Removing pistons from a m30b35 block

[BigKriss]

I have two pistons stuck taking them out of a blocl. Here are some pictures. http://picasaweb.google.com/Kristianandlily/DropBox

Any tips guys?

The block has been outside for 4 months and the bores are a bit rusty, 4 came out okay, but two are stuck good.

Cheers

[whiskychaser]

From the order of the pics I'm guessing you took 4 out of the top and then removed the crank so you could get these 2 out of the bottom?
My tools of choice would be lots of penetrating oil and light taps on the crown of the pistons with the wooden shaft of a 2lb hammer.

[BigKriss]

The order of the pics is random.

I took the crank out first and then I tried and removed the pistons. I dont think they will come out from the bottom, it looks like there's not enough room there for them to come out the bottom. I couldn't find my 2lb hammer today, but I found it just know. I will use that to wack them out the top tomorrow.

[whiskychaser]

Never taken a piston out of the bottom. Actually I have but that was on motorbikes Looks like it wont go past the crank journals so thats probably why I'd just be a bit wary of marking the bottom of the con rods-dont want any trouble seating the shells afterwards. Bet they come out with a couple of taps. Best of luck with it

[Tiger]

I went to mechanic school long ago... but never went into field... it was for fun. I recall you have to shave the ridge on the top before you try to pup the piston out.

As for stuck piston... try penetrating oil or top end oil like Marvel Mystery oil... but I think plenty of penetrating oil like PB Blaster will loosen it easily.

[genphreak]

Maybe there's a slight lip in the cylinder that the rings are catching on before they come out. Maybe one simply douses it with oil and jiggles jiggles jiggles until you're truly jiggy with it... or they're out.

[Tiger]

That's why you have to shave the ridge.

[bsell]

Have you soaked them with penetrating oil from both ends?

If you don't want to reuse the pistons, you can break them apart to get them out in pieces. Ugly work, but gets the block back into use...

I'd soak the pistons good from both ends, letting the oil penetrate for a day or two. Then tappy, tap back and forth, using a piece of wood as the 'go between' for the piston and hammer. Criss cross the piston when tapping so you don't wedge the pistons in the bore.

[whiskychaser]

Maybe there's a slight lip in the cylinder that the rings are catching on before they come out. Maybe one simply douses it with oil and jiggles jiggles jiggles until you're truly jiggy with it... or they're out.

The pistons are stuck at the bottom of the bores so I dont think the problem is the lip at the top. The bores look pretty rusty. I vote for the 'tappy, tap back and forth' method to free them off. As Tiger says, its probably best to get rid of the lip but I bet they come out without that. A good clean and a couple of passes with a honer should sort them out.

[BigKriss]

I've never heard of shaving the ridge of the piston before. I did spray with wd40 today, 4 of the pistons came out okay. It's just the end two I am having trouble with.