How hard is it to pull a piston from 2.3?

[JimBee]

Apart from the idling problem I have with a '96 850, it's clinking on one cylinder (#1, I think). I suspect a wrist pin.
I might pull the head and replace the piston and rod if I could confirm it's not in the head. I took it to an indy the other day and he said it was a rod bearing or wrist pin.
Oil pressure is good and the engine doesn't seem to burn any oil, so I'm thinking of tearing into the bottom end—without removing the engine.

If a rod bearing was worn enough to make a hammering sound could there possibly be good oil pressure on these engines?

Is there any reason I couldn't just drop the pan, unbolt the rod cap and push the piston out through the top?

Does the pan just drop with the perimeter screws all removed?

[wheelsup]

On the 2.4 you can drop the pan but you have finagle the thing out. It's not simple.

[precopster]

I recently stripped a 5 cylinder on a stand just to see how it works and I used a soft pinewood hitting from the conrod side end caps (without the bearing shell) and out through the top. When you get to the unworn cylinder edge it gets tight so lots of lube on the cylinder walls will help it come out. I don't see why you can't do this with the engine in the car.

[JimBee]

That was kind of my thought—use a soft wood driver. I'm thinking of harvesting a couple of pistons/rods from a junkyard '97 850 2.3 turbo. I would take them to a machine shop to check for alignment, skirt wear, wrist pin, rings, etc., then reuse one of them.

If the bearing journals in my '96 2.3 are at spec or close to it, could I just change a piston/rod with engine in the car?

I suppose the journal in mine could be mic'd, but would that be necessary if oil pressure is within tolerance? Could I just use a stock new bearing shell and put it back together?

My preference would be to plasti-gauge it, but that might be hard to do from underneath. What do you think?

[keepersboy]

I've done alot more work on big diesel engines, but "inframe' over hauls are pretty standard. Your not going to have a new engine, but if the crank looks clean you should be good. Not a bad idea to plasti guage the bearing, at least you know where you are or how much wear you have, I don't think I would mess with used parts on this job. I think you will find a new piston, connecting rod. etc not really that expensive in comparrison to the work involved getting to it.

[gilhuly]

You should have no problem with measuring/plastigauging the crank from underneath. See the write ups on oil sump o-rings for technique on removing the pan. It can be relatively easy. This is a hell of a lot easier on a lift.

[JimBee]

I appreciate the encouragement. This will be a project for next summer. Any suggestions as to where to purchase the rod, bearings, etc.?

[KSUMMEY]

The 2.3T from my understanding comes with forged Mahle brand pistons. I pulled my car down at 300k miles due to stuck oil control rings and to have the hear reworked the turbo cars are really hard on the exhaust valve guides. I drove my car like I stole it and it runs 14lb of boost. If the car has never starved for oil the guys at the local Volvo place told me put rings and a head gasket in it and let it go . I asked what about rod and main bearings? I was told I could replace them if I wanted to but it most likely would not need it. They were right the bearings much to my surprise looked great. Sadly not what you would see tearing down an American car brand from experience. I would say unless your car has starved for oil the bearings should be good.

Here is what you need to know. If you are removing one piston or all. the piston in your car will have a letter marked on the piston. C-G each represents a standard or over size for the piston. To correctly fit in the used piston from another car you will need to know what size your piston is. C-G is still for a standard bore car but the minor differences make up for machining variances so the piston fits with out it being loose.
Just match the letter use a ridge reamer and remove the cylinder ridge, lightly hone the cylinder wall and reassemble.

If your going through the trouble to remove the piston from another car take the rod too just in case it cant hurt.

Piston marked C: 82.98-82.99 mm
Piston marked D: 82.99-83.00 mm
Piston marked E: 83.00-83.01 mm
Piston marked G: 83.017-83.032 mm

I would wonder what caused the one cylinder to knock. Something important to check would be in the 2.3T uses piston coolers it sprays oil on the bottom of the cylinder to cool it. This also adds lubrication to the cylinder walls. make sure yours has not broken. In 84 Volvo used a vw made inline 6 cylinder Diesel engine in the 760 cars and a few others with the piston cooler. It broke the cylinder did not receive enough lubrication and the cylinder wore out beyond repair and had to be sleeved. Just check everything. Make sure you remove the cooler from your block before trying to remove the piston.