Harley-Davidson Shovelhead - Cylinders and pistons

Cylinders and pistons for Harley-Davidson Shovelhead














Cylinders for Harley-Davidson Shovelhead

Cylinders for Harley-Davidson Shovelhead

Cylinders for Harley-Davidson Shovelhead

These replacement Shovel cylinders are available as the thin flange 74" and the thick flange 80". Aside from the flange thickness and number of fins, both versions of these cylinders are essentially the same, with the exception of the bore size. The cylinders are available individually, but if both need replacing on the earlier 74, we recommend using the thick flange 80" version and fitting +.060 oversize 74" pistons. As with the original Harley cylinders, the thick flange version is obviously stronger. The later, longer, cylinder base studs will also need to be used. See our Shovelhead crankcasesection.

Because the cylinder manufacturer doesn't know what pistons will be used, these cylinders are supplied undersize of the standard bore. They must be honed out to suit the actual pistons being used. We can, of course, do this here. Because of their slightly heavier construction, using the standard OEM head bolts is awkward, and we recommend using our big bore head bolts for easier torquing.

Big bore cylinder head bolts for Harley-Davidson Shovelheads

Big bore cylinder head bolts for Harley-Davidson Shovelheads

Big bore cylinder head bolts for Harley-Davidson Shovelheads

Originally designed for use with big bore Shovelhead cylinders, these high tensile bolts and washers have a 7/16 12 point head. This gives far better access when retorquing the cylinder heads with the engine in the frame, which is awkward due to the size of spanner or socket used with the standard bolts which have a 9/16 6 point head. Available as a set of 10 with hardened washers, in black or chrome.

S&S Forged Pistons for Harley-Davidson Shovelhead

S&S forged pistons for 74

S&S forged pistons for 74" Shovelhead

For 2011, S&S have rationalised their piston options for the Shovelhead engine. The cast pistons have been discontinued, as have the older style forged pistons, which required quite large bore clearances. These new forged pistons run at a tighter clearance than previously, and we have different compression ratio options.

These are available in standard bore, as well as various oversizes, as replacements for stock 74" and 80" motors. We also have them available for stock bore strokers (84", 86", and 88"), as well as for the bigger bore 88", 93", 96", 98", and 103" conversions. We can also bore and hone your existing cylinders to suit these excellent pistons..

Keith Black pistons for Harley-Davidson Shovelheads

Keith Black pistons for Harley-Davidson Shovelheads

Keith Black pistons for Harley-Davidson Shovelheads

The cheap "imported" copies of the original strutted OEM pistons are now of very dubious quality, and we don't supply them. Although more expensive, these hypereutectic cast pistons from Keith Black are proving very useful in a Shovelhead application. Available as 8.5-1 compression for the 74, and 8.0-1 compression for the 80" motor, and in a full range of oversizes, they work very well with cams such as the Andrews J or A grind.

These pistons, however, are not a direct replacement if only a rebore is required. They use an Evolution wrist pin, which is .792" diameter, compared to the original .791 diameter Shovel wristpin. Also the combined weight of a pair of these assemblies is typically 300 grams lighter than the original OEM piston assemblies, and this has a major influence on crankshaft balance. For this reason we only recommend the use of these excellent pistons as part of a complete rebuild, where we will be rebuilding the existing connecting rods (or we can easily hone the wrist pin bushes if a new rod set is used), and balancing the crank anyway.

Wiseco forged pistons for Harley-Davidson Shovelhead

Wiseco forged pistons for Harley-Davidson Shovelhead

Wiseco forged pistons for Harley-Davidson Shovelhead

These are very strong and durable pistons, and are ideal as replacements for the stock cast strutted pistons, particularly in more arduous applications, or when a compression ratio change is desirable. Wristpins are the standard .791" diameter, and the rings are Hastings. Despite being forgings and running in cast iron cylinders, these well designed pistons only require .003" clearance. Forget the old wives tales about forged pistons being noisy.

We have these available for the 74" (1200cc) motors as 9.0-1 compression in Standard to + .080 O/S.

For the 80" (1340cc) engines they are available as 7.0-1, 8.5-1, and 9.5-1 compression. Std to +.030 O/S. We can also supply new cylinders, sized here to suit the Std pistons, or bore and hone your existing cylinders to suit the O/S versions.

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