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Series 3 109: 3.9 V8, LT85 + LT230 write-up

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Hi everyone!

First post here :) I'm in the throes of completing my Series3 V8 conversion and looking for a place to document it. Hoping it's welcome here, but just wanted to check. I have tons of photos (which are currently uploading) and a load of knowledge I'm keen to share as most was difficult to hunt down.

Key project points are (over and above the usual Series V8 conversion):

3.9 serpentine engine running twin Stromberg carbs. Mallory dizzy with electronic points. Couldn't bring myself to put injection into a Series...

LT85 gearbox plus LT230 transfer box converted to selectable 4WD. No metal coleslaw if heavy with the right foot or towing.

Existing engine and gearbox mounting points are used. Also mounted slightly higher (defender style) to aid front axle and prop clearance.

Footwells not modified. Engine mounted further forwards than usually seen in most V8 coversions.

Custom copper radiator mounted inside a slightly modified Series front panel.

Smiths RVC rev counter inside Jaeger housing added in place of right hand instrument cluster. Custom electronic circuit created to drive this.

Custom transmission tunnel to fit the huge gearbox.

Stainless side-exit exhaust.

Smiths/VDO voltage, fuel, oil temp, water temp and oil pressure instruments added to centre dash.

Defender heater, plus auxiliary heater in the cabin between the seats

Eberspacher coolant pre-heater.

Slim-line bonnet catch created, which looks stock, but fits into a 1/2" gap above the radiator.

Load of other little bits and pieces that have been engineered (or re-engineered) along the way!

Most of it is finished, apart from the extra heater and Eberspacher. She's now road legal, driving very nicely and making a beautiful noise that makes me grin like a Cheshire cat...

I'll do the write up in little chunks, but here are the pics as they are now: http://landyv8.imgur.com/all/

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Pics should now be in the correct album and public, so you can have a browse around. I'll do the write up in chunks as there's a lot to cover! Will start shortly.

Plenty of pics if you want to go and have a nose at the catch before I get to writing that bit up :)

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Thanks for the warm welcome :) taking a little while for moderated posts to be approved.

So, before I begin, a little history: I bought Ermintrude the 109 in 2002 as a bone stock 2.25 petrol, and for several years she was used as such. Eventually the petrol hungry dog of an engine totally gave up (I think maybe camshaft wear), and I decided to go turbo diesel after a little research. 200tdi blocks were big money back then and I managed to pick up a Perkins Prima adapter kit and engine locally for not very much. Axles, gearbox, overdrive, steering all came off for overhaul and the brakes got an upgrade to 3" front drums from a 6 pot that I just happened to have lying around, plus a vacuum assisted split circuit master cylinder. She drives and stops really well, I have to say! When everything is in tip-top condition, the Series is not a bad drive.

In went the little diesel with a bargain recon head I picked up, though I had some reservations about bore wear. Was advised (badly) "it'll be fine", and after several years got a little tired itself. I bought a 200tdi, which by that time had come down in price, but after some musing sat idle on holiday a quick look on Ebay located a 3.9 V8 locally. Having had a 3.5 88 previously, I decided to take the plunge. Went to see it running in the vehcile, then stripped it out that afternoon with all the bits I thought I'd need. Off went the diesels to everyone's favourite auction site.... This takes us up to September last year.

Much research, head scratching and deliberating left me with the feeling that I wanted to run the engine on carbs (injection seems so wrong in a 1973 vehicle) with a stronger gearbox. Short LT77, or the mighty LT85? Well, I went with the LT85 as it seemed to suit the Series' agricultural nature and wouldn't be too much longer than the 77 once an adapter plate had been to the mix. I sourced a few boxes and ended up with one split case and two solid case LT85's (don't ask). Initial measurements were encouraging enough to proceed, so out came the series box as well as the little diesel.

That's the vehicle... Me? I'm 34 years old, have been messing around with cars ever since I was old enough and have owned Series Land Rover's for almost as long as I've been able to drive. I used to work part time doing engine management installs for drift and drag racing cars, so I know my way around the more modern stuff as well. Engineering knowledge comes from years of tinkering with cars and restoring steam locomotives (another passion of mine).

Next installment I'll walk through (with linked pictures) removing the old powertrain and positioning the new one. It's at this point one looks at the project and thinks "ah hell, what have I started". There is literally so much to do, which is why it's taken the best part of a year researching, fitting and fettling.... Stay tuned!

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Well, first job on the list was to get stuff mobile. I have to work outdoors, and lug stuff around uneven surfaces, so using an engine stand with tiny metal wheels is not really an options. Using the castor wheels from an old trolley, some cheap pneumatic wheels from ebay and an old engine stand, I managed to know this up:


Which got things moving. Next job, having unloaded the V8, was to take the plunge and remove the old diesel. An easy job with all the room, everything still being freshly bolted together in recent times, and my obsession with greasing bolts for easy future removal. And out she comes:


Next is the seat box and floor with its many millions of bolts, to enable the series box to be removed through the door:


You can see we were expecting rain that day....


At this point, I decided it was about time to fit the Ashcroft part time 4WD conversion kit to the LT230. Remove the front housing:


This requires taking the front output flange off, disconnecting the diff lock and range selector linkages and removing the botls with 10mm heads, noting their locations: Six bolts actually hold the centre diff together, which IIRC were a bit of a pain to remove due to clearances with the bolt heads:


Here you can see the cross pins and gears that need removing:


These are the bits that come in the Ashcroft part time 4WD kit:


Pressing the front support bearing into the diff housing:


Replacing the cross pins:


Fitting the permanent drive for the rear output:


You have to mess about with the shims a little to get the backlash right, but it goes back together like this:


Reassembly is the reverse of removal. Here it is slung in the vehicle behind the engine which is on stands:


Engine positioning. The viscous fan would later be removed:


Having to it lined up where I wanted, I started on gearbox mounts. Primary considerations were: Enough clearance to remove engine without removing gearbox mounts and moving everything. Exhaust downpipes clear the engine mount points on the chassis. No grinding out massive chunks of the bulkhead. No messing around moving engine mount points. Gear stick and transfer in correct position. Clearance for radiator. Clearance of front prop to bellhousing crossmember. Bonnet clearance. Those things don't photo well, but making engine mounts does:



These are made with the original Series mounts, heavily modified. You can see now that the box fits, but if you ever need to service the transmission brake you're in trouble. the choice was either rig up a disk brake conversion, move the crossmember slightly, or make it removable:


The prop height and positions largely dictated placement of the gearbox, so once that was done, I set the engine at its correct height and set about making engine mounts:



These were later stiffened with extra ribs before final fitment.

While that was ongoing, I set about getting the Stromberg carbs rebuilt and getting the manifold in shape:


A little air die grinder and some carbide burrs made short work or port matching to the precision cast (by comparison) injection heads. You can see how poor the carb manifild casting is:


The fruits of much labour:


After that, attention turned to the distributor. While looking for a decent dizzy (this is a crossover serpentine which still has one), I stumbled across a bargain Mallory on eBay. The guy said it was knackered, but I took a chance and found all that was wrong was some wear to the vacuum advance connecting pin. Easily rectified with a few minute on the lathe:




In went an electronic conversion kit, and it was ready to go in:


After completing the manifold, carbs got rebuilt and fitted on the bench:


Before finally fitting the engine, the mounts were re-enforced and welded up:



Flywheel got tidied and fitted:


Clutch going on with home made centring tool:


With as much as I could fitted up, I dropped the engine in. Clearance was a worry, as I hadn't tried getting the engine in with the clutch on up to this point:


In it goes with loads of room to spare;


Getting the splines aligned can be tricky:


But in this case, a little joggle of the output flange with the box in fifth and it slid together of its own accord:


I'll leave it at that for now. More coming soon!

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Great write-up so far, I have a thing for engine swaps, I can't explain it, but it makes me all fuzzy inside, even when its just swapping one 2,25 for another :D I like your choice in gearbox, and engine for that matter, really the best of both worlds. Except for poor factory fitted bearings, the LT85 is darn near as reliable as the LT95 but with the obvious benefit of a fifth gear. And the 3,9 with Strombergs, as simple as a petrol engine gets really and plenty of oomph for a Series. Keep up the good work :i-m_so_happy: Oh and get a better welder ;)

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Hehe, I know just what you mean. and thank you! It does drive nicely with that setup. And easy drive with all that torque and goes effortlessly. I'm glad I upgraded the brakes! I've got a bit of a challenge getting the needles right - it clearly wants a lot more fuel than the 3.5 the carbs were originally jetted for. OK up to about mid range in the revs (rev counter still to come), then power picks up and I can see it going lean (I have a wideband lambda temporarily installed). Shame about the bearings as you say, but I do like the 85.

I have a MIG too, which I use a lot, but I much prefer the arc for doing heavy stuff. Also blasts through less than pristine metal without spitting, popping and sitting on top, which is helpful on jobs like that. I have my eyes on a nice TIG set, though...

Love your work, by the way! I remember reading your PTO article with fascination some time ago. Lovely engineering :)

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A few notes on bits and pieces that don't necessarily have pictures...

The clutch is a standard LR part. Make sure you get the Land Rover flywheel rather than an SD1 as they are different widths. The clutch slave cylinders in the Series and 90/110 have different threads. I bolted the Series slave cylinder up to the LT85 without an issue - I couldn't be bothered to mess about with adapters.

The carb manifold fits on the injection V8 just fine, though you'll need an extra one of the long bolts. Coolant hoses are differently layed out, there being no connections on the back of the water pump. I blanked the outlet at the front of the carb manifold and added a rear connection for the heater. Return from the heater is tee'd into the radiator bottom hose, leaving the pipe on the bottom of the carb manifold redundant. I should have removed it.

Throttle cable is a diesel Defender unit, I believe. I had to weld a little lever to the accelerator shaft next to the pedal and drill a hole to poke it through the bulkhead. Nothing hard here, but I'm lacking a picture, sadly.

The radiator top hose is a chopped and joined Disco one.

The battery tray sits on the old (and now unused) throttle linkage cross shaft. It's held in place at the top by a couple of brackets welded to the bulkhead.

The standard Series choke cable is too short. A generic one doesn't fit in the hole. I made one up by carefully removing the end of the series cable and epoxying in a longer bit of bowden. Nothing hard here.

Expansion tank is from the Disco. large hose at the bottom tees into the bottom rad hose along with the heater return. Little air escape pope from the top of the carb manifold goes to one of the connections that used to go to the injection manifold doing a similar job. Coolant flow in the Rover V8 is as follows: The water pump intakes water through its hose connections and exhausts through the front housing into the block. Coolant then circulates through the block cooling the cylinders, then enters the cylinder heads via ports in head to block joint sealed by the head gasket. Coolant exits the manifold via the heater connections, thermostat bypass (if fitted) and/or via the thermostat to the radiator top hose. it seems important to let a certain amount of coolant bypass the thermostat when closed, which can either be achieved with a bypass hose connection fitted to some thermostat housings, or via a heater connection that does NOT have a valve which can be close to prevent circulation. Preventing any circulation seems to lead to heat cycling.

I've (for the moment) blanked off the oil cooler hoses. The oil cooler on the serpentine Rover V8 just taps into the high pressure side of the pump and robs some of the flow. Return is back to the sump via the bottom of the front housing. Makes no difference to the oil pressure that I can see.

Remote filter is a Mocol unit mounted to the inside of the drivers side wing. Nothing special here.

All I can think of for now.

The alternator wiring is pretty easy, just requiring clipping off the series connector and crimping on some ring terminals. I'll get back with colours...

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I had a 3.9 with Strombergs and absolutely loved it too. A great combination.

Just a word about your leanness - it's not simply the needle you use but also the absolute jet size. At large throttle openings and with the revs up, a 3.9 shifts more air than a 3.5 so needs a correspondingly larger jet. At smaller openings, the needle position regulates mixture (and is easy to set) but at large throttle openings the jet takes over. Find bigger jets or, if you are brave and capable, open the jets out slightly! In my case, I was more interested in the torque and actually restricted my throttle movement. It didn't stop the car leaping forward when overtaking from 60 m.p.h. though. Cue large grin...

I, too found the manifold a bolt-on swap but went one further and put the older timing cover/front end on (as it sat the fan higher in my Stage One V8). Contrary to common wisdom on this forum about crank lengths, that was a bolt-on swap as well, though I did have to open up a hole on the alternator bracket to match a larger thread in the block.

I also used a Mallory distributor on my last Range Rover (3.5 e.f.i.). In that case, it was an optical one and had the wonderful characteristic of working when fully submerged! Simply brilliant.

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Thanks, that's a helpful nudge in the right direction. There aren't any bigger jets that I can find - .100" being the biggest - but reaming them larger had occurred as a potential solution. Running B1FH needles, for Future reference.

Interesting info on the cover swap too, thank you. A waterproof V8? What witchcraft is this??

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A waterproof V8? What witchcraft is this??

I've had two that seemed to shrug off vast amounts of water. The Range Rover with the Mallory had water over the bonnet five times in one trip and never missed a beat. Literally. Even the carpets stayed dry! Modern plug and dizzy caps and make sure the coil has sufficient protection. A piece of plywood in front of the radiator for deep crossings surely helps.

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Sure, I'll take a few extra pics. Only a little section of either side of the rear of the front panel needed cutting and the rad sits directly on top of the cross member, which places it 2" back from the grille. With the viscous fan removed, the nose of the water pump sits 2" behind the radiator, which is enough to squeeze the kenlowe fan blades between. It's close, but neat. Lots more pics in that imgur album that haven't yet been linked from here.

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  • 2 weeks later...

OK, time for another instalment... This on is slightly out of order, as I want to get it all down while it's still fresh in my mind.

I finally got the fueling right today. I could get things right at idle, but would go quite lean approaching higher loads and engine speeds. So thankful I have my wideband setup! After much research, thinking, calculating and messing with timing, jets and metering needles, I've finally arrived at a solution.

First up, we have ignition advance. Stock setup for the Strombergs I've got would have been the arrangement for duel advance/retard vacuum setup on the distributor. Advance connected to ported vacuum at the top of the carb, retard connected to the manifold vacuum under the carb. I'm running a Mallory distributor with only once connection, but which one to choose. The obvious choice is ported vacuum at the top of the carb. This is taken from just IN FRONT of the throttle plate, so no vaccum at idle. Which, I'll be honest, I found curious. Static timing for the V8 is 6 degrees before top dead centre (quoted with the vacuum hose disconnected), which makes for a slightly rough, HOT idle. Is this right? The engine seems much more comfortable with more idle advance than that. Smoother, more responsive and cooler running. My experience with fuel injection systems told me that you run more advance at high vacuum and leaner mixtures, so this made no sense. I'm not the type to take anything at face value, or indeed leave well alone, so off I went researching.... a lot of FUD, glibly stated opinion with nothing to back it up, and I found this: post by Steve D, 12th march 2006 and this. OK, so looks like ported vacuum is out and I should definitely be using the manifold vacuum connection.

Now, after some reading, I found that the Mallory dizzy is adjustable! But how? I couldn't see any way of adjusting the vacuum canister and I hadn't even looked properly at the bob weight and springs. Off it came and into the workshop. A little reading revealed that the vacuum advance is adjustable by sticking an Allen key into the hose connection and the total centrifugal advance can be set via a stop inside.

With that established and everything check for free adjustment, it went back on the vehicle. Started up, timing set and checked. Sure enough, with the manifold vacuum connection, the vac advance does its job and activates at idle. As vacuum drops, the timing retards back to the base curve set by the static timing plus mechanical advance. Perfect! But the fuel was still way off. I'd fiddled with this a little, but to no great satisfaction - she still went lean at higher loads/revs. With the timing correct, it had to be the carbs! Setting the timing is important before setting the fueling up, as the two are related. Retarded timing will show rich, advanced timing will be leaner. Now, the Stromberg carbs are constant depression type with a tapered needle which moves inside the jet to vary the orifice size - exactly the same as SU carbs. I've got late model 4104 CDSE carbs meant for some sort of Land Rover 3.5 V8. As I understand it, a lot of the carb LR V8's were de-tuned with a restrictor, and in any case, the EFI heads in the 3.9 have far better precision ports that the early types (plus my ported carb manifold), so better flow is to be expected. 100 thou jets are fitted to all this size of carbs, and most of the needles are roughly the same profile. I've got B1FH and B1EJ needles (I bought a few sets of spares carbs just to see what different needles I could get). Sadly, there's no online resource to look up the needle profiles online, but Burlen do a little book which gives them. Stromberg needles are measured across the diameter at 13 intervals 1/8 inch apart from the top of the tapered section to the bottom. Looking at the book having observed where the lean condition started in relation to the needle movement, I decided the B1FN profile would be a good place to go for trying to get the fuel right for my 3.9 engine. the only thing is, a set of a needles is a lot of money and would take a while to arrive. As it turns out, the B1FN and B1EJ needles are very similar and made of brass. The B1EJ needles went in the pillar drill set as quick as I could make it go and I attacked them with some wet and dry paper to thin them down to the B1FN profile, which is smaller towards the narrow end. This was a surprisingly quick and easy process taking a bit of material off, checking with the micrometer and repeating as required. Final finish to polish with some fine grade and we were good to go. Swapping needles in the Strombergs is as easy as removing the top cover, taking the plunger out, using the adjustment tool to unwind the needle carrier and unscrewing the retaining screw at the side. refit is reverse of removal. With the reprofiled needles, she idles at 13.7 AFR, climbing to 12.5 under load and high speed. A final tweak of the timing and she pulls like an absolute train! I saved myself a small fortune by not spending out on needles, but for anyone trying this in the future that's unwilling to modify their needles, for a 3.9 litre Rover V8, the B1FN needles ought to be a good starting point with the Stromberg carburettors.

A little side note: Don't be afraid to modify the jets. If you're a little lean across the range and have run out of needles adjustment, taking the jets out a thou or so is an easy fix. Be warned, though: each thousandth of an inch = an increase of roughly .25 AFR (in my limited experience). Be very, very careful doing this, but it is a powerful tool. Also, changing the jet height can get you out of trouble. Jets in these carbs can be adjusted, although it needs some force. I made a tool that fits into the top and seats neatly over the jet I could hammer gently. Pushing the jets down is similar to moving the needles up, though within limits. I'd advise against moving more than 10 thou or so, but it is a useful tool if you've just run out of needle adjustment and need a quick fix.

Bob weights in the Mallory dizzy:


You can see the torx advance stop adjustment screws with the stops next to them:




How to adjust the Mallory vacuum advance canister:


Marking a Stromberg needle up for measurement:


Measuring the diameter with a micrometer:


Old profile on the right, new on the left:


Two reprofiled needles ready to be refitted:


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That's fantastic, when you get into it properly and it works out. Often it doesn't, with me, because there's a tiny something I missed.

I know exactly what you mean by "pulls like an absolute train". I used to love that! Well done on a nicely sorted job and thanks for giving such good info.

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Thanks all for such an enthusiastic response! It did feel like I was delving into the dark arts, but having come out the other side, I feel able to tackle just about anything.

Believe me, I missed a lot of bits along the way, deep! This represents a couple of months worth of tweaking, testing, measuring, researching and repeating as required. The hallelujah moment was getting the timing nailed properly. Once that was established, setting the fuel up was quite easy. Once I had all the knowledge, of course!

It positively hustles and runs much cooler - surprisingly so. Makes me beam like a Cheshire cat when I drive her, I'm absolutely loving it. Oh, and pops and bangs most satisfyingly when off throttle at higher revs. Cheeky and completely unnecessary, but mostly to do with the throttle plates lacking the anti after burn valves that most people solder shut anyway.

AFR's - averaged

Idle: 15:1

Cruise: 14.5:1

Full throttle: 13:1 (12:1 at lower revs)

I seem to have hit the magic needle profile right off the bat. Very pleased.

I'll try and gather some economy figures as I go along. More on the conversion to follow.

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This is absolutely superb info! I could probably use this on my Stromberg carb'ed 3,5 SD1 with 10,5:1 compression, sounds to me like those needles would fit the bill just perfectly. Are you running a free'er flowing air cleaner with this setup? And could you be persuaded to post up those measurement on the needle after modding? :i-m_so_happy:

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Thanks, I hope it proves to be of use to someone! Of course, here you go:


Running twin K&N filters, yes. I would have liked to have gone with a proper air box and standard filter as it's a bit more suitable for off road, but space didn't allow because of the battery location. I'll revisit this at some point, though.

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Oh, just a quick not on the measurements above: I didn't bother to measure to a tenth of a thou! Figures quoted for the stock needles (B1FH and B1FN) are from the needle chart by Burlen. I'd be interested to hear how you get on!

I had a bit of an issue today as she suddenly went really rich after a full throttle blast through a few gears. Had a hunch that the needle had slipped its delrin washer and moved up with the spring. Still ran but two points richer and didn't want to start warm. Got back home, took pot luck on which carb and sure enough, the washer in the RH had popped off allowing the spring to push the needle up half an inch! This wouldn't normally be quite so bad, except the Land Rover needle holders have a little piece of the wall of the holder peened in over the top of the needle, rather than miniature rollpins you seem to get on other models. The peened bits are missing on these holders.

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Thank you very much! Will try it sometime over the winter, and let you know how it turns out :) Apparently there's quite a lot of restriction in the stock RRC airfilter box/ element because when you remove them the engine runs very lean. I just never really liked those boxes, they are so flimsy, hard to seal properly for wading and always in the way when you have to adjust/check something on the throttle linkage. So hopefully the needle mod will see me able to live happily without it! :D

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