l short motor for now?

Well, thats a decent option, which i was considering, but apparently the standard carbies tend to lean out over about 4,000 rpm (off the top of my head). Not a problem if you aren't going to rev the tits off it, I suppose.

Although, the cost of a 4.6 short is quite a bit, last time I checked?

The best and cheapest option is the 4.4 Leyland P76 engine. There getting harder to find, especially the good ones is the only drawback but most of your Rover V8 bits will fit.

I picked up a whole Rangie for a grand, used the engine and sold the rest off and made money out of it Best engine swap I have ever done, considering I swore that i wold never get, or have, a 4.4 Rangie. Guess I contrdicted myself once again

Just another option.

Trav

OK, you are all starting to turn me. I think I have decided to keep the manual....for now.
Also I will probably keep it on carby....for now.

So, who has the technical knowledge? What is the power difference between:

P76 4.4l carby v 3.9l carby v 3.9l efi???

I really like the idea of a 4.6 short motor but after ringing around they are all but impossible to get 2nd hand and the best I can do is $4k for a new one.

Let's here the opinions of all of you out there. What motor would you put in & why? Remember money is an issue!

well, what about a 4.0 short? don't know what they cost, but they MAY be cheaper than a 4.6... and I have heard whispers that the only difference between a 4.0 and a 4.6 is the crank - not sure of the truth here, but maybe a bored out 4.0 litre could be the go?

Reason for saying a bored 4.0 litre is the 4 bolt mains, for strength. If a 4.0 is still too expensive, you could bore a 3.9 out maybe?

Ok im currently doin a similar engine change. My 3.5 died and i bought a 3.9 short to replace it. While installing it we are putting in a better cam and maybe looking at some head work. Keeping standard manifold and carbies because they seem to go well enough off road and to keep costs down. Will be looking at about $2500- $3000 by the time its done!

Dunno what sort of power im going to get out of it but one thing i do know and that it is going to shit all over my Grimace 3.5!

Goodluck

Thanks, both of you.

So there is a difference between the 3.9 & 4.0 other than the efi system? I thought they were identical?

Steve, where did you get the 3.9 short? I was thinking if I went with a 3.9 I would get a reconditioned one as they are fairly cheap to begin with.

I have asked around, but 4.0 short motors seem as rare as 4.6.

All 4.0 litres have 4 bolt mains, as do 4.6s. Early HSE (P38) 4.0 litres have Lucas injection quite similar to 3.9s, but using coilpacks, and cam and crank sensors, couple of other pieces of electronic trickery. When the series two disco came out, all the V8s went to the Bosch injection (curvy intake manifolds), which encompasses 4.0 V8s as fitted to series II discos, which I believe is almost but not quite identical to 4.0 as fitted to P38 rangies, and then of course the 4.6 also went Bosch. Common for air flow meters to give up the ghost on Series 2s, but not common on P38s.... Not sure what the subtle difference is there, but anyway.

Point is, 3.9s are still 2 bolt mains, 4.0/4.6 are 4 bolt. Differences in timing cases and fuel/injection gear, also exhaust manifolds.

Keeping budget in mind... the 4.0 & 4.6 are both good engines given the 4 bolt mains but are designed for different purposes. the 4lt is a good highway motor, the 4.6 is better for off road with better low down torque. Both are probably out of the question due to cost.

A 3.9 will of course have more than your 3.5 and there are plenty off them around, so finding a good one at a reasonable choice should not be too hard.

The 4.4 P76 is a great engine for the rangie with loads of torque and would be my pick. Your problem will be finding a good one.

So all things considered you will probably be best off going for the 3.9. Keep the manual and spend the cash on your diff ratio's. Perhaps big steve can tell you where he got his bargain basement short motor from.

I have found a 4.6l short motor at a good price. Only problem is it has come out of a warranty job where they had a blocked radiator and the head either cracked or warped. I have been told the block is fine, is there any likely damage to it since it has overheated?

TuffRR wrote:*cough* 4.4 *cough*

awww the pain like it was yesterday......

Range Rover heads do not crack, or generall y warp enough to lose water.

4.6 sleeves shift, causing water to well up and into the combustion chamber.
a 4.6 need only be overheated once to be toast.
Do not touch, do not pass GO , do not open wallet.
regards Philip A

Philip A wrote:Range Rover heads do not crack, or generall y warp enough to lose water.

4.6 sleeves shift, causing water to well up and into the combustion chamber.
a 4.6 need only be overheated once to be toast.
Do not touch, do not pass GO , do not open wallet.
regards Philip A

I know few 4.6 ex warranty jobs, same as walker mentioned that are fine..... the blocks normaly dont screww up it's the over tighnting of the heads that caused most of the problems... but yes it's a gamble

OK, it's a gamble...........but I like it on the edge!

I bought the motor this arvo. At $2k it was too good to refuse. Had a good look over it, none of the pistons/linings were discolored and it does come from a "reputable" place. Well I hope they are, they have been around for a long while...Deacon Automotive.

Give me another few weeks to get everything sorted and I might get my head reconditioned before I put it back on. Then I can tell you if it was a good gamble or a bad one.

As for autos go, get a torqueflite 727 with a manual valve body. Easy to bolt up to any of the engines you might wanna put in it and it is strong as anything. Most Hemi drag cars use them. A m8 put one in with a modded 4.6 with a wolf 3d computer and he can churp the wheels on the road.

Nooooooo. They are strong for sure but old and pull too much power!

ZF 4 speed for sure.

walker wrote:Nooooooo. They are strong for sure but old and pull too much power!

ZF 4 speed for sure.

Very true on the auto... go the ZF but try and get a late model from a disco, beefed up cooler and lines.

Try LRA for prices on the engine rebuild, Andrew has a machine shop in his factory and builds a lot of rover engines and 4.6’s. He knows how to build em good!! He rebuilt the heads for my 3.9 to 4.6 spec with stronger spring’s valves etc in them for a good price, compared to what I was getting quoted anyway… my 3.9 goes very well for what it is and loves to rev!!!

Mick

btw 2k for a 4.6 isn't bad at all seeing they are getting hard to fine with out farked cylinders

With your 4.6 - firstly, good work on finding one, and good choice

Now, make sure you get your block pressure tested, to make sure it isn't leaking up next to the liners. If it is, get it resleeved in the cylinder/s it is leaking, and bobs your uncle. Been done by two of the guys I know, one has been running it for about a year and a half, and he gives it a lot of stick. The other one, well its been back on the road about a week, he had to do 3 cylinders in his block, but he did get it almost free......

I thought of pressur testing but I would not have thought this would pick up any small cracks. I was recommended to put some solution (can't remember it's name) into the coolant which will seal up any small small leaks if they are there.

G`day Adam

As mick sorta suggests you`ll need to work out what comp ratio you`ll end up with , which gasket types , if you want to take some metal off the heads , etc .

If you have heads prior to ERC 0216 you may want to replace them , only because the 4.6 will like the larger valves that come with ERC 0216 heads on .

All the best , peter .

I am trying to keep compression down at standard. I want a "chugga" off-roader not a race car. I have been told to use 3.9 head gasket as this is meant to hold the liners in better.

I'm sure that my heads will have the smaller valves but I have been told that it will run OK but I will just not get the full potential power of the motor. I am not too wirried about this as it is a 28 year old car only used for weekends and I think too much power will just start breaking things.

G`day Adam ,

The heads on your 77 should be ERC 0216 which have the same size valves as the haeds on the 4.6 .

Wasn`t suggesting a race engine just that higher rather than lower compression ratio is more efficient , better power , torque and economy .

Pressume you mean a tin 3.9 gasket , which is only a 3.9 gasket in a 3.9 same gasket can go in a 4.0 or 4.6 .

Ours has a 4.0 ltr 8.23:1 with composite gaskets and metal removed from the same heads as yours has around 10:1 ratio .

The 4.6 heads have around 28cc combustion chambers .
These 3.5 heads have up to 38cc combustion chambers .

The 3.9 tin gaskets are a little thicker than 3.5 tin .
The piston deck height on a 3.5 and 4.6 are different .

If your 4.6 is stamped 8.13:1 all i`m suggesting is if you don`t get close your ratio could be around 7:1 .

Anyway in the overall scheme it won`t really matter coz the 4.6 will have heaps more than the 3.5 and when your looking for more you`ll know where to find some , also matching ports and soldering in the carbs will give more .

When i did ours i wanted the most out of it i could easily get at the time , in the future it can be converted into a 4.6 by using crank rods pistons as these are the only differences between a 4.0 and 4.6 . Unlike the 3.9s which are a totally different engine to these two .

All the best , peter .

When I bought the motor, the guy at Deacon said to use 3.9 head shims rather than 4.6. By this does he mean the head gasket?