Modding a SureFire L2 with the MC-E (cont) ** Driver close-up pics in post # 3 **

Modding a SureFire L2 with the MC-E (still in process)

This is sort of a combination How-to, How-do-I-do-it?, and How-it-went thread. This is going to be a work in progress for a while, as I'm just starting out on it - any input from the many experts here would be most appreciated.

I've owned a SureFire L2 for ~3 years now (it was one of my first two SureFires), and to tell the truth I've never been 100% happy with it. I very much like the UI of the L1/L2 series, but was never all that enamored of the Luxeon V emitter in the L2. 100 lumens sounded OK at the time, but being a rather floody overall design, there seldom seemed to be enough lux for me, especially coming from a flashlight of that size (6.1" in length, approximately equal to my 3xCR123 SF C3 / M60). In addition, I've found that the slightly greenish tint common to the LuxV was a bit distracting.

I was inspired to pursue this mod after reading up on some related threads featuring the transplant of the Cree MC-E into a SureFire, particularly this excellent L2 / MC-E thread by Energie, which included lots of helpful pics:
Surefire L2 with Cree MC-E

I also read these other threads (not necessarily L2 modding threads) for additional background info:
KL4 neutral white MC-E modding service
SureFire KL4 MC-E mod
Surefire L4 (KL4) with Cree MC-E
One Surefire L4 with MC-E emitter
(This last one is only a sale thread by AaronM for L2's & L4's modded with MC-E's, but still included useful info including beamshots showing various MC-E tints)

It seems like the SF L2 is a great candidate for the MC-E:

• the existing SF L2 driver is a very good match for an MC-E wired 2s2p
• since the existing driver is a 'boost' driver, it will work well with 1x LiIon (@ 3.7v) as well as still retaining compatibility with 2x CR123 (@ ~5.0v) for backup.
• the existing (& quite sizeable) heatsink in the L2 can be used with only minor modification
• the existing reflector is a relatively good match to the new emitter, particularly when the MC-E package is shimmed up ~1.4mm from the existing heatsink.

So here's the light:

Boring the body:
The first thing I need to get done is to very slightly bore the body from 0.660" (16.8mm) ID to 0.674" (17.1mm) for 1x17670, as the diameter of the AW 17670 is 17.02 +- 0.05mm. (Edit: I just rec'd the AW17670 that I'll be using for this light and its max OD is 0.669" = 16.99mm.) This will take the minimum wall thickness of the L2 body (measured at the o-ring groove) from (0.727"-0.660")/2 = 0.0335" down to 0.0265". As a point of reference, "18mm boring" the SureFire 6P takes the minimum wall thickness from 0.042" to approximately 0.018"-0.015".

I chose to go with 1x17670 rather than 1x14670 (which wouldn't require boring) becuase my calcs show that 1x 17670 results in ~10-15% more total watt-hours compared to 2xCR123 primaries, for a configuration of the same overall length. From my (very) limited experience with 18mm boring & related cell measurements, boring the diameter 0.1mm oversize seems to be adequate. Worst-case, I can just peel off the silver label from the AW 17670 if I get some oversize cells.

A second O-ring groove:
One detail that is important to me will be adding a second O-ring groove so that the existing O-ring can be placed slightly further from the tail:

The reason for this is not to add a second O-ring (so as to gain additional water resistance), but instead to permit the tailcap threads to engage prior to getting the tailcap over the o-ring (which would be slightly further away from the tailcap after this modification). I've always been slightly annoyed when installing the tailcap on this light (as well as with my SF L1), trying to engage the threads while trying at the exact same time to get the lip of the tailcap over the o-ring. I prefer the tailcap relationship on the SureFire P/C series, where the tailcap threads engage prior to having to compress the O-ring under the tailcap. Just a small detail, but since it's going to be on the lathe anyway, adding this will be a nice detail IMO. I'm confident that there will be enough remaining overlap so that the O-ring will be fully covered & protected in its new location.


In addition to the above...
So after I open the head & remove the existing LED, the existing heatsink needs to be slightly modified (by enlarging the wire routing holes for the extra pair of wires that are required for the 4-die MC-E). In addition, I also gather that I'll have to have the other side of the head very slightly milled out to permit optimum focus of the MC-E in the reflector. But that's a bit down the line from where I'm at for the moment...


And the beamshots:
Initial (i.e. the unmodified light):
Normal exposure:
SF L2 (low) _______________ SF L2 (High) ______________ Malkoff M60 (as a reference)

Underexposed:
SF L2 (low) _______________ SF L2 (High) ______________ Malkoff M60 (as a reference)

Re: Modding a SureFire L2 with the MC-E

Prior to boring the L2 body, the driver needs to be removed so as not to be exposed to cutting fluid & aluminum chips. Any suggestions for the best way to get all those plastic clips disengaged? Just looking at it, the aluminum retaining shoulder they are in behind is pretty sharp. I'm sure someone here has figured out the best way of doing this without mucking the plastic clips up?



Opening the head to access the heatsink & existing LED - not pretty but it works well, without marring anything:
(and yes, it took quite a bit of force...)

OK, I finally managed to get the plastic driver retaining clips disengaged from the body shoulder, removing the driver module prior to 17mm boring - that was a pain. I was finally able to do that by using a dental pick and 0.002" steel shim stock. Four of the eight plastic retaining clips were wedged in so tight with so little clearance that I ended up slightly bending the tip of the dental pick in the process. Some slight marring of the plastic and aluminum but all-in-all, it's OK.







I found it interesting to see how well-protected the driver is from getting banged around - mechanically it's somewhat isolated from the rest of the light. :thumbsup:


Next will be desoldering the emitter from the heatsink assembly and boring the body from 0.660" to 0.674" ID...

Thanks for sharing your project Kestrel! Looking forward to future installments. :thumbsup:

Wow, great review.


I too have an L2 that I was thinking of having a MC-E or K2 TFFC installed.



You can put 2 AW 17500 in it right?

bigC

ninemm said:

Thanks for sharing your project Kestrel! Looking forward to future installments. :thumbsup:

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Thanks for the feedback, I was beginning to think that nobody is interested in these "outdated" lights anymore, with lightly-used SF L2's selling for only ~$80 on CPF/MP - undervalued IMO, especially considering how few modifications are required to get this well-designed 2-stage light running with an MC-E and a LiIon rechargeable. :huh:

bigchelis said:

Wow, great review.
I too have an L2 that I was thinking of having a MC-E or K2 TFFC installed.
You can put 2 AW 17500 in it right?

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Thanks. However, the only way that I know of to get 2x17500 in there would be to permanently remove the driver from the body section & install a new driver in the head unit (like Scott did in Crenshaw's 'Legolas' SF L1 build, so as to bore the body completely through to obtain the required interior length). The body could hold 3xCR123 if the stock driver assembly didn't take up approx. the length of 1xCR123 in the body. Here's a pic depicting the length relationship of these two possible configurations (body & driver & 2xCR123 vs body & 2x17500), as that is a very good question:



If money was no object, I would probably go that route. However, that extensive of a modification is definitely outside of my limited ability. This is only a 'secondary' light that I want to update for a minimum of expense. However, once an MC-E is sucessfully installed in this great host (obtaining over four times the original output and ~10% more runtime, I have a feeling that it will get a lot more use this coming winter.

Kestrel said:

Thanks for the feedback, I was beginning to think that nobody is interested in these "outdated" lights anymore, with L2's selling for ~$80 on CPF/MP - undervalued IMO, especially considering how few modifications are required to get this 2-stage light running with a MC-E and a LiIon rechargeable. :huh:

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I'm sure the output will be pretty impressive. I had a Milky L2 (SSCP4 w/SOB1000) for a bit. I didn't care for the very long form factor. Otherwise it was a great light!

Thanks much for the close-up pictures - those are great

Good stuff Kestrel! Can I ask what's inside those hose clamps protecting the finish? Also, does the L2 head have a name designation like the KL4?

Inliner said:

Good stuff Kestrel! Can I ask what's inside those hose clamps protecting the finish? Also, does the L2 head have a name designation like the KL4?

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the L1 and L2 used "dumb" heads and are not available as a separate part, I do not believe they have special designations:thumbsup:

Slightly off topic, I see the potential for such in-line drivers resembling close to a single CR123a [assuming it contains something like an Willie Hunt LVR]. If its possible to build them individually [from third party] the dream of having an C2D in the body of a C3 might not be too far off. Unlike the LED trends, regulated incandescent fans don't falter in interest because of newer bins

Re: Modding a SureFire L2 with the MC-E (still in process)

ninemm said:

I'm sure the output will be pretty impressive. I had a Milky L2 (SSCP4 w/SOB1000) for a bit. I didn't care for the very long form factor. Otherwise it was a great light!

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I definitely know what you mean about the length, regarding size this is pretty much not an EDC light, so it does bedside & backup duty for the most part. If it was a primary-use light, I'd go with 2x 17500 and considerably more modification (and expense). However, it still wouldn't come anywhere close to matching the performance from my comparably-sized C3 (or my C2 for that matter), so I'm just having fun improving this one on a budget.

Inliner said:

Good stuff Kestrel! Can I ask what's inside those hose clamps protecting the finish?

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Just some ~ 1/16" thick rubber sheet that I cut to fit. I can tighten down those hose clamps just enough to stop part rotation, then take the vise & wrench to it. Works perfectly, not a scratch - very easy to defeat the SF Loctite once all of this was set up.

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I do feel somewhat guilty on how slow I'm going on this light. Hopefully this week I'll desolder the existing LED & drill the two add'l wire holes in the heatsink. I could get everything done quickly if I just threw money at it, but I'm trying to do this inexpensively, and as much as I can myself. (And I'm definitely pretty busy this summer with other things.)

You full-time modders might smile at this, but my goal is to finish this secondary-use light before winter.

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I know I've asked this in other threads here, but I'm still trying to decide upon what binning/tint of MC-E to use - there really is quite a selection and I'm not sure what the latest & greatest would be. I was leaning towards a J-binned 5A like this, but just ran across a mod up for sale that used a 6A or 6B (?) and maybe that might be what I'm looking for with regards to a modern binning somewhere between neutral and warm... ? :thinking:

Edit: I've been using some neutral XP-G's recently (a first-run M31W @ 5000K and a Moddoo XP-G triple Neutral @ 4500K ) and I'd have to say, the tint on those is perfect IMO - I'm going to go with that.

Checking in to see how you're coming along with this project, Kestrel.:tinfoil:

Sorry, it's been really slow. I have the L2 body 'checked in' with my machinist for 17670-boring, and am waiting on more news with regards to the new MC-E bin, Cree MC-E N0 Bin, which I very much want to use for this. :thumbsup:

Bringing this one back from the deep, dark past - Kestrel, did you ever finish this one???

JNewell said:

Bringing this one back from the deep, dark past - Kestrel, did you ever finish this one???

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ooo you shame me, sir.
It's still here in my desk drawer, I'd like to finish it but have my hands more than full at the moment.
I've sorta been kicking around the idea of the 6V Cree XM-L EZW instead of the MC-E. :shrug:

No shame intended! I know how that kind of thing works...

Kestrel said:

ooo you shame me, sir.
It's still here in my desk drawer, I'd like to finish it but have my hands more than full at the moment.
I've sorta been kicking around the idea of the 6V Cree XM-L EZW instead of the MC-E. :shrug:

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nice mod ! got me inspired to mod some of mine too, will post pics later