SDPC adjustable timing set ?????
You can't worry about the DOTS if your using advance or retard other than using the DOTS as a reference EXCEPT for the cam DOT which never changes (always at 6 o'clock). You must only use the DOTS (crank sprocket chain DOT and crank sprocket keyway DOT) as a reference so you get the new timing position you select set properly. You must maintain the SAME RELATIONSHIP between the advance or retard keyway you choose to use and the associated crank sprocket chain tooth as you see in the STANDARD (ZERO) DOTS. On the Rollmaster this is approx 2 3/4ths crank sprocket teeth from DOT TO DOT. Check it yourself to be SURE on the SDPC. If you want to illustrate this you can use whiteout or a felt tip pen to mark the keyway you want to use and the corresponding crank sprocket chain tooth that is ASSOCIATED with that keyway. The relationship MUST be maintained. The cam sprocket always remains at 6 o'clock during this process, but the crank sprocket chain DOT will NOT be at 12 o'clock if you choose to use advance or retard. If you choose to add advance you will have to rotate the crankshaft slightly CCW once you place the crank sprocket on the crankshaft in its' new position to get the crank sprocket tooth that is associated with the keyway you have selected PRECISELY at 12 o'clock. This can be confusing, but if the cam always remains in the same position during the timing process as it should then the crankshaft MUST be moved in relation to the cam for timing to change. Advancing the crank has the effect of retarding the cam and vice versa. Are you more confused now or less?
ok let me ask it barney style and maybe ill get a barney answer, if i want to retard 2 deg. where will the dots be, I KNOW THEY ARE NOT USED TO SET THE TIMING anymore but when its set up correctly, where will they be ie: if the set were retarded 2 deg the crnk dot would be at 11 and the cam dot at 7, is this correct?
This is how I do it (keeps everything straight).....
Retard:
1) Set the crank and cam sprockets dot to dot (0 degrees advance/retard) without the chain on
2) Pull the crank sprocket off the crank and retard it (rotate the sprocket to the left 2 degrees)
3) Reinstall the crank sprocket
4) Now the crank dot will be at ~11 o’clock (2 degrees retarded) and the cam will still be at 6 o’clock
5) Turn the crank till the crank and cam are dot to dot
6) Install the chain
This will move the crank "ahead" of where it would have been in relationship to the cam at a "standard" dot-to-dot line up (0 degrees advance/retard) and thus the cam will be retarded (behind)
Retard:
1) Set the crank and cam sprockets dot to dot (0 degrees advance/retard) without the chain on
2) Pull the crank sprocket off the crank and retard it (rotate the sprocket to the left 2 degrees)
3) Reinstall the crank sprocket
4) Now the crank dot will be at ~11 o’clock (2 degrees retarded) and the cam will still be at 6 o’clock
5) Turn the crank till the crank and cam are dot to dot
6) Install the chain
This will move the crank "ahead" of where it would have been in relationship to the cam at a "standard" dot-to-dot line up (0 degrees advance/retard) and thus the cam will be retarded (behind)
ok so i would not move the cam sproket? to retard 2 degrees just move the cranl sproket to the left, then rotate till its dot2dot then put on the chain?
Joined: Nov 2001
Posts: 3,043
Likes: 0
From: Texas and Qatar
When you adv/retard with keyway position, you cannot use the 0 adv timing mark anymore. You have to make a new TDC mark on the crank gear. If you pull your stock crank gear off while at TDC, and set the new gear right back on with 2 deg advance, you'll see that the old timing mark is 2 teeth off. So from there if the crank hasn't been turned over, your new crank TDC mark will be at 12 o clock. You can verify that the #1 or #6 piston is at TDC also.
ok so i would not move the cam sproket? to retard 2 degrees just move the cranl sproket to the left, then rotate till its dot2dot then put on the chain?
Now if you were using the factory timing chain (or other "non adjustable" version) to advance/retard the cam, you would need to make NEW dots on the cam sprocket at 2/4/6/8etc degrees (because it only has one keyway) and then line the cam dot to the NEW dot on the crank.....




