Below are some engine specification and output figures for the SOHC engine. I'll try and compile this in a more tabular format, but for now this will do.... INCLUDEPICTURE "http://www.turbo124.com/forum/images/smilies/icon_wink.gif" \* MERGEFORMATINET

128 sedans

128 sedan 1100 1969 type128A.000 8.8:1 C/Routput 55hp @ 6000 (din) torque 7.9mkg@3600 (din)12/52 52/12 camshaft single choke 32ICEV weber(source "Specifications and features" 128 sedan july 1969 Fiat)I know all sedans have a single front exhaust pipe

128 sedan 1972 (usa specification) engine type 128A.0408.5:1 C/R output 52hp @6000 (din)torque 7.5mkg@3400 (din)10/54 54/10 camshaftsingle weber 32ICA(source "specifications and features" 128 sedan supplement USA 3/72)

128 sedan 1975 (european specification)engine type 128A.000 (1100) / type 128A1.000 (1300)both engines 9.2:1 C/Routput 55hp/60hp (din)12/52 52/12 (1100cc) 20/44 60/4 (1300cc)both engines single 32ICEV (source "owners handbook" 128 sedan/wagon 1975 1st edition)

128 Sedan 1300 1976 (north american specification) type 128A1.040.6weber 32DATRA11/100 carb, non catalytic(source "specifications and features" supplement emissions USA 6/76)

128 sedan 1300 1976 (north american specification) type 128A1.031.6weber 32DATRA14/100, catalytic converter(source "specifications and features" supplement emissions USA 6/76)

128 Rally 1300 1971 type128AR.000 8.9:1C/R67hp @ 6200 (din) twin choke carb 32DMTR 20Single outlet exhaust manifold(source "Caratteristiche E Dati" Fiat 128 Rally 1/1972)

128 coupes

128 coupe 1100 1971 type 128AC5.000 8.9:1 C/Routput 64hp @ 6600 (din) 8.3mkg@3800 (din)twin choke carb(source "All the Fiats 1984")from my other info, twin front downpipe, 24/68 64/28 cam

128 coupe 1300 1972 type 128AC.000 8.9:1 75hp (din) @60009.4mkg@360024/68 64/28 camshafttwin venturi weber 32DMTR 20(source "specifications and features" 128 sport coupe 1st revision 11/72)

128 coupe 1300 1972 U.S.A. version type 128A1.0408.5:1 C/Routput 51hp@5600 (sae) torque 8.5mkg @3000 (sae) 10/54 54/10 camshaft, single weber 32ICA(source "specifications and features" 128 sport coupe 1st revision 11/72 U.S.A supplement)(dont ask me why some figures are quoted as S.A.E. because I dont know, it could just be for the US market, maybe that is the standard there?)

128 3P's128 3P's

128 coupe 3P 1100 1975 type 128AC5.000 (?)9.2:1 C/Routput 65hp (din) (up 1 hp fron prev) torque 8.9mkg@4100 (din)(up from 8.3mkg @ 3800)twin choke carb(source "All the Fiats1984")

128 coupe 3P 1300 1975 type 128AC.0009.2:1 C/Routput 73hp (din) (down 2hp from 75) torque 10.2mkg@3900 (din)(up from 9.4mkg@3600)twin venturi weber 32DMTR/??(source "All the Fiats 1984")

128 coupe 3P 1300 1978 (aust specification) type128AC.0239.2:1C/R12/52 52/12 camshaft 32DMTR/32 carb, has emmision control gear on it (fuel vapour recirculation) the inlet manifold has much smaller inlet ports, it quotes 73hp (din) (but I dont think so...like the inlet manifolds supplied to USA 3P's)(source "owners handbook" 128 3P )

128 3P (North American version) type 128A1.040.5 non catalytic (1975)type 128A1.040.6 non catalytic (1976)type 128A1.031.6 catalytic (1976)8.5:1 C/Routput 62hp @6000 (sae)torque 9.3mkg@4000 (sae)10/54 54/10 camshafttwin choke weber 32DATRA1/100 non catalyst ' 75twin choke weber 32DATRA11/100 non catalyst ' 76twin choke weber 32 DATRA14/100 catalyst ' 76(source "owners handbook" 128 3P US version 1976)

X19's

X19 1300 1972 type 128AS.000 8.9:1 C/R75hp @ 6000 (din) (source "All the Fiats 1984")from my info, twin choke carb, twin front pipe,24/68 64/28 cam in europe

X19 1300 1977 (australian specifications) type 128AS.0239.2:1 C/R12/52 52 12 camshaft 5 degrees static ignition and 28 degrees + - 2 of centrifugalsingle front pipe, no catalytic, but the system as per catalytic with just a test pipe fitted, weber 32 DATRA 19/100(source "owner handbook" X19 9/77 3rd edition)I can confirm all of this too, as i've dialed the standard camshafts, and cc'ed the standard chambers, standard output unknown, quoted as 73hp (din) (din_think_so )

X19 1300 (usa specifications) type 128AS.031.5 non catalytictype 128AS.031.6 catalytic8.5:1 C/Routput 61.5hp @5800 (sae) (C.C. cars 61hp)torque 9.3mkg@4000 (sae) 10/54 54/10 camshaft32DATRA (various) carburettor(source 'specifications and features" X19 (us model) 1977)

X19 1978 (five speed) type 138AS.0009.2:1 output 85hp (din) torque 12mkg@3200 (din)twin choke carb (listed as 34DATR 7/250)(source "All the Fiats 1984")these definitely have the twin front downpipe, non catalytic, camshaft is 24/68 64/28 in europe)

X19 1981 (US specifications) type 138BS.0318.5:1 C/R output 75hp @5500 (sae) torque 79.6ft/lbs @3000 (sae)bosch L jetronic, catalytic convertor(source "specifications and features" X19 supplement fuel injection 10/81)

X19 1982 (carburettor) 1500 (australian specification) type 138AS.0239.2:1 C/Routput 80hp@5750 (din)torque 12kgm@3250 (din)10/54 54/10 camshafttwin choke carb 32DATRA 23(source "owners handbook" X19 Five speed 1980 1st edition, supplied with my 1500 5 speed X19, and once again I can confirm all this as I have verified the original cam specs)

Others

Ritmo / Strada 60hp / 65hp / 70hp1116 / 1301 / 14989.2:1 / 9.1:1 / 9.1:18.3mkg@3500/10mkg@3500/12mkg@3000these use single choke carburettors 32ICEV 1100/1300 34ICEV 1500(source "All the Fiats 1984")

A bit more research on standard camshafts.

Fiat 128 1116cc Type 128A.000 12/52 52/12 (checked at 0.50mm) 9.1mm gross liftRunning clearance 0.30 inlet 0.40mm exhaustNett lift 8.8mm inlet 8.7mm exhaust"Specifications and Features" July 1969

128 Coupe 1116cc Type 128AC5.00012/52 52/12 (checked at 0.50mm)9.75mm gross liftRunning clearance 0.30mm inlet 0.40mm exhaustNett lift 9.45mm inlet 9.35mm exhaust"Specifications and Features" Nov 1971

128 Coupe 1290cc Type 128AC.00024/68 64/28 (checked at 0.50mm)9.75mm gross liftRunning clearance 0.40mm inlet 0.45mm exhaustNett Lift 9.35mm inlet 9.30mm exhaust"Specifications and Features" Nov 1971

128 Rally 1290cc Type 128AR.00024/68 64/28 (checked at 0.50mm)9.75mm gross liftRunning clearance 0.40mm inlet 0.45mm exhaustNett Lift 9.35mm inlet 9.30mm exhaust"Specifications and Features" Jan 1972

X19 1300 Type 128AS.000 (Euro spec)12/52 52/12 (checked at 0.60mm inlet / 0.65mm exhaust)9.75mm gross lift Running clearance 0.40mm inlet 0.50mm exhaustNett lift 9.35mm inlet 9.20mm exhaust"Specifications and Features" June 1973

X19 1290cc USA 1975 spec Type 128AS.031.5 (leaded)Type 128AS.031.6 (unleaded CC)10/54 54/10 (checked at 0.50mm)9.1mm gross liftRunning clearance 0.30mm inlet 0.40mm exhaustNett lift 8.8mm inlet 8.7mm exhaust"Specifications and Features" Nov 1975

X19 1500 Australian Spec Type 138AS.02310/54 54/10 (checked at 0.50mm)9.1mm gross liftrunning clearance 0.30mm inlet 0.40mm exhaustNett lift 8.8mm inlet 8.7mm exhaust"Specifications and Features" June 1979

Thats all the OE Specs I have to hand....

These also from the Haynes X19 manual (scattered around the manual, but Haynes have been known to get it wrong on occasion)

X19 1290cc Type 128AS.040.512/52 52/12 (checked at 0.50mm)9.75mm Gross lift Running clearance 0.40mm inlet 0.50mm exhaustNett lift 9.35mm inlet 9.25mm exhaust

X19 1500 Type 138AS.00012/52 52/12 (checked at 0.50mm)Gross lift 9.85mm inlet 9.90mm exhaustRunning clearance 0.45mm inlet 0.60mm exhaustNett lift 9.45mm inlet 9.25mm exhaust

X19 1500 Type 138A2.00012/52 52/12 (checked at 0.50mm)Cam lift 9.20mm inlet 9.25mm exhaust

X19 1500 USA Type 138AS.040Type 138AS.031 (california)gross lift 9.20mm inlet 9.25mm exhaust

I would guess that the X19 1300 128AS.000 cam would be the same as the 128 coupe / rally (24/68 64/28 9.75mm) but it's duration is listed differently due to the different check clearance specified (0.60/0.65mm compared to 0.50mm)

I really need to get hold of a "Specification and Features" for an X19 1500 1979 -1982 euro / uk carb engine (138AS.000) to confirm the camshaft lift and duration figures quoted by haynes... but perhaps the Euro spec 1500 cam isn't "the best" of the standard bunch, for total duration anyway....

Some stuff about pistons///Mike... well you have probably seen the internals of more US spec 1500 sohc than I have.... I have only stripped a couple down.

I've also never bothered to measure the flycut depth or volume of the US spec pistons which I found so can't offer any figures on these. Both BTW were FI and Cat engines from cars I imported to Australia from the US as vehicles to be broken for spares... we didn't get very many 1500 5 speeds here in Australia, and we had even less EFI Bertones (we only saw EFI and cat in 87/88 model year and then just 50 vehicles in the country)

The pistons I found looked like these.

I never tried, but I believe these pistons make the engine non interference. I never measured it, but I believe the FI cat cars in the US are under 8.5:1 static CR and around 75hp...Lets refer to these as Type1

I've never striped down an Australian spec EFI cat 1500...as there's about 10 cars in the whole state of W.A. ... so I honestly couldn't tell you which crown shape/ flycut depth these have.

Our 1982/1983 model year were 1500 5 speeds (138AS.023) These are almost a euro engine (138AS.000) but not quite. We had a 32datra carb instead of the 34dmtr of the euro/UK spec cars. We also had a different camshaft (10/54) but other than these two differences, all other major specs (9.2:1 CR , inlet manifold runner size, exhaust manifold runner size, combustion chamber shape and volume etc etc) are the same. The Australian spec engine is rated at 80hp, not 85 hp like the euro/UK equivalent. That's understandable as the carb butterflys and venturis are smaller and we have less cam lift and duration. These are an interference engine. The pistons found in euro/UK/australian engines look like these. Lets refer to these as Type2

We also get the 1500 (carbed) engine in the 85S Regata, and the piston used in this engine is different to the euro/uk/aust spec piston for the X19 1500. They look like this. Lets refer to these as Type3

the top of these pistons is flat, but the compression height is 0.2mm higher than the three other types pictured here, though they use a Astadur non retoque gasket which is around 0.35 thicker (crushed) compared to the other engines. CR for these engines is quoted for aust spec as 9.5:1. these are rated at 85hp, use a 10/54 cam, but a 32/34dmtr (smaller venturis than the euro spec X19 though), same runner size in the twin out ex manifold, a smaller port size thru the inlet manifold and egr fittings on the manifolds.... same engine (but without EGR) is fitted to many models of Uno/Tipo/Strada in UK/Europe...

Then there are the euro/australian spec 128 coupe/rally X19 1300 piston. These have a very small dome across the head of the piston. Notice how the flycut front flatish edge isnt truly straight like the regata85s piston above...thats where the outer circumference of the circular dome is and it's 0.6mm high... When these are used with the euro/australian spec head - no full circular recess- in a 1500cc engine, the CR is up around 9.6:1 depending on head gasket choice. They look like this. Lets refer to these as Type4.

The listed pictures are examples of the piston crown shapes I have seen in the sohc (86 and 86.4mm engines) but there is nothing to say some markets didn't get pistons with different compression heights.

For example the piston shown as type 3, is listed in the 2009Mahle online catalogue with two different compression heights, mahle P/N 0087200 has a CH of 34.15 flycut depth of 2.7mm, Mahle P/N 0087400 has a CH of 34.9mm with flycuts 2.7m deep.

The piston shown as type 4 is listed in the mahle catalogue as a 0078000, CH of 34.7 with flycuts 2.6mm deep, dome height 0.6mm

There is also the added complication that some manufacturers actually lower the CH on oversize pistons to keep the CR close to stock!

If your building a sohc it's one for the first things you check on the dry build, the deck height gets set when you've trial installed the pistons you've chosen to use, and personally I like zero as a good baseline, and set the squish /quench clearance with head gasket clearance...

So asking what clearance others have isn't neccesarily going to be exactly the same as you deck height / VP etc etc that you will have, as every engine will be "slightly" different due to "production tolerances" .... but it will give you ballpark numbers.

Anyway, I have found that the sohc is definitely sensitive (power output wise) to a tight squish clearance, as it is to inlet valve shrouding by both the chamber walls (throughout the entire valve event) and the piston valve flycuts (mostly around TDC of course), though the exhaust valve is the one that gets really close to the piston around overlap...so the tiniest flycut isn't always the best...

USA to UK /Euro differences

There are quite a few minor differences that make the 85hp carbed engine different to others.

The cylinder head is different, it does not have the full circular machined recess that the US spec engines do. (In answer to Dave's question the head is made flat and then the recess is macined in afterwards, I have seen heads with the same casting number with both flat and recessed faces, so the chamber SHAPE is the same, but the US spec head gets a 1.5mm circular plunge cut on the milling machine).

There are also quite a few different versions of the head available, ie some with air injection port and some without (in Australia X19 heads have the air injection port there cast in, but it isn't used)

The inlet manifold is different, the ports thru the 1500 carbed euro/Uk and australian spec cars have larger ports. 4425193 is the cast in part number on this one.

The exhaust manifold is different. I'm not sure what manifold the US 1500 cars had, but suspect it was a single outlet design. X19's in europe/UK use a dual outlet design (similar to the US spec 74 manifold) the 1500 manifold has larger ports, the part number cast into this manifold is 4392487. The 128 rally/coupe/x19 1300 euro use a similar manifold but it has smaller ports, the part number cast into this manifold is 4252518.

Interesting Note: The exhaust manifold and front pipe actually has the most benefit (HP wise) of any of these differences. A superb example of how much difference would be to compare euro spec 128 rally and 128 coupe engines. same head design, same CR, same inlet manifold and carb, same cam specs. the 128 rally used a single outlet design manifold (67hp) the 128 coupe used a dual outlet design (75hp)

The carb used in the UK is a 34DATRA, here in Australia we still had a 32DATRA (precisely the same carb as our 1300 spec cars strangely enough) and our cars were only rated to 80hp.

I believe that the euro and UK X19 1500 spec cam is 24/68 64/28 with 9.9mm lift (same duration as the 128 rally/coupeX19 1300 euro spec cams, but the 1300 ran 9.75mm lift)

And the piston crown shape.. the 1500US spec had HUGE flycuts and the engine was non interference, whereas euro/UK spec engines had small flycuts and were interfence (the exhaust valves touch the pistons and bend when the timing belt breaks)

Chassis specifications

SteveC