03-06-2021, 09:35 PM
Hi flywheel
I have had a listen to the videos. Sounds like an A7 engine to me, I think I would have to hear it in person to diagnose much more. Only exception is the odd squealing. My own engine has a late Ruby HC head with a 2 bearing bottom end, and this combination definitely resulted in a harsher sounding engine - something other forum contributors have noted over the years.
The main distinction with engine noises is whether they are related to the engine load/throttle opening or happen just as a consequence of rotation almost regardless of load.
Load related would be big and little end bearings, pistons and combustion. Over advance will cause harsh running which will diminish noticeably as you back off the throttle and thereby reduce cylinder peak pressure. With modern fuel octane it will never pink, but given way too much advance it can get to the point of a diesel-like rattle. In my experience the 2000 to 2300 RPM range is the severest test, which annoyingly coincides with about 30 mph in top gear. One option is accelerate through this range, but this is easier in a light special than (say) a saloon climbing a gradient.
Non load related would be camshaft, valve gear, dynamo, distributor etc. Sometimes a stethoscope or large screwdriver as a conductive listening device can pinpoint the source. If something is binding you should feel it on the starting handle, maybe easier with the plugs out.
I have dug out my data on the standard ignition advance for the late Ruby. The static advance is about 5 crank degrees, and the additional centrifugal advance climbs linearly from nothing below about 900 engine RPM to 16 degrees maximum at 3200 RPM and above, i.e. a rate of 7 degrees per 1000 RPM. I don't have any data for the electronic distributor. All I can suggest is setting the advance by trial and error for best performance at the RPM range you use most, using the least you can get away with without letting power drop too much. The advance at idle is not separately adjustable, so you will have to accept what it is.
I have had a listen to the videos. Sounds like an A7 engine to me, I think I would have to hear it in person to diagnose much more. Only exception is the odd squealing. My own engine has a late Ruby HC head with a 2 bearing bottom end, and this combination definitely resulted in a harsher sounding engine - something other forum contributors have noted over the years.
The main distinction with engine noises is whether they are related to the engine load/throttle opening or happen just as a consequence of rotation almost regardless of load.
Load related would be big and little end bearings, pistons and combustion. Over advance will cause harsh running which will diminish noticeably as you back off the throttle and thereby reduce cylinder peak pressure. With modern fuel octane it will never pink, but given way too much advance it can get to the point of a diesel-like rattle. In my experience the 2000 to 2300 RPM range is the severest test, which annoyingly coincides with about 30 mph in top gear. One option is accelerate through this range, but this is easier in a light special than (say) a saloon climbing a gradient.
Non load related would be camshaft, valve gear, dynamo, distributor etc. Sometimes a stethoscope or large screwdriver as a conductive listening device can pinpoint the source. If something is binding you should feel it on the starting handle, maybe easier with the plugs out.
I have dug out my data on the standard ignition advance for the late Ruby. The static advance is about 5 crank degrees, and the additional centrifugal advance climbs linearly from nothing below about 900 engine RPM to 16 degrees maximum at 3200 RPM and above, i.e. a rate of 7 degrees per 1000 RPM. I don't have any data for the electronic distributor. All I can suggest is setting the advance by trial and error for best performance at the RPM range you use most, using the least you can get away with without letting power drop too much. The advance at idle is not separately adjustable, so you will have to accept what it is.