Q on magic jet injectors

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hitman
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Q on magic jet injectors

#1 Post by hitman » Mon Mar 04, 2019 4:38 pm

I have these fitted and have had a few problems with deterioration of the o ring that sits right on the end of the adjustment barrel that the spring sits in.
Q is can I just remove these and bin them and rely on the spring stopping them hitting metal to metal as the shuttle does its thing?
There is another better designed o ring half way down the barrel to stop gas escape but the one on the end is a poorly retained thing on a tiny chamfer to stop it moving.

I can't be the only one with this issue so what to do?

In portugal now and getting things here that are not hand carried is an issue.

hitman
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Re: Q on magic jet injectors

#2 Post by hitman » Sun Mar 10, 2019 10:07 am

Anyone?

Simon have you had this issue any time ?

LPGC
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Re: Q on magic jet injectors

#3 Post by LPGC » Sun Mar 10, 2019 11:37 am

The end stop rubbers are there for a purpose which is to act as the stop which prevents plungers opening further and probably also prevents clatter and bounce during the opening stage, if you remove stop rubbers the plungers may open wider and perhaps to a different extent on each pulse (or different extent on different injectors). This would at least effect the closing time of injectors and mess up calibration, maybe not a big deal if it affects them all in exactly the same way but a problem if it doesn't effect them all in exactly the same way.

The fact that you have removed and stripped injectors implies that you probably noticed something wrong with them... were they noisy and/or fuelling seem messed up?

Since you have a few bad ones with rubbers deteriorated I suppose you could go for broke and remove all rubbers and see what happens.. Would at least expect you'll need to adjust calibration. If you seem to get calibration something like you could then check for injector to injector consistency by switching engine cylinders back to petrol and seeing if/how that effects fuel trims... if they're all flowing the same switching any cylinder back to petrol should cause trims to shift by the same extent as when switching any other cylinder.

Bit of a coincidence because we're talking MJ injectors and I know you have an L322... I spent a bit of time sweeping up here this morning and swept up some broken MJ injectors that got broken due to a failed reducer that fed them with coolant (was a repair job on a Merc I didn't convert) and I've just had a supercharged L322 dropped off for conversion (owner literally just left - yes I know it's Sunday!).

I wouldn't have bothered trying to fix/rebuild the injectors following them being filled with coolant long term given what new injectors cost. I will be fitting MJ injectors on this supercharged Rangerover (and will be trying a single 540bhp rated AMR reducer on this one for a change to compare results to other reducers options on supercharged Rangerovers). MJ injectors seem to be getting more and more reliable, there have been some changes not only to the more recent MJFX line but also to the original full size MJ line. Both lines are very linear and high flowing, FX slightly better linearity, full size slightly better flow but really only talking by a tiny amount in extreme conditions in both respects. I'll be fitting full size MJ's on this supercharged L322.

Simon
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hitman
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Re: Q on magic jet injectors

#4 Post by hitman » Sun Mar 10, 2019 12:52 pm

Cheers Simon

I'll persevere with them and a drop of superglue to keep them in place.

Had one or two causing issues of rich running but once cleaned and reassembled they're ok for another 2 or 3000 miles.

I have them - old type -without any nozzles in and quite happy with them other than this o ring issue but may get family to bring a full set out just in case .

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Re: Q on magic jet injectors

#5 Post by LPGC » Sun Mar 10, 2019 9:17 pm

No probs.

Also watch gas and reducer temps, cold gas can cause injector rubbers to fail prematurely.

Simon
Full time LPG installer
Servicing / Diagnostics / Repairs to all systems / DIY conversion kits supplied with thorough tech support
Mid Yorkshire
2 miles A1, 8 miles M62,
http://www.Lpgc.co.uk
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07816237240

hitman
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Joined: Fri Aug 22, 2014 7:12 pm

Re: Q on magic jet injectors

#6 Post by hitman » Sun Mar 10, 2019 9:54 pm

Ok will do , that may have been an issue in the uk as it could be a bit lumpy on cold days when it just went onto gas .
Not a problem out here with higher ambient temps and must admit it runs smoother on change over , plus longer runs out here than town driving in uk which helps I think.

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