Initial Ignition Timing Before First Start
#1
Rennlist Member
Thread Starter
Initial Ignition Timing Before First Start
1982 928 4.5L Manual Trans.
The workshop manual clearly states to set timing to: 23 degrees BTDC at 3000 rpm with vacuum hose disconnected. No problem there.
But I've taken most of the engine apart and am now just getting it ready for first start. And I would prefer to fire it up with the timing at least close to accurate.
Is there a way to set the timing without the engine running? In an old air-cooled VW, I would do this by hand-cranking the engine and twisting the distributor until it sparked at just the right place.
Can I do something like that on a 928? What degree should it fire at at 0 rpm? If its in the WSM and I'm missing it, please let me know.
The workshop manual clearly states to set timing to: 23 degrees BTDC at 3000 rpm with vacuum hose disconnected. No problem there.
But I've taken most of the engine apart and am now just getting it ready for first start. And I would prefer to fire it up with the timing at least close to accurate.
Is there a way to set the timing without the engine running? In an old air-cooled VW, I would do this by hand-cranking the engine and twisting the distributor until it sparked at just the right place.
Can I do something like that on a 928? What degree should it fire at at 0 rpm? If its in the WSM and I'm missing it, please let me know.
#2
Rennlist Member
Curious what the pros like Stan will offer on this.
On my similar 84 USA.... crank pully installed with writings readable from vantage point in front of car, set at TDC vs water pump mounted pointer; divit on backside edge of each cam gear aligned with pointers on front of each of the forward facing cam gear backing plates ( Mickey mouse ears ), distributor installed with leading edge of rotor aligned with divit on distributor base. Those are initial conditions. Distributor 13mm bolt loosened. Distributor rotated to about midway in its range, maybe a bit counterclockwise of mid range.
Should start. I've then put on thick rubber glove for safety and rotated distrib for ear tune.
Above just in case you need the very basics to get going....
On my similar 84 USA.... crank pully installed with writings readable from vantage point in front of car, set at TDC vs water pump mounted pointer; divit on backside edge of each cam gear aligned with pointers on front of each of the forward facing cam gear backing plates ( Mickey mouse ears ), distributor installed with leading edge of rotor aligned with divit on distributor base. Those are initial conditions. Distributor 13mm bolt loosened. Distributor rotated to about midway in its range, maybe a bit counterclockwise of mid range.
Should start. I've then put on thick rubber glove for safety and rotated distrib for ear tune.
Above just in case you need the very basics to get going....
#3
Rennlist Member
Thread Starter
Thank you! I will see if a 'pro' weighs in, but this is good info. I had assumed that the divits in the cam gears would line up whenever the crank was set at TDC, but maybe I have to go through a couple rotations for that to happen. I put the distributor cap on a while ago and must have missed the divit on that distributor. Also, thanks for the rubber glove reminder. Been shocked by a coil once before and it ain't fun... plus, 'the ticker' is a lot older than the last time that happened.
#4
Team Owner
FWIW the crank damper will line up at TDC once with the cam marks and once with the cams 180 degrees away from the timing marks.
Chris gave a good route to follow for the initial timing.
TO BE Clear the damper is on correctly when, at TDC
your facing the engine you can read the numbers IE they are not upside down
Chris gave a good route to follow for the initial timing.
TO BE Clear the damper is on correctly when, at TDC
your facing the engine you can read the numbers IE they are not upside down
#5
Rennlist Member
Thread Starter
Thanks Landseer and MrMerlin! I was following another post where the dampner was on backwards, so I know why you might say that. The photo below should confim mine's on correctly. Plus I shared a photo of the finished work before it went in... just to show it off!
The following 2 users liked this post by smai:
Flinstigator (02-21-2023),
Mrmerlin (02-21-2023)
#6
Rennlist Member
Thread Starter
Glad I asked! The way I had the distributor in initially, my timing was off by a lot. This is what it looks like with TDC and both cam timing belts lined up:
#7
Team Owner
That should get it started