Lister d piston ring size

Hi guys.

Need some help ok so what I need to know is the piston ring size. What measurements I need to check. Iv checked the bore best I can its coming out at 2.9960 just under 3". The piston is 2.9945. The only ring I could measure is the oil scrapper ring as the others was stuck and broke trying to free them the ring measures not compressed 3.1130 and compressed 2.9625.

I'd this standard size piston and rings?.

There is a few different size rings so don't want to get the wrong ones.

Ryan

Hi, if that is a standard piston, I have a piston with rings if you're interested, I could post!

https://www.stationaryengineparts.com/lister-d-dk-f-piston-rings/
From the above it looks like yours is not an oversize.
If in doubt buy the +10 and adjust the gap to fit the bore

They don't have the standard in stock so I'll have to wait till they are or buy the +10, is that what makes them bigger then longer on the end of the ring and I could just take a little bit off and they will fit ?.

Ryan90w wrote:They don't have the standard in stock so I'll have to wait till they are or buy the +10, is that what makes them bigger then longer on the end of the ring and I could just take a little bit off and they will fit ?.

. You fit the ring in the bore about an inch down and make it level by using the inverted head of the piston, adjust the gap to the specified minimum. If your bore is standard you will need to increase the gap on a +10 ring

+0.010 is paper thin the gap mite not even need adjustment? I checked the gap on the oil scrapper ring like you said a inch down use the piston it had a good gap probably 0.050 gap at a guess without checking again. Do you know what the specified minimum gap is Andy?.

The lister D restoration book says 8-12 thou and to aim for 8

Thank you for that. The bore is standard in metric its 76.2mm my calipers will go in the bore tight at 76.2mm and the standard rings are for that size.
Andy have you used oversize rings in a standard piston and bore before? I'm worried that they may not fit right if the bores out of shape or tapering abit I kean I know 0.010 is very small but reading online some say oversize rings can work some say it dont I'm just more confused then before.

Ryan.

I have but not on a Lister D
I used oversize on a Petter A1 1958 85mm piston no problem

That good very clean and nice. Ok so stationary engine parts have got back to me said will be 6 weeks till they get standard size rings in. So I wait 6 weeks and get the right ones or a take a chance with the +10 rings.
I have a question if someone could answer it when I measured my bore it was just under the 3" 2.960 is that right ? As its ment to be 3" bore or 76.2mm in metric im splitting hairs here but in bore and piston ring that could be a big difference ? What I'm asking is have I not measured it right should it Be bang on 3" ?

The book I have says it should be 3" . Tolerance is plus 1 thou minus 0

What book do you have ? Can I buy one

https://www.ebay.co.uk/itm/254932287782?hash=item3b5b260126:g:-P8AAOSw1QNgbbUN

I'm going to buy that book right now. So according to that book it can be over by 1 thou but can't be under at all of 3" so iv clearly not measured it right because 2.960 is 0.040 under thats a lot isn't it ?. My apologies iv always worked in millimeters so thou is not my strongest point.

I've sent you a PM with sizes and pictures

Would it make any difference using rings that have a tapered end over a straight end ?