Signs of bad rings

[Zornyan]

If you are doing a compression test that should identify ring problems. Once you have done it put a drop of oil around the top of the piston and do it again. If compression goes up then its a ring problem!

not correct^^ it's very common that oil control rings can fail, causing oil to burn, but the top piston rings be fine, I.e a compression check can show perfect psi but if the oil control rings are fubared it could smoke like a bitch.

Pistons generally have 3-4 odd rings round themx, the central ones are called oil control rings and are designed to control the amount of oil allowed past, obviously too tight a tolerance and the bores will run dry, too loose and it will poor out.

They also tend to stick as their always covered in oil, seen a few times people remove pistons and literally spray wd40 on them and their free again, which is the idea behind frequent oil changes to prevent this.

[pippin89]

not correct^^ it's very common that oil control rings can fail, causing oil to burn, but the top piston rings be fine, I.e a compression check can show perfect psi but if the oil control rings are fubared it could smoke like a bitch.

Pistons generally have 3-4 odd rings round themx, the central ones are called oil control rings and are designed to control the amount of oil allowed past, obviously too tight a tolerance and the bores will run dry, too loose and it will poor out.

They also tend to stick as their always covered in oil, seen a few times people remove pistons and literally spray wd40 on them and their free again, which is the idea behind frequent oil changes to prevent this.

This is very true. The test that I suggested is IF the compression is low then adding a bit of oil and running the test again and seeing higher compression would indicate the rings. If the compression is good to start with then it doesn't rule out rings but in that case the oil test wouldn't work anyway.

[Mark]

not correct^^ it's very common that oil control rings can fail, causing oil to burn, but the top piston rings be fine, I.e a compression check can show perfect psi but if the oil control rings are fubared it could smoke like a bitch.

Pistons generally have 3-4 odd rings round themx, the central ones are called oil control rings and are designed to control the amount of oil allowed past, obviously too tight a tolerance and the bores will run dry, too loose and it will poor out.

They also tend to stick as their always covered in oil, seen a few times people remove pistons and literally spray wd40 on them and their free again, which is the idea behind frequent oil changes to prevent this.

This isnt 100% correct either

Pistons have 3 rings, top ring, middle ring and oil control ring. The top 2 are for compression.

Its unlikely that if the oil ring goes and oil gets past the compression rings then it will have good compression as if oil get get past one way then compressed air will get past the other way Control rings to gum up but that doesnt mean it will smoke as the compression rings then scrape the oil off the bore but after time they will also gum up and thats when the compression drops off

[Zornyan]

Only sharing experience from pervious engines mx5s especially mk2s are notorious for having good compression yet smoking due to the oil control ring design for instance

[jj205mi16]

Every oil control ring stuck solid with crud on mine, only smoked on over run.



Photobucket isn't working but i uploaded pics to of the pistons earlier http://www.sxoc.com/vbb/showthread.p...toy-S14A/page4

if this was the case i dont know if theres some sort of additive that could have been added to the oil or spayed down the plug holes that may have free'd these off without stripping it down. just an idea.

[sausages]

mine did this i have now put a oil flush in it run it up to temp and then drained the oil. removed the sump pan cleaned it out aswell as the pick up while i was there. replaced the filter. topped it up with valvaline 5w-50 and fingers crossed it seems to have stopped smoking all together

[jj205mi16]

meant to say mine still made 150psi across all 4 cylinders, only the oil rings were stuck.

[jj205mi16]

mine did this i have now put a oil flush in it run it up to temp and then drained the oil. removed the sump pan cleaned it out aswell as the pick up while i was there. replaced the filter. topped it up with valvaline 5w-50 and fingers crossed it seems to have stopped smoking all together

let us know how this goes mate, could solve a few issues for people without removing the engine.

[sausages]

yea sure well i did this yesterday and did around 50miles yesterday without any smoke how ever it was dark lol
ill keep an eye and update

[Jonny Wilkinson]

A very common problem with CAs after reducing the back pressure in the exhaust (as the OP has done) is the turbo letting a little oil past the seals.

A common trick for solving it is to fit a one-way valve in the breather pipes.

Don't see why it wouldn't be the same for SRs

[Mark]

mine did this i have now put a oil flush in it run it up to temp and then drained the oil. removed the sump pan cleaned it out aswell as the pick up while i was there. replaced the filter. topped it up with valvaline 5w-50 and fingers crossed it seems to have stopped smoking all together

Well thats your engine fooked then

I would dump that oil asap and refill

Engine flush is a very strong detergent normally along the lines of kerosene so it like pouring petrol into your engine. it will go into all the nooks and crannies and wont all drain out so when you next put your engine oil in it starts breaking it down and then means its not protecting your engine properly. Also if there are any larger areas of crud in the engine like an oil gallery they can move and block a piston cooling jet or bearing feed.

I hate the stuff and would never use it.

[jj205mi16]

ive never used the stuff Mark but ive never heard it advised against, you had previous Mark??

[scotch_kris]

See my problem is opposite to the video I'm smoking occasionally on idle and revving it clears it.

[Zornyan]

I'm 50/50 on the engine flush camp. I never would have used it before due to horror stories.

But my last mx5 had sticky oil control rings. So I chucked some forte flush in, followed instructions to the letter of just letting it idle. Then drained and filled with cheap oil. Then did another oil change after 100miles to ensure nothing was left of it.

Result was it completely stopped smoking, and the engine generally felt/sounded healthier.

I think alot of problems come from when you hear people saying they put the flush in then drive for a few miles or sit there revving etc.

[scotch_kris]

Was just going to say surely with the flush, once drained surely if you stick in some cheap oil run it up to temp and drain again it should remove all the flush stuff really

[Mark]

It will help but you still have the issue of dislodged shit going somewhere you dont want it.

Just use decent oil and do some low mileage changes.

[diamondsink]

Get a proper leak down test done then go from there.