MED STEEL CONRODS - 6.000 LENGTH - 18MM PIN - 'S' 1.625 ENDS
Technical Video:
Description
The MED steel conrods are one of the lightest and strongest ever designed for the 1275 A-Series engine, weighing just 430g. Long 6-inch length for use with short height pistons.
Longer rods alter the basic geometry of the rotating assembly to improve performance. Running a shorter compression height piston then offsets the minimal weight gain of the longer conrod.
Our 6-inch conrods only weigh 5g more than our 5.750" design!
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
- 6.000" length, for short height pistons
- Fully machined
- Uniform machine peening
- Balanced end-to-end within a gram
- 100% magnaflux tested
- Laser-etched MED logo
- Fitted with ARP fasteners
Please see the additional information tab for more detail and recommendations.
Supplied as an engine set of four.
Frequently Asked Questions
Where are they made?
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?
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?
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?
This set features a bushed little end to accept fully-floating gudgeon pins in the lightweight 18mm design. They are an ideal match for our competition-grade Omega forged pistons with 18mm pins and shorter 1.248" compression height. This retains the same overall stroke length as standard; with regular 1.498" height pistons, the crowns would protrude too far from the top of the block.
Will these work with all 1275 A-Series crankshafts?
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?
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"?
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?
Yes the MED steel conrods allow good clearance of the camshaft on an Arden 8-port engine.