Thread: new 3.9 block

Well, I was thinking of building my own NAS-spec 110 wagon with a 4.6 engine, a Thor inlet manifold and a 14CUX ECU, but you've all got me so bloody nervous I think I'm going to rather consider a nice big GM 4.7HO engine and the Jeep gearbox/t-case combo running permanent AWD and with the automatic center difflock.

I mean, at least the GM 4.7HO puts out an unstressed 200kW and 448Nm. And gets better fuel economy than the 4.6 Rover V8.

No need to be nervous. A T hatted post 94 3.9 or 4.6 provides great bones for a light offroad power plant. The RV8's bore to stroke ratio when stroked to 4.6 or larger and with an appropriate cam and breathing.....the GM would probably come off second best in the stump pulling department.

Check out my country of residence.

To get a top-hatted short engine shipped to me from the UK would cost me on the top end of AU$1000, that's just the shipping.

Then I'd have to pay the full UK price, as well as import duties and taxes.

Probably not much change left from AU$10,000.

Originally Posted by jakeslouw

Check out my country of residence.

To get a top-hatted short engine shipped to me from the UK would cost me on the top end of AU$1000, that's just the shipping.

Then I'd have to pay the full UK price, as well as import duties and taxes.

Probably not much change left from AU$10,000.

Why would you need a top hat engine from the UK?
We have the mod done locally - is there a reason why you couldn't?

Nobody here does it. Not enough Rover V8s to make the tooling cost effective. And the old school engine remanufacturers have all but disappeared due to various issues such as government interference in labour.

I'll be looking at joining a group buy and maybe get a discount.

Originally Posted by Traco

TRS suggested to me that the porous block syndrome may be caused by localised hot spots developing in the motor. Nothing about head bolts.

Mark Adams believes there may be a correlation between cracking and the use of stretch bolts, but even he concedes nobody is absolutely certain what the cause, or combination of causes, is.

The only thing agreed on is that the only 100% guaranteed solution to the problem is to fit flanged liners.

Like I said before some RV8 specialists in the UK are refusing to guarantee any non top hatted new LR / Coscast blocks due to instances of cracking occuring even on the latest castings.

TRS should know this - they may be just trying to offload old/new stock LR blocks which were all sold off when Coscast took over production.

I'm beginning to agree with the last comment given what I've now learnt. Pity if they are BSing customers given the thousands spent on re-powering my car which now owes me more than double what it is worth.

Their name will be toast if mine fails prematurely, ie, before we get rid of it So far TRS has stood by the faulty front cover that needed replacing because it would not make oil pressure soon enough...so hopefully they will stand by the engine too if something goes wrong. Stranger still given I was prepared to pay for a top hat 4.6....argh..

Okay, what If I send my 3.9 block to to get top hat lined, what would the cost be around? I would need new pistons etc? Has anyone done this rather than getting a new block?

Perhaps this would be better than getting the 8000km 3.9 high comp RV8 motor?

Very Interesting topic. I had my 3.5 V8 drop a liner after I bored it 20 thou, it lasted 20k before making knocking noises, this was back in 1986,and it was not overheated The fix for me was to have the standard 3.5 liners removed and 3.9 liners fitted(not tophat) and these were pressed home down to the ridge at the bottom of the block and then decked, with the head on there was no way they could move. The original liners were not all pressed down to this lip from manufacture,so its not just the 3.9s that had the issue. This motor has now done over 400k with holden 186 80thou pistons fitted. I have since sold the rangie but its still going today.
I have also had another 3.5 converted with 3.9 liners which is now in my current rangie, so for me its who does the conversion that matters, I know that Rovertech and purcell autos were the ones here in Perth that used
M & D auto engineering and rovertech still use them today.
Would I do it again ..yes with top hat liners..possibly but the standard liners are ok if done right..in my opinion of 33years of Range Rover ownership.
The cost back then to do all the machining was only $1100.00
Brad