Crane XR700 install

[blairwag]

With God's blessing, today I will turn the key, and hope the car starts.
Last night I completed the first phase of the XR700 installation, using help from this forum, John Hassel's invaluable document, and the CRane installation guide. I *BELIEVE* all went well.

I have one question, regarding ignition phasing.

John's document clearly instructs me to ensure that the rotor be absolutely centered under the ignition cap's spark wire electrode when the shutter window leading edge crosses the optical trigger sight path.

This will cause the ignition to fire the spark when the rotor is roughly centered under the electrode while the engine is running at 2400RPM or higher, with the timimg retard defeated.  I say roughly becase the centrifugal advance may case the rotoer to be offset slightly.   *BUT* what about dirung low RPM, with the vacuum retard enabled? On't this case the rotoer to be well offset from the electrode?

I have currently adjusted the optical trigger to be positioned so that when the vacuum retard is enabled, the center of the roter will have just barely passed by the cap wire electrode, and when the vacuum retard is defeated, the rotor center will not yet have passed directly under the cap wire electrode.  Since the electrode on the end of the rotor is about 2 cm wide, a portion of the electrode will ALWAYS be dead under the cap wire electrode.  Does this sound ok, or am I asking for trouble.

I will post some crude diagrams I whipped up with M$ Paint to better illustrate.

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Cees Klumper]

Hi Blair. I'm not familiar with the Crane setup but I do have an optical trigger electronic ignition. What I did both times after installing it, is just setting the initial timing roughly right, so that the car would at least start. After that, I used the regular procedure for setting the timing with a strobe light to get it into the proper specs, which worked fine. It seems to me that, if you go the same route, you should be ok? Anyone else with the Crane setup may be able to comment better.
Good luck (also with the coolant leak etc etc)!

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[jeffc280sl]

Hi Bill,

For the trigger alignment I followed the instructions on page 13 of the Crane instruction book.  I mocked up the system as per John's figure 2-6.  When the ignition module diagnostic led illuminated on the leading edge of the disk I fixed the trigger position.  It was not necessary to consider advance and retard distributor conditions as the distributor was not installed during this alignment.  It all works great.  Crane talks about the led making the alignment easier.  Maybe earlier models didn't have the led.  Hopefully you do!

Jeff C.
1970 280SL 4-speed

[blairwag]

Thanx, Cees. As always, your wisdom gives me comfort!  Keep your fingers crossed for me. I attempt to start her up tonight!

Hi Jeff. Yea, I've got the LED. I can't imaging doing this without it. The Crane doc doens't talk about advance/retard considerations, nor does John. But understanding how the ingition system works makes me think about it. Maybe knowing too much is the problem. Anyway, that's why the electrode on the end of most rotors is so large. It needs to have a long left-right area, so that the spark still can have the shortest distance to junp when arcing from the rotor to the cap wire electrode, regardless of where the distributor strike plate is in relation to the TDC-cyl-1 marker/position. Both the Crane doc, and John's doc made it sound critical to success to have the rotor positioned at *EXACTLY* TDC-cyl-1 when the leading edge of the shutter window passed by the trigger.

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[blairwag]

Here are the pics reflecting the way I set the phasing initially, before installing the distributor and attempting the first turn key...

This is John Hassel's suggestion, which also agrees with that of the Crane installation documentation:

Download Attachment: Phase-0.jpg
26.18 KB

These diagrams reflect how I set it up, considering both the retard position and the advance position of the rotor:

Download Attachment: Phase-Ret.jpg
26.51 KB


Download Attachment: Phase-Adv.jpg
22.84 KB

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[blairwag]

All put back together... and running too!  The Crane XR700 conversion was very successful. The car doesn't run much better than before, but it was running pretty good before... so that's still good news.

I thing Cees was right. Getting the phasing exact is not necessary, just get it close, and set near ignition of 0 TDC so the car starts. Then set the timing accordingly. With the XR700, I was finally able to set the proper ignition timing per the BBB:
 8 degress ATDB @800  RPM w/vacuum
10 degrees BTDC @800  RPM w/o vacuum (on the mark)
 5 degrees BTDC @1500 RPM w/vacuum
30 degrees BTDC @3000 RPM w/vacuum

I did not get to take it out for a test drive, to ensure there are no severe misses under load. The hood is still off, and it's raining outside.

I installed the Crane box under the battery where the MB un it was. The install was clean and neat. Other than the red and yellow wires from the Crane box, you can't tell that the car was modified with electronic ignition.

Here are some pics to show off my art work...

Download Attachment: Crane-1.jpg
56.73 KB

Download Attachment: Crane-2.jpg
40.48 KB

Download Attachment: Crane-3.jpg
76.6 KB

Once I get the new Beru ignition wireset from the Good Doctor, I'll reinstall the distributor and coil dust covers, and make the whole thing complete. The electronic ignition will be virtually invisible then!


--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[Cees Klumper]

Congratulations Bill! Nice work!

Now to add to your list of to-do's ... the engine could do with a modest detailing (sorry) ...
Of course it's the proper performance that's most important.

Cees Klumper in Amsterdam
'69 white 280 SL automatic

[blairwag]

Hi Cees.  YEa, laugh!  You're right.  However, I can hardly afford to keep the darn thing running, let alone spiffing up the engine compartment with shiney new parts   .  But, it's on the radar scope ...along with engine rebuild, and car restoration.    Likely wont happen any time soon, though  

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~

[blairwag]

Test drive went GREAT! Car runs like a top. Doesn't start quite as quickley, since replacing the plugs with Bosch W8DC. Previous plugs were W9DC gapped at 1.0mm.  The Good Docter suggests a wider gap, so I'll try that, to see if it improves the starting. It's not hard starting, just not as quick as before.
Note: Dan the Docter uses W9DC plugs, at Bosch factory gap.

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~
William Blair Wagner: blairwag@earthlink.net
Education is not always knowing the answer,
...but rather knowing where to look for it!
1971 280SL US Automatic
~~~~~~~~~~~~~~~~~~~~~~~~~~~