Need to reverse rotation of a Abarth A112 engine to counterclockwise

Discussion in 'Rear-Engine Fiats' started by cozzoi, Dec 15, 2018.

  1. cozzoi

    cozzoi George

    Hi Guys,
    I Need to reverse rotation of a Abarth A112 engine to be able to fit in a Moretti Sportiva and couple it to the existing 850 transmission
    Anybody knows what to modify beside the camshaft?
    Any feedback would be appreciated.
    George
     
  2. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    George, sorry I can't help with this. But if you happen to have the rest of the A112, I want it. Even without an engine. It's one of the cars on my 'list'.
     
    mkmini likes this.
  3. Frank L. Di Gioia

    Frank L. Di Gioia True Classic

    Location:
    las vegas, nevada
    George, I'm trying to pull things from memory which is getting a little fuzzy as of late. One thing to check on is the crankshaft end of the A112. It will need the 850 bushing installed, easy fit. Next, here's where the fuzzy comes in, I seem to recall the 850 transmission input shaft will bottom against the back of the A112 crankshaft. This resulted in not being able to tighten the 4 mounting bolts mounting the bellhousing to the engine the last 1/4". Either drill the end of the crankshaft or shorten the transmission shaft is/was the solution. Hope this helps. Also the gear drive on the vertical shaft will need to be replaced so as to keep the distributor and OIL PUMP turning CW. You want to pump oil, not suck it.
     
  4. Frank L. Di Gioia

    Frank L. Di Gioia True Classic

    Location:
    las vegas, nevada
    Another fuzzy thought. I seem to remember the A112 pressure plate may not clear properly. Slight amount of grinding on the bellhousing cured the problem. This COULD be on a 600 application as I had both 600's and 850's at the same time.
     
  5. JimD

    JimD Waiting for Godot... Moderator

    Location:
    Missouri, USA
    Hi George,

    I really have no idea, but I Googled the topic and it turned up this set of gears at FIatPlus. The description is a little confusing to me, but reads as follows:
     
  6. cozzoi

    cozzoi George

    Hi Jeff,
    I may have one Autobianchi Junior A112 ragtop 1980 in 2 months from now. Pic Attached
     

    Attached Files:

  7. cozzoi

    cozzoi George

    Frank,
    thank you for sharing those ultra secret tips with me, I also heard that the conecting rods are off center and need to be turned 180 degrees (may be the pistons too?)
    Regards
    George
     
  8. cozzoi

    cozzoi George

    Jim,
    I came across the same info too, and you are right it is very confusing.
    I wrote an email to C. Obert asking to clarify it.
    Thanks for the feedback!
     
  9. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    Me want! I love it. Assume you intend to keep it? Please tell me how you found it and what's involved in getting one here.

    Regarding the reverse rotation gear set from Chris. I know nothing about these cars so I'm just speculating. But I would guess it is a pair of gears, one on the crank and one on the cam, in lieu of a timing belt/chain (I don't even know what these have). That way the crank can spin the opposite direction from it's norm, but the cam and related accessories still turn in the original direction. Or if these already have a gear drive for the cam, then it might be a set of 4 gears - much like the gear drives for American V8 cams (2 small floating gears between the 2 larger main ones). Rather ingenious method in my opinion.
     
  10. NM850

    NM850 True Classic

    Location:
    Albuquerque NM
    Check Berni Motori. They carry the gears, it’s just two that’s needed.
     
    Dr.Jeff likes this.
  11. cozzoi

    cozzoi George


    Looks like the gear set conversion is the best alternative, I ll dig into it.
    Regarding the Autobianchi, it is in Italy and belongs to a friend who is bringing some stuff to US from Italy inside a shipping container. I can get you in touch with him and if you both come to an agreement he may put the car in the container for you. PM me for contact info if you are interested.
     
  12. cozzoi

    cozzoi George

    Thanks for the info
    George
     
  13. myredracer

    myredracer True Classic

    Instead of a reverse rotation gearset, you could use an 850 cam which are interchangeable. You might want to spend the money on a hotter 850 cam instead of the gears. You *might* be able to sell the A112 cam to someone who wants to reverse the rotation of an 850 motor for use in a 600. An Abarth Autobianchi A112 1050cc engine uses a cogged belt drive for the cam so reverse rotation gears won't work. Not sure if you can modify an A112 engine with cogged belt to chain drive. I think you can because you can buy a cogged belt drive kit to install on an engine with chain driven cam. One version of the A112 engines does have a chain drive cam.

    Using an 850 cam, you'd need an 850 distributor due to the direction of the distributor drive gear on the cam or you could remove the gear off the shaft of an 850 distributor and install it on the A112 one (cheaper too). Be very careful if you do this so as not to damage the gear. I have several used 850 distributors if interested. If swapping distributors/parts, note that the 903cc and A112 engines use a longer shaft.

    I also have an 850 292 degree reground performance cam for sale. It's newly reground and got it from Germany a number of years ago. An 850 cam would have the lobe for fuel pump and it might need to be ground down for clearance. I just sold a set of the reverse gears a few weeks ago to a forum member. The "new" Scuderia Topolino in Germany has the gears too, listed at 229 Euro. Berni Motori items aren't inexpensive and I think you still need to go through a US distributor here.

    I have an 850 903cc block with A112 crank, cam, rods, pistons & head. It's basically an A112 1050cc engine in an 850 block and looks stock 850 from the outside. The rotation was reversed (from 850 rotation) to mate to a 600 transaxle. O gawd, at my age now, I can't remember all the things that were done to the motor... :mad: I had it built by Paul V. before he moved back to Europe quite a while ago. I have a vague recollection that the snout of the A112 crank needs a minor modification. I think what it is, is that the 850 transaxle input shaft works with a bronze bushing in the snout of an 850 crank. It might be that the A112 has a roller bearing with different diameter?? It should be immediately obvious with both cranks side by side.

    Not sure if you can use the A112 flywheel as-is or you need to use an 850 one or if the clutch covers are interchangeable (could have different mounting hole locations?).

    I could be wrong but I don't think you need to worry about the direction of the pistons/rods in an A112 engine. I'm pretty sure A112 pistons don't have a directional arrow on them. If you do pull the pistons out, make sure to mark the order so they go back in the same cylinders. Of course, inspect the bores for wear. It might be a good idea to remove the head regardless for inspection and remove carbon deposits if needed. Unless it's a low mileage engine, I'd inspect the rocker arm shaft and rockers for wear. The underside of the shaft can be badly scored/worn sometimes, esp. if oil wasn't changed regularly. If you need to have the head surface machined, make absolutely certain to remove only the minimal amount of material possible (like a few thou. only). Many heads have been ruined by taking off too much material by machine shops that don't know what they are doing.

    You'll want a clutch cover that can rotate in opposite direction. The fan blade on the alternator is rotational. You may find the A112 one works fine. From what I can see so far is that you can't just swap an 850 fan blade on as the hole for the shaft is a different size. I have an A112 fan blade that won't fit on an 850 alternator. A bushing might solve this or drilling out the hole in center of the blade.

    IIRC, an A112 engine has higher compression and you'll need the appropriate grade gas. A Euro distributor may work better? You might want to check the plugs to see if you have the right heat range, esp. if you use a different profile cam (ie., 850).

    The Abarth A112 engines I believe use an electronic Marelli distributor as standard. If your engine doesn't have one you can buy these. A mechanical dist. would look more original though.

    An A112 engine has the oil filler cap on the rocker cover at the opposite. Use an 850 cover. Not sure what carb an A112 uses. You would have a number of choices and there are aftermarket intake manifolds so you can use a different Weber. I think it is the Abarth A112 engine that has a one-piece rocker cover + intake manifold so if you use an 850 rocker cover, you'll need a new intake manifold (stock 850 or aftermarket).

    I think this pretty much covers it - I think... The A112 engine will have 70 HP stock which will be a lot more than the original engine. If that isn't enough tho., you could always do a few performance mods.:)
     
    Last edited: Dec 16, 2018
  14. Jeff Stich

    Jeff Stich True Classic

    Location:
    Norco, CA
    An 850 cam & 903 (not 817/843) oil pump/distributor intermediary drive shaft could be used, but the 1050 cam has a better performance profile. With the high price nowadays for "performance" 850 cams, this is where just using the reverse-rotation timing gear set instead can pay off. ;)

    All A112 engines use a timing chain/gears set-up just like the 600 & 850 engines. The cogged belt drive set-up was an aftermarket kit, not OE (offered by various makers like Graf, Abarth, Triger, etc., & for other cars, as well).

    The drive gear isn't on the 850 (or A112) distributor, it's on the intermediary shaft that goes between the oil pump & the base of the distributor shaft. This allows one to use either distributor, with the OE 1050 Marelli electronic ignition being the preferred one to use. Both distributors turn CW in their respective engines, & will still run CW if the correct mix of parts are used when reversing the crank rotation.

    Yes. An 850 cam would also need the main body turned down (machined between the lobes), in order to provide clearance for the 1050's 74mm crankshaft throws.

    The 1050 crank end will need to be drilled/bushed to allow for the 850 transaxle input shaft.

    In this particular CCW (850 based) application, just using the Moretti's whole 850 flywheel/clutch assembly would probably be easiest.

    Correct, no need to reverse the pistons. Reversing the con rods would also be a "no". This goes for reverse-rotating 850 engines (for a 600 chassis), as well. Also, reversing the higher-compression (stepped-top) OE 850 pistons, or most aftermarket high-compression pistons, could/would prove catastrophic; with the wedge-shaped combustion chamber on these cylinder heads, the h/c piston top could/would hit the head, valves &/or spark plug.

    Re-using the Moretti's original 850 generator would be easiest. This would also negate the need for any wiring/regulator changes.

    Weber 32DMTR.
     
    Last edited: Dec 17, 2018
  15. Jeff Stich

    Jeff Stich True Classic

    Location:
    Norco, CA
    You can either swap a reverse-rotation timing gears set in place of the OE 1050 timing chain/gears, or swap in an 850 cam & 903cc 850 oil pump/distributor intermediary drive shaft PLUS an 850 timing chain/gears set (the OE 1050 timing chain/gears have different cam indexing). The 1050 chain/gears could be re-used in this situation if the cam index hole is re-drilled to an 850 setting (using the old OE 850 gear as a pattern) & the chain direction is reversed. This would only be recommended if the 1050 chain/gears are new or near-new, otherwise just use a new 850 chain/gears set. No need to modify & re-use sloppy, worn-out timing parts!

    The A112 crank will need to have the flywheel end drilled & rebushed to fit the 850 trans input shaft. This should only be done by a competent machinist with the proper tooling.

    You will also need to swap in a set of 850 (CCW) crankshaft oil seals, as the A112 1050 seals are usually CW-specific (depending on age/brand of seals - later ones are non-directional). Failure to do this may result in oil seeping/pouring out of the seals whenever the engine is run.
     
    kmead likes this.
  16. Jeff Stich

    Jeff Stich True Classic

    Location:
    Norco, CA
    That is correct. This is what the reverse-rotation gear set looks like:

    fiat903cc_timing_gears.jpg
     
    Dr.Jeff likes this.
  17. Dr.Jeff

    Dr.Jeff True Classic

    Location:
    Sin City
    Do it make that cool whining sound like V8's with a gear drive cam? :D
     
  18. Jeff Stich

    Jeff Stich True Classic

    Location:
    Norco, CA
    Not quite as loud, but yes, it does make a similar sound. :)
     
    Dr.Jeff and kmead like this.
  19. cozzoi

    cozzoi George

    Wow Guys!,
    I m overwhelmed with the amount of info and help I just received.... Thank you very much!!!!!!
    The A112 Abarth engine (just rebuilt) is still in Italy and I m planning to pay it in full once I know it can be converted and it is not hugely expensive to do it. I ll be able to load it in a friend's shipping container next week. Pics attached.
     

    Attached Files:

  20. Jeff Stich

    Jeff Stich True Classic

    Location:
    Norco, CA
    You might want to separate the transaxle & starter motor from the engine before loading/shipping it, as you won't need those items when installing the A112 engine into the Moretti. This makes it easier to move the engine about & leaves more room for "other stuff" to fit in the container. You might also be able to negotiate a better price for just the engine without those 2 items(?). ;)

    Hopefully your Moretti came with an 850 engine in it? You'll need to borrow a few parts from it for the 1050 conversion.
     

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