Setting Ignition Timing To Full Advance
I just bet your Mechanic gave you a funny look ~ this is one of those things you only learn if you're a really nosy student who asks questions and pays close attention ~ look at it this way : racing engines are always tuned at full power RPM's , right ? it only makes sense , it runs more efficiently , cooler and so on .
So ;
@ idle / tickoever of 600 RPM's , the BB lines up as the timing is fully retarded
as you rev. the engine and watch the timing marks , the BB will march out of sight in the little window as the vacuum & mechanical advance mechanisims in the distributor advance the timing .
@ 3,000 RPM's , the engine is wound up to it's happy spot and isn't going to advance any further so you hold it there then twiddle the advance dial on the dynamic timing light until the OT mark (Chevron or Triangle) lines up with the pointer , now look at the dial and whatever it is pointing to , is the total spark advance . hopefully , it'll be between 28° ~ 33° .
If it is pinging , you may try retarding it a degree or two at a time then re-test drive it . one degree is a LOT so don't just mindlessly twsit the distributor to and fro, you'll go mad and it'll never run right .
For it to have audible pink @ 28° BTDC , means you shaved the head or block WAAYY too much or maybe you have domed pistons instead of flat ones .
The CR on these engine is absurdly low so they'll run quite well on 1/2 evaporated fuels that were left there at the end of the last season...
Ping / Spark Knock is unheard of on these engines unless either you raised the CR or maybe an old engine is full of carbon deposits, that's easy to fix .
If it's running roughly , set the timing to the BB @ idle and then check for vacuum leaks , tight valves etc. and once it's sewing machine smooth again (think carburated 1962 Mercedes inLine 6 cylinder) come back and try my timing method , you'll love the extra power and your engine will love it too .
Gotta do everything in the proper order , step by step though . takes time.
I hope this helps ? .
I just bet your Mechanic gave you a funny look ~ this is one of those things you only learn if you're a really nosy student who asks questions and pays close attention ~ look at it this way : racing engines are always tuned at full power RPM's , right ? it only makes sense , it runs more efficiently , cooler and so on .
So ;
@ idle / tickoever of 600 RPM's , the BB lines up as the timing is fully retarded
as you rev. the engine and watch the timing marks , the BB will march out of sight in the little window as the vacuum & mechanical advance mechanisims in the distributor advance the timing .
@ 3,000 RPM's , the engine is wound up to it's happy spot and isn't going to advance any further so you hold it there then twiddle the advance dial on the dynamic timing light until the OT mark (Chevron or Triangle) lines up with the pointer , now look at the dial and whatever it is pointing to , is the total spark advance . hopefully , it'll be between 28° ~ 33° .
If it is pinging , you may try retarding it a degree or two at a time then re-test drive it . one degree is a LOT so don't just mindlessly twsit the distributor to and fro, you'll go mad and it'll never run right .
For it to have audible pink @ 28° BTDC , means you shaved the head or block WAAYY too much or maybe you have domed pistons instead of flat ones .
The CR on these engine is absurdly low so they'll run quite well on 1/2 evaporated fuels that were left there at the end of the last season...
Ping / Spark Knock is unheard of on these engines unless either you raised the CR or maybe an old engine is full of carbon deposits, that's easy to fix .
If it's running roughly , set the timing to the BB @ idle and then check for vacuum leaks , tight valves etc. and once it's sewing machine smooth again (think carburated 1962 Mercedes inLine 6 cylinder) come back and try my timing method , you'll love the extra power and your engine will love it too .
Gotta do everything in the proper order , step by step though . takes time.
I hope this helps ? .
