lo-fi

A more sensible approach with petrol is variable twin scroll (also sometimes called VGT): https://youtu.be/J06nj5-B_AE A little off topic, but a point of interest nonetheless. Turbo engines - particularly turbo diesel - have come a long way precicesly because of tech like VNT. Take the venerable Audi 1.9tdi, for example. Pre VNT, it was 80hp with a well chosen turbo (by this I mean something that doesn't take half the rev range to spool). Then the AFN comes along and you've got the same drivable, quick spoiling turbo, but better breathing at higher flow rates and 110bhp. Either twin scroll or VNT essentially give you variable A/R and increase the limits between which the turbo works efficiently. I have some experience with twin sequential turbos in the Supra and RX7. Nice idea, but far more complex than a single VNT, and I think you might struggle to get an efficient setup with two very tiny turbos for a 2.5 diesel anyway, packaging issues aside. Don't be scared of a little electronic wizardry here and there!

If you can feel axial play, it's too much. No quick fix I'm afraid, other than get it reconditioned, or grab a new core. I've rebuilt many myself - they really aren't complicated - but depends on your skill level and how brave you are knowing its likely to cause a lot of damage if it does go pop!

I've moved bits of chassis about with a high-lift jack, so I'm sure 10 will be fine. Any idea what buckled it?

Agreed on the argon mix, it's much nicer. Try http://www.hobbyweld.co.uk for cost effective gas. BOC and the like cost a fortune as a hobbyist. And practice, practice, practice. Get some scrap and go for it, you'll soon get a feel for it. One of the reactive Speedglass type welding masks is a godsend, even if it's £50 eBay cheapy. Finally, with mig welding, prep is everything. Get the rust off, get back to some solid metal and keep it clean. Stick welding you can blow through just about anything and the slag (fnarr) carries it away out of the weld pool. With mig, it'll pop, spit and protest if you're trying to weld rust, paint and grime and you'll end up cursing, covered in tiny burn holes and the welds will be 'orrible. Once you've got the hang of it, it's incredibly satisfying, though, and a skill I'd encourage anyone who likes working on their own landy to develop. I began teaching myself years ago, and I honestly have no idea how I'd get by without now. Good luck! And do keep a small fire extinguisher handy "just in case"

Check the cold start mechanism on the injector pump is working correctly: http://forums.lr4x4.com/index.php?showtopic=63051 Otherwise, I've had similar with an old perkins with very worn bores. It used to pump out white and blue smoke until you got a bit of heat into the rings, they expanded, closed the ring gaps, and the compression came up to something sensible. Was very unresponsive until warm. Take the oil filler cap off just after you start it from cold: If you get a big blast of air coming out, you've probably got the same problem.

I've just rebuilt two LT230's. Dead easy to work on, kits available from Ashcroft with excellent quality everything. A set of bearings pullers needed if you want to change them, but otherwise just a few spanners, torque wrench and hand tools to do a seal and gasket refresh. Measuring and setting bearing pre-load as per the manual requires a dial gauge, spring balance and fine torque wrench, but I agree with Vulcan that the shims are there to adjust for variations in casings, rather than the precision made bearings, so I'd be surprised if you found you needed different shims. Have a nose through the manual to get a better idea - you can find on Ashcroft's site in the section with the rebuild kits.

It is sounding like a resonance thing. No throttle plate, no overlap and short duration will create quite a pulse in the intake, and the defender must be an NVH engineers worst nightmare... Just to clarify, you can only feel air flowing out of the air box filtered side through a little bleed hole? The booming only happens at certain revs/load? You could rig up a simple manometer with some tube and a couple of clear bottles which should be sensitive enough to measure small changes. Maybe have a go with that and see how it relates to the booming sound?

I think someone posted this a while back: http://dmn.kuulalaakeri.org/vnt-lda/ Which looks to be going the right way about it. I suspect you could make a VNT work using a simple mechanical actuator, but I very much doubt you'd get the most of it.

A quick way to assess the state of a V8 is whip the inlet manifold and rocker covers off. It'll let you have a look at cam wear and the general colour/state inside which can tell you a lot about how it's been treated and what you can expect from it. Heads off if you want to check for the dreaded liner slip/bore crack they can suffer from. Inlet and rocker covers are easy and replacement gaskets are cheap, so that's not a bad place to start. Whip the sump off and see what's luring in the bottom too. Some good pics and tips for assessing the state of a V8 buried here: http://www.v8engines.com/engine-4.htm Worth bearing in mind that they want to sell you parts, though, so don't let it panic you! Do you have the whole injection system with loom, ecu, fuel pipes, fuel pump etc? Always about a hundred little bits you end up needing when doing a conversion...

Love this project, thank you so much for sharing Inverted bull horn at the front?

Thanks for the info, I'll have to get myself booked on a course this year Running lean often results in surging, spluttering and misfiring, so I'd be tempted to look at fueling before doing too much with the ignition. A wideband lambda is such a good diagnostic tool here, especially if you do bung a megasquirt in later

Good explanation here: http://www.v8engines.com/engine-4.htm under a section about 1/3rd of the way down called "Pre-96?, then this is your Head Gasket Problemsre-96?, then this is your Head Gasket" (and the pictures certainly tell a tale). Go for the ten bolt stud kit, and bung a few old ones in the outer rows, lightly torqued, to stop the crud getting in.

Congrats on passing the trailer test! Did you do a course first, and what was the test like if you don't mind me asking? It's something I need to do myself. Regarding the pot, as long as the resistance varies the correct way for the direction of rotation (this can be changed by swapping wires), the absolute resistance value shouldn't matter too much (within reason) - 100K is typical. If it physically fits, you ought to be able to make it work. I might have missed it, but we're talking about a 3 pin tps, yes?

I've got one sat in my workshop that hasn't been messed with, I'll go and take a look later. From memory, the choke is supposed to just knock the throttle open a little. If the throttle plate isn't closing properly, the cam won't hit the peg, and it will do nothing, though, so that's a good place to start checking. Have you just done an overhaul?

That's an interesting question. I mounted my LT230 high to avoid taking a chunk out of the crossmember for the front prop, but this required modifying the bulkhead and making a new tunnel. My crankshaft and gearbox mainshaft line is roughly 3" higher than standard series placement. My feeling is that the drop is about the same on the series and lt230 boxes, but interested in confirmation. Well done with your conversion!

It's not that it's unacceptable, it's just ridiculous. In the same fashion that people jump in and throw a curve ball like dry sumping in, somebody needs to step up and say "hey, wait a minute, just look up some specs before making an issue out of a problem that doesn't exist". Just trying to keep it sane, factual and on the straight and narrow, that's all. Look at it this way: VNT conversion kits exist for the 200tdi. You'd expect that those producing the kits have done the research and engineering to ensure that it will work correctly within specifications and won't ruin the engine it's installed on. To make sure, and so as not to rely on taking someone else's word for it, do your own by looking up some figures and studying what's been done successfully before jumping in at the deep end elsewhere.

Why on earth is this going off on a tangent with dry sumping?! And for the record, if set up correctly, dry sump is better for extreme angles. Instead of wild, uninformed speculation, let's maybe look up the 200 and 300 engines oil pressure specs to compare. I'm sure the oil pressure spec for the turbo will be available too. As for fussing about the big ends, I'll try and rake out my copy of Allen Allard's book on turbocharging. There's a good section on cylinder pressures, con rods and bearings. TL;DR: you're worrying about nothing.

Why the attitude, Hobbit? You've made some pretty glib statements and been called on them. Surely this is normal within what should be an informed discussion? I have to agree with Aragorn: By what mechanism does changing the fueling at the top end have to adversely affect the bottom? I also agree that head work is unlikely to yield much gain at low revs, which is what the OP is asking for. It's a diesel engine, which means very conservative lift duration and very little or no overlap; it's not ever going to flow particularly well without a turbo packing the air in. Port match and equalise flows if you're feeling fussy, but leave it there and spend the money elsewhere. Making sure compression is tip-top with fresh rings, valve guides and lapping as suggested is a good place to start before moving on to pushing more torques ( ) out of it, though. Otherwise you're into a lot of messing with the flow bench and dyno testing to check what you're doing is *actually* having a positive effect within the desired envelope - it's unlikely to be straightforward. Unless you can find someone that's done the work on that head design, has arrived at a good solution and has figures to back it, but I can't honestly see how any kind of porting could bring about the gains you'd find with a properly sized VNT turbo, which is why I'd be looking that direction. I notice there are various conversion kits available, though I'd be wary that the purely mechanical actuator actually gets best out of it compared to an electronic solution.

Has anyone actually tackled this successfully? I wouldn't mind a little challenge making a standalone vnt control ecu. Setting up a micro controller with a pressure sensor to drive a little solenoid using a PID control loop could be quite fun...

Very cool. Looks like you've just got room to get the handbrake drum off without resorting to extreme measures once it's all together. A mate of mind has a previously converted 88 with 77 and 230, but whoever put it together obviously didn't really feel that the handbrake shouldn't be a job that requires moving the entire drivetrain! Needless to say, MOT coming up, and the handbrake is totally fubar. I'll be following this with interest! What engine, by the way?

Hehe. Cheers! I always use pre-sensitized boards from RS - usually 100 x 160mm - laser printer acetate sheets, and software from http://www.freepcb.com/ just because it's simple. Most simple stuff can be made single layer with a little thought to the layout, so I tend to stick to that. The cheap fluorescent blacklight works a treat for exposure with a piece of glass on top to keep it all flat, then it's just a case of developing with whatever is recommended by the board manufacturer and etching. I usually keep the tray with the ferric chloride warm, and agitate frequently as it speeds up the etching time and gives sharper traces with less undercut. A proper etching tank would be nice, but they're pricey! I went through all those questions and more when I first started messing with it! What I found is that the movement I was using is calibrated for a linear response to pulsewidth change, so getting it right at 3000rpm means it's correct (or very close) across the range. The pot in my circuit adjusts the pulsewidth/frequency response of the monostable. There may be a way of adding a constant (to make it over-read by a fixed percentage across the range), but I haven't looked into that yet. Those little tabs you can see in that pic are for fine calibration if needs be. I believe you bend them a little to change the response at that point on the dial. You can see that a few are tweaked a little bit from the factory calibration, and the ones near the top end are actually slightly longer. Very clever IMO! I hadn't actually thought about the odometer when musing about the electronic speedo. I'd have to put some thought into that, but it shouldn't be difficult to get something up and running, and cutting it off when off road will be trivial. I'll keep you posted! EDIT: Sounds like your IDM connection is marginal for that tacho. I'd definitely try splicing into one of the connections between EDIS module and coil pack. As I recall, there are three wires, one of which is +ve, the other is switched ground for each coil, and it's one of those you'll want to splice into. Pretty sure that'll work!

Cheers guys. I never got to do this kind of stuff at school, but picked it up when I was messing with audio amps. A lovely skill to have IMO. Yeah, I saw those little units on ebay. They looked good, but this cost me about a fiver, so went my own way. Are you running it spliced into one of the connections between the EDIS module and coil packs? It ought to give a signal just as solid as any electronic coil trigger. If you wanted to mess about a little, it would be easy to put the movement of an electronic tacho into a speedo and adapt my little circuit to trigger off the transducer. The calibration range is (deliberately) huge! Thinking about it, I have an LT230 with electronic speedo, so I might look into that. Hmmmm... Thanks for the idea!

I went on an interesting little journey adding a tacho to my V8 converted S3. Having made a custom panel to house Smiths fuel and temp gauges in the centre to make room for a 4" tacho in the right hand space in the instrument binnacle, I duly went to hunt one down. I wanted a Smiths/Jaeger look, but couldn't find one the right size/number of cylinders, so I did a bit of poking about and bought a few. I found a Jaeger mechanical one the right size, and a Smiths RVC the wrong size, but with the right type of electrical movement... The Smiths RVC electronic tacho: The Jaeger mechanical tacho: Getting the bolt pattern for the electronic movement to drill the 4" housing: Face re-drilled, fitted to movement and fitted to housing: Here's what it looks like installed: But of course, it doesn't work yet. You may see the little "4-cylinder" mark... So, a bit of research revealed that it works in the very simple way: The original coil on the movement is connected to 10v from the voltage reg, and the other side via a little circuit to ground. The circuit grounds one side of the coil for a fixed time every time it detects a pulse from the ignition coil - the rest of the time, it's left to float up to 10V. This varies the amount of time the coil is grounded, producing an average voltage which drives the coil to a given position against the spring and fixed magnet for that given voltage, carrying the needle with it. Simple tech! The technical term for this type of circuit is an "monostable": It's only stable in on state. The linked circuit is made with a few transistors, plus a little extra to drive the coil and handle ignition pulses. I shamelessly uses the tach input from the Megasquirt, given that's exactly what it's designed to do! Output is an common-emitter buffer. The original: Some photos of the breadboarded prototype and testing: The more evenly spaced trace is my simulation of the coil with a signal generator. The other trace is the output from the circuit: Having draw up the circuit and PCB artwork, then laser printed to acetate, I UV exposed a copper clad board with photo-resist pre-applied: Developed, the etched with ferric chloride (devil stuff): The finished product against my breadboard prototype: Drilled ready for components: Populated and ready for testing: Packaged up and ready for be installed in the case: I'd calibrated it on the bench (it's easy to work out what frequency 8 cylinders at, say, 3000rpm gives you), but a final twiddle of the trim pot while on the vehicle got it perfect before finally installing. Hope it makes some sense, and you enjoyed the read. I haven't seen too much electronic stuff on the forum yet, so something a bit different I know I could probably have bought a VDO or similar, but where's the fun in that?? I had loads of fun setting this up, and now have an electronic tacho design I can calibrate to any number of cylinders. I'm sure it'll come in useful in the future... I'll post the circuit diagram and PCB artwork at some point too. And as the copper clad boards are standard size, and it's a waste not make a whole batch, I have 10 or so spare PCB's, so if anyone wants one feel free to shout! It's only a couple of quids worth of components to complete. All the best Ian

If you can get an impact driver to it, you might have some luck. Just keep trying to nudge it back and forth and you may be able to get it free.

That's a good call. I'm wondering now if I've got enough space around my pillar drill to get an axle in! A magnetic base drill would be handy here... I do have a plasma cutter, but that tends to be more than a little messy starting blind. I do like a challenge