rebuilding slant 6 engine

May 16, 2007 16 Replies

I am rebuilding a 225 slant 6 engine in a 73 Valiant because it needs new oil control rings. However, when I try to pull the piston out of the block, I can't do it- the rod gets stuck at the bottom of the cylinder.



There are little extra lips of metal on either side of the rod that prevent the rod from fitting into the bore and being pulled out.



The block and crank are still in the car, so it's not like it would be that easy to just grind these off or something.



Has anyone run into this, rebuilding an engine of any kind? What did you do about it?



Thanks.



Are you trying to remove them from the bottom of the cylinder? I don't know if that is possible. I think they have to come out from the top. You may need to remove the ridge that may have developed near the top of the cylinder to get them out.

-KM

Well, you obviously have the pan off, file/grind from below.

No, I am trying to remove them from the top. The lip of metal that is preventing me from getting them out is on the connecting rod.

And make the rods now out of balance with each other, and useless as a core return.

If the rod is too wide for the bore then the pistons were obviously installed from the bottom. rebuilding an engine with the block still in the vehicle is chancy at best, anyhow.

He ought to just pull the block out, mount it on a proper engine stand, pull the crank and tear the block down properly. Or better yet, buy a short block from a rebuilder. Just putting oil rings in it is just asking for trouble, the cylinders are likely out of round by now.

Typical cheap fix attempt. Do the job right or don't do it at all.

Ted

Hmmm - maybe I'm missing something, but I have two questions: (1) How do you *pull* pistons out from the top (especially if it meets any more than minimum resistance, such as a ridge at the top of the cylinder)? (2) Is it possible that the normal features/shape of the bottom end of the connecting rods are simply catching on the bottom of the cylinder bores - i.e., not too wide for the bore, but laying over to one side (gravity) and catching on the bottom of the bore - and if so, not having access to the bottom of the engine with the pan still on, how do you force the con rod not to lay over to the side and catch on the bottom of the bore?

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

How would he have gotten the Connecting Rod disconnected with the pan on?

(Couldn't resist.)

Larry Behold Beware Believe

Tap upward on the conrod (with an appropriate soft mallet and with rubber hose pressed over the rod bolts)- that's the standard procedure. Even with most (not all) engines on a bench and the crankshaft removed, the pistons usually go in and out the top. That's the easiest (in most cases ONLY) way to compress the rings so that the piston can go back into the bore at all. You can't work a ring compressor from the underside of the block!

That's my guess. Either that or the engine's been hydro-locked and the conrod is deformed.

Well, I know somebody said, "Go to your room"! :)

Oh crap! Forget I said that.

I misread the OP's post "No, I am trying to remove them from the top" as being in response to this question from Joseph Myers "Well, you obviously have the pan off, file/grind from below" - which it wasn't - and I failed to think it through (like - how did he get the con rod bearing caps off!). Oh well. :)

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Picky picky picky!!!! :)

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

Now *that* I recognize from Laugh In.

Speaking of which, I do remember the "I didn't know that" line from Laugh In, but I think I am right in saying that Carson had a variation on that where he said "I did not *know* that" with different inflections and speaking each word distinctly.

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

You bet your sweet bippy!

Well - sock it to me!!

Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

You are. And he usually did an exagerrated head-nod, bobbing down on the "not" and then ending on an upswing and looking at whomever he was talking to just as the said "that."

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