Timing (again)
Thread Starter
Burning Brakes
Joined: Mar 2001
Posts: 1,203
Likes: 147
From: dalton ma
Timing (again)
I didn't want to piggy-back Frankies thread so I'll ask the same question for the umpteenth time. I have a '62 with a 340 HP clone in it except I'm using a vac dist. My numbers are:
Initial 10 deg
Vac 17 deg
Mech 28 deg
For a total of 55 deg.
Cheap timing light doesn't have a tach so no good timing map as yet. The question is: is 55 deg max in the ball park ? On 93 octane there is no hint of ping and the engine runs really well. should I expect more ?
Thanks, Bob
Initial 10 deg
Vac 17 deg
Mech 28 deg
For a total of 55 deg.
Cheap timing light doesn't have a tach so no good timing map as yet. The question is: is 55 deg max in the ball park ? On 93 octane there is no hint of ping and the engine runs really well. should I expect more ?
Thanks, Bob
Team Owner
Joined: Aug 2007
Posts: 58,061
Likes: 7,145
Army
I think you are definitely in the 'zone'. I've found these SBC engines like the timing just a tad higher than 10...more like 12 - 14* but 10 is acceptable...that along with the 28 mechanical gives you 38* total which is also fine for these motors (some might think it's a couple of degrees high but this works fine on my stock 283ci motor) and with the vacuum on top of that -- a total of 55*. If it's not pinging at that then I wouldn't worry HOWEVER that is as high as you want to go ... its at the extreme upper end of the timing range. My 283ci runs around 52* with vacuum advance and some say 48* is closer to ideal. I think you are fine. You want that mechanical to be 'all in' at around 2800-3000 RPM..
Again, if the engine starts easily, idles well, doesn't ping or "trailer hitch" at light cruise and is responsive I'd leave it alone.
Again, if the engine starts easily, idles well, doesn't ping or "trailer hitch" at light cruise and is responsive I'd leave it alone.
Melting Slicks
Joined: May 2007
Posts: 3,461
Likes: 18
From: cooper city florida
IMO you have about 7 degrees too much vacuum advance, but everything else is spot on, providing the total timing is all in between 2500-3000rpm. Depending what your vacuum is at idle, you could try an AR22 or VC1852 can that will add 10 degrees of crank shaft advance, at 14" of vacuum. I think you will find your low speed performance, along with your idle, will be much smoother, with improved throttle response......at least that what I noticed when I went with that vacuum can in my L79.
Team Owner
Joined: Aug 2007
Posts: 58,061
Likes: 7,145
Army
Sounds to me like the car is running fine as is....wouldn't hurt to chop some off the vacuum advance but as long as there is no pinging it's a judgement call. This is why I run adjustable vacuum advance canisters in all my cars. Each car is different - my 396ci '67 Chevelle can't be run over 44* "all in" with vacuum advance or it starts surging.
