Engine is comin out. Rebuild or upgrade?

[Danus]

Hi guys I have a 98 3.9 v8 disco. I've got some over
heating problems. Also just did a rear main. Would like
some advice weather to rebuild the 3.9, get a 4.4 or4.6, or
do a Holden 304 conversion. I want it to be super reliable
and on a bit of a budget if possible. I'm running 35s, 5inch lift,
and twin air lockers. Cheers

[presto]

4.6 I reckon. No real technical knowledge or basis behind it apart from personal preference. And I feel like having an opinion on something because I'm bored
Not a fan of the 304, reckon the Rover motors sound better plus the 4.6 should bolt straight up so less mucking about. As for reliability, I hear a lot about cylinder liners slipping in the Rover motors but I've never had it happen to me (luck?) If you were going to put something other than Rover in it then Chev would be the best bet (in my not too educated opinion). Probably pick up a crate motor for near the same price as a full rebuild of the 3.9 but then there's the adaptors and everything you'd have to worry about and the price goes up. So there's a totally round-about and probably not too informative ramble for you to feast your eyes on Atleast you kept me entertained for ten minutes before I nap, so thank YOU Danus.

[TRobbo]

budget rules out engine conversion as they always cost $$$.

rebuilding with a 4.6 block isn't cheap either but everything will bolt straight up and look standard to mr plod. The 4.6's have been known to slip liners so you have to make sure your cooling system is top notch. More HP and torque although to get them going really well requires an aftermarket ecm

3.9 is certainly the cheapest of all options. You know what those engines go like.

With any rebuild it worth doing over your cooling system, replacing all belts & hoses and seeing what your electrics under the bonnet are like to ensure reliability.

[starky]

if you want cheap i suggest you rebuild your engine with a aftermarket cam and maybe some porting this will both increase power and effiency.

i would steer away from the 304 only because it is cast iorn and would ingrease the weight over your steering axle.

i'm troying with the idea of the 4.6 into my disco but when you cost in computer exhaust adaptors and all the other BS you will not get any change out of 10K

[Danus]

Thanks heaps guys for the info. I got told the radiators need to be
pulled out and properly cleaned every three years so that should
fix my heat prob. And there's a possibility that iv only done a sump
gaskit, so I'll try that first. The engines only done half it's life expendency
so it shouldn't need a rebuild either. I'll keep you all posted and see you
all out on the tracks soon. Cheers

[TRobbo]

if you want cheap i suggest you rebuild your engine with a aftermarket cam and maybe some porting this will both increase power and effiency.

i would steer away from the 304 only because it is cast iorn and would ingrease the weight over your steering axle.

i'm troying with the idea of the 4.6 into my disco but when you cost in computer exhaust adaptors and all the other BS you will not get any change out of 10K

If you swap your 3.5 or 3.9 block for a 4.6 block and retain all your original bolt on accessories you minimise cost.
Original exhaust should be capable of reuse. If you are efi then you need to reprogram your ecu. There are better ways of controlling your efi but then you are down a couple of grand with a motec or similiar.
Paying someone to do the job will set you back about 10K assuming you replace water pump, all hoses, and recor the radiator. A brand new 4.6 short motor is around 4k.

[starky]

if you want cheap i suggest you rebuild your engine with a aftermarket cam and maybe some porting this will both increase power and effiency.

i would steer away from the 304 only because it is cast iorn and would ingrease the weight over your steering axle.

i'm troying with the idea of the 4.6 into my disco but when you cost in computer exhaust adaptors and all the other BS you will not get any change out of 10K

If you swap your 3.5 or 3.9 block for a 4.6 block and retain all your original bolt on accessories you minimise cost.
Original exhaust should be capable of reuse. If you are efi then you need to reprogram your ecu. There are better ways of controlling your efi but then you are down a couple of grand with a motec or similiar.
Paying someone to do the job will set you back about 10K assuming you replace water pump, all hoses, and recor the radiator. A brand new 4.6 short motor is around 4k.

are you sating exhaustv and intake manifolds alt brackets ect have the same bolt configuration and are all inter changable?

[PacMan]

They have even the same heads like a late 3.5 carby so far i know. - Only got that told!