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Piston rings - removal, cleaning and refitting


glynherron

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On to the next step...

Pistons numbered and out on the bench.

I'm yet to read the service notes on the wear parameters but supposing they do not need replacing:

For each piston do the rings have to be refitted the same way around ie not upside down within the groove?

How to take them off

How to clean the oil control ring

How to replace

I hope this makes sense!

Thanks as always

Glyn

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uhhh... generally they break getting them out... All mine did.

I replaced them with new rings (with pistons attached).

 

When they go back into the cylinders, it is very important not to have the gaps lined up, space each ring's gap at 120deg to the other ring gaps.

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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not so important Travis.. the rings are moving al the time around...while engine running

but for (between the ears ) I agree

 

normally Glen,  you  renew used rings ,

the rings are bed-in ( running in)  into the cylinders, and so are the cylinders  ( a bit )

 

so if you use  used rings in used cylinders , you get oil consumption , they never running in again

and if you use new rings, let the cylinders honing again, ( not  the normal way, because they are nikasil  they must "lapping" the cylinders )  if it is alusil  the honing work is different, then with nikasil)

 

use cast iron rings, the running in time is short, as Travis mentioned the rings lotus used, are cast iron (they broke)                                                                                                                                                                                                                                                       

if there is no other way  than use old rings,  use R.I.C. (running in compound) from BP,  to let them running in.

greetings  sietse // holland

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Good point.

 

The manual has the oil control ring gap toward the front of the engine 12 o'clock viewed from above, the top compression ring gap at 4 o'clock, and the 2nd compression ring gap at 8 o'clock. 

 

The rings are different, the top ring is chrome plated, and the 2nd compression ring has a taper which must be on the top, smaller OD at top, larger OD at bottom.

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Took off rings yesterday without an issue.

The ring grooves are really gunked up especially the top groove which has no ring.

What do you use to clean out the grooves?

I've also looked on the workshop manual and expected to see gap sizes when the rings are fitted to the bores to calculate serviceability but found nothing. Have I just missed them?

Thanks

Glyn

There are piston ring expander tools available. I have one made by Blue Point, but there are many others. They support the ring during removal and replacement. I've used it many times, and never broke a ring yet.

Thanks

not so important Travis.. the rings are moving al the time around...while engine running

but for (between the ears ) I agree

normally Glen, you renew used rings ,

the rings are bed-in ( running in) into the cylinders, and so are the cylinders ( a bit )

so if you use used rings in used cylinders , you get oil consumption , they never running in again

and if you use new rings, let the cylinders honing again, ( not the normal way, because they are nikasil they must "lapping" the cylinders ) if it is alusil the honing work is different, then with nikasil)

use cast iron rings, the running in time is short, as Travis mentioned the rings lotus used, are cast iron (they broke)

if there is no other way than use old rings, use R.I.C. (running in compound) from BP, to let them running in.

greetings sietse // holland

Hi Sietse

I've kept the rings with their respective liners including orientation.

Can you explain why they will need running in again and why oil consumption will go up.

Thanks

Glyn

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A piece of broken piston ring :lol:

You are so funny.... Travis can you post me one lol

BE very careful with some cleaners on the pistons. I used Simple Green and it stripped the chrome of the domes of the pistons...

Gulp...

I've left mine dripping with swarfega Jizer

Can't get to wash them till tomorrow!!

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That Swarfega Jizer should be ok (had to look it up... we don't have that here, and something with that name would never sell in the USA!!!)

 

It is a hydrocarbon based product, and not an alkaline.

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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Glyn,

when put new rings  (they are  round )  in new cilinders ( also round)  no problem,

but when put on the cilinder head , the cilinders wil deformate a bit .(they are not round anymore)

now the round (new)  rings must runing in  into the cilinder wals , (and also the wals  formate to the rings (visa versa)

the result is a perfect  match  between  the rings and the cilinder wal ,   

the case is running in wel, hopeful it is oil consumtion free.

and take a lot off miles

google the "abbott curve"

also the ruf pixels are disapeard from the rings , and from the liners

 

-------now you dismantle  the cilinder head, maintenance, and put the old stuf again into the used cilinders.

put the cil.head back on,  and suprice the cilinder deform again , but just a bit else than before,

the ring are smooth surfaced, the liners  are smooth  surfaced,  and the rings wil never run in,

they wil not fill the unroundnes  of the liners , and result in oil consumption . if you  have luck , it 's ok.

( do you take the gamble?)

( it is for me dificult to write down  the hole case, i am not english )

 

in the past,  the mini (blmc)  have a lot of problems  when skim the head and put it back on, even when the pistons are not removed, today the opel (vauxhall)  have the problem a lot.

sietse

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