I have made a model using 3ds max and have expoted it as a .smd model, i have also made a simple model for my collision model and exported that as an smd. I have compiled the .qc file using the studiomdl you find in the sourcesdk folder. Here is my qc file:

$modelname "DingyEngine.mdl"
$scale 0.40
$cdmaterials "models"
//$staticprop

$body "Body" "C:Program FilesSteamSteamAppsSourceModsExposedmodelsDingyEngine.smd"
$sequence "Idle" "C:Program FilesSteamSteamAppsSourceModsExposedmodelsDingyEngine.smd" fps 30 ACT_IDLE 1

$surfaceprop "metalsolid"

$keyvalues { "prop_data" { "base" "metalsolid" } }

$collisionmodel "C:Program FilesSteamSteamAppsSourceModsExposedmodelsDingyEngineCM.smd"
{
$mass 15.0
$concave
}

So ive compiled it into a .mdl file. In the Hammer Editor I can see my model in the browse model section in the properties of Prop_physic, in the info section it is ticked as a physic model but my model does not appear in game, without the line $keyvalues { "prop_data" { "base" "metalsolid" } } it works as a Prop_dynamic, I have tried very hard to get it into game and looked at various tutorials and cannot figure it out, any help with this will be very appreciated.