3.5 EFI reliability

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Frequent oil changes, are a must, change my oil and filter every 6 months, firstly because I am bored and secondly these old V8s hate ****ty dirty oil. Use an oil with a high zinc content and it definitely saves wear on the lifters and cam. Oh and invest in a decent radiator and a new water pump too, they hate to overheat.
I am running the two SU carb set up, and it runs pretty good once I sorted the air leak on one of the elbows and balanced them, the twin SU's are fine off road, don't seem to flood or have starvation issues, I would agree with Mr Evil that webber carbs are excellent too. What you will find is that most 3.5's are requiring rebuilds as they are long in the tooth now and if that oil has not been regularly changed certainly it will have cam wear and be down on power. I sourced two SDI engines that were removed from the cars in 1989, then stored in a barn until I got them last year, I have one striped down and it shows little piston/crank/ cam wear so I will send the heads off to be cleaned ported/ valve seats replaced for unleaded and start again with what should be a low mileage fresh engine.
 
Ok thanks for all the info, I am not very familiar with the V8's - have only experience with the tdi's. I guess you could say I am pretty new to this... Might just stay with the tdi for now then might go for a hybrid turbo or something too. I reckon I can get a fair few more ponies out of it yet. I originally wanted to just throw a TD5 in but after some research I found first of all a good one is f-ing £££££££ and they are a pain in the arse to convert into a tdi fender. Oh well. I am young and there is much time :)
 
There is no definite answer because we all have our own preferences, but I think the 3.9 V8 set up properly to run on LPG is a lovely engine. The block liner problems arise from the efi fuel mapping causing the engine to run weak when on a moderate throttle, which is overcome with an LPG set up. As has been mentioned, keep the oil clean, and the rad in good condition and they will run for ever.
 
Sheffield said:
There is no definite answer because we all have our own preferences, but I think the 3.9 V8 set up properly to run on LPG is a lovely engine. The block liner problems arise from the efi fuel mapping causing the engine to run weak when on a moderate throttle, which is overcome with an LPG set up. As has been mentioned, keep the oil clean, and the rad in good condition and they will run for ever.
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the block issue ariss because bores have an extra 200 thou removed to cater for 3.9 liners thus making block thin
 
I should say that you may well have problems finding somebody to read the 14CUX. It is not OBDII, and when I was having trouble my mechanic was reduced to trying to read the voltages on the connectors for things like Lambda sensors, as nobody within 100 miles had the old kit any more.

I got round it with this,
https://code.google.com/p/rovergauge/ and this.
HardwareInterface - libcomm14cux - Details of the hardware serial interface - Library for serial communications with the 14CUX engine management system - Google Project Hosting
 
The liner problem in V8's is quite interesting. It is mostly in the latter engines (p38's seem the worst) and what happened is that the jig used to align the casting tooling had become misaligned and consequently after the block had been bored the casting could be very thin on one side as can be seen in the pic below. then where the head bolt goes in the block could crack at the bottom of the hole, the crack would go through the block to behind the liner and then coolant could leak into the cylinder.
The other issue was that when boring the block the workers didn't always clean all the swarf out and when the steel liner was pressed in this swarf could become trapped between the liner and the lip at the bottom of the block. The top of the block was then decked ready for the head. In service the swarf could fall out and then the liner could slip down of become loose and rattle up and down in the block.





 
jamesmartin said:
head ports need notching, simple enough with a die grinder etc
Click to expand...

You don't even have to do that, but it does help with the spray pattern for the injectors. But seeing as you get head gaskets in a top end gasket set then personally I would do it.



D90mitch said:
EFI - Electronic Fuel Injection.. Converting would be a bit of a job. Would need an ECU too.
Click to expand...

That's a load of bollocks! :p If you get a complete injection system then all you need to do is swap the inlet manifolds over. Electrical connections to the injection wiring loom, high pressure fuel pump. Weekends work if you take it slowly.
 
D90mitch said:
You'd have thought when they started having the problems with the early 3.9 they'd have sorted it out for the 4.0 and 4.6!
Click to expand...

they did try , on early 3.9s the water pump favoured rhs of block and cracked bores were usually found on the lhs ,later 3.9s had redesigned water pumps feeding both banks ,though it didnt stop cracking
 
RPI used to claim that Land Rover had set the efi engines to run weak to give better fuel economy, and this could cause over heating leading to liner slippage. The suggestion made above that poor manufacturing was a significant factor is interesting and indicates that there were a number of related problems and is perhaps why not all engines were effected. Our 3.9 had a new short engine from LR following this problem, and the replacement engine, which ran on LPG, did well over 100,000 miles, gave no trouble and remained very clean inside. I still think it is a grand engine, and sounds lovely.
 
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