Big end shell bearing

[Steve kay]

So the next question is; are both pinch bolts and circlips merely duplication and can be ignored, or are they incompatible and one or other should be removed?

[JonE]

I think this has been answered in the two previous posts? i.e. dependent on the type of rods you are using.

[Howard Wright]

So the next question is; are both pinch bolts and circlips merely duplication and can be ignored, or are they incompatible and one or other should be removed?

Hi Steve

I think you may have pistons that are designed for circlips and a fully floating pin.  If they have a circlip groove then they will be circlip pistons. Pinch bolt pistons are unlikely to have the circlip groove. If the pin has a small relief ground half way along then the pin is for a pinch bolt.

I don’t think you can mix and match these.  Clearances for piston lateral movement may be different.

Are you re-using pistons and pins?  If the sets are new then they should match and should have been bought to fit the con rods you are using. if not you need to ensure you are using the correct pins and pistons.

Hope this helps?

Cheers

Howard

[Terrytuned]

Slipper pistons are universal they all have circlip grooves and are supplied with either plain or notched pin depending which rods you have.  Terry.

[Charles P]

Many pistons appear to come with circlip fittings. Just ignore them if you are using a pinch bolt.
Some vendors, like Jamie at The Seven Workshop, sell plain gudgeon pins to use with their pistons, which as far as I recall, are identical whether clamped or circliped.

[Howard Wright]

Thanks for the correction Terry and Charles.

Cheers

Howard

[Steve kay]

So tomorrow it’s pistons out, circlips removed and pistons back in. The forum really is a great contribution to anyone less than certain about how to correctly put Sevens together. Many thanks to all!