help ID these pistons

[baxsom]

interesting,

well there isnt a ridge. just a smooth wall from bottom to top. i figured what the hell, its apart this far lets give it a try so i unbolted the #1 piston, put some tubing on the threads and it popped right out.

the bearings are a little shiny in the middle but from the pictures i have seen it fits into the normal wear category.

what the hell, whats the worse that can happen, i put it all back together and have to do it all over again?
id probably go ahead and pull the block at this point except for the fact that at this i cant get a cherry picker into the garage to get over the car.

 

[Rodney Gold]

You will have a problem with clearances - blocks need to be honed to suit a piston , you will most likely not seat the rings to the smooth bore correctly this way and will not be able to balance the rotating assembly apart from other issues. Surely its not a problem to roll the vehicle out the garage , get the engine out and roll it back in?

 

[TimAT]

Even the issue of not being able to get a cherry picker in the garage is not a problem. My garage is in the basement- 7' ceiling. I can swing a BB out of a Vette no problem.
THe difficult part is getting it over the nose. I pull a front tire/wheel and go over the side. If you don't have a really long cherry picker that's about the only option anyway. Unless you have a narrow 1 car garage it's do-able.

I can understand your point of not wanting to pull the block out. But why take a chance? Unless the pistons fit correctly, there's a good chance you build an oil burner that you can't get dried up. Extra true with hyper alloy pistons.

 

[JohnZ]

Pull the engine and take it to a machine shop. Your chances of buying a set of new .060"-over pistons and having ANY of them fit properly are slim to none. You need a fresh hone to fit the pistons, and correct cross-hatch in order for new rings to seat, and differing piston weights will affect your balance. You can't just "change the pistons" - there's more to it than that.

 

[baxsom]

damn this sucks,
machine tells me face to face one thing,
now i get the exact opposite.
i probably shouldnt have already pulled the pistons.
it was actually quite easy. caps off and pushed them right out.

thats what i get from listening to my machine shop.

looks like i am going to have to try and figure out a way to get the block out.

 

[TimAT]

Bax, you got the block pretty well stripped now. Unbolt the bellhousing and convertor (automatic?) disconnect the block to frame ground, 2 motor mount bolts, throw a chain over it and pull.

And I don't want to appear to be telling you that just throwing a set of pistons in won't work. It WILL WORK- I've done it. All that anyone is saying is that for max performance and engine life- (that means low oil consumption too BTW) the BEST way is to have the pistons properly fit.
I don't know your machine shop, and I'm not about to diss them. Here's a question I always ask when I go to a different machine shop- How do you install the wrist pins?
Different schools of thought on this one- the factory presses them in with a press. I've seen lots of small shops heat the small end of the rod in an oven or with a torch. After that, the end of the rod is usually blue. My next question is how much did the heat change the structure of the material of the rod? I'm no metallurgist, just a car guy. I did talk to a machine shop that builds some serious race stuff in KC- he told me he presses the pins- when you heat the small end, he said it never quite shrinks back to the original size. true or not, I don't know. But he didn't heat my rods when he put the new pistons on.

 

[JohnZ]

the factory presses them in with a press.

Yes, they did - after induction-heating the pin end of the rod; pressing them cold can damage the pin, the rod, and the piston.

 

[TimAT]

Agreed. But I've never pulled any of them out of a factory engine and saw the rods were blue.

 

[JohnZ]

Agreed. But I've never pulled any of them out of a factory engine and saw the rods were blue.

Induction heating doesn't discolor them like a direct flame does - it's almost instantaneous.