Piston Ring Replacement Prob

[nd240sx3]

ok my motor is out of my car and need to put piston rings on well my question is can u change rings goin through bottom of motor or do u have to go through the top cause on my 300zx u gotta go through the top

[orion::S14]

You can pull the crank out, then pop the pistons out the bottom...but that's the hard way.

Pull the head, do it right.

- Brian

[nd240sx3]

why is that the hard way i would think thats easiar i goin to replace the bearings why i am at it so thats whay i asked. and there is just so much shit to deal witt when removin the head

[kandyflip445]

Why would pulling the head be the right way? (Just curious on your opinion) You would still have to open up the bottom end and you would have to wrap the connecting rod in a towel or something to protect the finish of the cylinder wall. Of course if you did take out the crankshaft then you would have to be careful to no scratch the journals too...

[orion::S14]

I meant pull the head, do the whole job right...rings and new bearings is not a "rebuild"...and new rings on old cylinder walls = smoking in a couple months, and blow by.

At least use a dingleberry hone on the cylinder walls, or something...and for that you need to pull the head.

- Brian

[kandyflip445]

!!! :rofl: DINGLEBERRY HONE!!!! That's the first time I've ever heard that one. I would just get a 3-stone hone. Also if there is a ridge at the top of the cylinder he would have to take that off.

[deviousKA]

You cannot pull pistons from bottom, let alone reinstall. not even a remote option unless you would like to grind the sides of your pistons down (think main bearing location), and then fight putting the rings in with ring compressor, on a non-flat surface, "humor". Pull your head.

[kandyflip445]

You take out the crankshaft to pull them from the bottom which requires removing the main bearing cap. IF there was a ridge at the top of the cylinder then you would want to take them out from the bottom anyways. But You would want to put them in from the top, with a towel around the rod or at least something around the bolts.

[orion::S14]

!!! :rofl: DINGLEBERRY HONE!!!! That's the first time I've ever heard that one...

Mmmmmm...OK

Dingleberry Hone = Flex Hone

http://www.mytoolstore.com/kd/2486.gif

Good way to get a new, smooth surface, without taking off much material.

Search Google, you'll see.

- Brian

[deviousKA]

You take out the crankshaft to pull them from the bottom which requires removing the main bearing cap. IF there was a ridge at the top of the cylinder then you would want to take them out from the bottom anyways. But You would want to put them in from the top, with a towel around the rod or at least something around the bolts.

No you cannot do it. Ok think about this, the ka has 5 main bearings (all .975" wide). So There is a main between each bore, and on the ends. Take a look at the space between the bores on a ka, definately no where near .975". The 89-90mm ka piston absolutely will not fit between the mains. Even if it did fit (some engines you can do this with, if they stretch 2 rod journals across one set of mains) You cannot properly install rings (as in you will probably damage them installing).

[kandyflip445]

I know what a flex hone is.....just never heard it called a dingleberry hone.

I was talking about the DOHC engine. The main bearing cap comes off as one big unit, according to the FSM.

[deviousKA]

The main caps have nothing to do with it, and yes on the sohc/dohc 240sx ka have a girdle (so all the caps remove at once). Think about it, you remove the main caps, the mains do not "disappear". The lower main bearing mounting is cast/part of the block. Pistons can ONLY come out from top.

[kandyflip445]

Hmmmm...on the engine we worked on in class we took them out the bottom. Might be because like you said about sharing a journal. :shrug:

[andrave]

I took out the oil squirters and removed mine from the bottom, devious...
but the engine was stripped and sitting on a table, and the crankshaft and girdle were removed.