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1979 shop manual states to set rotor between #1 and #8 at TDC
Been fighting with my 1979 L48 timing. Went back and looked at the 1979 shop manual I have and it stated to set TDC #1 with harmonic balancer mark at 0 and then point rotor between #1 and #8 distributor cap towers before dropping the distributor in. Which when I do the distributor rotor turns clockwise as it goes into the cam gear and moves closer to #8, did not sound correct. I will attach pictures of manual. I read Lars papers on timing, the manual I have does not match Lars recommendation, also tried with no luck.
Problem I have been having is my engine is requiring a 30+ degree of initial advance to run, not sure why. My harmonic balancer is brand new, I have set TDC with piston stop at least 10 times. installed a new cycloes timing set and yes I have the dots lined up. Can't figure why high initial timing. The engine is the original L48 engine with original distributor all with 88K total miles on it.
Would be interested if anyone else ran into this and found a solution.
did you do anything to the original timing tab on the cover?
the harmonic balancer is the same diameter as the original?
forgive this question if too basic but you do have the timing light connected to the front spark plug wire on the drivers side?
you are setting the timing with the vacuum advance disconnected?
the distributor weights are fully retracted by the springs?
what is the manufacturer and part number of the balancer?
What exactly are you "fighting with my 1979 L48 timing".
During your initial setup, are you feeling the compression with you finger over the spark plug hole on the exhaust or power stroke?
"Yes I have the dots lined up", are you sure the right dots are lined up?
Some gear sets have degree dots marked on the gears to advance or retard the initial timing using the gears and timing chain during assembly.
The final instruction is to set timing, so the only effect that instruction would have is to possibly move where the distributor is rotated when properly timed. In other words, move the distributor rotation a gear either way.
Did you try a different timing light to confirm it wasn't the timing light?
Describe the steps you did when using the piston stop to find the 0* timing mark. I have a feeling you may have done this part wrong since you never set TDC using a piston stop.
Last edited by lionelhutz; 05-24-2018 at 01:47 PM.
did you do anything to the original timing tab on the cover?
the harmonic balancer is the same diameter as the original?
forgive this question if too basic but you do have the timing light connected to the front spark plug wire on the drivers side?
you are setting the timing with the vacuum advance disconnected?
the distributor weights are fully retracted by the springs?
what is the manufacturer and part number of the balancer?
Great questions, I have put answers below
did you do anything to the original timing tab on the cover? No kept reinstalled the original
forgive this question if too basic but you do have the timing light connected to the front spark plug wire on the drivers side? yes I did connect to front plug, but will go over that again
you are setting the timing with the vacuum advance disconnected? Yes it is disconnected
the distributor weights are fully retracted by the springs? Yes I took a look at that and they retracted
What exactly are you "fighting with my 1979 L48 timing".
During your initial setup, are you feeling the compression with you finger over the spark plug hole on the exhaust or power stroke?
"Yes I have the dots lined up", are you sure the right dots are lined up?
Some gear sets have degree dots marked on the gears to advance or retard the initial timing using the gears and timing chain during assembly.
During your initial setup, are you feeling the compression with you finger over the spark plug hole on the exhaust or power stroke? Yes I checked that, will double check again
Some gear sets have degree dots marked on the gears to advance or retard the initial timing using the gears and timing chain during assembly. Yes mine has three I picked the one for factory which is half moon. I have a picture some where I can publish if you would like to see it, have to go dig it up
when you verify TDC on the compression stroke is the harmonic balancer mark also pointing to 0* ?
are you using a dial back timing light?
the disributor will always advance the same amount when you drop it in....you can measure it its always the same amount. you can "clock it" easy one tooth in either direction by moving it slighty. use blue tape on the distributor base and measure where the rotor is pointing when you start taking it out and where it ends up.
you can use the spark plug towers to approximate where the rotor needs to point just mark a line with a sharpie at the bottom of the tower on the distributor base.
if i had to guess.....you have a harmonic balancer that has the index line not where it needs to be.....no biggie just paint a new line on it. and this is because the timing chain covers oftern get switched and the pointer location is in a different spot
The final instruction is to set timing, so the only effect that instruction would have is to possibly move where the distributor is rotated when properly timed. In other words, move the distributor rotation a gear either way.
Did you try a different timing light to confirm it wasn't the timing light?
Describe the steps you did when using the piston stop to find the 0* timing mark. I have a feeling you may have done this part wrong since you never set TDC using a piston stop.
Yes I checked alternate light.
Description of finding TDC #1 with engine stop
1. insert engine stop into #1 spark plug
2. turn engine over clockwise by hand until piston 1 stops against engine stop
3. Mark line on balancer at 0 position
4. Turn engine over counter clockwise (reverse) until piston 1 stops against engine stop
5. Mark another line on balancer at 0 position
6 measure distance between two new lines and the middle is top dead center. Which in my case is the same line that the balancer has marked as 0. See my attached pictures, from what I have read that is the correct way let me know if I am missing something. thanks
Been fighting with my 1979 L48 timing. Went back and looked at the 1979 shop manual I have and it stated to set TDC #1 with harmonic balancer mark at 0 and then point rotor between #1 and #8 distributor cap towers before dropping the distributor in. Which when I do the distributor rotor turns clockwise as it goes into the cam gear and moves closer to #8, did not sound correct. I will attach pictures of manual. I read Lars papers on timing, the manual I have does not match Lars recommendation, also tried with no luck.
Problem I have been having is my engine is requiring a 30+ degree of initial advance to run, not sure why. My harmonic balancer is brand new, I have set TDC with piston stop at least 10 times. installed a new cycloes timing set and yes I have the dots lined up. Can't figure why high initial timing. The engine is the original L48 engine with original distributor all with 88K total miles on it.
Would be interested if anyone else ran into this and found a solution.
can i assume you had intake off?
what reason did you change timing chain?
many times people get the carb set wrong and chase timing.
have you tried opening idle as you retard timing?
During your initial setup, are you feeling the compression with you finger over the spark plug hole on the exhaust or power stroke? Yes I checked that, will double check again
Some gear sets have degree dots marked on the gears to advance or retard the initial timing using the gears and timing chain during assembly. Yes mine has three I picked the one for factory which is half moon. I have a picture some where I can publish if you would like to see it, have to go dig it up
when you verify TDC on the compression stroke is the harmonic balancer mark also pointing to 0* ?
are you using a dial back timing light?
the disributor will always advance the same amount when you drop it in....you can measure it its always the same amount. you can "clock it" easy one tooth in either direction by moving it slighty. use blue tape on the distributor base and measure where the rotor is pointing when you start taking it out and where it ends up.
you can use the spark plug towers to approximate where the rotor needs to point just mark a line with a sharpie at the bottom of the tower on the distributor base.
if i had to guess.....you have a harmonic balancer that has the index line not where it needs to be.....no biggie just paint a new line on it. and this is because the timing chain covers oftern get switched and the pointer location is in a different spot
when you verify TDC on the compression stroke is the harmonic balancer mark also pointing to 0* ? Yes
are you using a dial back timing light? Yes but when I installed the distributor I did with harmonic balancer 12 BTDC and then had to turn another 20 degrees to get it to run smoothly
The timing chain cover is original and I think the harmonic balancer I bought was match to original at least that is what summit told me. I appreciate your help
can i assume you had intake off?
what reason did you change timing chain?
many times people get the carb set wrong and chase timing.
have you tried opening idle as you retard timing?
can i assume you had intake off? Yes
what reason did you change timing chain? It was stretched and I notice on tooth missing from the original cam sprocket
many times people get the carb set wrong and chase timing.
have you tried opening idle as you retard timing? I have not tried this will you please explain what you mean by opening idle. Thanks for the help
Someone correct me if I'm wrong, but shouldn't both timing marks be at the 12:00 position?
Is the op now 180 degrees out?
Or am I backwards, it's been a long time.
Even if he is 180 degrees out this set up can still work, he just needs to set up the distributor differently?
Someone correct me if I'm wrong, but shouldn't both timing marks be at the 12:00 position?
Is the op now 180 degrees out?
Or am I backwards, it's been a long time.
Even if he is 180 degrees out this set up can still work, he just needs to set up the distributor differently?
that shows #6 cylinder is on tdc ready to fire.
turn crank 1 full rev and now #1 is tdc ready to fire,
to OP
turn idle screw in to open throttle will raise rpms.
until you try to get the right timing by adjusting idle,
you can't diagnose any issues.
when setting up the motor after the work you did
idle often needs to be adjusted.
idle screw either in or out as you set timing.
05-23-2018, 11:49 PM
1979 shop manual states to set rotor between #1 and #8 at TDC
That's exactly how you find/check the 0* mark on the balancer.
