Piston Rings

[Kevin-G]

Hi, I have just received from ESM a set of piston rings, however the oil control rings are different to the existing ones.

The original set was in 4 parts. Two thin rings, a castellated ring and a wavey ring that goes around the expander ring.

The replacements are in 3 parts, with a thicker castellated ring, and no wavey ring.

Does this sound normal?

[oliver90owner]

Does this sound normal?

Looks fairly normal. There are options. Search the net for variations by different suppliers?

Questions might be : Are your piston ring grooves the correct size for the compression rings - particularly the top ring? Are you honing the bores? Is there a wear ring in the bores? Are the bores oval?

[philthehill]

The piston sets advertised on the ESM web site have four parts to the oil control ring.

http://www.morrisminorspares.com/engine ... 20-p830164

The piston ring sets also have the four part oil control ring.

http://www.morrisminorspares.com/engine ... td-p830049

If only three parts you need to go back to ESM and query.

The wavy ring goes into the groove first, then the castellated ring and then the oil control rings proper - one above the castellated ring and one below the castellated ring.

Make sure that the rings are the correct way up - see schematic below.

[Kevin-G]

The rings on the pistons that I have taken out don't seem to be like you have described - were they wrong?

P6267380.JPG (655.08 KiB) Viewed 3987 times

[philthehill]

The rings fitted to the piston photographed above are a different style from the ESM oil control rings.
Without reference to the ESM ring fitting instructions but with reference to the photos in the links above I believe the fitting procedure I have described above is correct.
Read the wavy ring as being the 8 sided flat ring
You should have the ESM piston ring fitting instructions supplied with the rings.
Have you resolved the missing 4th part of the oil control ring assy?

[Kevin-G]

I have sent ESM photos of my original piston rings. Cant say for certain but I do believe that these are the original factory fitted rings. Has no one come across them before?

Do you think that either a 3 part or alternative 4 part oil control ring will fit correctly?

[philthehill]

Firstly you must ensure that what you have been supplied from ESM is correct.
As I said above the - the link picture showing the ESM oil control rings is of a 4 piece ring assy - get the numbers right and the fitting instructions and you should be home and dry.
As regards the rings fitted to the piston in your picture and mentioned above there are a multitude of oil control ring designs each supposedly better than the previous design. The rings may be right and assembled right but just looking at a picture you can only determine so much.

[biomed32uk]

The set of rings I had for a 1098 from ESM last year I believe were made by Grant, and were 3 part oil rings.

The castle middle ring for want of a better description, and then a very thin upper and lower ring which must be carefully curled around the castle ring.

Picture below on a damaged piston, that's an old and sad story but the rings are the same.

2017-07-13 18.36.26.jpg (3.32 MiB) Viewed 3924 times

[philthehill]

Biomed32uk
Interestingly the oil control piston ring assy on your damaged piston is not the same as the assy shown on Kevin-G's piston or the oil control rings shown on the ESM web site.

Kevin's piston oil control ring is a four piece ring assy as are the oil control rings shown on the ESM web site.

I believe that your 3 piece oil control assy (as pictured) is correct and fitted correctly.

On my schematic you will see a 4th vertical ring which is the expander ring which may or may not be fitted dependent upon manufacturer. The ring between the two scraper rings is the castellated ring which has tags attached which sit behind behind the top and bottom scraper rings to ensure that the castellated ring does not scrape the bore.

I have referenced the fitting instructions which should be with the ring kit but there seems to be no reference by Kevin as to whether he has them or not.

It may be that ESM have posted a picture of a generic piston ring set but to me that is bad form especially if there are no fitting instructions for what is supplied.
Phil

[biomed32uk]

Yes there are indeed tags on the castellated ring to stop it escaping once the scrapers are fitted.

The new pistons were supplied with Grant rings as well, and came with very good instructions for fitting, all in labelled bags for position with the rings marked top.

Some websites do just use generic or stock photos, so what you see is sometimes not what turns up.

I have fitted a couple of sets of these now, once to the pistons before the disaster in the picture, and then on the rebuild with new pistons etc.

Since then the engine has done about 2500 miles and hardly touches any oil, I had some real cheap stuff in for the first 100 miles or so, that did move a little down the dipstick but to be expected for initial run in. I changed the oil back in April and its not moved at all on the dipstick in 1300 miles this year.

[philthehill]

biomed32uk
Thank you for your reply above.

Kevin
Were the fitting instructions included with the piston rings and have you had any feed back from ESM?

Phil