Tear down a seized 340

[mgm1986]

Looking for some expert advice. I bought a 340 over the weekend and it is seized, according to the seller, from sitting for 20 years. I have no intention of trying to get it to run as it sits, I simply want to tear it down and take it to the machine shop.

What is the best way to get things unstuck so I can disassemble with as little harm to the internals as possible?

It is on an engine stand so I considered draining the oil (which is still very clean looking) and filling it with ATF then flipping it upside down for a week or so. But then I thought, let me ask the experts instead of relying on Google!

Any advice is greatly appreciated!

 

[vdk2010]

The experte here told me to do the same but use 50/50 ATF and acetone!

Good luck with your engine!

 

[mgm1986]

The experte here told me to do the same but use 50/50 ATF and acetone!

Good luck with your engine!

With Acetone, i guess it helps penetrate cause its so thin. Makes sense to me. Thanks for the tip, I will try to get it done the next few days.

Thanks!!

 

[patrick66]

Let it soak in that 50-50 mix for a while, then you can start seeing if it'll turn by hand or not. If it needs persuasion, use a wooden block and a mallet on the piston tops (assuming the heads are off, of course!).

 

[Big_John]

Pull the pan and heads before you do too much. Make sure it's seized from the pistons being stuck and not from something like a broken rod.

ATF and acetone sounds as good as anything to soak the cylinders.

 

[mgm1986]

Pull the pan and heads before you do too much. Make sure it's seized from the pistons being stuck and not from something like a broken rod.

ATF and acetone sounds as good as anything to soak the cylinders.

Great advice, this is what I am doing now I just can't get two of the bolts out of the intake manifold. It seems they used smaller bolts for three of the center holes and they are rounded. One down, two to go.

With a little luck the PO was being honest when he said it was running when stored. Until I get it apart I am going to have faith in humanity and assume he was telling the truth!

 

[66SportFury]

How did you make out? Did you find what is causing the seize?

 

[68plymouth383]

Why are you trying to get the engine to spin if it's going to a machine shop for a rebuild anyway??

 

[commando1]

To disassemble it I presume. Evaluate the block....
No sense bringing them a boat anchor.

 

[MrMoparCHP]

Why are you trying to get the engine to spin if it's going to a machine shop for a rebuild anyway??

For me it would be my time that is free to do the tear down and freeing it up even if I was having them do the build.
It took me about 20 man hours to free mine up (not including the soaking time) at the typical shop rate it would be over a grand just to get to a starting point.

The 50/50 mix worked for me but it also needed its daily beating.

Alan

 

[mgm1986]

Why are you trying to get the engine to spin if it's going to a machine shop for a rebuild anyway??

A couple reasons, primarily for those already mentioned, so I can disassemble it before taking it to the machine shop. But also because I have never done anything like this so it will be very educational for me.

As for an update on my progress. On Tuesday I finally found time to drain the oil (Black but no sediment or water) and pull the pan to inspect the crank. I see a little surface rust but otherwise it looks like new to me. I also drained the filter, where I found a small amount of water. I put the pan and filter back on, flipped it over, and filled her with roughly 6 quarts of trans fluid (all I had on hand). I also used what PB blaster I had left in the spark plug holes. Been sitting since.

I finally bought acetone and more trans fluid so tonight I hope to get out there and fill the spark plug holes with the 50/50 mix. Still fighting the two remaining intake manifold bolts which have been soaking 2 days as well.

 

[mgm1986]

How did you make out? Did you find what is causing the seize?

I am hoping its just a little rust holding the piston rings to the cylinder. I pulled all the plugs one by one and only two had a bit of rust on them. My limited understanding of things makes me suspect these two cylinders where likely on the intake stroke and as such the moisture in the air was able to find its way through the masking tape used to cover the intake, past the intake valve into the cylinder. If I could get the darn intake manifold off and pull the heads I can confirm if this is true or malarkey!

 

[66SportFury]

I am hoping its just a little rust holding the piston rings to the cylinder. I pulled all the plugs one by one and only two had a bit of rust on them. My limited understanding of things makes me suspect these two cylinders where likely on the intake stroke and as such the moisture in the air was able to find its way through the masking tape used to cover the intake, past the intake valve into the cylinder. If I could get the darn intake manifold off and pull the heads I can confirm if this is true or malarkey!

Can you get a cutoff wheel in there where the rounded bolts are in the intake? You could cut the heads off then you would have about a half inch or so still sticking out of the head that you could grab with vise grips. They also make all kinds of sockets for rounded off bolt heads. Local parts store would carry them. Gotta post some pictures.

 

[MrMoparCHP]

I am hoping its just a little rust holding the piston rings to the cylinder. I pulled all the plugs one by one and only two had a bit of rust on them. My limited understanding of things makes me suspect these two cylinders where likely on the intake stroke and as such the moisture in the air was able to find its way through the masking tape used to cover the intake, past the intake valve into the cylinder. If I could get the darn intake manifold off and pull the heads I can confirm if this is true or malarkey!

Mine was two cylinders so I suspect that it was the rings. When I did get it to spin I then started the tear down and 5 or so wrist pins were siezed as well (or at least VERY tight), that'll fight you.


Alan

 

[mgm1986]

I do have the "reverse" socket that is supposed to remove stripped bolts, gonna try that tonight. Maybe my Dremel tool would work; my air grinder is too big to fit without damage to the intake itself. Otherwise I will chisel the heads off the bolts cause I am dying to get the intake and heads off!

 

[1978 NYB]

How about a couple of pictures.

 

[mgm1986]

I FINALLY got the last two manifold bolts free! The rest was cake, intake manifold off, heads removed, pictures snapped. Now I wait and see what miracles this atf/acetone mix will work. Way more rust in the tops of the pistons than I would have expected. The two with the rusty plugs being the worst offenders, with huge piles of rust! Cylinder 8 is completely covered and crusty with rust.

Will post pics shortly.

 

[mgm1986]

Hopefully this link works. https://plus.google.com/photos/1057...s/6021622952866226769?authkey=CPGsxLrnp5mYoAE

Here are some highlights as well.

 

[saforwardlook]

Seems like there was a head gasket failure long ago that let old rusty coolant into some of the cylinders (and the poor coolant probably precipitated the head gasket failure). Kind of curious, though, since those are not original head gaskets either. Maybe water entered the intake though and some of the valves were open, like you thought. I wonder if that can be salvaged? Time and soaking will tell.

 

[mgm1986]

Seems like there was a head gasket failure long ago that let old rusty coolant into some of the cylinders (and the poor coolant probably precipitated the head gasket failure). Kind of curious, though, since those are not original head gaskets either. Maybe water entered the intake though and some of the valves were open, like you thought. I wonder if that can be salvaged? Time and soaking will tell.

Yes, time and lots of beating and soaking. I am hoping it can be salvaged otherwise I lost the gamble buying the engine! My goal is to get down to the block and take it to a machine shop for inspection and hopefully minimum boring. Either way it has been a fun project tearing it down!