ddarnell

M28/11 transplanted in a 78 USA 5sp.
About 4K miles since:
TB, WP, tensioner rebuild. Tightened within spec with factory tool.
All new vacuum lines, seals, O rings, etc.
New plugs, wires, cap.

My wife parked it after she said it starting pinging with any throttle. Checked timing and found it far too advanced with 57° total with vac advance. Tried to dial it back but could only get it to 39° with the adjustment room on the distributor.
Took it for a run. Detonation on heavy throttle. With no self serve in Oregon, it's possible it had regular pumped into it.
Back to the shop, disconnected and plugged the advance line and it was at 34° total. Took it for a spin and it stopped running about a mile down the road. No warning, no symptom, just quit like the ignition had been switched off. Will not restart.

I'll do the diagnostics on the ignition, check belt tension and perhaps verify all the timing marks. But I'm not sure why the timing would suddenly change and could use a little direction.
It timed perfectly and has been running exceptionally well since the swap.
There is vacuum at the retard line. Vaccum at throttle opening at the advance line. Have yet to pop the cap and verify the canister's operation.

Thanks.

dr bob

Check the cam timing for the left (driver side on US cars...) side cam drive gear. It's probable that the belt has "walked up" a tooth. If both cams are advanced it's moved at the crank gear; if just the driver's side then it's just at that cam gear. The crank gear is the Usual Suspect. It usually breaks the nose off that driver's side cam when the belt skips.

GlenL

Gotta time w/o vacuum. Still, that's a lot. More than one tooth. Check the sprocket alignment and brlt tension.

Are you using the right plug wire?

ddarnell

Thanks for the input. I'll pull the covers and check the marks at TDC.

Mrmerlin

you might do well to check the cam pulley bolts torque and the fit of the woodruf key, from the info it sounds olike the cam pulley is almost ready to crack down the middle