Need some opinions on where to go from here...
Regarding the phasing on the cap. If you have a vac advance and it is not hooked up, that could account for the arcing on the side of the terminals. The vacuum can when applied will sweep the rotor across the terminals lining up the rotor with the cap. Hope that makes sense.
Also when retesting the leak down. Try listening more carefully without background noise. Put your ear to the tailpipe and the carburetor and the crankcase. Check adjacent cylinder spark plug holes and the radiator. If still leaking and no source can be found try tapping the top of the valve to dislodge any carbon or foreign material that may be stuck in the seat. Try the oil in the cylinder last. 70% is a lot of leakage. If it is leaking that bad you should be able to source where it is coming from.
Ah okay, I had no idea that could be the case regarding the Vacuum advance, and no, it was not hooked up, so that makes sense.
When I did the leak down, the shop door was closed, I had the rear axle on stands so I get under the mufflers with my ear right to them...Had all 4 throttle blades opened with my ear pressed to the throat of the carb...all plugs out, putting my thumb over neighboring spark plug holes, over the dipstick tube...I agree that it is a lot of leakage and found it weird I couldn't find its location. Water in the block and checking the rad will be one more thing for me to check.
Do you think grabbing an inexpensive smoke machine would help? Filling the carb with smoke and then cylinder to see where it's escaping?
Funny you mention that, I was actually thinking about doing that last night. If my current to do list of checks comes up short, im going to jump on amazon and see about that.
I wasn’t aware that anyone was installing used rings as I never have and never would. It just seems *** backwards to me. I’m like why go thru all that work and then have to do it over. You never by chance re installed the rings upside down did you?
I get it, but many wouldn't bat an eye to it if the engine is in good health originally. Rings are definitely installed correctly, I triple checked that, and judging by the fantastic leak down numbers on the other cylinders, I'm even more confident about that.
Hoping to have some clear direction from troubleshooting in the next couple of days.