This area will contain all specs on Fiat 850s.
I can also tell that some info is wrong and will fix it when everything is inputted.
Engine | |
Cycle | 4-stroke, gasoline |
Cylinders | 4, in-line |
Bore | 2.559in (65mm) |
Stroke | 2.500in (63.5mm) |
Sport Coupe stroke | 2.68in (68mm) |
Piston Displacement | |
US smogfree | 49.85cid (817cc) |
Standard | 51.44cid (843cc) |
Sport | 55.10cid (903cc) |
Compression | |
Standard | 8.0 : 1 |
Super | 8.8 : 1 |
Special | 9.3 : 1 |
Coupe | 9.5 : 1 |
Max HorsePower | |
Standard | 40 / 5300rpm |
Super | 42 / 5300rpm |
Special | 47 / 5300rpm |
Coupe (DIN) | 52 / 6500rpm |
Block and Crankcase | |
Cylynder bore | 2.5591 to 2.5610 |
Tappet Seat Dia. | 0.5516 to 0.5523 |
camshaft seat bushing: | |
.....valve gear end Class B | 1.9882 to 1.9886 |
.....valve gear end Class C | 1.9886 to 1.9890 |
.....valve gear end Class D | 1.9961 to 1.9965 |
.....valve gear end Class E | 1.9965 to 1.9969 |
.....intermediate | 1.8276 to 1.8287 |
.....flywheel end | 1.4142 to 1.4154 |
Length of interm. transverse member | |
between thrust ring seats | 0.9149 to 0.9173 |
Piston Clearance | 0.0008 to 0.0016 |
Wear limit | 0.006 |
Cankshaft and main bearings: | |
Main bearing journal standard diameter | 1.9994 to 2.0002 |
Standard main bearing shell thickness | 0.0721 to 0.0725 |
Main bearing inserts for serice | Standard, 0.01-0.02-0.03-0.04 US |
Crankpin journal standard diameter | 1.5742 to 4.5750 |
Main bearing-to-journal: | |
clearance of new parts | 0.0008 to 0.0024 |
wear limit | 0.004 |
Length of centre main bearing journal, shoulder-to-shoulder | 1.1055 to 1.1071 |
Width of centre transverse member, between thrust ring seats | 0.9149 to 0.9173 |
Centre main bearing thrust ring thickness | 0.0909 to 0.0929 |
Oversize thrust ring thickness | 0.0959 to 0.0979 |
Crankshaft end fit, thrust rings installed: | |
clearance of new parts | 0.0024 to 0.0102 |
wear limit | 0.014 |
Max misalignment of main bearing journals | 0.0020 |
Max misalignment of crankpins to main bearing journals | +/- 0.0197 |
Max out-of-round of crankpin and main bearing journals, after grinding | 0.0002 |
Max taper of crankpin and main bearing journals, after grinding | 0.0005 |
Squareness of flywheel resting face to crankshaft centreline: | |
Max out-of-true with dial indicator plunger set laterally some 1 7/32 inch apart from crankshaft rotation axis | 0.001 |
Flywheel: | |
parallel relationship of driven plate face to crankshaft mounting face: max out-of-true | 0.004 |
squareness of above faces to roatation axis: out-of-true | 0.004 |
The cylinder head | |
valve guide seat bore in head | 0.5098 to 0.5109 |
valve guide outside diameter | 0.5122 to 0.5130 |
bore of valve guides fitted in head | 0.2765 to 0.2772 |
--for the Special | 0.2768 to 0.2775 |
valve guide-to-seat press fit | 0.0013 to 0.0031 |
valve stem diameter | 0.2750 to 0.2756 |
valve stem-to-guide fit: | |
-clearance of new parts | 0.0009 to 0.0022 |
--for the 850 Special | 0.0012 to 00.25 |
wear limit | 0.006 |
valve seat angle | 45 deg. +/- 5' |
valve face angle | 45 deg 30 +/- 5' |
valve head diameter: | |
-intake | 1.063 |
-exhaust | 0.984 |
-intake for 850 special | 1.142 |
-exhaust for 850 special | 0.906 |
valve spring inside diameter | 0.8228 |
length of free spring | 1.7087 |
850 special: | |
Inner: Inner diameter | 0.552 |
Inner: free length | 1.563 |
Outer: Inner diameter | 0.8228 |
Outer: free length | 1.7087 |
Sport Coupe: | |
Inner: Inner diameter | 0.5276 |
Inner: free length | 1.4488 |
Outer: Inner diameter | 0.7874 |
Outer: free length | 1.6220 |
valve lift: intake & exhaust | 0.3386 |
850 special: intake & exhaust | 0.3465 |
rocker shaft support-to-shaft fit: | |
-clearance of new parts | 0.0004 to 0.0016 |
-wear limit | 0.006 |
rocker-to-shaft fit: | |
-clearance of new parts | 0.0004 to 0.0016 |
-wear limit | 0.006 |
rocker spring: | |
inside diameter | 0.6102 |
free height | 2.0353 |