08-11-2018, 10:58 AM
Yes, it's entirely possible to run a 3-bearing engine with a broken crank! Back in the 'seventies I drove my van 140 miles home from Swindon to Chesterfield thinking I had run a big end, but when I dismantled the engine the crank came out in two halves! It is quite common for the break to be across the centre bearing, and with luck the two halves still manage to hold together.
Having said that, you say that the noise increases when the engine is not under load, which suggests a loose flywheel is a possibility. As you say, a strip-down will reveal all.
Having said that, you say that the noise increases when the engine is not under load, which suggests a loose flywheel is a possibility. As you say, a strip-down will reveal all.