850 glt replacing piston rings

kv893t · Post by **kv893t** » 23 Jan 2010, 10:52

hello everyone. in the recent past i have replace the head gasket on my 95 850 Volvo glt.the problem i have is oil spilling from the oil cap and smoke coming from the dip stick.i overheated on a tip.use a radiator sea lent to patch the leak.now i want to replace the piston rings .can anyone steer me in the right direction on this project.maybe a step by step procedure with picture preferably.thanks so much.oh i should say that i have replace the radiator .

Post by **charlyW** » 23 Jan 2010, 12:08

Hi have you checked the PCV behind the inlet manifold on 850's they fail causing the issues you have described and its far cheaper than piston rings

Changing piston rings is an engine out job because you cannot complete the job with the engine in.

You will need the following

Clean area
Cleaning solution [power washer tank]
Engine hoist
Engine holder or substantial bench not soft wood
Full set of piston rings
Full set of bearing shells big ends and crank
Bore hone tool
Piston ring setter [not sure what you call it but it helps compressing the rings to drop back into the bores]
New Head bolts
New Gasket kit full
New Cam belt
water pump is a good thing to fit if youre pulling the engine out
Selection of tools including Torque wrench and Angle gauge.
A flat plate to check that the head is still true [best left to an engine shop but a thick sheet of glass will do and a metal rule]

Once you've got all this then you can start. Let me know if this is what you want to do and ill do a write up of how to replace the piston rings.

Charlotte

Post by **jblackburn** » 23 Jan 2010, 12:43

the problem i have is oil spilling from the oil cap and smoke coming from the dip stick

Those issues are indicative of the classic clogged PCV system. Much easier fix (in comparison), I suggest you start there.

Replacing piston rings is a hugely annoying job, even on something as simple as a 30-year old tractor engine.

kv893t · Post by **kv893t** » 24 Jan 2010, 07:30

charlyW wrote:Hi have you checked the PCV behind the inlet manifold on 850's they fail causing the issues you have described and its far cheaper than piston rings

Changing piston rings is an engine out job because you cannot complete the job with the engine in.

You will need the following

Clean area
Cleaning solution [power washer tank]
Engine hoist
Engine holder or substantial bench not soft wood
Full set of piston rings
Full set of bearing shells big ends and crank
Bore hone tool
Piston ring setter [not sure what you call it but it helps compressing the rings to drop back into the bores]
New Head bolts
New Gasket kit full
New Cam belt
water pump is a good thing to fit if youre pulling the engine out
Selection of tools including Torque wrench and Angle gauge.
A flat plate to check that the head is still true [best left to an engine shop but a thick sheet of glass will do and a metal rule]

Once you've got all this then you can start. Let me know if this is what you want to do and ill do a write up of how to replace the piston rings.

Charlotte

hello.i have just complete a head gasket job,where i replace head bolts ,water pump and new belts.i have also had a machine shop do a head job.i have also done a complete pcv repair kit,new radiator,heater core with all that being new do i have to purchase new head bolts and gasket?i have sank a lot of money into this car but i really love it.in your option is it worth it to spend more money and time or just let go?

Post by **charlyW** » 24 Jan 2010, 11:49

If you have replaced the cylinder head you have a few problems because to replace the piston rings the head must come off also the engine must come out of the car. I priced the engine rebuild up using my trade account the figure came out at over £400 for a complete rebuild, you might find a good recon engine is cheaper or financially appropriate.

I have submitted a write up on how to replace piston rings assuming the worked knows how to replace/remove the cylinder head and assocated parts also has the necessary hoists holders and tools.

If any moderator wishes to add it as a stick please feel free to do so and if you wish for anything to be added please ask and I will give you the additions. Please punctuate to suit your regional needs.

Charlotte

Post by **jblackburn** » 24 Jan 2010, 12:28

Charlotte, this is great!

I'm adding this to the repair database. I'll talk to Matt about making you a "contributor" - I think that's well-deserved.

Post by **vegasjetskier** » 24 Jan 2010, 13:06

charlyW wrote: Changing piston rings is an engine out job because you cannot complete the job with the engine in.

Why do you have to pull the engine? Is there insufficient clearance to get the pistons out with the block in the car?

Post by **charlyW** » 24 Jan 2010, 14:21

I'm not saying it can't be done but the following points would need considering: It would be very difficult to get the sump past subframe. To replace piston rings the bores need honing, formation of a criss cross pattern around the bores to form an air/gas tight seal, whilst this is very easy it produces metal/carbon shards if any of these debris got into the crank oilways it would destroy the engine not to say anything about how hard it is to get the upper bearing shells on without them dropping back or slipping out of place.

The block is a two part construction this requires new bolts if disturbed.

On high mileage engines the top of the bore gets a large lip this would need specialist equipment to remove so the same caution of the crank shaft needs to be considered. If anyone is going to go to the expense of replacing the piston rings then it makes sense to replace the rear crank seals thus needing the engine out.

Most importantly the engine will need cleaning with a quality engine cleaner these chemicals are toxic to aquatic soil and all authorities would take a very dim view if you were cleaning your engine out on the street or parking area.

Post by **vegasjetskier** » 24 Jan 2010, 14:32

Good points, charlyW. But I have heard of a "quick-and-dirty" ring replacement (not on Volvos) by just pushing the pistons up out of the bores. A ridge reamer is used to remove the ridge at the top of the cylinder before the pistons are pushed out. Rags are placed on top of the crankshaft, then the cylinders are given a light honing. New rings are installed and the pistons replaced, then the head is installed. I'm not saying it's the "right way" to do it, just that it has been done before (and probably will be again).

Post by **charlyW** » 24 Jan 2010, 15:10

Over here it was a popular way on fords to do it that way along with vauxhalls.

Heavy grease was used here to hold the upper bearing shells on.