REDEEMING THE FORGOTTEN Y-BLOCK

Updating Ford’s Y-Block to Give It Modern Performance While Retaining Its Old-School Charm

The Y-block was Ford’s successor to the Flathead. It was meant to service everything from Ford’s performance-oriented Thunderbird to pickup trucks. The block is substantial, to put it mildly. The tradeoff for the extra weight is durability. The cylinder bores can usually be opened up as much as 0.120 inch. Also note the holes in the top of the deck; these are pushrod holes.

The bottom of the block features a deep skirt for extra rigidity. Unfortunately, Ford engineers didn’t take advantage of this design and didn’t cross-bolt the mains. Two-bolt mains are standard

When Ford introduced its Y-block engine in 1954, it labeled the engine the worthy successor to the venerable Flathead. The Flathead gained a loyal following of hot rodders and racers, but the big Cadillac overhead-valve V-8 and Oldsmobile’s Rocket 88 were stealing Ford’s thunder in terms of power, so something had to be done, and Ford decided to respond. The answer was a clean-sheet V-8 design, featuring overhead valves and improved cooling compared to the old Flathead. It was dubbed the “Y-block” because of the way it looked and because of its deep skirt and tall cylinder heads.

One of the defining features of the Y-block is the stacked intake port, which limits intake flow. Troutman performed significant porting work on the cylinder heads, but he says there is only so much that can be done with this design.

The exhaust ports are more conventional by modern standards. Notice, however, that the interior exhaust ports are side by side, as you normally find on a Chevrolet.

The combustion chambers are small, so they keep the compression ratio up. However, they are also very deep, which makes valve shrouding a problem. If you are rebuilding an original set of Y-block heads, you will probably need to install hardened exhaust seats to accommodate unleaded gas.

This picture shows how the combustion chamber and port throats have been cleaned.

The new springs are matched to the custom-ground Iskenderian cam that Troutman will use. At the 1.755-inch installed height, these springs will have 130 lbs of pressure on the seat and 250 over the nose, which is about 110 extra pounds of pressure than the original springs.

It debuted in 1954 as a 239ci engine—just like the Flathead—and boasted slightly improved grunt with 130 hp. Subsequently, the Y-block gradually grew in size until it reached its peak, 312 ci, in 1957. Although it would continue to be used in trucks for years to come, 1957 was the final year that Ford would use a Y-block in its passenger cars.
After decades of service from the Flathead, Ford’s life span for the Y-block was disappointingly short. Although its overhead-valve design made it more efficient than the Flathead, the Y-block was a heavier motor. When Chevrolet’s revolutionary small-block V-8 appeared in 1955, it was almost universally accepted as the better design. Although the Y-block was raced and even won NASCAR events, the engine seemed destined to be nearly forgotten by the rodding community and was unceremoniously phased out. It was eventually overshadowed by the Windsor and Cleveland small-block engines.

The Y-block uses mushroom lifters, which require special considerations. Besides the camshaft, Iskenderian also sells new lifters. Because of the design, solid flat-tappet lifters are the only option, and they don’t oil through the pushrods.

The unique lifter shape means that they must be installed with the engine upside-down or from the camshaft side of the block. It must be one of the first assembly operations performed on the newly prepared block.

Before you can turn over the block, the camshaft must be installed to prevent the lifters from falling out. Don’t get confused by the distributor gear by thinking that this is the front of the engine. The distributor is located at the back of a Y-block.

Here’s a view of the lifters from the top.

Troutman was able to find a set of ultra-strong, ultra-light connecting rods used for Nextel Cup-level racing. Ordered by a Nextel Cup race team, a change in engine build specs made them obsolete before they could be used. The rods are 6.300 inches long versus the stock 6.270 inches, and they have 1.888-inch bearing journals. These smaller journals allowed Troutman to offset-grind the crank to achieve the extra stroke.

The rods are mated with custom lightweight Ross forged pistons, complete with floating wrist pins and spiral locks. Lighter pistons and connecting rods allowed Troutman to cut the bob weight, which is used on each of the crank’s rod journals. It mimics the weight of the rod/piston/bearing and ring assembly. This is a good barometer of an engine’s rotating weight, which was reduced from the stock Y-block’s 2,020 grams to a relative light weight of 1,563 grams. This is a 22.6 percent reduction in mass!

The pistons may be custom, but the cylinder bore size of 3.885 inches allows a ring pack for a 0.010-over 283 Chevy to fit perfectly. The rings are fitted and gapped at 0.020 inch.

The stock crankshaft was retained, but the rod journals were offset-ground to match the 1.888-inch connecting rods. This allows an increase in stroke from 3.438 inches to 3.600 inches. To maintain as much crank strength as possible, Troutman specified a 3/16-inch radius on the fillets. One of the drawbacks to offset-grinding any crank is that it moves the oiling holes closer to the sides of the bearing journals. This can cause oiling problems to the bearings unless you grind lubricating reliefs on either side of the holes to help direct the oil flow.

Here are the reconstructed rod journal oiling holes.

After performing the oiling work, Troutman thoroughly polishes and cleans every journal to ensure that no burrs or trash remain on the crank.

Main bearing clearances were set for 0.0022 inch. The thrust bearing on the Y-block features a 360-degree thrust face, as opposed to the 180-degree thrust face found in Windsor motors.

After the rods were cut down to size, the journals were honed and measured to give the proper 0.0018-inch clearance.

If you are building the larger, 312ci version of the Y-block, be aware that when installing the crank, the mains are only bolted down with 85 lb-ft of torque compared with 105 lb-ft for a Windsor. Too much torque will crack the webbing.

Here, one connecting rod has been fitted into place against the crank journal. You can see how the rod and bearing allow room for the crank fillet. When reducing rod width, it is important to remember that the same thing must be done to the corresponding bearings.

Troutman checks between a pair of connecting rods with a feeler gauge to see if he has the proper side clearance between 0.007 inch and 0.012 inch. This is especially critical when cutting the connecting rods to a custom width.

The rotating assembly was set up so that the pistons would be 0.001-inch in the hole at TDC. This, along with a slight piston-top dish, produced a 9.5:1 compression ratio. The front timing cover is the approximate size and weight of a small fire hydrant, but it is one of the defining characteristics of this engine.

Because of the age of the block and the increased compression, Troutman worried that the head-bolt threads wouldn’t hold. He used a set of ARP studs to secure the heads because this does not stress the threads in the block as badly. A modern set of head gaskets also helps to improve cylinder sealing.

The cylinder heads are installed and torqued to ARP’s specifications

Along with its deep skirts, once the heads are installed, it’s easy to see why this engine was nicknamed the “Y-block.”

The valvetrain uses cupped pushrods, which are made specifically to cradle the rocker adjusters.

The solid mushroom lifters do not allow oiling through the pushrods. Instead, the rocker arms are oiled through the rocker shaft, so a good lubricant should be used between the pushrods and rocker adjusters in order to keep from killing parts when the engine is first turned over.

The rockers are mounted on a shaft system, and the adjusters are directly above the pushrods.

Springs help to locate the rockers. Oil flows through the shaft and lubricates the rockers with a small oiling hole underneath each galley.

The lifter valley is sealed by this aluminum piece. It is held in place with two bolts in the center of the plate. If this plate is warped or bent at all, it will not seal. Because of this, it’s a good idea to invest in a new plate whenever you are doing a rebuild.

The dual-plane intake manifold is unmistakable because of the way it feeds air and fuel into the stacked intake ports of the cylinder heads.

The intake is held in place with four clamps that pull down on retaining ears on each side of the runners. A four-barrel Holley Street Avenger is used to feed the fuel.

Troutman replaced the old distributor with a modern Mallory piece, which provides a stronger, cleaner spark.

When you have an original finned set of Thunderbird valve covers this perfect, you have reason enough for a motor build like this—so you can show them off!

Another modern touch is the racing-style alternator, which replaces the old generator. Besides its small size and light weight, it produces good power with minimal engine drag.

The coated tubular headers are obviously a modern addition, but the performance gains over the old cast exhaust logs are definitely worth the investment.

Dyno testing showed peak torque of 359.8 lb-ft at 3,400 rpm and 285.4hp at 4,700 rpm.

The finished product wouldn’t look a bit out of place in any classic Ford of the period.

The original rods are forged and are not of poor quality, but the weight and large journal size are detrimental to any serious performance building.

The Nextel Cup rods were made for much wider Windsor journals and required that the width of each rod be narrowed by approximately 0.025 inch. The exact amount removed depends on the radius of the crank fillet. This material is entirely removed from the inside face of the big end of each connecting rod (the left side in this photo) because the outside face must be correctly chamfered to fit around the fillet of the crankshaft journal.

Preparing the timing chain is a little unusual; instead of lining up a set of marks between the top and bottom gears, you must have 12 pins in the timing chain between the two marks. To simplify the process, Troutman marked the correct number of pins in blue and then aligned those marks with the dots on the timing gears.

Article Sources

KT Engine Development

704/784-2610

384 Industrial Ct. Concord, NC 28026

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Jeff Huneycutt

Jeff Huneycutt has been in the automotive industry long enough to collect more project cars than he can afford to keep running. When not chasing electrical gremlins in his '78 Camaro, he can usually be found planning unrealistic engine builds.

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