Engine Rebuild: Part three - February 2019 & March 2020
It's all about the correct balance...
It's been a long, long time since my last report, one would have expected by now the engine was back in the car and running. Well it was but now it's out again.
To put it simply it appears the crankshaft balance is not correct. When I started the engine I got a buzz type vibration through the whole car at any rev range. We double checked the valve and ignition timing, disconnected the fan belt, loosened the engine mounts, tightened the engine mounts, disconnected the rear gearbox mount, depressed the clutch, nothing made any difference.
The crank had had two weights added, see photo, I even tried removing them, again no difference.
The latest now is the crankshaft has gone off to a different balancing company. When it come back and the engine is back up and running I'll post a full description of what was what!
March 2020. It's been a while since I've posted an update!
So here is a summary of what has been done.
Peter Renou kindly arranged for me to take the crankshaft to Orger Engines in Bayswater to have it rebalanced. The invoice below shows what they did. Most notably the used a balace factor of 15%, not 32%. When they did this the previously added crankshaft weights were reduced from 50 gm to 27 gm. Each piston/conrod was weighed then each individual crankshaft bob weight was adjusted to match, they didn't want to take any weight off the alloy rods. Also balanced was the flywheel, clutch pressure plate and crankshaft pulley (click on photos below for more info), this had not been done during the previous balancing attempt.
When it all came back the engine then had to reassembled. I won't go into detail of my failed "do-it-yourself" attempt to fit the crankshaft except to say it's a job that requires an expert who knows what they are doing, in this case the brilliant Marc Bondini.
Now one would assume that once the engine had been reassembled and installed into the car everything would have been fine, sadly NOT SO...
See the next exciting instalment here: