L48 Timing
Thread Starter
Intermediate
Joined: May 2010
Posts: 44
Likes: 0
From: Austin Texas
L48 Timing
I am trying to time my '74 with an L48. Manual says 8 deg. BTDC. Problem is I am not sure if it is the original cam. It sounds stock or very close to it. Where would a good baseline for initial timing? Right now I have it at about 9 degrees (Vacuum advance disconnected) and it sounds like it wants more. Idles well though. 750 RPM in neutral and 650 RPM in drive.
Thoughts? Advice?
Thoughts? Advice?
Le Mans Master
Joined: Jul 2009
Posts: 6,647
Likes: 1
From: East Aurora N.Y.
St. Jude Donor '10
I'm at 12*, and like it a lot. I toyed with it from 8-14, and 12* seems to be the best for low end response, and all around driving w/o pinging......
Last edited by jeff79'; Mar 21, 2011 at 08:17 PM.
Melting Slicks
Joined: May 2009
Posts: 3,079
Likes: 315
2024 C3 of the Year Finalist - Unmodified
Initial timing means nothing as far as performance goes. Get an advance timing light or timing tape for your crankshaft balancer. You need to set your total advance (initial plus centrifugal) for maximum performance...36 degrees is fairly standard but no more than 38, all in by 3000 rpm. You could always keep advancing the timing a little bit at a time until you hear the death rattle (detonation) under load, then back it down. That is your engine's way of telling you what it's optimum timing is for the fuel you are running.
Le Mans Master
Joined: Jul 2009
Posts: 6,647
Likes: 1
From: East Aurora N.Y.
St. Jude Donor '10
All that is a bit complicated for just a stock engine.....Plug the advance hose, and just get a timing light on it, and drive it after each setting, until you find the performance band that you like.....Low end, and top end, can be very different settings, and it depends what you want....I'm liking 12*, like I mentioned earlier.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
Initial timing means nothing as far as performance goes. Get an advance timing light or timing tape for your crankshaft balancer. You need to set your total advance (initial plus centrifugal) for maximum performance...36 degrees is fairly standard but no more than 38, all in by 3000 rpm. You could always keep advancing the timing a little bit at a time until you hear the death rattle (detonation) under load, then back it down. That is your engine's way of telling you what it's optimum timing is for the fuel you are running.
Total timing is probably more important than initial timing. There, we agree.
Where we disagree, is that I wouldn't go as far as 38 degrees total. That is really on the ragged edge. One tank of substandard gas and he might drive over the crank. 36 degrees is plenty, and 32 to 34 is probably safer for an everyday car. Also, since he has an automatic, he should probably stay a bit on the low side, anyway.
