OMEGA FORGED PISTONS 73.5mm - VARIOUS SHORT HEIGHTS

How to machine standard little ends
1. Fit 18mm bushes to little ends and hone to a finished size of 18.015mm-18.020mm.
2. Machine little end of conrod on the short side to give a finished width of 21mm.
3. Drill 1/8-inch hole through the little end and bush at the top of the conrod.
4. Lightly countersink this holes allow oil feed to gudgeon pin. 

Running clearances
We would recommend a skirt clearance of 0.004", however different engine builders will have their own preferences.

The recommended ring gap is 0.010"-0.012".

Compression height
We keep a wide range of piston sizes and compression heights to suit all manner of engine builds. Here we give the option of 1.248", or super short 1.115".

This is primarily to allow the use of longer conrods and/or longer stroke crankshafts, however it can also be useful if the block face requires extensive machining of if you wish to lower the compression ratio by increasing the deck clearance.

Please contact us for further advice if you are unsure.

Forged vs diecast
Omega forged pistons are stronger yet lighter than our diecast range, making them particularly well suited to higher performance applications. They are specifically designed for high RPM competition engines. 

Forged pistons utilise a smaller, lighter 18mm floating gudgeon pins, which give less chance of damaging the pistons on insertion, and are easier to disassemble than press-fit pins. 

As a general rule, opt for forged pistons if you wish to exceed a static compression ratio of 11:1, have a very high performance engine or wish to run high boost levels on a forced induction setup. 

Conrod compatibility
We'd highly recommend using these pistons with MED steel conrods, as they come with an 18mm bushed little end to suit. If your race regulations or budget do not allow the use of MED steel rods, the standard conrods can be modified with 18mm bronze bushes (please see above).

Production process
High silicone alloy is first cut to billet size and the faces machined to a smooth finish. Each billet is pre-heated in an air-circulating furnace to a temperature close to the operating temperature of the piston crown, then compressed into a rough shape using Omega's in-house forge and custom-designed dies.

The specific temperature, together with tightly controlled speed of the forging process, gives a dense and very fine grain structure to the piston for high strength and superior fatigue life.

Any excess material is then removed before the forgings are heat-treated and wet blast cleaned. From here each piston is subject to a highly developed process of CNC machining, with constant measurement and quality control checks by experienced perfectionists. 

Once final machining is complete, the pistons are engraved with a model and batch number, cleaned and sorted into matched weight sets. It's a time-consuming process to create such a high quality product, but the end results are well worthwhile.