#1
IP: 24.218.150.114
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Mystery Distributor Plate Orientation
While wrapping up my head and water jacket rebuild i have discovered a new point of concern... it appears the previous owner may have installed the breaker plate with the wrong orientation. The part that juts out for ensuring you have the rotor lined up for installes is off by 90 degrees. This also means the orientation of the points and condenser are off also. Does this matter? Part of me thinks it doesn't since the motors runs but it seems like it should be reoriented properly.
The second thing i found in this search is that at TDC when #1 is all the way up the rotor essentially points opposite the motor and slightly to the left... though the electrode witin the distributor cap is 15 degrees behind it assuming a clockwise rotation.... it seems like this is way too far "advanced". Secondly I was looking at the inside of my distributor cap and thinking it didn't look bad until i looked closer and saw a 'V' shaped bit of plastic leading up to the electrode... what I can;t tell is if this 'V' shape was home to the lower part of each electrode or if it is simply part of the delco distributor design? If worn... all electrods look evenly worn.. please note i did have an overheating issue and i suppose this far advance in the timinng could have been a contributing factor? I have a 74 late model in a Catalina 27. Last full tuneup including distributor cap was 2 years ago. I have an electronic ignition waiting to go in but i want to make sure the old system was peoplely calibrated before creating any new variables. Any helpful hits woudl be appreciated. |
#2
IP: 64.252.193.231
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Distributor Orientation
The gear on the distributor has 14 teeth, so there are 14 possible orientations for the rotor when #1 cylinder is at TDC on the compression stroke. I install mine so that the tip of the rotor is point directly outboard away from the engine. The distributor body then is rotated so that the points are just opening and the ear on the plate is also pointed outboard. This will also put the coil lead on the aft side. When the cap is installed, this puts the lead to the #1 plug on the outboard side away from the engine.
Al |
#3
IP: 69.237.145.149
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"Picture Perfect"
Fvigeant,
The correct orientation of the distributor can be seen by going to the panoramic picture on the home page and rotating it around to the right side of the engine. As Al states, this puts the wiring in the "neatest" position and also eliminates alternator belt clearance problems that show up sometimes. With the #1 cylinder at TDC on the compression stroke the rotor will wind up pointing directly to starboard at 0 degrees of advance. Since you have indicated that you will be changing to an electronic ignition (assumming that you are converting your dist.) this would be a good time to clean and lube your advance weights. Normal base timing specs are 0 degrees at idle and advancing to 17 degrees at about 1700 rpm. Had a Cat 27, nice boat. Tom |
#4
IP: 24.218.150.114
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Thanks took a look at both your comments and the online pic. I also watched Don's ignition timing video. It seems like from what you are saying the orientation of the braker plate is a matter of preference so long as the rotor is aligned to the #1 wire position when at TDC?
My rotor is aligned to point directly away from the engine at #1 so we are all in agreement with how this element is oriented... however the breaker plate is actually off 180 degrees! as indicated by the alignment tab... my concern is 2 fold: 1) Does this matter 2) If it does... do i unscrew and reorient the breaker plate or spin the housing only so the plate alignment tab actually aligns with the rotor at TDC... right now it is the opposite of aligned. My assumption is this will affect the time at which points open and close as well as the fly weights. Sorry to be dense I just can deal with blowing my rebiuld by inncorrectly messing with the timing. |
#5
IP: 64.252.193.231
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Breaker Plate
The breaker plate will only fit into the distributor body one way. There's an insulator grommet on the edge of the plate that fits into a notch in the body. To make it 'picture perfect', you should rotate the body (and the plate) so the ear on the plate is outboard and the wire back towards the transmission. The exact angle is such as to have the points just opening as you move the body slightly CCW. When you put the cap on, the #1 wire will be outboard, then #2 #4 #3 proceeding CW.
There are obviously 3 other orientations that will work, but they make leading the coil wire more difficult. |
#6
IP: 64.231.108.224
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What kind of distributor do you have? Delco/Remy or Prestolite? They each orientate in a slightly different direction and can be retrofitted to either early or late model A4's.
If you are not the original owner you never know what the P/O may have done to the engine prior to your purchase. |
#7
IP: 24.152.131.220
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Just Because it Works Doesn't Make it Right
In the purest sense of the exercise, the plate can be misoriented at 90 degree intervals and the system will work just fine. The Ignitor system (or points) tells the coil when to fire, the distributor cap and rotor determine which plug gets the jolt. For reference, a 6 cylinder's misorientation would still work at 60 degree intervals, an 8 cylinder at 45 degree intervals - not the distributor cap and rotor but rather the internal trigger mechanism that fires the coil.
I'd be more concerned over the Ignitor wires exiting the distributor as it relates to chafe and pinching. As Al said, with the plate oriented properly there's a relief and grommet to protect the wires where they exit. Even if it works positioned wrongly, there's merit in doing it right regardless of the P.O.'s handiwork.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 07-03-2010 at 05:49 PM. |
#8
IP: 24.218.150.114
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I have a late model with a delco. I mustered up the guts to reorient it...I think the PO had this thing way off... glad it didnt wreck my engine. My process was to take it to TDC then carefully pulled out the distrib unit went back a couple teeth so the rotor was straight out at TDC and then spun the body so the alignment tab lined up. Will check continuity next. I have the MMI electronic ignition kit... provided the engine starts up with my most recent timing mod do you reccomend throwing in the electronic ignition? Also any thoughts about doing the dynamic timing aspect before or after installing the electronic ignition?
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#9
IP: 71.252.8.223
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fvigeant,
one thing at a time. If you think it was dis-oriented, get it running first. Then you can upgrade to the electronic ignition and keep the old points system as a spare. I am like you....I want to do 18 things at once, but then I never know which one fixed it....I am learning to be methodical with this motor. By the way (BTW) - Once you have the motor running well, I'd definitely recommend the electronic ignition.
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-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#10
IP: 142.68.242.241
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From MMI's panoramics at http://www.moyermarine.com/360/index.html.
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1974 C&C 27 Last edited by rigspelt; 07-04-2010 at 09:30 AM. |
#11
IP: 24.218.150.114
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Good news, the engine fired right up with teh new destributor orientation with a better smoother sound than ever and much higher RPMS. Thanks!
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