Clip on injectors

Is it feasible to use a 6.0 fuel rail and injectors on an earlier car to eliminate the leak-prone hoses?

Not an expert but I would expect that the injectors flow characteristics would not be the same.
@SD_Faircloth would know better.

I am probably not a lot of help here, and can’t quite remember, but something is telling me that there are some physical differences and the hookups are different

It’s been tried, but it proved not to be easy. Much easier to just replace the hoses every decade or so.

The same rail is used on the 1992 5.3L - easier to go this way.
BTW, 6.0L parts are unobtainable. We have FPR 3.0 bar, vs the 2.5 bar for the 5.3L.
The latter, plus the hoses = too expensive.
As Kirby says, maintain yours.

Is it feasible to use a 6.0 fuel rail and injectors on an earlier car to eliminate the leak-prone hoses?

Which injector are you referring to ? IIRC, the earlier 6.0 liter engines used a Bosch injector, which had flows and ohms matching the earlier HE V12s that used hoses. That 6.0 liter injector used upper and lower o-rings. The later 6.0 liter V12 (95, 96 year model?) used a Nipponese injector, which was a high ohm injector with flow rates around 20 % higher than the HE V12. Need to be VERY specific when discussing the 6.0 liter engine. The above is off the top of my head, on a Saturday morning, with no research, but I don’t do Friday night binges. SD Faircloth

Dave, there was never distributorless NipponDenso ignition on XJS.
Those were used only on the XJ12s

Mine is 95, one of the last ones. You replaced the two hoses between the A- and B-bank rails for me 3-4 years ago. The supply and return lines could not b dealt with at the time, since as already mentioned, are NLA.
I’d like to replace the rubber and reuse the metal connectors but still haven’t found anyone who can make those for me.

Dave, there was never distributorless NipponDenso ignition on XJS.
Those were used only on the XJ12s

I have the tendency to discuss the engines rather than the models in which they were fitted, an obvious fault. But, the 6.0 liter engine was fitted in the XJS and the XJ12 ? Different ignition systems, different injectors. Yes, no ? SD

The '92 V12 5.3 uses the same fuel rail as the 6.0, and the injectors are the same '92-'95. I don’t know if there are any differences in the fuel line plumbing to the fuel rail, but the '92 5.3 uses a 26 CU and the '93+ use a 36CU. I suspect the Intake manifolds are the same as the 6.0 because of the same injectors are fitted, and new badging. See atttached photo.

My remarks were with regard to the XJS only.

This discussion would be a better fit for the V12 engine list. Maybe one of the @moderators could move it there.

Thanks Fellas

if one were to want to use clip in injectors- will they fit into the manifold?

Yes indeed. I moved it there.

Although it does “clip-on”, that is not the usual term to describe this type injector. Better referred to as “o-ring fitment”. Top o-ring and/lower o-ring. Excluding the newer Denso injector, what you are considering is the size of the injector/manifold seal OD and the size of the o-ring OD. Both fit and seal in the manifold. The manifold hole size for the injectors did not change. SD Faircloth

Perhaps a sidebar if this discussion is about the HE.
I found that the injector holes to be a smaller diameter on the Pre-HE manifold.

You may be correct. I have never physically measured to hole diameter of either the preHE or HE manifold. What I do know is I have supplied the same injector/manifold seal for both manifolds for the last 16+ years and the same seal works for both. Even supplied three sets of 12 each in the past 60 days for pre-HE engine with no reported problems. And a shout out to AJ. SD

Some years ago I was fortunate enough to score a set of Pre-HE manifolds that had been graced by the hands of Roger Bywater. (For those that don’t know, Roger is able split open the manifolds and insert equal length tubes, then weld the whole thing back up again). In an attempt to install the Pre-HE manifolds onto the 6.0 heads I quickly came to find out that the injectors did not fit into holes on the manifold.
After mounting one of the manifolds onto the table of my Bridgeport It became clear to me that this seemingly simple task of enlarging the hole to fit the 6.0 injectors was well beyond my skill set without the use of a DRO (to be clear, I would never even dream of associating the word machinist anywhere near my name). In the end, the manifolds eventually found their way back to the shelf from whence they came, and the original manifolds went back onto the car.
Right back at you SD, Big shout out to you too :grinning:

I do not think that these injectors :

Will fit onto anything but the correct/associated inlet manifolds:

Hope this helps.


One item I tell all my customers…for the pre-HE V12 and the HE V12s that use injector to rail hoses…for proper fitment the manifold/injector seals must be fitted into the holes in the manifold and the injectors then pushed thru the seals. Doing thus expands the OD of the seal to fill the hole and provide the vacuum tight fit. If the seal is slipped onto the injector FIRST, the OD of the seal expands very slightly and is then larger than the manifold injector hole diameter, resulting in being unable to fit in the hole.
Cheers, SD Faircloth

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