FAQ |
Members List |
Social Groups |
Calendar |
Search |
Today's Posts |
#1
|
|||
|
|||
Timing marks
Question for everybody 1966 389. Is there a mark on the factory balancer that shows top dead center? I put my MSD pro billet distributor in today and I want to make sure I have it lined up correctly. I know there's a Mark that whips around and it corresponds with the 046 marker but I don't know what the 046 marker is actually indicating.
|
#2
|
||||
|
||||
The marks indicate 0-4-6 degrees before top dead center. So the line on the balancer lined up with the 0 should be TDC. You need to verify that it is TDC of the compression stroke by observing the valve position.
|
#3
|
||||
|
||||
Those balancer marks only reference number 1 piston being at or near TDC.
It’s still possible to not have the cam installed right to also have both valves not being closed at TDC like they need to be. When the piston is at TDC then number 6 exh valve should be open somewhat. If this is the case then you can drop the Dizzy in with the rotor facing a head of number one cap tower a little bit. Remember that the Pontiac Dizzy spins counter clockwise. I like to not install the timing cover, valley pan and intake until I confirm I know which way to drop the Dizzy in. If your piston is at TDC, but one of the valves is open on number one cylinder then you need to have the Dizzy rotor facing number 6, not number one. All this means is that you have the cam gear set up 180 degrees out and is absolutely no problem as long as the Dizzy goes in the motor the needed way,
__________________
I do stuff for reasons. |
#4
|
||||
|
||||
By the way those balancer marks are minus 4 degrees, 0 and +6 just to make sure where all on the same page.
If the balancer is not on the motor yet then I would carefully measure from 0 to 6 and then with a hack saw cut 5 more notches in the balancer. Then you will have marks at 12,18,24 30 and 36 which will make checking your total timing without vacuum advance easy.
__________________
I do stuff for reasons. Last edited by 25stevem; 09-05-2022 at 07:39 AM. |
#5
|
|||
|
|||
Quote:
|
#6
|
||||
|
||||
I had that same thing take place with that brand balancer, only I did not loose all the markings .
On the ones that remained I sprayed a epoxy clear coat over them after a redid the wiped off makings with black marker. We always seem to reach for brakekleen when we should be trying Windex first, lol!
__________________
I do stuff for reasons. |
#7
|
|||
|
|||
Okay guys thanks .... So tdc #1 is the lil notch in the balancer. And the 0 on the "timing pointer" is tdc#1 .... So if i get the diameter of the balancer i can order some timing tape from jegs/summit and know what my timing is while running? Am i thinking correctly?
Distributor is locked out so no timing curve To adjust. (I am aware of the drawbacks of no timing curve) |
#8
|
||||
|
||||
Did you choose to have a Dizzy with no curve?
Besides the drawbacks that kind of thing is for a race only motor where the motors power band is aways above the rpm where the full advance would be in anyway.
__________________
I do stuff for reasons. |
#9
|
|||
|
|||
Quote:
|
The Following User Says Thank You to mgarblik For This Useful Post: | ||
#10
|
|||
|
|||
So I think I did it right I actually had to turn the oil pump drive shaft slightly to get the distributor lined up on cylinder number one.
|
#11
|
|||
|
|||
...
|
#12
|
||||
|
||||
To make things easier you can just drop the Dizzy in with the rotor pointing where you want it.
Next install the Dizzy hold down clamp only very lightly so the Dizzy can not pop up from where it is by the amount that could disengage the two gears. Next do whats needed to kill the spark and then crank the motor over 2 complete revolutions and the Dizzy will load itself right onto the oil pump drive shaft for you.
__________________
I do stuff for reasons. |
#13
|
||||
|
||||
Quote:
Stan PS let me add if you can get an accurate measurement of the balancer diameter you can calcuclate where to put your marks. Balancer Distance for Every Diameter 6 Degrees 3.80000 0.19897 3.90000 0.2042 4.00000 0.20944 4.10000 0.21468 4.20000 0.21991 4.30000 0.22515 4.40000 0.23038 4.50000 0.23562 4.60000 0.24086 4.70000 0.24609 4.80000 0.25133 4.90000 0.25656 5.00000 0.2618 5.10000 0.26704 5.20000 0.27227 5.30000 0.27751 5.40000 0.28274 5.50000 0.28798 5.60000 0.29322 5.70000 0.29845
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm Last edited by Stan Weiss; 09-05-2022 at 01:57 PM. |
#14
|
|||
|
|||
Can anybody confirm the diameter of my 1966 dampener I think it's 5.75"
|
#15
|
||||
|
||||
5.250”, the 68 and up balancers where 6.750”.
This info is from my ancient HO racing guide. At the moment I do not have either a early or a late one to confirm this for you.
__________________
I do stuff for reasons. |
#16
|
||||
|
||||
Quote:
As B-Man explains in a post over in the 66-67 Section, the hub is what needs to be measured when making your own marks and he provides a quick way to do so.
__________________
Fort Worth/Dallas TX area 1966 GTO Fontaine Blue 389 CID Carter AFB Muncie 4 speed (orginally an automatic car) |
#17
|
|||
|
|||
I used the 5.25" tape here ... Is that the correct size and location?
|
#18
|
||||
|
||||
Yes it’s right!
The dash markings on the tape match those on the timing cover tab, and actually with surprising accuracy!
__________________
I do stuff for reasons. |
#19
|
|||
|
|||
Thank you I believe I actually got the tape 1.25 to 1.5° off of the actual mark on the hub but that should be okay as long as I'm conservative with the timing.
|
#20
|
||||
|
||||
Yes it’s off a smidge, but you know that and like you say be conservative.
__________________
I do stuff for reasons. |
Reply |
|
|