Ariel Owners Motorcycle Club

I am just about to fit a set of the latest batch of club rods to a mark two engine that I am building. When I was going through the recommended five times tightening and loosening procedure before installation I noticed that when the bolts were fully tightened to the recommended torque of 26 ft/lbs the bolt stretch was only about .004 instead of the .005 to .0055 as was mentioned in the instructions that came with the rods.

I am using a nearly new Britool torque wrench and a Moore and Wright micrometer, so they both should be reasonably accurate.

So the question is do I go for final assembly with the 24 ft/lbs of torque with the torque wrench as recommended in the instructions, or should I tighten the bolts more than this in order to achieve the .005 thou bolt stretch, again as stated in the instructions.

Has anyone else encountered this, and if so which of the two alternative methods did you use, only if I get this wrong it could be disastrous.

As usual any advice would be much appreciated.

I would suggest that you ask the supplier of the rods. Note that if you bought these recently they are NOT club rods although made to the same spec, drawings and by the same firm etc. I would not be concerned about a small difference and torque to the recommended figure, as long as the rods move freely with no initial resistance they will be fine.

After putting this post on here I did indeed contact Bennet Longman about this, and within a couple of hours I received a comprehensive reply.

To quote from his reply "The torque figures that are quoted are to achieve the stretch specified. However, there is some inaccuracy in the torque method due to friction in the fixing. Measuring stretch if done carefully and accurately is a preferred method."

So if anyone else has come across this problem then the bolt stretch is the important criteria to go with, rather than the torque measured with a torque wrench.

If anyone has this or any other problems with these rods, or indeed any of the other products that Bennet sells I would suggest that you contact him directly, as I'm sure you will receive immediate help and back up as I did.