I know they will be far more familiar with Yank stuff, but not sure if they'd balk at the thought of rebuilding a German autobox.

Reckon you'd probably only really need 3rd gear on a 3spd auto in most muscle cars, top speed only maybe 110mph in 3rd due to gearing even then. I used to love the Hill St Blues opening scene with a line of police cars all burning rubber out of the station, smoking tyres in every gear. My mate used to reckon he had the fastest car in town until I took him out in my Cosworth years ago... but he told me about the time he tried to race a TransAm from the lights...#

I've converted plenty 500ci engines, plenty torque in them!

Simon

Hate to say it but there might be more info on an American website.. In the UK autoboxes are considered a black art but in the US many home mechanics will have a crack at rebuilding them, probably because the info on autoboxes is much more readily available, there are chain stores of autobox rebuilding firms etc... just pop into a shop any buy a rebuild kit for a gearbox. I've delved into building them myself but it's a lot of faff and there are very specific tolerances.

Simon

With the injectors you've got I'd expect optimal pressure to be between 1 bar and 1.1 bar, but the installer probably left pressure set at the Bigas standard of 1.2 bar.

3mm Nozzles will flow 1.44x as much gas as 2.5 nozzles, since even V30 injectors will be working within spec at 4.5ms I would set pressure at 1..6 bar and adjust from there if necessary... but 1.6bar will work and the Bigas twin reducer will go to above that pressure.

Calibration will need a tweak anyway following fitting different LPG injectors, especially of a different type with a smaller nozzle size. If you left the old LPG injectors in place and they were working OK, fuel trims while running on LPG wouldn't be effected by changing petrol injectors - though it is possible to cause problems if fuel trims are very different when running on LPG versus running on petrol. I've never tried to look up info on specs of P38 injectors versus K series injectors, they'd have to be a fair match for petrol trims to be anything like correct when running on petrol and tbh I think they won't be that far wrong.

Simon

Yes it will mean 3mm nozzles.

In which case you could still fit Valtek type 30 rails but would need to increase reducer pressure and do a full recalibration. There are two allen sockets, one on each side of the reducer, alternate adjusting them in turn while watching pressure readings in software because you want them both to be fairly equally matched. If pressure from the individual reducers isn't well matched what happens is one reducer does all the work until it can flow no more (when you put your foot down) and then actual pressure suddenly falls to the setting of the lower pressure reducer.

The V30s are still a decent bet for a cheap no hassle fix because they're available with outlets to suit 4mm pipe (Bigas has 4mm outlets) and have very similar open/close time characteristics to Bigas. If your Bigas injectors had 2.5 stamped on them you could probably have got away with doing a straight swap without even connecting a computer and it would run at least as well as with the old injectors. .

Not all types of Bigas injector are available anymore (I still have some working ones of each type but they're old), the V30s are a better match for your Bigas injectors than the newer type Bigas injectors. New type Bigas are £100+vat for 4, you need 8, V30s are £35 including VAT for 4 but you will need to add a combined inline temp sensor / pressure T (easily fitted into piping) which is about £10 and will need the interface to recalibrate.

Simon

Orangebean wrote:

Now this is where the current job has the potential to get silly. Idly sitting planning my day- the thought creeps in...
" Really should drop the sump to clean all the crap out. When the sump's off and heads off it would be really easy to pop the pistons out and re-ring them, and of course with conrods out a new set of big end shells would be great preventative maintenance. If I did big ends, may as well do mains".
I'm my own worst enemy sometimes!

Might as well take the block out at that stage too OB, re-hone the bores, gearbox rebuild etc.. lol

RutlandRover wrote:

I think other elements of the car need information/signals from the engine to keep working too - like the gearbox. If you remove the engine from the equation I think it gives you problems elsewhere.

You'll know more about that than me, I know the gearbox needs TPS signal but that might easily be addressed, I've made a TPS up for catb'd Fiat Ducato's before just so the LPG mixer system could read it. Unless the gearbox ECU gets TPS from engine ECU over canbus?

Simon

I'll check out all your links later when I've a bit more time... fag break during the hailstorm! The 6x6 I saw would have been in the mid 80s.

Can see all your points and not intending a wind-up, just curious. On the immobiliser point was thinking along the lines of just sticking a carb'd V8 in, no engine ECU to need to talk to other ECUs, with a mixer LPG system off you go... or does the immobiliser prevent BCM stuff working too?

Half expected replies to bring up the weight difference, no problem there? How would costs involved with fixing up a Rover engine to prevent cooling / HG issues compare to picking up a small block from a scrappies and putting it in? Thinking the small block doesn't have the same problems and once fitted would open up the full world of tuning goodies available for what is probably the most modded engine ever with more torque / power from the off anyway, and you've got something a bit different / more powerful that might be worth more money when you sell it on..

Would think possible to fit a wide range of engines if the work was put in but to keep it simple use a carb v8 and one where parts to mate to the gearbox are already available. My mate fitted the engine from a Lexus400 into his Capri, expect that will have taken more shoehorning and involved with the electronics.

Simon

Don't ban me for this lol, I mention it out of interest - Has anyone suffering combined major engine problems and immobiliser / ECU type problems considered fitting a completely different engine altogether? As a kid I regularly saw a super long wheelbase Classic 6x6 Rangerover, it had an all iron small block V8 instead of the Rover V8, probably a Chevy motor..

Simon

There is no internal pressure balancing on your Bigas double reducer.
2 In 2 out filters can be used for pressure balancing. Your Bigas setup will use 10mm vapour pipe, though, not 12mm. 12mm is the standard size for filters etc..

Highly likely that your Bigas injectors are worn. Valtek type30 are a good match provided nozzle sizes on Bigas are 2.5mm or less. Don't strip your Bigas injectors to measure nozzle size, on those injectors the degree of nozzle tightening affects injector response and rails are calibrated at Bigas, removing the nozzles ruins the injectors.

Not sure if LPGshop will know much about the Bigas twin reducer, very likely they would phone me to ask anything they didn't know about it.

TinleyTech was the long time importer of that reducer, and injectors.

Simon

Pics of the general leak position below, though I could only just about see the actual leak. It's about as far forward as the rear airspring and just in from the chassis, I removed the wheel arch liner to see if I could get a better view from that angle. While under the P38 I noticed all the brake pipes look shot, I didn't check when it passed the MOT but it must have been borderline then. The only thing I did to cause the leak was press the brake pedal fairly hard while holding just above idle rpm in drive while stationery (useful to do as early part of calibration), probably just as well the leak happened under those conditions than while customer's wife was driving it.

I knew I had a busy day with about 5 customers coming including the owner of the Elgrand I just converted coming to collect it, another Elgrand owner coming for a chat and 'East Coast Customs' owner bringing his Jeep back from Hull hat I swapped the front end on maybe 6 months ago. Off topic but the Jeep was fixed in 5 minutes, just as I predicted from what he'd told me on the phone the problem was just a bad system earth.

So I copped out of fixing the leak and decided to let my mate at Joe's Garage sort it lol. Joe's only half a mile away and East Coast Customs guy didn't mind following me through as I drove the P38 trying not to use the foot brake, brought me back and I fixed the Jeep. Joe didn't get to look at the P38 until 5pm, then called me to say 'I cant fix this mate, cant even get to where the leak was but I pulled on the pipe and the broken bit just came off so I crimped it up to slow the leak'. Joe came and picked me up and I drove the P38 back to mine. I've called Simons Services, a Landrover specialist in Normanton WYorks who I've done a lot of work for before.. He'll definitely be able to fix it but I'll leave that up to the owner. I've emailed the owner, don't have their phone number (maybe because I recently got a new phone when old one broke and last synchronised old phone numbers years ago), explained all this, I await their reply!

Pics. The screwdriver is there to mark the position of the leak.

Simon

Thank you both Gilbert and Marty.

Got some paperwork and final check of calibration to do on the Nissan Elgrand I just converted and then hopefully I'll be able to get onto it..

Cheers, I'll keep you posted.

Simon

Above I mentioned the P38 I'm working on at the moment. No problem regards what I'm doing with the LPG... but sat in it in the yard with my foot on the brakes there was a sudden noise from under the bonnet which then continued, sounded like a PAS pump low on fluid. Got out to check and there's a pool of brake fluid near osr wheel! Noise would be ABS unit? I was late picking the missus up after tea from her mums so haven't even been under it yet to see where the leak is from, hopefully the flex pipe. Topped up the brake fluid reservoir and the noise went as expected. I've previously read comments from I think Gilbert about just turning the ignition on and ABS unit will prime the rear brakes, comments welcome in case it lands on me to sort this aspect out! How soon will ABS unit fail with lack of fluid to that corner, say should the owner decide to risk driving it away to repair elsewhere? How much of a bugger is routing new copper pipe in case it's the main pipe that's failed? Sods law this is gonna land on me over yet another weekend!

I realise I should maybe have started a new thread or posted this on a more relevant thread, might do that myself or won't mind if mods do it.

Simon

720mm diameter x 270mm height are the biggest dimensions that will fit while keeping the boot floor flat at the original height. Tank of those dimensions will be around 93L with side exit or 85L with middle exit, you should be able to fill to 80% of those capacities with LPG or 90% if the tank valve float arm is bent a bit. There is also a '4 hole' tank option, where the pipes can enter / exit the vehicle in just about any position you wish but they are more expensive and typically hold a couple of litres of gas less than the side exit full toroidal type.

I am very close to Frickley off-roading centre (otherwise known as Frickley pit tip) and have converted quite a few 4x4s including P38s that frequent the place. Like Gilbert said there will be no problem off-roading, and if you should ever roll an LPG converted vehicle the LPGl can't escape.

Working on a P38 at the moment, removing it's Piro LPG ECU and fitting a King, which involves changing the LPG wiring loom and interior switch, then we'll see how well the 10+ year old injectors and reducer work... parts have got better since then.

Simon

Got to be easier when you've done it many times, can also pick up a lot of insight into what's going on. I don't much get involved in fixing any others aspects of cars other than LPG installs and engine management / fuel injection problems but concentrating on those aspects will have concentrated my skills on those aspects. I'm not bad at general mechanical stuff but my mates who run garages in the area are far more likely to know all the ins and outs of most usual type mechanical jobs for a random model of vehicle than I am... I recently ummed and ahhed whether to change my son's Mondeo clutch myself (son helping) or to stick to what I do best and let mates garage change his clutch. We bought all the bits, or so we thought, then decided on letting mates garage fit them, mostly because I was too busy with LPG work. The garage said 'Ooh I'd really rather change the hydraulic release arm at the same time, when the clutch is nearly worn out the arm can in effect get stuck at the full extent of it's movement, or even if it isn't stuck it may fail soon due to being worked at the full extent of movement. Mondeo's subframes have to be lower to change the clutch and the bolts are often seized, it may involve some cutting and welding of the subframe'. We bought the arm and had him fit it at same time as the clutch, turned out he did have to cut and weld the subframe - I could still have done it all but was pleased we let him do it. If my mate at the garage were to fit his own LPG system I doubt he'd second guess me but if he did I would liken the situation to role reversal but where I decided to crack on and not change the hydraulic clutch arm and not anticipate the problems with subframe... and I could be oblivious to the pending failure of the arm until it failed.

Fuel trims will always bounce about just + and - of 0, they're supposed to do that as management never reaches a steady state, it is designed to flick lambda slightly rich and slightly lean constantly, on engines that meet usual OBD2 standards with narrow band probes the stft will always flick at least around +-0.8%. Calorific value of fuel doesn't effect calibration, if the engine doesn't make as much power due to lower cv the driver simply puts his foot down more so pinj increases to match... stochiometric ratio does effect calibration but would result in lower ginj than pinj, though the difference between 14.7:1 and 15.4:1 is only 5% and petrol trims could cope with this easily. The difference between petrol injector and LPG injector properties is the biggest reason we need an LPG ECU at all, followed by need to more accurately account for fluctuating density of fuel (pressure and temperature, due to LPG being a vapour not a liquid, which again is why we can't use petrol injectors for vapour LPG). In some respects it could all be easier for direct injection engines - supply the di injectors with LPG at the same pressure as petrol and an LPG ECU isn't strictly necessary because no calibration is necessary.

Engines running on petrol are far more likely to deliver more power with a rich mixture than engines running on LPG, you don't get the charge cooling (charge density increasing) effect from injecting vapour LPG and the LPG vapour takes up more of the volume of airlfow, so you lose volumetric efficiency. It is safer for the engine to go too rich rather than too lean but max power will usually occur a bit leaner than on petrol, implications of which will effect fuel consumption while booting it. Closed loop single point LPG mixer systems generally aim for about 0.75v lambda 4000rpm+ with wide throttle where petrol lambda reading would max out at 0.9v because petrol mixture would be a lot richer than the probe could measure. Some of the NecamKoltec engines continue to aim for stochiometric (0.5v) lambda even during flat out conditions and f they make any less power on LPG because of this it is negligible.

All AEB ECU's have temperature correction which can be adjusted in software settings if software allows it. To access those settings you need the correct dongle, dongles were originally parallel port types but later on USB types became available. I have a range of dongles for different AEB systems, they also allow you to make changes to the full map in pre V6 versions of software, set the ECU to start on gas everytime even with a cold engine (in case of monofuel i.e. no petrol tank even fitted), adjust lambda emulation waveform on the grey lambda wires (aka AEB175s), etc etc. You can probably do more with V5 software than with V6 if you have the correct dongle. I have been known to bring an old desktop PC outside with a parallel port dongle attached to access those settings on an older ECU, even run the desktop and monitor from an invertor to calibrate lol.

If LPG calibration is rich petrol trims will of course go negative, and then if engine management applies trims during cranking it can lead to problematic starting.

Simon

If you're happy it runs properly on petrol, lambda flicking well and going rich during high load open loop operation, all you've got to do is match pinj while running on gas to pinj when running on petrol - then fuel trims will be the same under all circumstances as they are on petrol. P38s are particularly easy to achieve this on even without looking at fuel trims, but fuel trims can be used to confirm.

There are a few schools of though on calibration - 1 calibrate so trims are close to zero on LPG, but I'd only do that if trims were close to zero on petrol or on specific models of vehicle such as a supercharged L322's / 2 aim for trims to be the same as on petrol (which is what I just suggested above, and I'd only do that usually if petrol trims were reasonable i.e. not sailing close to being minned/maxed out), / 3 aim for trims somewhere between zero and petrol trims.

Many older vehicles only have one ltft, as vehicles get newer they tend to have more and more ltft;s each covering a specific range of rpm versus airflow (or map or less commonly TPS). Some have a different set of trims for different coolant temperatures. On some there is an underlying trim for idle before ltft is even applied which is learned on the basis of something like average trim for off-idle conditions (e.g. BMW). BMW's even have a trim for each individual cylinder called 'smooth running.value'. Out of all the Rover V8 engine'd vehicles I've worked on regards LPG, as memory serves only the late model Rover engine'd D|isco's with EGR have fuel trims which are much like the norm but they are all a low demand engine and very forgiving regards fuel trims and LPG calibration.

It is quite usual for installers such as myself, Dai and Andy to calibrate a system to be close to petrol trims, steering slightly to the side of zero, until the engine goes open loop and then our maps go a bit leaner.if we want more power on an engine that runs enough ignition advance because in this case there is no advantage to high load enrichment when running on LPG which would only start to impart on volumetric efficiency (especially on turbo vehicles with chipped woefully rich maps), or the same mixture if not quite enough advance (for LPG) means running a lean mixture would degrade power due to slower burn and overheat the valves, or a bit richer mixture if it is an engine with soft valves to protect the valves.

The default temp compensation values in AEB are exaggerated, you only really want a range of about 12% from 0c to 60c with zero comp at around 40c. Hardly any systems except AEB compensate for reducer temperature by default and on vehicles with AEB where under bonnet heat doesn't affect gas vapour temp readings I zero all reducer temp related compensation... but it can be handy on installs where under bonnet heat does incorrectly affect vapour temp readings.

It can be best not to obsess about trims on P38s, far better to get ginj suitably above pinj by selecting suitable pressure and nozzle size. Smaller nozzle with higher pressure, and the opposite, can do much the same thing when you get away from idle but at idle things work a bit differently, and Boyle's law works perfectly for an ideal gas but LPG apparently isn't an ideal gas, and you don't need as much relative pressure when manifold pressure is higher.. .

Got a P38 coming in for at least a new ECU on Thursday, and since it currently has a Piro fitted it will also at least need a new loom... but I'll have it calibrated about as good as it could within about 10 mins of changing components without using a Nanocom ;-) I'v e just converted about 10 Nissan Elgrands almost back to back, mostly 3.5L E51's but some 3.3L E50's, my first guess on pressure, shape of map and map levels was almost spot on. Nearly finished conversion of an Elgrand E51 2.5L, and dare say my first guess on pressure and map will be just about spot on for that too! ;-)

Simon

My post and OB's post crossed, like he says the software is free, it isn't universal because each make of LPG ECU uses specific software. I can give you the software for just about any system including of course the systems I supply / fit, and the specific software for any system I supply is available for free download from many places on the internet. I even have quite a bit of LPG software behind the scenes on my website, so can send people a link to download from my website or dropbox..

Simon

You'd need to bring the car to me to take advantage of my free calibration. I don't include an interface cable in the prices above but can supply the proper one for around £30 (I just pass on the price to me), you might want the cable just in case you fancy a dabble yourself in future or for diagnostic purposes in future but would need one from the outset if you didn't intend on bringing the car to me for calibration.. in which case my tech support extends to talking you through calibration (but would be best if you could bring it to me for calibration). My price includes a cert I produce, it doesn't mean much but is good enough for DVLA and some insurers but not all insurers as some insurers will only offer cover if a converted vehicle is on UKLPG's database. I can register a vehicle on UKLPGs database but it costs me £80 to do so, if you want your car on UKLPGs database I just pass on the £80 to you. I make sure your install is fitted safely before I'll issue my cert or register it on UKLPG's database. If you were to buy a kit from elsewhere and wanted it on UKLPG's database you would need to take your finished install to a UKLPG registered installer for a safety check, and could expect them to charge you more than the £80 I charge only to fail it, because by failing it they may hope to charge you for 'remedial work' to 'bring it to spec'. Bit just like if your car fails an MOT on brakes.. most of us here won't have a problem sorting brakes, but if you pay the MOT man to fix brakes he's then got to pass the vehicle on the brakes aspect lol. If you bought a kit elsewhere I could still register your car on UKLPG's database but I would then also charge more than £80 to do so, though I wouldn't want to fail it and wouldn't charge more than once for inspection until it passed. At this point, if you are considering coming to me for a kit or conversion, don't mention your registration or chassis number on forum - I'm not a member of UKLPG and the information could be used by someone to discover which UKLPG members are willing to register a vehicle on UKLPGs database on my behalf, which could result in them losing membership of UKLPG. The irony is that anything I fit or approve is likely to be safer than if fitted by a UKLPG member, particularly if drive-ability is also considered a safety aspect.

Simon

I wrote most of the following before anyone else had replied, just never clicked to post, so sorry if if it goes over the same ground as other people's replies or doesn't address some of their points.

Thanks for the mention Oldshep, got to agree you don't do anything near enough mileage to make an LPG conversion financially worth it.

RutlandRover - Don't buy that front end from Ebay. It is an old OMVL system, judging by the spud location I might even have originally fitted that system to the Rangerover the guy on Ebay removed it from! I would now expect the pictured OMVL injector rails with black coils (a very old type) to have a lot of wear on them (the new OMVL Superlight type with plastic rails and blue coils last a lot longer and are far more reliable), the reducer will have seen better days, as will the pressure sensor and ECU. The pictured parts wouldn't cost a great deal more to buy new than the old parts pictured, but all new parts would mean you would have to drill and tap your manifold (which isn't a big deal and in no way should be considered a plus point for buying second hand).

Front end parts mean just the parts that go under the bonnet, no tank, filler or any piping and wiring that run under the vehicle between the filler, tank and engine components. You would be well advised to fit new piping everywhere anyway rather than piping of that age.

Not a bad brand at all though, when I first started fitting sequential LPG systems I fitted nothing but OMVL because it had comparatively decent performing injectors and a reducer that could handle big power (far better than modern day OMVL reducers in fact) and back then front ends were bought as a complete set (ECU and loom, injectors, reducer), where these days we tend to buy individual components. The components in the second hand system are older spec than a new OMVL system though, the injectors are not as reliable and the ECU though sequential isn't truly sequential.. That's all I'll say here about sequential but not truly sequential or I'd be going into too much detail! The old ECU can give just as good results on a P38 as a new truly sequential ECU.

These days you'd have trouble buying a new front end that was mutlipoint but not sequential (but such systems do exist and were commonplace at one time... Tartarini Etagas is one example of such a system), you could easily get hold of a single point mixer system but I would only advise a multipoint sequential system.

I could sell you a complete (including tank, filler, piping, etc etc) brand new DIY kit for about £800, or you could buy the same bits from a supplier for less, but I give very detailed tech support with my DIY kits while the customer fits the system, and then the customer can bring the finished install to me and I will sort any minor problems and calibrate it properly without charging any extra. Don't forget the £800 includes the tank etc, I sell new front ends for P38s for £500. To supply and fit job done I'd be looking at £1400. To be honest I didn't join this forum with intention of making money out of being here, I'm here out of interest and won't think anything if you buy bits elsewhere etc.. Gilbert and a few other forum members could talk you through the install if you bought bits elsewhere and I would still chip in with tips and help on forum. The front end parts I'd generally supply for a P38 would be much the same as those in the LPGShop link above, though I may supply a different reducer. The reducer in the link is the modern version of OMVLS Dream unit, which (as said above) won't flow anything like the same amount of gas as the old spec Dream reducers (won't go to the same bhp level) but is capable for a P38, the old spec Dream reducer would be capable or at least just about capable for a supercharged L322!

Seems ages since I last did any major LPG work on a P38, in reality it's probably only about 5 weeks, but I've got one coming in on Thursday and will at least be removing it's OMVL Piro ECU and loom to fit a different ECU and loom. Piro was supposed to be OMVLs replacement ECU for the AEB2568 spec OMVL Dream ECU like the one being sold on Ebay (and one from LPGshop) but they never did manage to get Piro working properly and it was a short lived system, even OMVL went back to AEB2568.

Simon

I'm not at all familiar with Nanocom but going on what you've said it's fuel trim readings seem similar in concept to Jap import stuff where 100% Alpha would equate to Euro ltft=stft = 0, one of your trims at 1.50 might equate to Alpha 150% or ltft=sftf = 50%. I'm converting a lot of Jap import stuff these days!

Using the scope in software would have to be done at the same time as monitoring trims, because during proper closed loop operation ginj will remain the same when you adjust calibration while pinj figures change.. Suppose If trims were highly negative, then for a given pressure and nozzle size ginj might be suitably higher than pinj but only because of the negative trims, if calibration were then adjusted to bring trims close to zero ginj might be below pinj... Got to compare ginj with pinj when trims are about right to know if pressure and nozzle combination are about right, though tbh it won't make a great deal of difference on a P38 if ginj is a bit below pinj, all it will do is momentarily slightly richen mixture during positive throttle movements. The switching method can be used instead of the trims method, I use a combination of trims monitoring and switching method during the same run.

Simon

Hehe, It is for reasons like this that I tend to be a bit over-explanatory.