What is the ring gap?
What are the ring gap tolerances?
For original Ferguson/MF rings and liners…
Top ring gap 9 to 17 thou
Second and third ring gaps 9 to 14 thou
New rings out of specification
We have had a few people email us to say that they have got new pistons, rings and liners and that they have measured them before fitting and found that they are out of spec.
These have all been manufactured by a non-genuine parts supply company and unfortunately some of these companies seem not to be able to manufacture parts to the necessary accuracy.
Typically the following ring gaps have been measured from these parts suppliers…
Top ring gap 23 thou
Second and third ring gaps 18 thou
Oil ring 15 thou
What to do?
Firstly measure either your tool or (more likely) the liner you are using to measure the ring gap in. Check it is within spec. If it is within spec and you are experiencing ring gaps which are too large then compression is likely to be compromised.
Ideally these ‘new’ components should be rejected and replacement parts sourced from another manufacturer.
Daryle has emailed to offer this tip…
Excellent advice on Liners, if I may offer a tip, is to keep your liners standing. Laying them on their side will often distort them.
Thanks Daryle, much appreciated – Steve and Ian.