blackbird939
New member
- Joined
- Sep 8, 2015
- Location
- Orlando
Hello once again,
Recently rebuilt B20. Head, Stage 1 redone by John Parker. Dual springs, new guides, opened combustion chamber, ports. New bearings, resurfaced flywheel, 123 distributor, mikuni HSR carbs. New crane cam, coil, plugs, plugs wires, lifters, pushrods, milled head and block, etc. The pistons had been replaced 3k miles ago with new and were within spec. No sign of piston slap, cyls were lightly honed at the machine shop. the works.
Well, it ticks loudly. I used the rule of nines to set the valve clearance to .41mm no fewer than thrice, before and after the break-in and final torque of the head. Plug gap at .7mm dead on. I sprayed starter fluid around intake gasket (which worked last time ) and it's not leaking- at least not badly. The rocker assembly is old, untouched, the alternator is an older Bosch. When I walk around the head with a stethoscope I hear a loud tapping/clacking near #1 or #2. The valve lash is dead on according to the 9s. The sound increases with rpm and temperature does not affect it. I get a vibrating needle on the vacuum gauge at 15hg. Vibration dances 0.5hg, not wild. The cam might be causing the vibrating needle. Timing at 12?BTDC at idle.
It used to diesel terribly, now that is all gone, thank goodness. But this ticking stinks.
My guesses are- ?? Sticking valves, bad rockers? exhaust manifold leak?
Here's a video I just took. Volvo B20
Recently rebuilt B20. Head, Stage 1 redone by John Parker. Dual springs, new guides, opened combustion chamber, ports. New bearings, resurfaced flywheel, 123 distributor, mikuni HSR carbs. New crane cam, coil, plugs, plugs wires, lifters, pushrods, milled head and block, etc. The pistons had been replaced 3k miles ago with new and were within spec. No sign of piston slap, cyls were lightly honed at the machine shop. the works.
Well, it ticks loudly. I used the rule of nines to set the valve clearance to .41mm no fewer than thrice, before and after the break-in and final torque of the head. Plug gap at .7mm dead on. I sprayed starter fluid around intake gasket (which worked last time ) and it's not leaking- at least not badly. The rocker assembly is old, untouched, the alternator is an older Bosch. When I walk around the head with a stethoscope I hear a loud tapping/clacking near #1 or #2. The valve lash is dead on according to the 9s. The sound increases with rpm and temperature does not affect it. I get a vibrating needle on the vacuum gauge at 15hg. Vibration dances 0.5hg, not wild. The cam might be causing the vibrating needle. Timing at 12?BTDC at idle.
It used to diesel terribly, now that is all gone, thank goodness. But this ticking stinks.
My guesses are- ?? Sticking valves, bad rockers? exhaust manifold leak?
Here's a video I just took. Volvo B20
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