15 replies to this topic

[redmini]

I bought an engine second hand a few years back and have lost the build spec provided by the seller, I thought it was about time I put it together and put it in the car.  When I picked up the engine one of the pistons slipped down in the bore and the lower piston ring got stuck against the casting and couldn't be withdrawn.  Long story short, a local engine centre have had to break the ring to get the piston out and now claims he can't find a replacement ring.  I haven't seen the pistons but he said the numbers on it are 2150 +20 and 105 521 or 125S21, there are 3 rings per piston, can anyone help to locate the right rings please?

Edited by redmini, 16 December 2016 - 11:35 PM.

[MINI-TURBO]

hi im not sure if i can help or not but i have a set of rings that came with my 18cc dished forged pistons from MED +20thou as i brought the lightweight forged rings from MED seperately. if someone can confirm they do fit your pistons I'm willing to sell the rings that I'm not using

[MINI-TURBO]

are you sure its not 21250? they have them on mini spares, ill post the link but i think these are the ones for your pistons

http://minispares.co...ston rings.aspx

[mini13]

The med piston rings will almost certainly be too thin, total seal can provide a ring pack for just about anything, and I know of people that have used them on metro turbo pistons.

[redmini]

I've been to look at the engine as I have spend hours online searching and spent a few hours calling people with no success, so here's some pictures I took that now show the correct numbers.

21250 +20 ID5 S21.

Attached Files

•  IMAG2198.jpg   28K   15 downloads
•  IMAG2199.jpg   47.83K   80 downloads
•  IMAG2198.jpg   28K   17 downloads

[Northernpower]

I've been to look at the engine as I have spend hours online searching and spent a few hours calling people with no success, so here's some pictures I took that now show the correct numbers.

21250 +20 ID5 S21.

Minispares sell two types of rings for the 21250 + 20, if you follow this link http://minispares.co.../classic/piston it will explain the differences.

Edited by Northernpower, 22 December 2016 - 12:01 PM.

[redmini]

 

I've been to look at the engine as I have spend hours online searching and spent a few hours calling people with no success, so here's some pictures I took that now show the correct numbers.

21250 +20 ID5 S21.

Minispares sell two types of rings for the 21250 + 20, if you follow this link http://minispares.co.../classic/piston it will explain the differences.

 

Thanks Northernpower, I'll try them again now and see if I can get something sorted.

[Gr4h4m]

The ring land looks broken or is it the pic? I would have thought new Pistons time if it's broken.

[Northernpower]

Looking at the picture of the piston in the block it certainly looks like the casting is broken in the area between the gudgeon pin and the oil control ring. If that is the case, you'll definitely need a new piston.

[redmini]

It's just the picture, all the pistons are the same.

[Northernpower]

It's just the picture, all the pistons are the same.

Wow, I'm surprised you say that, I've just had another close look at the picture of the piston in the block and it does look as though the casting is broken. Obviously you can see it, I can only see a picture. Good luck with the build.

[redmini]

I'm currently away and the engine is still with the machine shop, looking at the picture on my phone it's a lot clearer and to be honest I have to agree with you, it's got me nervous and I hope they have insurance as I'm not forking out for a new piston!!!

[Gr4h4m]

Hope you get it sorted.

[Sprocket]

Looking at the picture of the piston in the block it certainly looks like the casting is broken in the area between the gudgeon pin and the oil control ring. If that is the case, you'll definitely need a new piston.

I think the gap you are talking about is normal, its the drain from the oil ring (it helps to lubricate the gudgeon pin), much like that overly large groove behind the oil ring on the thrust sides of the pistons. These are not performance pistons and I would refrain from using much more than standard boost levels or excessive RPM with them.

Edited by Sprocket, 19 January 2017 - 11:16 PM.

[Northernpower]

Looking at the picture of the piston in the block it certainly looks like the casting is broken in the area between the gudgeon pin and the oil control ring. If that is the case, you'll definitely need a new piston.

I think the gap you are talking about is normal, its the drain from the oil ring (it helps to lubricate the gudgeon pin), much like that overly large groove behind the oil ring on the thrust sides of the pistons. These are not performance pistons and I would refrain from using much more than standard boost levels or excessive RPM with them.

It's difficult to see one way or another from the supplied picture and the op is away. He'll know as soon as he compares it to the others. It'll be interesting to see what the result is.
I agree with you, they're not a good piston to use in his intended application.