Newbie oil ring question...

[yorkshire_spam 2 Vehicles]

So I get the 3 bits on the left - centre part and top and bottom thin rings. But what's the other piece of tin in the red box for?

 

Cheers,

Sam

 

[richy_rich]

Not seen anything like that before..  Some new fangled oil scraper ring design?   What are they for?

[JohnD]

Is it possibsle to ask the ring, or piston makers, or else your supplier, Sam?

J.

Edited November 8, 2019 by JohnD

[yorkshire_spam 2 Vehicles]

Just left the engineers that supplied it (I was there picking the crank up)... he said "oooh they are the old fashioned type" - apparently it sits behind the oil ring to keep it expanded.

Thanks chaps!

[Nick Jones]

Never seen them before but a bit of googling suggests that the highlighted part is the expander spring for the centre section and is fitted first. There is also comment passed that they are tricky things as the expander spring can sometimes get behind the thin outer rings and prevent them going fully flush in the groove making the piston impossible to fit in the bore. Further comment says they have high pressure on the bore walls making them quite effective for oil control Even on imperfect bores but giving high wear rates And sapping power at higher rpm.  Ideal for a part worm Triumph 1500 then?

[yorkshire_spam 2 Vehicles]

22 minutes ago, Nick Jones said:

 Ideal for a part worm Triumph 1500 then?

Definately not ideal for my project... :-( But hey-ho I'll get it built and see how it goes and maybe look at alternative ring/pistons at a later date.

 

[Nick Jones]

No reason why you can't fit a different set if you want to.  Should only be £ 35 or so for a set.  Just need to get them sized for the piston size you are using, or possibly, as this is a hone of worn bores, the next size up and file the ends as necessary to get the gaps.

Nick

[yorkshire_spam 2 Vehicles]

Block has just had a pretty serious rebore, so should be pretty much spot on size wise. I've got a way to go before I get to the piston fitting stage, so I'll sleep on it in terms of the rings.

[Nick Jones]

4 minutes ago, yorkshire_spam said:

Block has just had a pretty serious rebore

Ah, ok, sorry - mixing you up with Pete I think...... must pay more attention   Match the piston oversize then.  Gaps will need checking though

[sparky_spit]

Hi Sam - after your rebore, do have a think about blanking off those two blind jigging voids that are close to the fire rings on No.1 and No.4 bores.

See - 

I'm not saying that you will definitely have this trouble, but it might be worth considering while you have it apart.

[Nick Jones]

Good advice I think. Those holes are design madness

[yorkshire_spam 2 Vehicles]

Thanks Sparky!