MED STEEL CONRODS - STD LENGTH - 18MM PIN - 'S' 1.625 ENDS

Technical Video:

MED STEEL CONRODS - STD LENGTH - 18MM PIN - 'S' 1.625 ENDS

Part No: MED-1275-CR-ST18
Regular price £1,125.00 £937.50 EXC VAT
Regular price Sale price £1,125.00 £937.50 EXC VAT
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Availability: In Stock

Technical Video:

Arrow

Description

The MED steel conrods are one of the lightest and strongest ever designed for the 1275 A-Series engine. 

The latest design sees weight reduced from 480g to 425g, which we believe makes this the lightest 5.750-inch steel A-series conrod available (weight includes ARP bolts and little end bush).

Made in the UK, with genuine ARP bolts.




Conrod features

    • Double air re-melt steel
    • 18mm little end bush for Omega forged lightweight pistons
    • 1.625" Cooper S size big end journals
    • 5.750" standard 1275 length
    • Fully machined
    • Uniform machine peening
    • Balanced end-to-end within a gram
    • 100% magnaflux tested
    • Laser-etched MED logo
    • Fitted with ARP fasteners




Supplied as an engine set of four.

Frequently Asked Questions

Where are they made?

Arrow

Our conrods are manufactured just 20 minutes from MED at Arrow Precision Engineering - the very best in the business! We've worked with Arrow for over 20 years to create the best possible product. Be wary when comparing our conrods to cheaper offerings, which are usually imported, and not comparable in quality, strength and weight.

What specification are these conrods?

Arrow

These are fully machined from double air re-melted 817M40 forgings. All rods are shot peened using an automated process to increase fatigue strength and durability. The rods are balanced end-over-end into matched engine sets and are 100% magnaflux crack detected prior to final inspection by CMM in a temperature controlled inspection department. As part of the design process, Arrow Precision worked closely with ARP to select the best available fasteners.

What makes these better than standard conrods?

Arrow

There's three benefits - strength, light weight and high quality. H-section steel conrods are considerably stronger than mass-produced standard conrods, which were never designed for high performance applications. Standard conrods can be lightened and balanced, but even then our steel conrods will be lighter and stronger. The highly accurate production process allows for exact build tolerances; you will not find a higher quality A-Series conrod.

Which pistons will these work with?

Arrow

This set features a bushed little end to accept fully-floating gudgeon pins in the lightweight 18mm design. They are an ideal match for any of our competition-grade Omega forged pistons with 18mm pins. These would usually work best with the standard 1.498" compression height pistons to retain the overall stroke length, however there are occasions where a shorter piston can be useful. Please contact us if you're unsure.

Will these work with all 1275 A-Series crankshafts?

Arrow

All MED conrods feature 1.625-inch big ends to suit 1275 Cooper S, MG Midget or MED steel billet crankshafts. We do not produce conrods for the larger diameter 1.750-inch big ends, as the extra weight here does not lend itself to full competition usage.

What torque setting should be used on the bolts?

Arrow

These should be torqued to 30lb.ft, or preferably checked using an ARP rod bolt stretch gauge and stretched to 0.0050"-0.0055". You will need a 12-point 9mm socket/spanner to do this.

Am I better with 6.000" conrods or 5.750"?

Arrow

This is the length from the centre of the big end journal to the centre of the little end journal. As standard on a 1275cc A-Series this is 5.750". Changing to a longer conrod and shorter piston will maintain the same overall length, but offer a reduction in friction in the engine and give a marginally longer piston dwell time at TDC. Overall this is considered a performance improvement, but it's only useful if the race regulations allow a non-standard rod length.

Do these conrods work in an 8-Port engine?

Arrow

Yes the MED steel conrods allow good clearance of the camshaft on an Arden 8-port engine.