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Engine Specific Info and Questions => IDI Engine => Topic started by: klang on August 09, 2009, 05:09:40 pm

Title: 2nd ring on a M21D24 piston
Post by: klang on August 09, 2009, 05:09:40 pm

Probably a stupid question, but I want to get this right.

I pulled my BMW M21D24 IDI Engine apart 8months ago, and had everything lined up, balanced etc.

Now, when I'm putting everything together, I'm not sure about the second compression pistonring (the middle one)

I can be mounted in 2 different ways.

The "groove" should be down? Is this correct?  ???


Dont want to have to pull the engine apart again just because of stupidity  :(

// Klang

Title: Re: 2nd ring on a M21D24 piston
Post by: Rabbit on Roids on August 09, 2009, 06:37:01 pm

pretty sure the groove in the scraper ring is supposed to face up.

Title: Re: 2nd ring on a M21D24 piston
Post by: Rabbit TD on August 09, 2009, 11:00:14 pm

Most rings that are designed to face a certain way have a mark on the flat surface right near the gap area.  Does yours have a small mark there, if it does it should be facing the top of the piston.

Title: Re: 2nd ring on a M21D24 piston
Post by: Rabbit on Roids on August 10, 2009, 11:14:29 am

oh yea, there are marks on the top of the ring. on the top edge.

Title: Re: 2nd ring on a M21D24 piston
Post by: klang on August 10, 2009, 03:45:05 pm

Thanks for the answers.

I checked the ring, and close to the gap I found "TOPC" written.

So I mounted it that way, and the groove is facing down. (the letters up)

The top ring had "PC" mounted on it, so I mounted that facing upwards as well.

The oil ring had nothing on it, looked to be the same on both sides, so I just put them on  ;D



Hope I have compression later =)


Thanks.

Title: Re: 2nd ring on a M21D24 piston
Post by: Rabbit TD on August 10, 2009, 06:23:26 pm

Quote from: klang on August 10, 2009, 03:45:05 pm

Thanks for the answers.

I checked the ring, and close to the gap I found "TOPC" written.

So I mounted it that way, and the groove is facing down. (the letters up)

The top ring had "PC" mounted on it, so I mounted that facing upwards as well.

The oil ring had nothing on it, looked to be the same on both sides, so I just put them on  ;D



Hope I have compression later =)


Thanks.

If you have those letters facing up you have them on right.

Title: Re: 2nd ring on a M21D24 piston
Post by: klang on August 11, 2009, 07:22:25 am

Quote from: Rabbit TD on August 10, 2009, 06:23:26 pm

Quote from: klang on August 10, 2009, 03:45:05 pm

Thanks for the answers.

I checked the ring, and close to the gap I found "TOPC" written.

So I mounted it that way, and the groove is facing down. (the letters up)

The top ring had "PC" mounted on it, so I mounted that facing upwards as well.

The oil ring had nothing on it, looked to be the same on both sides, so I just put them on  ;D



Hope I have compression later =)


Thanks.

If you have those letters facing up you have them on right.

Great!
Thanks

Title: Re: 2nd ring on a M21D24 piston
Post by: arb on August 11, 2009, 09:35:49 am

Quote from: klang on August 10, 2009, 03:45:05 pm

The oil ring had nothing on it, looked to be the same on both sides, so I just put them on  ;D
 

That's correct, the oil scraper rings have no up or down... (the spacer accordion ring goes between the 2 scrappers)