1075 engine?

Discussion in 'Rear-Engine Fiats' started by RocketMonkey101, Aug 20, 2018.

  1. RocketMonkey101

    RocketMonkey101 Daily Driver

    Location:
    Los Angeles
    Sorry for the mistake in the title of the thread, I meant 1050...Curious if any of you are running a 1050 in your 850? I have been thinking about using my 850 as more of a daily but I feel like I might need the extra power to scoot around a bit better than the 903 allows for. Any thoughts? Any feedback on your 1050?
     
    Last edited: Aug 20, 2018
  2. myredracer

    myredracer Daily Driver

    It's do-able but for starters, the engine rotation is the opposite direction to the 850-based engines. That's a lot of $$ and work right there to reverse the rotation. Then buying a decent used engine, that may or may not a rebuild is a lot of $$. The 1050cc motors have been a popular choice in 600-based cars because they basically drop right in.

    I have a 1050 cc engine that was built around a 903 cc block. It's going into my 600 resto-mod project. It's expected to put out around 90 HP compared to 70 HP stock for an A112 motor and 50-ish (??) for a 903 cc. You don't want to know how much it cost me but it also has a LOT of special mods and parts in it too. An A112 1050 cc crank can be used in an 850 block by turning down the mains to 850 size rather than align boring the block. Add A112 rods, pistons, etc. and you might be able to end up with a decent motor at less cost than buying a complete A112 motor and reversing it's rotation. Finding a crank, head, rods, pistons, cam (or maybe reverse rotation gear set), etc. at a decent cost tho. may not be easy. You'd also need to offset bore the 903 block due to 67.2 mm pistons, relieve the bores at the bottom to clear the rods, plus a few other special mods and parts. A person needs to know what they're doing to go this route. Not sure how many engine builders are around anymore that know how to do it correctly. I had my motor assembled by Scuderia Topolino just before Paul moved back to Europe. I spent several years collecting all the parts I needed and handed it all over to Paul.

    Supposedly the 1050 cc motors have noticeably more torque due to slightly longer stroke. Since these motors don't rev quite as high, the diff ratio doesn't match as well. I put a 9/39 R&P in my 600 transaxle. 'Course, just more money...

    Unless you have deep pockets and are up for a challenge, you're probably better off just hopping up the stock 850. A few have gone the turbo route.
     
    Last edited: Aug 20, 2018
  3. RocketMonkey101

    RocketMonkey101 Daily Driver

    Location:
    Los Angeles
    What sort of mods would you recommend? I'd like to stay away from turbos and just stick to an NA engine. if I recall correctly I think I saw some talk of a 948 cc engine as a possibility that would not require offsetting the bore...thoughts on that?
     
  4. fiatfactory

    fiatfactory Steve Cecchele

    Location:
    Western Australia
    Offset bore is actually quite simple machine work for someone able to use their machinery... 67.2 pistons with stock rods and crank is 965cc...a factory setup for various models (like panda with OHV engine and A112 non abarth) so it uses all standard parts (pistons and head gasket)

    SteveC
     
  5. Frank L. Di Gioia

    Frank L. Di Gioia Daily Driver

    Location:
    las vegas, nevada
    The camshaft must have a few lobes narrowed as the rods on the 74mm stroke will hit a few of them. I can't remember which lobes. Another route is to have a 903 crankshaft built up with welding and then reground to a 74mm stroke. Using 843 rods and 65mm bore will allow you to have a 1 liter motor. Watch piston/head clearance with the stroker as OT 1000 motors had special short pin to piston top clearance. Norb McNamara regularly reved his 1050 to 8400 RPM at what used to be Sears Point, now I think Infineron Raceway?
     
  6. tomnj

    tomnj Old fogie stogie

    Location:
    Scotch Plains, NJ
    Here's an 850 coupe with a 70 HP (1050) engine. You can see clearly it has much improved performance. I am so jealous of this, wish my Coupe had this kind of power. I'd like to build out a nice 1 liter car as well.

    He mentions in the comments that it's an Autobianchi A112 engine using a camshaft from a 903cc for correct rotation. Maybe he means crankshaft? Too bad the A112 engines are virtually impossible to source.

     
    Last edited: Aug 24, 2018
  7. tomnj

    tomnj Old fogie stogie

    Location:
    Scotch Plains, NJ
    Here's another where the guy (anyone know him?) says he increased the engine size to 1 liter. 1050? Doesn't explain how it was done.

     
    Last edited: Aug 24, 2018
  8. kmead

    kmead True Classic

    Location:
    Michigan
    It is the cam that you need which if you have a reverse rotation engine to start with it will all be easier.

    The crank is part of what gives these such a large displacement so you don’t want to use the 903 crank
     
  9. tomnj

    tomnj Old fogie stogie

    Location:
    Scotch Plains, NJ
    Ok so if you take a A112 (1050) engine and put a 903cc cam in it, it will reverse the rotation to work in the Fiat 850? Is that the only part needed? The A112 engine rotates the opposite of a 903cc because it was front-mounted (if I am understanding that correctly) in the Autobianchi.
     
  10. Frank L. Di Gioia

    Frank L. Di Gioia Daily Driver

    Location:
    las vegas, nevada
    Another consideration when using the A112 motor is that there is no pilot shaft bearing at the rear of the crankshaft if I recall. You need to drill the end of the crankshaft center deeper for the transmission to fully bolt up to the motor. This my fading memory is pretty clear on as I didn't realize that till it didn't fit while installing IN THE CAR. I also recall the need to change the distributor/oil pump drive gear to get the oil pump to push oil the correct direction. The reason the 850 turns CCW has something to do with offsetting the motor via the ring and pinion placement. That and tilting the motor allowed for a larger radiator in a rather cramped area. The full details escape me now as it's been several decades since I played with these combinations. That and combined with having both 600 and 850 based cars at the same time. It has nothing to do with being the far side of 70....
    Hell, one thing I do remember is that FAZA = Fiat Abarth Zagato Allemano from Al Cosintino. Time for a drink and a nap....
     
  11. kmead

    kmead True Classic

    Location:
    Michigan
    That is part of it. The Autobianchi engine is 600 based which was CW rotation.

    Being in the front could have had the engine rotating in either direction depending on how the transmission was designed. Fiat has always used engine on right and transmission to the left which has generally led to a CW rotation engine. Honda started out with transmission on the right and engine on the left which leads them to run their engines CCW.

    You will also need to flip the pistons around the opposite way, get a 903 oil pump, water pump, alternator and change to a different gear set to run the cam I believe.

    Something worth reading if you get a chance to get some other background on 600 and 850 based engines.

    http://www.abarthweb.com/abarthtricks.pdf
     
    RocketMonkey101 likes this.
  12. fiatfactory

    fiatfactory Steve Cecchele

    Location:
    Western Australia
    The Abarth block is based on the Fiat 127 block, different water pump mounting pattern, has a screw on oil filter (no centrifuge) and is set up for FWD.

    You don't spin the pistons (surprisingly) as the offset for an 850 CCW engine is actually incorrect... I know I know... but look closely and the 127 engine (CW) and the 850/903 (CCW) pstons are interchangeable as the 850 was actually offset the "wrong" way...

    The oil pump always spins in the same direction in both CW and CCW engines, same with the distributor... always turns clockwise...the difference is the cut on the gear for the oil pump drive jack shaft so you need the correct jack shaft for CW or CCW rotation respectively. Camshaft is different, so you need to use a CW/CCW lobe in the correct way... OR... use a set of cam drive gears to reverse the rotation of the cam, now these are not gears with a chain connecting then (both shafts turn in the same direction) they are helical/or straight cut gears that are in mesh (shafts then spin in opposite directions)

    Gear set for cam/crank when using a chain is the same ...what is different is the timing chain, this is specific for CW and CCW rotation, as the little "slingers" on the chain are offset to suit rotation... use the wrong chain and you'll have an awful racket from the chain!

    Alternators can be spun both ways and still work...the difference is the lay of the cooling fan fins.

    The number one simplest (and by far cheapest) way to increase the engine capacity to 965cc or larger is to offset bore the block and use 67.2 pistons from an Autobianchi A112 elite (not abarth) This engine still uses the same stroke crank as the 903, it still uses the same press fit gudgeon pin conrods as the 903, all that changes is the size of the piston.

    The 1050 engine is a different crank, very different conrods which are lighter and have the small end bushed, full floating gudgeon pins, pistons to suit the FFG with grooves for pin clips and a shorter deck height to the piston to suit the longer crank stroke

    SteveC
     
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  13. kmead

    kmead True Classic

    Location:
    Michigan
    Given the above then:

    Using the 903 camshaft will allow the use of the existing 1050 oil pump, the existing 1050 distributor by using the 903 jackshaft, the existing 1050 alternator (by taking the external fan off the 903 alternator and putting it on)

    Requires the use of the CCW camchain with reversed slingers from the cam to the crank.

    Seems relatively simple.

    As for the offset piston bores in a 903 block, that is a bit more challenging around these parts...
     
  14. fiatfactory

    fiatfactory Steve Cecchele

    Location:
    Western Australia
    well technically you don't even "need" to use a CCW or CW timing chain.. you could reverse the chain on the gears (i.e. put the outward facing side inwards) which makes it run backwards... the 1050 abarth engine comes with a toothed belt drive anyway, not a chain. I guess there would also be a need to remark the timing pulley or timing cover too, as the zero mark would be correct but the other marks would be on the retard side of zero, not on the advance side.

    and you would need an adaptor plate to allow mounting of a regular 4 bolt 850 water pump, onto the 127/a112 bolt pattern of water pump '''

    And you would need to change the front and rear crankshaft seals as they are rotational, or else you would have a massive oil leak...

    Only two bores are offset...1 and 4...2 and 3 remain on the same centres... very simple machine work for someone who knows how to set up a boring bar... you just take several smaller cuts.

    Can't find a machinist in Michigan...the home of motor city... I don't think you've looked hard enough Karl....it's got to be easier to find a capable machinist in Michigan than it would be to find a 1050 abarth engine in Michigan.

    SteveC
     
    kmead likes this.
  15. kmead

    kmead True Classic

    Location:
    Michigan
    Hah! So true.

    Try finding a 903 engine here, I have my one year only 817... No matter what I have to import the engine to start with :)

    Thank you for all the info, this like the ultimate SOHC thread are so very helpful.

    Karl
     
  16. RocketMonkey101

    RocketMonkey101 Daily Driver

    Location:
    Los Angeles
    I'm really glad all this info has come out on this thread. It's answered a bunch of questions.
     
  17. Frank L. Di Gioia

    Frank L. Di Gioia Daily Driver

    Location:
    las vegas, nevada
    Since getting back into rear engine Fiats I've become a fan of this Forum. It's the best one I've ever been a member of, well, er, actually the only one I've ever been a member of. Kinda neat seeing another generation like the older Fiats. On the 1050 subject I've dug up some 1050, 1000, and 1438 versions of rear engine Fiats I've had. If I'm able to get the two pics loaded they are: Yellow '67 with 1 liter PBS Engineering head and single 40mm DCOE. Later on I installed a PBS kit with a 1438cc DOHC motor from a 124 with reverse rotation. Car had 1300/124 springs, Carrera shocks, thicker sway bars, P-7 Pirellie tires and 4.11:1 gearing. Larger motor made the car feel planted to the road. Only added about 80lbs total.
    Second page hopefully shows my former white Abarth 750 GT. Motor is an Autobianchi 1050 A112 bottom end slightly over to about 1070cc. Head is a PBS with dual 40mm DCOE Webers. It ran an alloy flywheel (4 1/5 lbs?), A112 PP, and carbon fiber pushrods with an Alquati bump stick. Horsepower was about 105 and it would go to 9000 RPM and stay in one piece. It was never on a dyno but HP is based on a guess from Paul Swenson of PBS. An old tired 1050 STOCK cam with the PBS head would give slightly over 90 HP. New rings would give about 97+ HP. They knew small Fiat motors! Final pic with the red 600 is a PBS SOHC motor owned by a friend in the San Diego area. One of only a few made. NO, it wasn't mine.
     

    Attached Files:

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  18. Jeff Stich

    Jeff Stich True Classic

    Location:
    Norco, CA
    The 1050 uses a chain & toothed gears just like the 850/127 engines do. The Triger timing belt setup was an aftermarket conversion kit for these engines.

    [​IMG]
     
  19. fiatfactory

    fiatfactory Steve Cecchele

    Location:
    Western Australia
    Yes I know the Triger belt drive kits, there are also Abarth produced items... pretty sure there's at least one model of A112 that comes standard with this.

    SteveC
     
  20. Jeff Stich

    Jeff Stich True Classic

    Location:
    Norco, CA
    The timing belt conversion kits were offered by Triger, Abarth & I think Graf, as well? They were add-on items for 127, A112, Uno, Panda, etc.. All were pretty much the same except the name cast on the main (upper) cover piece, & AFAIK not normally installed as standard on the production A112 1050 engines. I've had eleven A112 1050 engines to date (3 of those NOS), & all of them came with the timing chain/gears setup as standard. If there were 1050's that came with the belt kit as standard, I'd be curious to know on which versions/years of the A112 that was.
     

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