BHB piston circlips or round wire clips?

Hi Matt,

You need to be certain what type of groove that you have. Round circlips will not seat securely in a square groove - and vice versa.

Worst case scenario is that the gudgeon pin will work its way over to one side, pushing out the circlip from the groove and into the side wall of the cylinder, resulting in grooves in the bore and the possibilty of the circlip becoming trapped between piston and cylinder wall. Result..... Carnage!

Best regards,

Chas

Yes, I made this mistake back in the 1970s with a 16H. Fitted a Seeger flat type into a rounded groove and as said carnage ensued not long after.

Its most likely to be the standard type of seager clip.

I think you will find the curved side of the circlip is the side they stamped it out from, hence making it rounded. Another fitting trick is to have the opening down or up, if it is to front or back then as the piston rises and falls one side of the clip can resonate so that the clip tends to close up! and ping out! Ouch. Another disaster pending.

And another point-some years ago I wanted to replace the clips in the pistons of a British car engine. (good practice replacing clips once used) the gudgeon pin hole was about 16mm so I went and bought same. They fitted but turned, I bought another lot-they also turned? I ended up talking to a supplier of said clips, he asked carefully what was the engine and was it imperial? erh yes. Aha you need to purchase 9/16 clips! which at a quick glance look like 16mm BUT are not. When asking about all the dimensions of said circlips he explained it is a bit like threads/bolts/nuts, given one dimension and the rest of the dims sort themselves out, ie once you know the size of the finished hole they sit in, the width and spring/final size takes care of itself.

Its most likely to be the standard type of seager clip. These have a squared off face and a slightly rounded face. Fit with the squared off face against the pin.

I always believed the squared side should face the direction of thrust ie outwards not towards the pin as this makes them less likely to climb out.

Al is right it's a function of the way they're stamped out.

Your right ,tis tother way round. Flat side to face cylinder wall. gap down,never at side.Edited out wrong info.

Previously matt crighton wrote:

Good evening all,

Just about to fit a pair of BHB pistons into 650ss engine and as they didn't come with gudgeon pin or clips just wanted to confirm whether best to use standard shape circlip or round wire type with this make of piston. Had a look at the groove and it looks like a square cut so reckon circlip would best suit but wanted to ask the question to be sure.

thanks

Hello for the correct information on BHB pistons There circlips, not wire clips So forget any other information you may have , BHB piston are the Original set os pistons For Norton Machines, gudgeonpin circlips part No 23276 x 4 of yours anna j dixon

forget all these comets and make or have made some teflon or ptfa plugs and never have to suffer either off the circlips migrating out which at some time they may well do .most professional race or competitive engine builders would do

forget all these comets and make or have made some teflon or ptfa plugs and never have to suffer either off the circlips migrating out which at some time they may well do .most professional race or competitive engine builders would do

If you do follow Anthony's advice drill one of the plugs to allow the air to expand out,and not push the plug out!.