You don't need to put oil down the cylinders - thats just a secondary test if compression is poor to see if its rings or valves. If you add a little oil & compression improves then its rings that are the culprit, if no improvement then its valves.
Ref your way of testing.
I think you did it a bit wrong. If you did not hold the throttle wide open you wont see good compression.
To test properly engine ought to be warm with all plugs removed. Disconnect + side of coil to avoid engine starting. Fix throttle wide open (foot to floor) by wedging something on throttle pedal etc.
Then turn engine on starter for a few turns until whoever is looking at guage sees no further increase in reading - usually 2-3 seconds is enough.
With a V8 you may see a drop on the last few cylinders as the battery will be getting tired.
As I said before, 10% variation across all cylinders is ok, your readings above are not too bad but cylinder 5 is a lot higher which is not a bad thing in itself, but possibly shows the others are not so good.
I would retest again following what is written above and see what the results are.
Good news on the increase in power, you might still need to adjust the carburettor to get more power, which may mean you can get more advance without pinking. Do you know what the timing is now you have backed it off to avoid pinking?
Originally Posted by blackpopracing
...Good news on the increase in power, you might still need to adjust the carburettor to get more power, which may mean you can get more advance without pinking. Do you know what the timing is now you have backed it off to avoid pinking?
I didnt measure it with a rev gun (forgotten what it is called) we just did it by ear.
Drove the car and it was pinking from the off, so stopped adjusted it back a bit, and drove it again etc, until it was only pinking at three quarter throttle.
It needs finishing and dealing back a touch more until it stops pinking completely, but there wasn't time yesterday as it was getting late.
I forgot to ask, did you fit new nuts on the rockers? I would suggest you do as this may be why everything had come loose.
You really need to get the engine timing set with a timing light, doing it by ear is not really good enough.
I think with it all set up correctly again you might get all of your power back.
at the very least fit a locknut on top of each adjuster nut so they can't back off.
timing settings are fuel dependant too. if you use cheap crappy low octane unleaded with your pop up pistons it'll pink unless the timing's backed off more than 'stock' settings. the 'stock' settings allowed for decent octane fuel that was available in the day (plus your engine's not stock so.......). personally unless using a rolling road i'd go with the back it off until it just doesn't pink method too, that way you're allowing for how the engine is now with the fuel you use now :tup:.
Octane now is far better than 'back in the day' unleaded is 95 octane. Old 5 star was only 98 octane.
If you use super unleaded it's 98 or 102 depending on brand. American fuel is around 92 octane.