Should I get new piston rings; Will it make a difference
Turbo Mini Forums

Oh dear, I managed derail my other topic by mentioning a rant worthy retailer. I won't attempt to bring it back on topic and it's pretty good just watching everyone vent. I've moved my question here...

When stripping it, the engine appears to be is low mileage, maybe less than 25k. I measured up 3 sets of used pistons and rings... Skirt clearance appears to be just in spec, but ring gap is double the max limit around 25-30 thou.

If I buy new rings, am I likely to get much closer to spec as this isn't a fresh rebore? Should I get standard size, or try to re-size some +20 thou rings, or just stick with the original out of spec rings?

Erm, the first thing i would do is measure the bores and see how worn they are. If they are still in spec id hone them and fit a new set of rings.

That's the thing... The bores appear "ok" to me. I'm measuring the piston to bore clearance using both feeler gauge and a telescopic bore gauge and the clearance is just below the max limit according to Haynes. The rings gaps however, are twice what the should be. The more I think about it, the more it makes sense to just fit new rings.

There you go :)

If in doubt, hone and whip new rings in, the ring gaps won't really make much odds (controversial maybe) I read an article on ring gaps and up to a certain point it made zero difference to compression and power during their tests due to the maze that the gases have to pass through