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piston ring damage

2373 Views 17 Replies 6 Participants Last post by  meredithcraig
hi i have stripped down my 2002 mondeo tddi after the engine up problem i had when i brought it what damage am i looking for to show that the piston rings have gone as looking at the pistons and bores they all look ok just alot of oil

also how will i go about checking if the turbo oil seals have gone
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Ring damage usually manifests itself with noise and upon inspection scoring of the block.

If the bores look ok - not too much scoring, then you'll need to remove the pistons from the block.

But before we go any further what was your engine problem? Was it burning too much oil, was it noisy or what?
hi mate it ran of it engine oil and up on removal of the intercooler and inlet found loads of oil when i cleaned it all out put it back together it was still smoking loads (expected) but also there was alot of smoke from the crank case
broken rings could allow sump oil into the combustion chambers and also allow compressed gases back down into the sump, if the pistons are out you can see any broken rings, and you can feel round the bores though a dial gauge would be needed to check for bore ovality


if not too badly scored, etc, you could try honing with a handheld drill

but if its bad you need a rebore/oversize pistons and may as well do the crank/big ends/etc
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so it will be noticeable when i remove the pistons if the rings have gone then as the bores look fine to me and will i need to split the gear box out to get the bottom of the engine out
Did you carry out a compression or leakdown test prior to strip-down?
If piston ring damage is suspected when a low compression figure is recorded, it can be checked by pouring a little oil in the bore and repeating the test.
If the rings have gone, or there's bore wear the oil will temporarily give you an increased compression reading.
However if compression is good, or there is no change in compression readings after using the oil - suspect worn valve guides as the reason to oil finding its way into the combustion chamber.
Apologies if this advice is too late, as it seems like you've already begun to strip down the engine!
Are you sure the turbo seals haven't gone, and this is what is feeding the engine, as this could also cause this
Yeah, I would think turbo seals more likely..?
pity you didnt do a compression test b4 dismantling the engine really, these can identify burned valves, broken rings, blown head gaskets.
meredithcraig said:
so it will be noticeable when i remove the pistons if the rings have gone then as the bores look fine to me and will i need to split the gear box out to get the bottom of the engine out
how far have you got?

whats off the engine?
hhead is off sump timing chain oil pump oil coller cranks case will be off tomorrow then pistons out how can i check turbo seals
Without a running engine you will struggle to check the turbo oil seals, Can you rock the spindle?

Best option take it off if you have not already & drop it off at a reconditions.

I think you jumped the gun a bit stripping the engine. As mentioned a compression test would have helped pinpoint the problem.
i did speak to a machanic first and i had 3 different ooppinons but they all said piston rings how much would you think for a turbo rebuild then
and does any one no a good turbo reburf company near shropshire telford
Well as mentioned a compression test, would of shown up a problem with the piston ring, and seeing that you have stripped the engine down, if it was rings, then I would of thought that you would see scoring in the cylinder bores.
there is sligh scoring on one but other 3 are clear
Hate to say it but if you spoke to 3 mechanics and they all said piston rings, I'd be surprised that they'd be that confident without a compression test.
broken rings normally make a ticking sound, whereas piston slap (worn pistons) would result in a knocking sound.
I'm not a mechanic, but I do a lot of work on my rally car. When I experience engine problems, I do a compression test and I use a mechanics stethescope to pin-point location, without fail.
Anyway that is by the by -your engine is already stripped. While it is in bits though, you might as well go the whole hog, and rebuild it all. Especially as some items might look ok on the bench, but actually be worn. And without carrying out micrometer measurement tests you wouldn't know.
ok that does sound a good idea and will prob rebuild it would just like some more advice does any one no the best way to take the crank case off as i have it lose but it seems to be held in still any ideas

and yeah i do agree i wish i had done the test but the cost was the same as doing the rings my self and would have been dead money really
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