How do you tell Factory abarth motor from regular motor ?

[DaveA]

Were there any special numbers put on a Fiat 600 motor when Abarth worked on it ?

I was offered an engine from Italy but I am not sure if it is an "originall" abarth motor or a regular 600 motor with Abarth parts on it ,

It has an Abarth valve cover and Abarth  oil sump and a manifold with 2 barel carburator,

Thanks for your help

dave

[Pantdino]

What displacement is the engine?  If it's an original 1000cc Abarth it should have an AH block.  The 850cc engines had a regular Fiat block.

If its an 850cc engine I think you would have to get some good photos of the inside of the engine, the crankshaft, where the block has been machined to allow the bigger crankshaft, etc. Then maybe Paul Van der Heijden could tell you if its real.  But I suppose if it has an Abarth crankshaft and the machining has been done the same as Abarth did, it doesn't matter.  I have never heard that Abarth put a different serial number on the engine block of the 850 engines, but I may be wrong



Jim

[guy moerenhout]

yes  ,its not so .I have here also 700 cc bloock(AH )that where sleved for bialbero heads .Also in a abarth (corsa models)there is more spase between the cilinderholes for better cooling .So normale there where outer m for abarth than fiat.I think that the where use only for abarth in race like many special parts on the factorycars.When I did a rally with the zagato corsa there where in the begin so many parts that broke that I was thinking :how is it possible that the race 12 H.After some testing I find out that in the Parts from M.Pont where complete outer parts than the standaard and I change it to this specifications.On casting from the OT blocks where al stamping with the Abarth sign on the front near no.There where two types of blocks to for the OT.On the corsa block you can also find the oil pick up near the camshaft( front)for giving suplement oil for the cam.

[Paul vander Heyden]

Dave,

I would begin by finding out what the displacement of the motor is.  One litre motors  were of course 65mm bore with a 74mm stroke (982cc).  The next thing would be to check if the block has an AH cast into the block on the waterpump side (there were two different locations).  AH blocks were used by the factory for both 850 and 982cc motors, both monoalbero and biabero motors.  All of these blocks were based on the Fiat 600 block design.   Finally, there were 1000 OT blocks that had what looked like a oil filter housing on the exhaust side of the block. These were also 982cc, but were based on the Fiat 850 blocks.  All of the blocks above were what I refer to as "short"  (approx 172mm) tall blocks.  This is measured from the top of the block to the center of the main bearing bore. 

The crankshafts in all of the 982cc blocks (whether Fiat 600 or 850 derivation) had the larger diameter main bearings (approx 53mm).  I have seen two 982 crankshafts that had the smaller, approx. 50mm diameter main bearings, but I do not consider this normal.  Original Abarth crankshafts are almost always stamped with an ID number matching the engine type for which they were built, and copper coated.  The copper coating is one of the steps in the heat treating of the crankshaft.  On other Abarth engines, such as the 750cc Mille Miglia motors the cranks were not copper coated and this resulted in a  crankshaft that was hardened over the entire surface.  This made for a brittle crankshaft, that when overstressed caused disastrous results.  The copper coating maintains a more ductile inner core and greatly increased reliability.  One final note - The A112 crankshaft is dimensionally the same as the 982cc Abarth crankshafts and is also copper coated, but does not have any identification stamped into it.  It can be successfully used as a replacement.

If it is an original AH block motor, it would more than likely have had a Hausermann clutch attached to end of the crankshaft.  These are fairly rare and do not look anything like a Fiat clutch/pressure plate.  The pressure plate has a bolt pattern that consists of 6 bolts in a symmetrical pattern with equal distance between all 6 bolts.  Almost all other clutches have differing distances between the bolts.

If it is an original Abarth TC type motor, either 850 or 982, then it will have a Fiat 600D type cylinder head with pistons with fairly large pop-ups.  The carburetor will be a Weber 36DCD7 and the intake manifold can either be a one, or two, piece design depending on the year.  Many people have substituted the Fiat 850/127/A112 head, and while the works, the combustion chamber is different (requiring different pistons) and the intake manifold is different.

On an original motor, the two piece oil pan would have been made from Elektron Magnesium, NOT aluminium.  There were also several waterpump configurations, depending on whether the car had a rear radiator or not.

Early Abarth motors would be equipped with a generator and voltage regulator, whereas later engines had a Motorola alternator.

There are many more detail items, but this should help you in determining what it is that you are looking at.  BTW - If it is an AH block motor, then the  price should be VERY high, as these types of blocks are very scarce.  Most were blown up while racing.  Scuderia Topolino specializes in these type of motors and has many replacement parts for them.

Good luck,

Paul Vanderheijden
Scuderia Topolino