Hi all!

The time has come to do that which I have been pretending that I wouldn't have to do... Yep, it's time to change the piston rings on my 1994 wagon.

There's probably an endless list of parts I should replace while I'm at it and stuff like that, but what I'm really wondering about is this:
Is it possible to replace the piston rings without lifting the engine out or dismantling the oil sump / crankcase?
In other words: Is it possible to access and replace the piston rings by simply removing the cylinder head?

That would be preferable, since lifting the entire engine (and transmission) out is a whole different ballgame.

Input on this would be very much appreciated as this would be the most extensive work I've ever done on a car.

Thanks!

Bakern,

If you ask me about a TOP-job, then the answer would be yes, it is possible and you dont have to remove the engine out. But if you want to do the pistons, errrrm, how then could you remove the pistons OUT?

You got me thinking there, as well...

Hmmm...

Hey Bakern, couldn't give you any advice as I myself am a newbie, just hoping that if you do find a way, please post it here with pics, dude! It'll be a tremendous help to every hell-bent DIYer around the globe!

All the best in your quest! :thumbsup:

Of course and you can,but you have to remove the head and the oil pan,of course.But if your car has many kilometres on,or damage,then I wouldn't suggest it.And just to know,you will have a hard time under the engine if you decide to change the rings with engine on.But also measure the cylinders,they may have damage.

Ok, thanks for the input guys!

Bear: So what you are saying is that with the cylinder head of it's not possible to get the pistons far enough upwards (by turning the crank) to actually change the piston rings...

Kim: So you would say that it's easier to lift out the whole thing than actually do it in situ? Well considering how much easier it is to work on the engine when it's lifted out it makes sense. It would also make it easier to do other replacements and maintenance.

Big Daddy: Hehe yeah I know, imagine finding a bulletproof way of replacing the pistons without all that work! Haha he who finds a way of doing that would probably do well. Seems it won't be me. Oh well :)

Uncle Bakern,

I will not insult your intelligence by acting as if i have done that before (because i havent), or even know exactly what happens during the procedure (:haha:) but i understand that removing just the pistons and all is NOT a straightforward job as it seems. I also know that refitting the piston seals is a hassle, especially to those who have never done it before (like ME!) even if you have all the sleeves in place.

:)

As the rings will not protrude either above or below the cylinder (luckily) you must have some way of getting to the rings. This is done by separating the main bearing caps from the conrod - and there's no way that I know of this can be achieved except from the bottom of the engine.

We now get to the part you are trying to avoid - the sump must then be taken off to expose the two bolts that hold the main bearing shells/conrod together around the crankshaft.

In every vehicle I've re-ringed, it wasn't necessary to remove the engine - but then again - they weren't FWD Volvos

I don't think the engine would have to come out of your Volvo if it was properly supported however, others on this forum might be able to supply the correct answer to this question.

Ampangbear - are you saying 850 Volvos have sleeved-cylinder engines?

See the point i am making?
:haha:


BTW, i thought you'd need to the sleeves to be able to drop the piston together with the rings proper into the block. Dont you?

Why do you think it needs rings ? how many miles is on the engine ? does it smoke / burn oil or is the compression just low ?

if i may ask, what vehicles have you re-ringed and not needed to remove the block? all the ones that i have done, all the blocks had to come out. even with a lift. just curious, not saying it can't be done, just never seen/heard of one that COULD be done like that.

Hi again, guys!

Haha don't call me "Uncle", Bear! Come to think of it I actually like it. It's naughty ;) And I find you more helpful and informative than insulting!

Volgrrr: Thanks, what you said confirms what I feared :)
The engine is in fact designed in such a way that the pistons never travel far enough up to make access to the piston rings, thus making it impossible to replace them without removing the pan.

Well I guess I'l have to do it the old fashion way.
Volgrrr: You seem like you have experience with these things.
What do you think is the best solution for replacing the piston rings? Lifting the engine out or doing it with the engine in place?

Just trying to prepare for this massive DIY-frenzy :)

By the way it's great to see so much response on this! It's nice to know that the forum is alive!

Hi, you seem to be asking us "how long is a piece of string". Without knowing your mechanical competence, the space available in your workshop, and the range of tools you have available to you, it is difficult to say what is best.

Economicaly, if you are going to have to hire / buy tools and lifts the answer may be to find a cheap garage that specialises in this kind of work, pay the price, but end up with a guaranteed job. Also when those "other" issues are discovered during the stripdown and rebuild they will be in a much better position to handle them.

Alternativly, if you have the confidence, tools, space, time and experiance then go for it by all means.

Personally i would be looking long at hard at the job and what i intend to achieve. You have not said yet why you believe it is the rings, ?

Best of luck :thumbsup:

Big Ben and Ryan:

The car is burning oil. It has done so for almost two years.
I even changed the cylinder head gasket and the valve stem seals (one was leaking), but the problem still exists. It's the second cylinder from the left, and it burns so enough oil to make the plug on this cylinder go bad and misfire after about anywhere between 150-500 kilometers depending on how the car is driven.
It puffs out blue smoke instantly when the RPM hits 3000, so I try to keep it under.

I haven't really measured how much oil is burned, but last year when me and my mates were on our traditional annual fishing trip we had to put in about 3,5 liters of oil. We didn't drive more than about ~1000 kilometers. The plug on the bad cylinder had to be changed twice, and even so the car ran on four cylinders the last kilometers home.

I have a compression gauge but I haven't even bothered to measure the compression as I don't think that's necessary. Maybe I should do it anyway?

I have considered giving Auto-RX a go. It seems to be the most realistic additive for helping clean out the engine. If a ring is stuck in its groove this might help it loosen...?

Me old buddy - if you've never taken pistons out without removing the engine, then I must be considerably older than you.

Most of the cars I owned and had to work on in my younger days (lack of the ready, due to investing too much of it on having a good time - you know how it is) were of English or Australian derivation and numbered amongst them were Humbers, Vangards, Jag's, a Chrysler Regal, Leyland P76 and Ford Zodiac.

While I can't claim to have re-ringed all of these vehicles I had to on a few, and I can tell you it was no fun laying on your back under a vehicle with the sump off and the odd glob of oil lobbing on your face when least expected as the big-end bearing caps were removed one at a time and then the crankshaft waggled around to allow the conrod and piston down past the crankshaft and out of the block. On some you couldn't do it this way so the piston had to be removed from the top of the engine - but not one of these engines ever came out (actually I lie, I took a Jag engine out once, but for a completely different reason - nothing to do with removing a piston).
:thumbsup: :thumbsup:

I would do a dry and wet where you ad oil to the cylinder compression test this will confirm if its the ring(s) on that cylinder. You said you replaced the valve stem seals what about the valve guides ? And how many miles is on the engine ?

hey volgrrr, not doubting you, but with my ham-fisted way, i need to remove the block to access everything. if i am taking the heads off, for any reason, usually it means that i am tearing it down to do some mods to it. maybe british and aussie models didn't need to be removed, don't know, i haven't ruined one. yet. give me time. :57:

Doesnt sound like a one-man job for the 850s at least. I've tried lifting the crankshaft once. Bugger was HEAVY. If it had my face under it, the 'glob of oil' would prolly be the last thing i'd be worried about... HAAHA.

Oh, OK,OK, sorry,sorry...
:)

:banana:

I'm guessing if it's burning that much then the bore / sleeve will be badly damaged as well.

No 4 on my motor is the cylinder with least compression, and like you i've noticed more oil consumption when the motor is continously above 3000, though nothing near as bad as yours. I've heard in the past that 4 + 5 are the cylinders most likely to do this as the narrow oilways have a long way to travel to this part of the motor and are more likely to block.

Im guessing (again) at new rings and a rebore/resleeve. Would also doublecheck the valves whilst the head is off :)

Good luck! (i.e. rather you than me) :P