14-07-2018, 11:04 PM
(This post was last modified: 15-07-2018, 02:56 AM by Bob Culver.)
This topic recurs endlessly
For sports regularly using and exceeding 4000 rpm and after power at any price the situation is somewhat different and the following is not for them.
Advance greatly increases crank loadings. For the owner of the average car, esp with original crank, it is prudent to err on the side of caution.
For manual advance owners were advised to set to 1 ¼ to 2 inch full advance and fine adjust after. For those blessed with a manual control this is dandy.
A full 2 inches is usually excessive. The Bill Willaims book recommends less even for specials.
A now very elderly former Seven guru who maintained many cars locally advocated a very modest advance.
There are two original auto distributors; early 3/6 deg and for the 37 head 8/16. Whichever is fitted actual internal components, wear, springs now fitted can hugely alter the advance characteristic, and hence the ideal static setting.
And there are the alternative distributors. (An auto with manual control can cause confusion.)
Unfortunately the early Ruby handbook repeated the manual advice and many other books copied. This has led to hours and hours of wasted time and stressed cranks over the decades. One inch is 11 deg.
For the early auto, static (retard) setting was advised as ¾ to 7/8 and for the later 0 to ½ inch.
For those familiar with Sevens and esp their own it is easy to find the appropriate setting. But for strangers it is a mystery. These seems no performance whatever!
It is important not to confuse engine and exhaust noise with performance. Both increase markedly with advance.
(With a little ingenuity distributors can be fully advanced and locked there for setting up)
If you can find a “hill” ie slight slope that car will take at 30 mph or more in top, a good test, remembering that performance improves as the oil heats and thins.
Fastest idle may or may not give the optimum.
Seven settings are based on turning the engine with carnk handle, not as shown by an idle speed timing light. (Owners of older cars often get in a muddle due to using a light; although the able canuse to check advance operation)
For sports regularly using and exceeding 4000 rpm and after power at any price the situation is somewhat different and the following is not for them.
Advance greatly increases crank loadings. For the owner of the average car, esp with original crank, it is prudent to err on the side of caution.
For manual advance owners were advised to set to 1 ¼ to 2 inch full advance and fine adjust after. For those blessed with a manual control this is dandy.
A full 2 inches is usually excessive. The Bill Willaims book recommends less even for specials.
A now very elderly former Seven guru who maintained many cars locally advocated a very modest advance.
There are two original auto distributors; early 3/6 deg and for the 37 head 8/16. Whichever is fitted actual internal components, wear, springs now fitted can hugely alter the advance characteristic, and hence the ideal static setting.
And there are the alternative distributors. (An auto with manual control can cause confusion.)
Unfortunately the early Ruby handbook repeated the manual advice and many other books copied. This has led to hours and hours of wasted time and stressed cranks over the decades. One inch is 11 deg.
For the early auto, static (retard) setting was advised as ¾ to 7/8 and for the later 0 to ½ inch.
For those familiar with Sevens and esp their own it is easy to find the appropriate setting. But for strangers it is a mystery. These seems no performance whatever!
It is important not to confuse engine and exhaust noise with performance. Both increase markedly with advance.
(With a little ingenuity distributors can be fully advanced and locked there for setting up)
If you can find a “hill” ie slight slope that car will take at 30 mph or more in top, a good test, remembering that performance improves as the oil heats and thins.
Fastest idle may or may not give the optimum.
Seven settings are based on turning the engine with carnk handle, not as shown by an idle speed timing light. (Owners of older cars often get in a muddle due to using a light; although the able canuse to check advance operation)