Chinese kits?

[Sniperx]

They compromise the petrol injector position as it causes the injector to sit further back, and disturbing the petrol injector gives you the chance to introduce leaks, either of fuel or air into the manifold.

I don’t think a quarter inch is going to make that big of a difference in a daily driver. I know the intake and exhaust are where a lot of R&D dollars go, but I don’t think that small change is critical.

“Disturbing” the injectors? All due respect as I don’t know anything about your background, but this is silly. Injectors are designed to be removed and reinstalled multiple times before needing and oring change. A little dab of lithium grease on the oring and you’re good to go. This is certainly less “disturbing” than drilling and tapping holes into the intake runners then hoping they seal when you put the nozzles in (if you remembered to use the correct sealant). Not to mention the “disturbance” of removing the entire intake assembly and trying to reuse an old gasket or correctly torquing a new gasket. I think pulling the injectors would “disturb” fewer things in the long run.

[Sniperx]

An affect I could see is the spray pattern. Nozzles usually spray in a cone pattern. If the nozzles are too far back the cone pattern could be “clipped” by the edge of the whole causing less adequate dispersion. This could be tested using 12v and carb cleaner spray or naphtha. The problem may be addressed by counter sinking the outlet on the brass fitting enough where it no longer interferes with the spray.

This is all theoretical since I haven’t seen the parts in hand before.

[Brian_H]

I did say a chance of disturbing them. You are talking about seals on a 20 year old vehicle after all. Yes as you say, there are chances you'd have the same sort of issues with reusing the gasket etc as well. There are relatively few posts on here regarding them, but the one by Tubbs in this thread suggests they can be problematic.
viewtopic.php?f=33&t=12602&hilit=injector+adapters

[LPGC]

Whether or not they cause a vacuum/petrol sealing problem, fuel spray patter problem, etc, will depend on the engine in question.

On some engines they're not great regards correct point of LPG injection either. They're a tube wide enough for the petrol injector to mount on top of with a 'watering can' type spout coming off the side which the LPG pipe (from LPG injector) connects to - so the LPG doesn't squirt directly into airflow in the manifold port runner, instead it squirts through the spout bit into the wide bit which is spaced away from the inlet runner... which usually won't be as ideal as having LPG enter the port directly from a narrow(er) nozzle into airflow in the port.

Regards 'disturbing stuff', again it depends on the engine is question. The bottom of the 'watering cans' have to seal as well in the manifold as the petrol injectors did, the petrol injectors have to seal in the top of the watering cans as well as they sealed in the manifold. You want the sandwich setup (watering can, injector, fuel rail) with the increased height and with the spacers that will need to be used to secure the fuel rail at it's new height onto the engine's original fuel rail mounting points, to be as rigid/secure as it was originally. Hopefully the bits supplied will achieve this on the engine in question, speaking from experience sometimes the installer has to modify/fabricate bits to ensure this because the 'watering can' bits are not engine specific, it can be surprising how much rigidity/security is lost when the fuel rail is remotely mounted on extensions rather than being attached directly to original securing points.

On a V6 if the fuel rail is solid and wraps around the engine, if petrol injectors are sloped toward the centre line of the engine then spacing petrol injectors away from the manifold can mean the fuel rail needs to be made longer. On some inline engines fitting spacers can mean engine trim covers won't refit.

Most pros don't use them, they might have tried them at some point and had some good results on some engines but poor results on other engines... this combined with increased costs and the extra messing about fitting them make them a bad bet from the outset. All considered if it seems difficult to fit LPG spuds in the correct place it's usually a better idea to fit straws. Then again the idea of drilling a manifold to fit spuds or straws won't be a big deal to an installer but might seem a bigger deal to an amateur.

[Brian_H]

Also need to consider if you need a valve saver, and if so where thats going to be connected to the manifold. Don't see that mentioned anywhere in the thread as yet, but you'd need to get that into the manifold somehow, plus a connection to the vapouriser (though you can usually either use an unused port for that or put a y connector into an existing vaccum line for that so generally not a problem)

[Sniperx]

LPG: You’re right about the stack having increased leak points and stability issues as well as overall fitment across various platforms. In truth it’s only discussion at this point, I haven’t examined my engine layout closely enough to know what’s involved. The placement and ease of use seemed ideal to me at first glance. My VW EFI system is pretty adaptable and would easily accommodate the watering cans....but then again is a very flexible design...a production vehicle will be a different story.

Brian: if the 20 year old prints are questionable upon removal they should probably be replaced and/or replaced soon regardless of LPG kit install.

Valve savers:
I’ve conflicted feelings on these. It sound like the upper cylinder Oiler of yesteryear. Mostly unnecessary. I haven’t seen a lot of info on why specifically it’s needed in many cases. I also don’t hear any reports of the Australians using them on their Delicas (very popular down there). Is there a known issue with the Pajero/Shogun/Delica engine where this is necessary?

[Brian_H]

LPG: You’re right about the stack having increased leak points and stability issues as well as overall fitment across various platforms. In truth it’s only discussion at this point, I haven’t examined my engine layout closely enough to know what’s involved. The placement and ease of use seemed ideal to me at first glance. My VW EFI system is pretty adaptable and would easily accommodate the watering cans....but then again is a very flexible design...a production vehicle will be a different story.

Brian: if the 20 year old prints are questionable upon removal they should probably be replaced and/or replaced soon regardless of LPG kit install.

Valve savers:
I’ve conflicted feelings on these. It sound like the upper cylinder Oiler of yesteryear. Mostly unnecessary. I haven’t seen a lot of info on why specifically it’s needed in many cases. I also don’t hear any reports of the Australians using them on their Delicas (very popular down there). Is there a known issue with the Pajero/Shogun/Delica engine where this is necessary?

Don't know if the engine your asking about needs one or not, Some engines don't need any additional protection for valve seat wear, others do. Ford and Honda are typical examples of engines that are reported to suffer without valve saver. The Rover V8 being a typical example of one that doesn't need it.

The factory fit Ford engines had a different cylinder head to the standard one so they clearly thought it was an issue there. The cost I was quoted for replacing valve seats if they got VSR and had to be cut out and an insert put in place, was £50 (Plus VAT) per valve. It is an upper cylinder lube as you suspect, and the same fluid can be used to allow the use of unleaded petrol on a vehicle that would have been using leaded petrol and hasn't been modified to allow the use of unleaded. Though in that case it can be added to the fuel tank (at least the blurb on the back of the JLM or flashlube bottle says that its suitable for that use, can't remember which says it without looking at the bottle).

Its at least worth being aware of it when considering converting beforehand. You don't want to find out later by means of valve wear having got bad enough you can notice symptoms.

[LPGC]

I have known Mitsubishi V6's suffer advanced VSR.. I once diagnosed poor compression on a particular cylinder on one without even running a compression test (by order of elimination of everything else that could be causing a misfire on LPG on that cylinder, sometimes a misfire at low rpm even on petrol). I told the customer my findings before running the compression test, then I ran a compression test in his presence, which proved the low compression. He later had a different garage pull the engine and fit rebuilt heads, the garage confirmed VSR on all cylinders especially the one my findings pointed to.

The vehicle had done around 100000 miles on gas without a lube system fitted. Most of the LPG injectors were worn and mal-fuelling, the injector on the most affected cylinder was the most under-fuelling so would've meant that cylinder got the leanest mixture of all cylinders. After the replacement heads were fitted I fitted a new set of injectors, calibrated it properly and fitted a lube system.

[Budgetbond]

Ordered the nozzles and some other stuff from www.lpg.auto.pl and arrived this week, seemed like good prices, service and delivery was surprisingly good and not much extra but a bit of a pain as I'm gonna have to return some stuff ordered in error.
The aforementioned nozzles seem quite good but I'm not sure whether they totally fit my injectors or I maybe missing some orings, pity cos injector positioning does seem quite a good compromise

[3sGTE]

Tell you what though, in recent years a well known producer we've all heard of has seemingly started to rip off other firms reducer and injector designs but make poor (in most cases) equivalents. The firm I'm talking about only used to produce ECUs, now they have a full line up of various model reducers and injectors, all seeming to be relatively poor quality rip off's of other well known firms designs. These parts do find their way onto a lot of UK vehicles - but I wouldn't be happy fitting them.

The company is a shortened term of 'Liquified Petroleum Gas Technology' perhaps
In fairness I always liked their ECU - seemed easy to set up & had some good features.

[LPGC]

The system I reckon you're referring to isn't the main offender in terms of copying other firms parts imo.

Not an ECU I like much tbh, quite a few features / controls in software which give the initial impression of offering a lot of control until you realise some of those controls don't work as they should and (worse) some of the basics don't work properly in certain conditions. OK for most run of the mill applications but not for when you need to call on a feature/control that you then find doesn't work properly, or if the run of the mill application has an operating condition that the ECU doesn't seem to be able to handle properly.

[Budgetbond]

Don't know whether the op 's still knocking around on here, but a quick update on this topic, I've tried those adapter injector nozzles and agree with most of the above, they may work well on other cars but on mine they were a real pita, I only really tried them because I had spare petrol injectors I wanted to install tbh, but found them really difficult to seal at all ends simultaneously, I think the drilling the manifold is a far easier method (I was initially daunted by the prospect) and actually more effective due to the proximity I can get anyway to the petrol injectors, certainly on my car anyway.