Replacing an oil control ring

[Eadie McCreadie]

I have managed to break the oil control ring when putting the cylinder back on my piston...

ARGHGHHHHHHHHHHHHHHHHHH!

Now, cussing aside, how do I go about replacing the ring?  Do I change the entire set, starting with the oil control ring at the bottom (of course), and work upwards, then lower the cylinder, or can I just slip the oil ring down over the other rings on the piston?

The engine is new, only run at the factory, so all rings as new.

Advice more than welcome.

Many thanks,

EM

[JohnF13]

It sounds like you are trying to slide the cylinder down over the piston with the piston still in place in the engine.  If so, don't!  Undo the big end bolts and take the piston out of the engine.  Next, set the cylinder upside down on a clean cloth and work the piston in from the bottom.  If stuck, you can even use the old "2 screwdriver" method of compressing the rings as they go into the cylinder - much easier and much less likely to break things.  That also means you can just replace the oil ring - from the bottom, so you don't have to go over the other rings.  It sounds like more work, but after you do it you'll realise how much easier it is than trying to drop the cylinder over the piston from the top.  After that, take the whole assembly (piston in the cylinder) and drop it over the studs - it is an easy matter to line up the big end shells on the crank.  Don't forget to mark the two halves of the big end bearing - make sure you replace them in the correct alignment -the rest is simple.

It should only take a couple of minutes to take off the big end nuts - don't forget to use NEW cotter pins.  Torque value I think is about 60-65 lbs.

[M61hops]

Put rubber or plastic hose over the rod bolts so as not to ding the crank throw bearing surface!  Or do the rod bolts come out easy?  Sharp edges can ding critical surfaces.  Of corse everyone knows this.... but when you try and rush things....                                         Leland

[ronmar]

Also watch out for the oil dipper on the rod bearing cap.  Use a socket long enough to clear it(don't ask:()

It is as suggested much easier to put the piston into the cylinder with the cylinder upside down on the bench. The rubber hose on the rod studs is also excellent advise to protect the pin.

Another trick I discovered when putting the cylinder with piston back in place on the block was to use a large horshshoe magnet on the top of the piston(you of course need a cast iron piston for this).  The magnet needs to be a strong one, able to lift the weight of piston and rod.  Thru the "U" in the magnet I placed a wooden stick that went across the top of the head.  This keeps the piston at the top of the cylinder so you can concentrate on getting the cylinder in place on the gaskets with nothing in your way, without worrying about the rod/piston falling out the bottom and landing on the crank.  It will freefall out the bottom if given the opportunity.

Ron

[Doug]

It is as suggested much easier to put the piston into the cylinder with the cylinder upside down on the bench. The rubber hose on the rod studs is also excellent advise to protect the pin.

Ron

Same trick works on the Petteroids, just enough fillet to make an easy go of it on the bench 

[Eadie McCreadie]

Thanks all...

About access to the big end bolts... is this done from one of the inspection hatches, or the large hatch and the one that holds the oil dip stick?

[carlb23]

Dont feel bad I broke my oil control ring and had to replace it as well.  I have done it both ways with the piston connected to the crank and with it off.  It is deffiently easier with the piston / rod disconnected.

I use both access holes to tighten the rod bolts, its just easier for me.

Carl

[Eadie McCreadie]

Would it be a silly question to ask if it is best to undo/re-tighten the big end bolts with the piston at TDC or BDC?

[ronmar]

Other than being easier to reach the nuts thru the access hatch at TDC, no it dosn't make any difference.

Ron

[Eadie McCreadie]

Thanks all.  I have some parts on order, so it'll be ten days or so before I do this work.

EM