put in my new distributor... little help.
#21
Edit: Having re-read your post I’ll just ask how your Light knows 60 degrees from TDC. Given one value, SPARK. How can it determine anything other than “there is a spark”? Set it to 0. Or better yet buy a vintage light that just flashes on spark. See where your spark is illuminating the mark’s position relative to the gauge.
Put the engine at TDC. Rotate the engine ( forward ONLY ) by hand using the crank nut, and checking piston position in cyl A1. This can be complicated as you want, or watch a screwdriver ride up out of the spark plug hole. You can judge if you’re on the compression stroke by looking For the valve, visible in the SP hole on exhaust. Put the dizzy back in pointed at A1. You’ll be close.
You can look through the stickys for Grants write up. I’m pretty sure he has one for this occasion.
It also sounds like you’re unsure of the pickup’s gap. It should be .007’’-.015’’ and you need a brass feeler gauge to set it due to the pickup’s magnet.
Put the engine at TDC. Rotate the engine ( forward ONLY ) by hand using the crank nut, and checking piston position in cyl A1. This can be complicated as you want, or watch a screwdriver ride up out of the spark plug hole. You can judge if you’re on the compression stroke by looking For the valve, visible in the SP hole on exhaust. Put the dizzy back in pointed at A1. You’ll be close.
You can look through the stickys for Grants write up. I’m pretty sure he has one for this occasion.
It also sounds like you’re unsure of the pickup’s gap. It should be .007’’-.015’’ and you need a brass feeler gauge to set it due to the pickup’s magnet.
Last edited by JigJag; 08-10-2018 at 10:25 PM.
#22
Edit: Having re-read your post I’ll just ask how your Light knows 60 degrees from TDC. Given one value, SPARK. How can it determine anything other than “there is a spark”? Set it to 0. Or better yet buy a vintage light that just flashes on spark. See where your spark is illuminating the mark’s position relative to the gauge.
Put the engine at TDC. Rotate the engine ( forward ONLY ) by hand using the crank nut, and checking piston position in cyl A1. This can be complicated as you want, or watch a screwdriver ride up out of the spark plug hole. You can judge if you’re on the compression stroke by looking For the valve, visible in the SP hole on exhaust. Put the dizzy back in pointed at A1. You’ll be close.
You can look through the stickys for Grants write up. I’m pretty sure he has one for this occasion.
It also sounds like you’re unsure of the pickup’s gap. It should be .007’’-.015’’ and you need a brass feeler gauge to set it due to the pickup’s magnet.
Put the engine at TDC. Rotate the engine ( forward ONLY ) by hand using the crank nut, and checking piston position in cyl A1. This can be complicated as you want, or watch a screwdriver ride up out of the spark plug hole. You can judge if you’re on the compression stroke by looking For the valve, visible in the SP hole on exhaust. Put the dizzy back in pointed at A1. You’ll be close.
You can look through the stickys for Grants write up. I’m pretty sure he has one for this occasion.
It also sounds like you’re unsure of the pickup’s gap. It should be .007’’-.015’’ and you need a brass feeler gauge to set it due to the pickup’s magnet.
#24
Reading the timing at idle will not include any centrifugal advance. So reading it at 3000 will be even further off the scale.
Light is is connected to A1 ( Right, front ) wire. Light set to 0. You get 60ish BTDC. That is 30 dizzy degrees if my coffee is working. 30 is a 12th of 360 right? Sounds to me like you’re out one tooth out of the 15 on the drive. Ish. There’s also the adjustment slots, and the adjustment cam.
Oh yeah! Have you tested your damper? Mark your pulley with a line across all the pulleys and rev it a bit. Confirm that the line still aligns on both sides of the damper. If this slips then the TDC line becomes meaningless.
Light is is connected to A1 ( Right, front ) wire. Light set to 0. You get 60ish BTDC. That is 30 dizzy degrees if my coffee is working. 30 is a 12th of 360 right? Sounds to me like you’re out one tooth out of the 15 on the drive. Ish. There’s also the adjustment slots, and the adjustment cam.
Oh yeah! Have you tested your damper? Mark your pulley with a line across all the pulleys and rev it a bit. Confirm that the line still aligns on both sides of the damper. If this slips then the TDC line becomes meaningless.
#25
Reading the timing at idle will not include any centrifugal advance. So reading it at 3000 will be even further off the scale.
Light is is connected to A1 ( Right, front ) wire. Light set to 0. You get 60ish BTDC. That is 30 dizzy degrees if my coffee is working. 30 is a 12th of 360 right? Sounds to me like you’re out one tooth out of the 15 on the drive. Ish. There’s also the adjustment slots, and the adjustment cam.
Oh yeah! Have you tested your damper? Mark your pulley with a line across all the pulleys and rev it a bit. Confirm that the line still aligns on both sides of the damper. If this slips then the TDC line becomes meaningless.
Light is is connected to A1 ( Right, front ) wire. Light set to 0. You get 60ish BTDC. That is 30 dizzy degrees if my coffee is working. 30 is a 12th of 360 right? Sounds to me like you’re out one tooth out of the 15 on the drive. Ish. There’s also the adjustment slots, and the adjustment cam.
Oh yeah! Have you tested your damper? Mark your pulley with a line across all the pulleys and rev it a bit. Confirm that the line still aligns on both sides of the damper. If this slips then the TDC line becomes meaningless.
#26
Oh man what a wasted day... got it all taken apart and moved the distributor one tooth the wrong direction. I moved it counter clockwise instead of clockwise. So after putting it all together and it not starting, I dug it all back out and tried to move it 2 teeth clockwise and I guess I only got it back one. So just to make sure I got back under with the timing light and sure enough it was the same. Haha dang it!
#27
Finally got out and turned the distributor one more tooth(the right direction this time!). Started it up and it ran so smooth I thought something else must be wrong. It’s never idled so quiet and smooth. I got under with the timing gun and it’s sitting right at 4degrees btdc. So it needs a bit of adjustment but I can’t believe since I’ve had the car it’s always been that badly off. I have a feeling I’ve never turkey yet felt the full power and smoothness of this V12.
#28
#29
#30
#31
Im assuming this 4 BTDC was with the vacuum advance connected. Is that correct? If so, disconnect the vac capsule and advance your dizzy until around 10 BTDC at idle. EDIT: This should read 0 BTDC.
I believe the dizzy in my HE has 10 degrees of centrifugal advance available. Best reading I could get in-situ. Reconnect the vac cap, hold it at 3000 RPM and dial it in to 18 BTDC. Go test it! Then read Grant’s “drive timing” writeup.
Last edited by JigJag; 08-16-2018 at 07:15 PM.
#32
Fantastic job!
Im assuming this 4 BTDC was with the vacuum advance connected. Is that correct? If so, disconnect the vac capsule and advance your dizzy until around 10 BTDC at idle.
I believe the dizzy in my HE has 10 degrees of centrifugal advance available. Best reading I could get in-situ. Reconnect the vac cap, hold it at 3000 RPM and dial it in to 18 BTDC. Go test it! Then read Grant’s “drive timing” writeup.
#33
disconnectimg the vacuum advance should make no difference at 3000. Vacuum should be below 5 with the throttle open. But disconnecting it ensures that you’re looking at nothing but centrifugal advance.
I edited the procedure above. Static timing at idle should be 0 BTDC according to AJ6eng.
Last edited by JigJag; 08-16-2018 at 08:12 PM.
#34
on the Jag V12 the factory timing is not specified at idle, but at 3000 RPM. This is to ensure centrifugal ( the really important one ) advance is performing correctly. Set it here then check static timing at idle and ensure it is approx 10 degrees less. If it’s the same at idle your cent adv is stuck. Fix it! Still, better to run with 18 degrees at idle than 8 at 3000!
disconnectimg the vacuum advance should make no difference at 3000. Vacuum should be below 5 with the throttle open. But disconnecting it ensures that you’re looking at nothing but centrifugal advance.
I edited the procedure above. Static timing at idle should be 0 BTDC according to AJ6eng.
#35
Set the timing yesterday... I kinda did a light/“feel” combo. The car is so smooth and quiet now that at times when braking I couldn’t hear the engine at all and thought it had quit. Ha
the only thing now though is it wants to shift to 2nd ASAP. I floored it a couple times while taking off from a turn onto the road and it shifted straight to 2nd. If I put it in first it holds and goes to about 5k before bucking and wanting to shift. So I’m guessing the governor still needs to be changed.
the only thing now though is it wants to shift to 2nd ASAP. I floored it a couple times while taking off from a turn onto the road and it shifted straight to 2nd. If I put it in first it holds and goes to about 5k before bucking and wanting to shift. So I’m guessing the governor still needs to be changed.
#36
#37
#38
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As you are on the right track, so I only have a couple of comments:
1. If the distributor drive gears are helical, one must allow for the twist as the gears mesh. Ie, start a bit back from the desired point. Tricky on SBC engines, as one also has to engage the oil pump.
2. The protocol for initial time adjustment is no vacuum. Determining the bas line for further diagnosis or adjustment. A popular initial setting sands vacuum or centrifugal advance. Around 10 to 14 degrees.
3. The vacuum or the lack there of changes the fire point,.
4. add in rpm's and the centrigfugal advances the time of fire.
Carl
1. If the distributor drive gears are helical, one must allow for the twist as the gears mesh. Ie, start a bit back from the desired point. Tricky on SBC engines, as one also has to engage the oil pump.
2. The protocol for initial time adjustment is no vacuum. Determining the bas line for further diagnosis or adjustment. A popular initial setting sands vacuum or centrifugal advance. Around 10 to 14 degrees.
3. The vacuum or the lack there of changes the fire point,.
4. add in rpm's and the centrigfugal advances the time of fire.
Carl
#39
#40
As you are on the right track, so I only have a couple of comments:
1. If the distributor drive gears are helical, one must allow for the twist as the gears mesh. Ie, start a bit back from the desired point. Tricky on SBC engines, as one also has to engage the oil pump.
2. The protocol for initial time adjustment is no vacuum. Determining the bas line for further diagnosis or adjustment. A popular initial setting sands vacuum or centrifugal advance. Around 10 to 14 degrees.
3. The vacuum or the lack there of changes the fire point,.
4. add in rpm's and the centrigfugal advances the time of fire.
Carl
1. If the distributor drive gears are helical, one must allow for the twist as the gears mesh. Ie, start a bit back from the desired point. Tricky on SBC engines, as one also has to engage the oil pump.
2. The protocol for initial time adjustment is no vacuum. Determining the bas line for further diagnosis or adjustment. A popular initial setting sands vacuum or centrifugal advance. Around 10 to 14 degrees.
3. The vacuum or the lack there of changes the fire point,.
4. add in rpm's and the centrigfugal advances the time of fire.
Carl