375cc 9hp (1949-1956)
Fitted to A and AU
3 bolts per side on the manifold, flat plane
Very thin intake runner
Fins on the barrel close together
Dynamo on crankshaft (6V)
4 or 8 blade steel fan
Vent mesh secured with 3 bolts, single bolt at the bottom
Old type gearbox

 

 

 

425cc 12hp (1954-1963)
Fitted to AZ and AZU
3 bolts per side on the manifold, flat plane
Dynamo on crankshaft (6V)
6 blade steel fan
Vent mesh secured with 3 bolts, single bolt at the bottom
Old type gearbox
 

 

 

 

 

 

425cc 18hp (1963-1970)
Fitted to AZ and AZU
4 bolts per side on the manifold, flat plane
Dynamo on crankshaft (6V)
6 blade steel fan
Vent mesh secured with 3 bolts, single bolt at the bottom
Old type gearbox
 

 

 

 

 

602cc M4 (1961-1970)
Fitted to Ami 6 and AK
4 bolts per side on the manifold, flat plane
Dynamo / Alternator on manifold (6V and 12V)
Plastic fan
Vent mesh secured with 3 bolts, single bolt at the bottom,

(AK350 only, no mesh on ami)
Old type gearbox
 

 

 

 

435cc (1970-1978)
Fitted to 2cv4, dyane 4 and 250
Parallel heat exchangers
Alternator on manifold (12V)
Angled manifold
Plastic fan
Vent mesh secured with 3 bolts, single bolt at the top
New type gearbox

 

 

 

 

602cc M28 (1970-1990)
Fitted to 2cv6, Dyane, Ami, Mehari, AKS, Acadiane
Heat exchangers go further apart toward the rear
Alternator on manifold (12V)
Angled manifold
Plastic fan
Vent mesh secured with 4 bolts, no mesh on dyane and ami
New type gearbox