Changing Engine Mountings
The engine appeared to be running well, but an increase in resonant vibrations through the body made me check the engine mountings. After checking the big-ends weren't coming loose after the overhaul, the engine itself seemed to be running smooth enough - but something had changed somewhere; maybe the engine mountings?
May 2006:
The engine had to be dropped to access the mountings - everything had to be disconnected just as if the engine were being removed. It was lowered using a jack under the sump.
the front mounting appeared easy to get at but the old silentbloc bush could not be pressed out in situ so the rivets were drilled through and the mounting removed to the bench where the remains of the old mounting were split with a saw to remove.
It was important to retain all the parts as the replacement mounting was longer.
This is the new silentbloc bush alongside the old parts.
Do check the outside diameters of the replacement silentbloc bushes as two I received would have been loose in the mounting, being 6thou and 8thou undersize.
The new bush had to be turned down on the lathe to fit and was then pressed into the mounting.
the front mounting ready to refit to the car
and the assembly was bolted back into the frame
the nearside rear mounting was looking a little sorry for itself, but once the perished bits were removed proved not to be all that bad underneath.
In view of the difficulty removing the bushes and then fitting a 1" diameter silentbloc bush into a 13/16" hole - and the very much smaller thickness of rubber in the new bush - the old bush was left in position!
in comparison, the offside bush looked to be in very good condition and didn't need replacing. So it was all bolted back together again!
on reassembly - there was some change for the better and after a resonating piece of metal (loose rivet) on the radiator cowl was secured, the overall vibration was definitely lessened.
May 2007:
As the engine bedded in, the vibration became much less of an issue, though I was left with an annoying buzzing sound at certain engine speeds.
It sounded as though it was coming from behind the dashboard or one of the toolbox lids but the buzz was eventually traced to the bonnet vibrating against the rear bonnet tape. Easily rectified by glueing a strip of 1mm thick rubber under each side of the bonnet. The original bonnet tape had a rubber insert to prevent this!