Well, it's been awhile - so more of just a 'wrap up' than anything else at the moment...

It's been running spot on on petrol - nice even fuel trims, and got decent amount of poke. I had a time where I gave it some right foot coming off a roundabout and I couldn't get it to go above about 3K, no matter how much I tried.. I have since tried it again on a trip back from the workshop when joining the main road, but this time in sport mode and it pulled up to about 4K - by which point I was already doing 60, so backed off. So I am thinking my issue with the struggle before is the autobox, rather than engine... It's always seemed to have a mind of it's own - but bunging it in sport mode definitely makes it feel more alive...

I've been away a fair bit for work, so I haven't had the chance to drive it much, and still haven't cracked 1K miles yet! but I'm planning on doing it's first oil change at the end of next week when I'm back from work - I'll take it up to the workshop on the weekend and do it all then. I'm going to aim to do the diff oils aswell and at least check the level on the transfer case, as that was new not too many miles ago.

LPG - well, I decided to get individual Hana injectors, so I could mount them lower in the inlet manifold and then hopefully save some space under the bananas, where the rails of 4 were catching. Well, that didn't go so well, as even though the injectors were lower (about 40mm of hose from injector to manifold on each one... the individual feeds to them meant they took up a load more space with the feed pipes to the injectors, so after a lot of cursing and swearing, I went back to the drawing board (maybe if I'd got the 'rail' type single injectors and hose adapters that came out at 90 degrees it would have worked, but hey..) I ended up going back to my original rails of 4 injectors and looking at what was hitting on these before, came to the conclusion that the individual superseal connectors on these were what was causing the crush.

So I went a bit off-track, and got the dremel out and cut the connectors off, exposed the metal terminals to the injector coils from the moulded plastic, and then soldered my own wiring on, which I then ran to a 5 way superseal connector (common ground and the 4 injector feeds). I then fitted 5 way superseal connectors to the LPG wiring loom under the bonnet, to match the ones on my modified rails. A dash of hot glue later to seal all around the solder connections on the top of the coils (to prevent any electrical shorting, and to keep moisture etc out) and I had a pair of 4 way injector rails, which are about 20mm shorter than before with the individual superseal connections.

The coils on these Hana injectors are all individually replaceable - so in future, if I decide to remove them for any reason, I should be able to get replacement coils, with connectors and they are back to stock...

After a test fit, and now finding that the upper inlet manifold fits in nicely, with just enough room, I took it back off again to finish tidying things up. I had some of the split plastic cable loom insulation, so have wrapped this over the top of the wiring on the injector banks aswell, which is then cable tied in place. It's probably overkill, but I wanted another (thicker) layer of protection between the wiring and the metal of the plenum in the case of any vibrations etc (though in theory the injector banks should be moving with the engine, since they are attached to the fuel fail!)

The hoses from injectors to the inlet manifolds are now about 8-10cm long (I didn't measure them! but they are all fairly even!) and it's all plumbed back in and back together.

Once the upper manifold was on and bolted down lightly, I removed the gas ECU and got the multimeter out to make sure that I had a connection between the appropriate ground wire in the loom, and each injector coil - which I did, for all 8 :) also checked for any shorts to ground on both the injector rail common and the 8 individual injector wires.

Wiring all checked out, resistance measured on each coil wire was pretty much identical across the board - so with that added reassurance that I hadn't damaged anything in installation, or squished/shorted something, I finished the reassembly.

Ran it on petrol again yesterday to make sure I hadn't messed anything up on that side of things, or there wasn't any vacuum leaks etc, and all happy there.

Got the laptop out today and ran the auto calibrate on the LPG system, after verifying it would switch to gas and run (badly) without any errors flagging in the ECU.

Got it to auto calibrate, and immediately idle was a lot better, so took it out for a drive to the courier drop off for a BECM I'd worked on and was sending back. Ran nice on gas, with lots of pull...

Got home and checked the fuel trims.. waaaaaaaayyyy out... (multi trims were down to about .86 on both bamks) looked like it was running silly rich on gas - then realised I had calibrated with the reducer pressure set to 1.1bar, but the actual gas rail pressure reading about 1.4bar... Changed it to 1.4 bar in the setup, and then re-ran th calibration... looked at the map afterwards, and the values are a lot lower than they were before...

Ran out of time after that to take it for another drive, but I'll take it out again tomorrow to see how it behaves and also check the fuel trims again when I get back.

All in all though - I'm happy to have it (finally) back running on gas again

If I were doing it again, I'd probably just cut the webbing between the bananas and then run longer hoses through and mount injectors on top of the sausages. My only worry doing that would be that they'd end up being horizontally mounted (or use Matrix injectors) to fit between plenum and bonnet without catching.

Why didn't I do it this time... I figured I could get the injectors to fit under the manifold (there is a LOT less space though than it looked when I had it mocked up on the bench, by the time there is gas feeds, wiring, injectors all fighting for real estate in there!), and was determined to do it... also with the fact that previously they were out the back of the manifold, and the feed pipes to the inlet were right on the limit of what's recommended - if not a bit longer - and it was definitely noticeable in the throttle response. Now I have the injectors fitted under the manifold, when I took it for the drive today, the throttle response (to me anyway) was as instantaneous as on petrol.

Also, with the new engine, and the torquemax cam, I wanted to give it the best chance at running properly on gas as I could, rather than just go 'sod it' and take the easy way out of remounting the injectors at the back of the engine.

So the LPG setup at the moment is:
Zavoli Alisei (AEB) ECU ('C' Series, going by the stamp on the ECU casing)
Zavoli Zeta/S reducer (bought a new one as I figured it was just as easy as buying an over haul kit for the 8 yr old one!)
2x Hana 2001 Gold 4cyl/rail injectors, with 2.1mm (two stripe) nozzles

Will see how the fuel trims look tomorrow and will report back... i'm guessing it will probably need a bit of tweaking whilst under driving conditions, but that's definitely a 2 person job!

Good stuff! Nice to see it's all settling down.

That's interesting Marty. We now have a very similar gas setup. Only difference is the injectors as I'm running the Zavoli badged matrix type.
It'll be interesting to compare maps, once we're both happy that our calibration is as good, as the only difference will be your Torquemax and injector setup.

You are doing a thorough job Marty, first having it run perfectly on petrol as that is your referencepoint for adjusting it on gas.
Running it up to 4000 rpm is only for testpurposes isn't it? (the old lady has a new heart but still an old lady ha ha)
As for injector location, I knew there should be little space under the banana's for injectors and wiring but it is worth a try, the short pipes to the nozzles have proven to be best. Splitting the injectors/electrical connectors is a job you do best, let us know the result. In this way you have a custom build one injector per cylinder set up.

I'll get some pictures of the LPG setup up in a bit... I took a few on my phone as I was installing it - but there was a lot of blue air as things weren't fitting properly, so documenting it all kinda went out the window a little bit at times!!

The setup I've got now doesn't use the individual injectors, but back to the 4 way rails as they are actually slightly shorter - even more so with the modified electrical side of things! - but they are still mounted as a rail of 4, as whilst I have no problem customising wiring etc, cutting the gas rail etc which is all moulded, to make individual injectors per cylinder wasn't something I was prepared to try!

Running it up to 4K under acceleration was partly because where the road joins the main road, it's on a bit of a corner, and it's very easy to get caught out with someone doing a bit over the limit coming around the corner when you're accelerating... so a bit of extra right foot is partly for piece of mind! I also wanted to give it a poke in sport mode, as my initial worry when it was seeming to bog down and not want to get above 3K no matter how much throttle I gave it was something wasn't right with the engine, or blocked cat etc etc etc.... but the fact it pulled quite happily in sport mode just says to me that the autobox a) has a stupid mind of it's own and didn't want to kick down the last time, for whatever reason and b)the box is probably a bit 'tired' as I don't think it had the easiest life before I bought the RR 5 years ago (time really flies! - this is the longest I've owned a P38!)

Under 'normal' driving the engine doesn't really get above about 2500rpm - occasionally up to 3k - but I don't even think on the old engine I ever got it anywhere near to red line revs... it doesn't need to rev that high to be quick off the line, and I'm happy to cruise on the motorway, which at 70mph ish is about 2500.

I'll put some pics up a bit later once I've got them off my phone and onto the laptop... I've got a couple of heater boxes, HEVAC controllers, and blend motors to work on in the garage today...

For the first 20-30 miles after getting it back from V8 Dev and putting it back together, mine didn't want to rev much over 2,000 rpm. My first test in it was run up to Leeds, about 100 miles, and it was only then that it started to loosen up. Now, after 42,000 miles I think it's bedded in nicely and with foot to the floor in sport mode I can see in excess of 4,500 rpm before it changes up.....

The only time my engine ever came over 3000 rpm (after rebuild) was at the LPG guy adjusting the stuff. I started thinking 'do you really need to do this' when I heard a rattle from up front: when revving the fanblades pulled so much backwards they hit the top-coolantpipe (the elbow) coming out of the manifold. That fan was wiggling because not fully done on the pumpshaft so I had to be greatfull to the man- in fact.

i'm still being pretty gentle with mine - though I did give it a bit of a poke when I went out this evening, with it on gas... purely for 'testing' purposes of course - to make sure the LPG system wouldn't cut out (now it's had the auto calibration) under acceleration... I think the BMW next to me at the lights was a bit surprised that it was left behind.

So, some pictures of the LPG side...

First - the single injectors I purchased, in the hope of getting it all sitting lower, than the rails. The feed pipes to the inlet manifold are REALLY short...

They do just fit under the manifold, but the fact that the front bit of the plenum bolts onto the bananas right where the front injectors try to sit doesn't help.

And there's a lot of wiggling required to get it all to sit down so the manifold is flush

Again, can see where the bolted bit causes issues aswell

And this doesn't look practical for getting gas hoses to fit in there... this is looking from the back. Thinking the individual 'Rail' injectors would have been better, as you can get top caps for them, which bring the gas inlet nozzle in on a 90 degree angle/horizontal, rather than these 'pipe' injectors

And after actually trying a couple of different combinations of hose routing for the inlets, I couldn't get it all to fit and the plenum to sit nicely, without that feeling of something is being crushed... so much cursing and swearing later, I gave up for the night (this was on day 2 of this project by the way!)

So I decided to go back to what I knew had fitted - the original 4 way moulded Hana H2002 rails. I had these fitted before, but it felt like a bit of a squish to get them in, and when I got a picture of everything fitted in there, it wasn't pretty... hence the reason for thinking single injectors would work better and mount lower, thus giving more space on top of the fuel rail.

So looking at these injectors, the power connection sticks out the top, and by the time you have the plastic body of the socket on the loom, and the wire, you're looking at 20-25mm in height over the actual injector coil..

I decided to take matters into my own hands, and get creative with the dremel cut off wheel. I removed the coils from the rails to prevent damage to any of the plungers, or the gas ways, and cut the moulded superseal connectors off, and trimmed enough plastic to leave 2 metal tabs sticking up, for each coil. I think got the soldering iron out and soldered my own wires to each coil, to run back to a separate 5 way connector. I've pair 2 coils per ground wire, and then these pair together at the crimp pin for the connector (the loom with the 4 superseals in it has all the ground wires join up aswell inside it - so attached the female end at this point, so there is only one ground coming out for each injector bank.

I then had a single trigger wire for each injector, which then had a pin crimped on the other end of it and inserted in the connector in the correct order to match what I'd done on the vehicle side.

A dollop of hot glue on the top of each coil served to a) keep moisture out and b) stop any chances of shorting of the contacts out, and to help hold the wiring in place.

So - the first rail done...

Back view:

I had to make the feeds from the injectors to the manifold a bit longer now, but they were all about 10cm long, maybe a touch more.

The second rail installed:

An overview of them both in place:

At this point, I sat the plenum back on to make sure it would all fit (all the measuring said it should, but the proof is in the pudding so to speak!), and there was a satisfying 'thonk' and the plenum sat on it's dowels and seated first time. I was a bit taken aback it went in so easily, with no struggle.

I decided that it was time to tidy things up a bit more, and also because things were still a bit tight under the plenum, I wanted to protect the wiring a bit more from any possible shorts/rubbing/vibration. You can see in the picture above that I'd already wrapped the wiring from the end of the injector rails to the connectors in plastic protection (the split plastic loom stuff), and this then got wrapped in insulation tape to keep it all together.

With the inlet removed again, I got a couple more short sections of the loom wrap, and installed it over the top of my wiring on the injector rails, using the split in the wrap to allow the wiring to come through where it's soldered to each of the coils. The wrap was then cable tied around the injector rail so it couldn't fall off, and also cable tied around itself, so it couldn't split and work free.

This just means there's an extra layer of protection between the injectors/coils and the painted metal of the underside of the plenum. Not that I think it's likely to wear that much, but better to be safe than sorry, and it cuts out the wiring being exposed, and thus looks neater too...

It fits!! You can see the plastic loom wrap around the wiring in this picture too

And a slightly lower shot, showing that there is actually a bit of clearance under there now.. no connectors sitting up, means nothing is being squished...

I actually found that when doing the wiring of the vehicle side of the loom, that the insulation had broken through on 2 of the injector wires where they had kinked over the top of the connector, from the previous tight fit.. now the connectors are gone and the wiring is all lower, this isn't an issue.

I finally checked all wiring back to the LPG ECU connector, and measured between injector coils, injector coils to ground, injector coil ground to ground etc to make sure there were no breaks/shorts etc, before plugging the LPG ECU back in and then finally running the calibration.

So now that it's done, and running - I'm happy... there's more space down the back of the engine above the coil packs (even with the vapouriser hoses running across there) as the injector wiring is tidied up a bit, and there aren't 2 injector rails there with feeds in, and long hoses coming out and under the plenum.

I'm happy with the end result, and the response of the vehicle on LPG... Next time... I think I'll probably cut the webbing in the bananas and mount the injectors on top of that... but for whatever reason, I was determined to prove they will fit under the plenum... and they can... just...

Marty

EDIT - my only other note, and semi-question... when I took the upper manifold off, there seemed to be a fair amount of oil (not gushing, but more than I expected) coming from the inlet tracts... any thoughts on this?

Both rocker covers were completely cleaned/de coked/gunged, and on the RH one (LH from the front of the engine looking back) had a new oil separator fitted too during the rebuild...

my only other note, and semi-question... when I took the upper manifold off, there seemed to be a fair amount of oil (not gushing, but more than I expected) coming from the inlet tracts... any thoughts on this?
Both rocker covers were completely cleaned/de coked/gunged, and on the RH one (LH from the front of the engine looking back) had a new oil separator fitted too during the rebuild...

I had the same thing when I was first doing top end work on the new one. Did the same cleaning (not that they needed it) and replaced the separator.
Ultimately decided it was one of those things that just goes on un-noticed in these engines, maybe when they sit around idling, or with low manifold vacuum or high manifold vacuum or something. Second time I took top plenum off- nothing!
I've decided to live with/ forget it. Doesn't leak, use oil, smoke, smell oily, excellent compressions, no leak down.
Could put a temporary catch bottle on it and find out exactly how much is coming out, but I don't think I really want to know!

A nice wiring job Marty, as expected. Always better to have some room for cables, I'm very curious how the injectors will handle the heat.
If I go that route I might have some advantage that my injectors have the plug at a 90º angle, until then I have to accept the 28 cm long gastubes.
Is that a special sort of isolating you use on top of the injectors, I think for fixation of the wires?

Having the plug at a 90degree angle would have made all the difference for me. It was the height of the connector pointing straight up from the rail that was the issue for me, and a bit annoying in some ways too, as they were the only things sticking up, the rest of the design is nice and compact!

The insulation is just the standard kind of plastic corrugated tubing which has a split down the length of it, and is used commonly for wiring looms etc. I considered padding, foam etc, but settled on this as a)I had a load of it, and b) it's fairly thick, used in looms, so figured it won't rub through if there is any vibration. It's also easy to install, and secure.

I don't think the heat should be too much of an issue.. can't be any worse for the LPG injectors as it is for the petrol ones.. that and the engine bay is pretty consistent in how warm it gets under there! Time will tell though... but I don't see it getting much hotter than where they used to be at the back of the inlet, on top of the coil packs.. I doubt there's not a lot of airflow around the back of the engine at the top to start with!

Fingers crossed it keeps behaving itself!

I'm talking nonsense about the 90º angle, it's a 180º difference with yours.
Two pics I already linked to, one as it is now:

and the aim:

Interesting.... what make injectors are yours?

The rails look very similar to the Hana's that I bought - but with the exception of the power connectors... if mine had been 180 degrees flipped like yours are, then I don't think any modifications would be necessary... as you can see, it gets pretty tight in there anyway, but yours look like they will fit alright!

Look like Bigas to me http://www.lpgshop.co.uk/bigas-sgis-4cyl-injectors-rail-with-t-sensor/

Mine are AEB:

Haven't been visiting this thread, title gave impression it was about the nuts and bolts of engine rebuild..

Think I mentioned the pros and cons of fitting injectors under bananas, including tightness of space for most types of injectors... Wouldn't have attempted to fit Hana injectors under the manifold, they're not very small in any dimension and Hana's on rails are a big block. Single Hana's have gas outlet at bottom and inlet at top, not great if you're limited to space above the injectors such as if there's an upper section of banana manifold to go over them!

If I were to fit injectors under bananas I'd go for MJ single injectors, which have gas inlet at the side and remote wiring connector at the end of a couple of inches of wire, they would have fitted no problem and have 3 ohm coils. Currently fitting some single MJ injectors on the Maserati I'm converting but that's because they're some of the most responsive injectors available and this thing has a high red line, plus the single MJs mean pipe lengths are all less than an inch. But I wouldn't go the under manifold route on a P38, I came up with the cutting webbing out between bananas to fit OMVL injectors in the correct orientation (side outlet injectors so injectors stand up vertically as they should) idea, which delivers the results on a P38.

There can be no direct comparison between maps on AEB systems if different spec injectors are set in the configuration, because injector config effects whether e.g. a map value of 130 gives a multiplier of 1 (say OMVL injectors) or multiplier of 1.3 (say Matrix injectors). Another thing to watch out for with AEB systems is that certain injector configs impose a minimum gas injector pulse duration, not good if you're running really linear injectors that work properly well below that minimum duration and you're fitting on a powerful engine that demands high pressure and big nozzle size, because this can mean the engine always idles rich with ginj bottoming out at say 3.5ms (OMVL example setting example).

Most AEB ECU's don't really like driving low resistance injectors, such as Hana (1.3 / 1.9ohm), anyway. Worst outcome could be premature ECU failure, but there can be issues with fuelling below 3ms ginj. Conveniently if you fitted Hanas, you shouldn't see less than 3ms pinj on a P38, pinj is probably close to 4ms at idle with warmed engine and you want ginj to be higher than pinj.

If you autocal an AEB system with system reference at 1.1 bar and actual pressure of 1.4 bar, AEB should do a decent job of accounting for the pressure difference, it shouldn't be of much consequence, so if it's too rich after running autocal I would expect to either need to manually adjust calibration, or the too rich condition might be due to the ECU imposing that minimum pulse duration. If at this point you changed reference to 1.4 bar without running autocal again it would be even richer, because numbers in map would be the same except the ECU wouldn't be subtracting any ginj to compensate for actual pressure being above reference pressure. Since would expect autocal to work OK with pressure being 0.3 bar out, it could be that fuelling seemed OK after adjusting pressure and re-running autocal because the gas temp had risen in the meentime - due to temp compensation ginj might then be above the imposed minimum of ginj. How does ginj compare to pinj at various loads including idle?

What size nozzles are in the Hana's (if Gold variety) or what spec are the Hana's? Those cylinder KW versus nozzle size charts are a very rough estimate, they presume too much and are something I never take notice of.

Simon

Read all this about lpg injectors, I now know one thing for sure,, I'll leave it to the experts,,

no10chris wrote:

Read all this about lpg injectors, I now know one thing for sure,, I'll leave it to the experts,,

I get glazed eyes just trying to understand a bit of it, Chris lol

If you read the other 10 pages of the thread, then it is nuts and bolts about my engine rebuild.. it's only the last part about LPG as the old engine was running it and I wanted to get the new one running happily on it aswell.

The injector rails I've gone with are newer moulded Hana Gold H2002, which, other than the electrical connectors, are quite compact compared with to other rails that you can make of the single 'rail type' injectors, with the aluminium rails.. There's no way they would fit. The shorter H2002 rails (which have a common side feed) with the wiring directly attached fit nicely.

Nozzle size is 2 stripe, which from memory is 2.1mm. I originally had bought 1 stripe, 2.3mm nozzles, but figure they are too big.. the cylinder size range was from about 26cc up, and the P38 cylinders work out to 28cc each ish, if you got with the 225hp that the engine should have.

I figured that double stripe, 2.1mm nozzles are probably better given its not a massive capacity engine, and it's not a sports car.

From memory, the pinj time after a trip out and everything warmed up to operating temperature is somewhere around 3.5ms at idle. I can't remember the ginj time.

After realising the pressure difference in calibration and reading what the reducer was delivering, I've rerun the calibration with the ecu set at 1.4bar, and after I'd been out for a run on petrol, and things had all warmed up, to the gas rail temp was up to about 65degrees.

Before the recalibration showed 210 around the bottom end of the table, and since recalibration it's not around 183. I ran out of time to take it for more of a drive with the laptop hooked up as I had to leave home (not in the RR) for work again, but I have to head out on Friday when I'm back, and I'll have a look at some more of the values then, and save an image of the map.

At some point in the future I'm looking at upgrading the front end control to maybe the LPG Tech unit, which has OBD connectivity, and auto adaptation, and a setting for Haha 1.9 ohm injectors, which I presume will drive them better than the AEB system.

Hi Marty, Yeh I've fitted loads of Hana2002's lately on stuff like Nissan Elgrand 3.5's. Would advise at least 2.5 nozzles on the P38 (I used 3mm on the Elgrand 3.5 engine at 1.4 bar..) - You don't really want numbers above around 150 in the map, especially if you selected some types of injector such as Matrix in firmware. Wouldn't advise the LPGtech ECU, if you intend to go anything other than AEB I would suggest KME Nevo (the top version has OBD adaptivity built in), or even Stag in preference to LPGTech. You could even just buy a King ECU and swap it in, you can buy an OBD loom to add to your existing loom, you just push female pins into relevant pin holes in your existing AEB ECU connector)... But I wouldn't advise connecting OBD anyway.. even if it would read your trims properly given the P38's none standard OBD (that means some OBD readers including LPG ECU readers return trims of 99% even if trims and everything else are perfectly normal). Nearly a quid a piece for Hana Gold nozzles - just drill them out! I grip them in the round grip section of pliers in one hand and use a small chucked battery electric drill in the other, when you get the knack of it you can feel if the drill is following the existing hole, takes me about 10 seconds each nozzle.

Simon