Quote:
Originally Posted by Bonzo
I have to dissagree with that one !!??
Many production cars use oversize engine mounting holes. with the use of the correct fixings & tightened correctly, there is no reason for the engine to move ??.
In any event, it would need both fixings to become loose in order for the engine to move 
If it were an unsafe practice to slot holes, it would not be allowed under the IVA regulations.
Remove a Ford Escort subframe & inspect the clearance holes in them 
They require the use of large temporary locating pins to allow the correct alignment of the subframe.
I would say that a subframe is under a lot more stress than an engine !!??
That's my thoughts for what they are worth. |
I'm very well aware that many production cars use a good many slots in their engine mountings and oversize holes for subframes, Ford Mondeos certainly do and presumably all other similar cars.
However, and to be fair, this discussion does have a context, and the context is the Haynes Roadster. With the type of engine mountings used in the book I would not use slots if it could possibly be avoided.
Reasons-
How much torque should this type of rubber mounting be subjected to? I don't have any workshop manuals featuring this type to hand, but basically it's a flat plate bonded to rubber, and surely should not be tightened beyond a moderate amount.
If just isn't necessary. In a production situation makers are working to tolerances and need to be sure that any slight variations in the different components can be compensated for by lining up the parts and then tightening the fixings wherever they happen to be in the slots. But in our situation we are fitting a specific engine to a specific chassis. Much better to offer up the engine, mark the mounting plates where the bolts make contact, then drill the plates and get the exact fit, and keep it! without having to tighten the nuts to provide the clamping force that would be needed to resist any possible movement.
Anyway, I did say "not
necessarily"
