DetailsSpecial short compression height pistons using 20.63mm gudgeon pins. For use with FT244/535 136mm long rods
Bore Size: 90.93mm
Compression Height: 33.0mm
Compression Ratio: 11.8:1 2wd/12.5:1 4wd head (estimated)*
Crown Thickness: 6.5mm
Apex Height: 4.0mm
Apex cc: 10.8cc
Gudgeon Pin: 20.63mm
Piston Bore Clearance: 0.0035-0.004"
Accralite Part Number: 1332XC9093
Parts Included: each piston is supplied with rings, gudgeon pin and circlips
* Please note that compression ratios stated are only a guidance based on new engines and will vary depending on combustion chamber volumes, block heights and differing head gasket thicknesses.
High performance engines demand high quality pistons. Accralite is dedicated to producing the finest forged pistons by combining the very best in materials, design and engineering technology. These tried and tested pistons have many features to aid performance and reliability machined into the piston as standard. So whether a requirement is for minor events or critical high performance applications, the same high specification is applied to the manufacturing processes of all Accralite Pistons. All pistons are matched balanced to within +/- 1 gram weight tolerance and are supplied complete with the finest quality ring sets and gudgeon pins.
The Benefits of Long Rod Pistons:
- Competition engines by their very nature use higher than normal revs. Changes can often be made to the design of the piston and rods to improve performance at higher revs since most engines were never designed for competition use. Although the modern breeds of engines are designed much better, there is much room for improvement in older engines such as the X/flow and Pinto. Firstly by making the piston lighter, it is easier to accelerate and decelerate it during each revolution of the engine cycle as the reciprocating weight is now much less.
- The lightness of the piston becomes more critical with increasing revs. Cosworth YB pistons have a relatively large mass above the gudgeon pin and it is this area that is removed to reduce the weight. They also have a relatively large and heavy gudgeon pin which can be replaced with a smaller pin, as modern material allows for much more smaller diameters whilst keeping or even improving on the strength, for further weight saving. Secondly to compensate for the shorter piston, a longer con rod must be used. Our longer rod has the benefit of less angular movement (6.2%) during a crank revolution resulting in less thrust on the skirt of the piston.
- The combination of changing to a long rod and short piston therefore results in a much freer revving engine as the aforementioned mass is now much less. The long rod Accralite pistons for the YB aspo weigh 86g (15.2%) lighter than the normal Accralite version whilst the Farndon long rods are only 1g heavier due to a lighter small end.
- Accralite forged pistons are manufactured from extruded 2618A bar to Aerospace specifications which are purchased from one of the leading mills in Europe. The bar exceeds all required racing specifications by far, and is traceable right back to its origin.
- Accralite pistons are forged from precision weighted and turned billets, which eliminates inferior finishes from stress raisers.
- Accralite pistons are forged using state of the art facilities to aerospace standards on electronically controlled and isothermal forging presses. All work pieces and forging dies are kept to the same temperature helping to eliminate stress as there are no temperature variations throughout the part, giving added grain compression, strength and durability to the finished piston.
- Accralite pistons are forged using a custom designed specific lubricant to give a perfect internal finish adding strength to the piston.
- Accralite piston forgings are heat-treated and artificially aged to allow your piston to meet the highest T6 specification. They are then inspected to British Standard Non-destructive Testing Standards that check for imperfections.
- Accralite piston forgings are vapour blasted internally. Not only to relieve stress but also to show any imperfections that could lead to the forging being rejected as not being suitable to their exacting standards.
- Accralite pistons have an individual reference point on their base forging to assist in giving the closest crown thickness and out-of-round tolerances possible.
- Accralite pistons are designed and manufactured to your exacting needs in-house from one location in the UK.
- Accralite pistons are hand finished and individually weighed by giving them that extra personal touch and then grouping into balanced engine sets. Tolerances are held so tight it is not unusual to have less than 0.3 grams between a set of pistons.
- Accralite pistons come with the highest specification rings. They are made to the world’s highest standards from the highest-grade materials, chosen for the application and manufactured by, what we feel, the world's leading ring manufacturer who also supplies all of the F1 racing teams.
- Accralite gudgeon pins come from the UK’s only specialist motorsport piston pin supplier. With pins manufactured using the highest grades of fully certified case hardening and nitrided steels giving maximum strength and durability.
- Accralite pistons come complete with the highest specification gudgeon pin circlips. They are sometimes over looked as being a crucial component of the piston. They are manufactured from top grade steel to the highest BS standards; with each clip being hand de-burred to help reduce groove wear.
- All the above results in Accralite pistons having greater longevity and in some cases, lasting over twice as long as that of the competition, saving money and time in costly rebuilds.
- Additional Information
Part No FT136/91 Fits Engine Type Ford Cosworth YB Product Group Pistons - Forged Stock Status Available From Stock Fits Engine Make Ford Catalogue 2018 Page Click HERE to view this part on page 23 of our 2018 catalogue Brand Logo Free Shipping
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