Background: A) 308 GTS, running dual distributors and single set of points B) Pulled the carbs off, wound up rebuilding them completely C) I needed to retorque the rear head so i pulled both cam covers to get them refinished. D) while replacing gaskets, I removed the distributors and tried to mark them carefully but screwed that up. Also, one distributor was in 180 degrees off so I wanted to correct that. E) i put the distributors back in per the WSM, lining up the timing marks for AF7 on both PM1-4 and 5-8 banks F) Once the distributors were back in, I hooked up a voltmeter to the R1 point terminal on each bankand turned the ingition on (fuel pump fused pulled), then i rotated the distributors until i recieved voltage (ie rotor aligned with cap terminal). Two questions A) The WSM says to initially set the distributor so its in the middle of the slotted holes. Using my method above, i didnt recieved voltage until the distr was rotated all the way to one side (both banks). I remember when i pulled them off they were both maxed out to one side. Do i need to reset the distributors so I get "voltage" more in the center of the slotted hole? B) since the car hasnt run since the carbs were off, and i removed the distributors, i have to worry about setting fuel and spark - is there a better way to get the timing as close as possible prior to starting/running? TIA, Geno
after doing some more research, i think my above post had some errors...sorry not an expert just learning how this thing works... With the ignition key on, and the voltmeter connected to the R1 post and the other end to ground, I should be searching (via turning the cap) for where there is zero current (open circuit), which represents when the points are open. All other positions should read current (when the points are closed). Is that correct? It is possible to get the timing set perfectly this way?
Yes, but if you are using a voltmeter connected in parallel with the R1 points (and measuring volts) it would be: With the flywheel at the idle firing location for bank X, turn the housing/cap of dist X in the opposite direction to the direction the rotor normally rotates until the points (just) open = the firing event = the voltmeter reads +12V (instead of the 0V it will read when the points are closed)
Thank you Steve. Two questions: 1) is the "idle firing location" the AF7 mark on the flywheel? 2) I get voltage when i turn the distr cap all the way pegged out clockwise. Should i reposition the dist so i get the voltage reading in the center of the slotted hole?
Yes -- for a US '78 308 using only the R1 points, AF7 (7 deg BTDC) is a reasonable idle timing (but there are different AF7 marks for each bank). Functionally, it wouldn't matter, but it would look better IMO to not be at the extreme of the adjustment. IIRC (and I'm only about 50% sure on this), there are 24 splines on the distributor shaft -- so each spline = 15 deg, while the slots are about ~30 deg wide total. First, try remounting the distributor shaft rotated by 1 spline CCW relative to the cam from where it is now -- this should cause the housing to also move 15 deg CCW and get you more in the middle of the adjustment slots (IF 1 spline = 15 deg, and the slots are 30 deg wide ). However, after you get things set-up, remove the cap and check that the rotor end is (reasonably) pointing at the alignment notch in the rim of the distributor housing (the red-filled notch in this jpeg) which confirms that the rotor end will correctly overlap the contact in the cap for the #1/#5 spark plug wire. If this relationship is not also correct, you will need to move the R1 point relative to the distributor housing to make it so: Image Unavailable, Please Login
Got it. I recall when putting in both distributors the other day they were really finnicky about going into the spline, they only wanted to seat in one spot (where I put them). Also, when i pulled them off, i notice they were both pegged to the clockwise side all the way. I will pull them off and see if i can get them centered and see what happens. Thanks for teh advice Steve, much appreciated. Geno
Steve (or anyone); I messed around with the distributors today, and found the following. Position A: As i first installed it, the points go from closed to open with the distributor rotated nearly all the way fully clockwise (they open when rotating the distributor counterclockwise just a tad from the fully maxed out counterclockwise position) Position B: Then when i pull the dist out an move it one spline position, the points go from closed to open with the distributor rotated nearly all the way fully counterclockwise (they open when rotating the distributor clockwise just a tad from the fully maxed out clockwise position). Bottom line, in either spline position the point where the points open/close is just a knats ass off of fully maxed out, meaning there will be no room to move the dist in one direction when i check the timing dynamically. So, which position is best to start with, A or B (ie, if the timing were to need adjustment, which way would it be?). Sorry if a stupid question. Geno
1/2 dozen of one or six of another -- how is your rotor end -to- alignment notch relationship? Maybe you could make an argument that as the point block wears it would favor readjusting in a certain direction, but it's not a big deal if you had it the other way to move over the 1 spline, if necessary, when making the readjustment IMO. Did you count the splines? There must only be 12 (i.e., 1 spline = 30 deg, like the slot) -- my bad.
thats about 16-17 degrees of adjustment. Are you sure the slot is 30 degrees? It looks more like 20 degrees. If it is in fact 30 degrees (maybe i will take it back off and measure it) and the splines are 16-17 I should be able to get it better right?
You're right, I mis-recalled the size of the slot. I dug thru my 308 notes, and I have the slot as being roughly 25 mm long end-to-end -- which works out to about 17.6 deg of adjustment for an 8mm diameter stud at a radius of ~55 mm. Thanks for confirming the correct number of splines.
