Timing marks.
Thread Starter
POSSE ZR-1 Driver
Joined: Feb 2002
Posts: 3,980
Likes: 138
From: Groton CT
Timing marks.
While attempting to fix a hot engine problem, I was re-checking my timing and got a bit confused. Initial timing should be 8*. The timing tab for my '64 327/300 looks like this:
-
-
-- A
- <- 2
-
- <- 1
-
-- 0
-
I thought I remembered back in the old days (30 yrs ago) that each mark was 4*. Originally I had the engine timed to the mark labeled <- 1. Then I read a thread here somewhere where one of our members stated that the marks were 2* apart, so I retimed the engine to the mark labeled <- 2. Now the car runs really rough at part throttle and seems to miss quite badly when I hold the rpms up around 2500.
So, Which is it? 2* per mark or 4* per mark. Thanks.
-
-
-- A
- <- 2
-
- <- 1
-
-- 0
-
I thought I remembered back in the old days (30 yrs ago) that each mark was 4*. Originally I had the engine timed to the mark labeled <- 1. Then I read a thread here somewhere where one of our members stated that the marks were 2* apart, so I retimed the engine to the mark labeled <- 2. Now the car runs really rough at part throttle and seems to miss quite badly when I hold the rpms up around 2500.
So, Which is it? 2* per mark or 4* per mark. Thanks.
Burning Brakes
Joined: Nov 2000
Posts: 813
Likes: 2
From: da up
Re: Timing marks. (Subfixer)
I've been going by 2* increments. Mine doesn't look like yours ,maybe because of the HP. mine has 0* marked then above it ,4 short lines and a fifth line that is longer which I believe is 10*
rod
rod
Le Mans Master
Joined: Feb 1999
Posts: 5,825
Likes: 370
From: Mobile AL
Re: Timing marks. (Subfixer)
The factory timing tab marks are 2 degrees apart.
You've made me wonder about something else that is timing related though. Have you checked the location of the Top Dead Center timing mark on your harmonic balancer? Chevrolet has changed the location of this mark on the balancer at least four times since the mid-sixties to match relocated timing tabs on the chain cover. If your car has a replacement harmonic balancer, it may have a balancer mark that does not match the timing tab on the original chain cover.
You can find the location of true Top Dead Center on the balancer by using a piston stop. I believe this method has already been described in a past post on timing.
You've made me wonder about something else that is timing related though. Have you checked the location of the Top Dead Center timing mark on your harmonic balancer? Chevrolet has changed the location of this mark on the balancer at least four times since the mid-sixties to match relocated timing tabs on the chain cover. If your car has a replacement harmonic balancer, it may have a balancer mark that does not match the timing tab on the original chain cover.
You can find the location of true Top Dead Center on the balancer by using a piston stop. I believe this method has already been described in a past post on timing.
Instructor
Joined: Jun 2002
Posts: 145
Likes: 0
From: Downtown
Re: Timing marks. (jerrybramlett)
I've got a new Harm Bal & new timing tab on my 63 and at this point, I dont really use the timing light all that much, I do it by feel and correct it if needed.
I know the perfectionists wont concur, but the car runs pretty well at all rpm's
I say go with what feels best and forget the old manual. experiment with little adjustments, and lock it in at what does well all around.
[Modified by 14-Paul, 2:01 PM 8/1/2002]
I know the perfectionists wont concur, but the car runs pretty well at all rpm's
I say go with what feels best and forget the old manual. experiment with little adjustments, and lock it in at what does well all around.
[Modified by 14-Paul, 2:01 PM 8/1/2002]
Thread Starter
POSSE ZR-1 Driver
Joined: Feb 2002
Posts: 3,980
Likes: 138
From: Groton CT
Re: Timing marks. (jerrybramlett)
As far as I can tell, It's the original timing cover and original balancer.
Can't figure why the engine runs so crappy at this setting when it ran so smoothly at what I would assume to be 4* initial timing (vacuum disconnected).
Vacuum at either timing setting is 17" at 550rpm and vacuum can works well.
Can't figure why the engine runs so crappy at this setting when it ran so smoothly at what I would assume to be 4* initial timing (vacuum disconnected).
Vacuum at either timing setting is 17" at 550rpm and vacuum can works well.
