Ford 640 Tractor Sleeves

pengc99

New User
Hi folks, i'm working on rebuilding a 640 tractor that had some engine damage and while working with the machine shop we have an interesting problem.

The old sleeves were removed from the engine but the machine shop found the sleeves (both old and new) do not match the step in the deck.

The sleeves have a 180 thou step on the top, but the block has a 208 thou step. If the sleeve was pressed in, the sleeve would sit under the deck.

Both the old sleeve and the new sleeve have about the 180 thou step on it, so we're wondering if this is correct or if there are variations on the sleeve.
 
I have always pressed it in where it is flush with the deck. And all the factory sleeves I have seen are flush with the deck.

Your call!!!
 
Thanks so much for the reply! I need to get my hands on a repair manual, but after some research it seems like the situation I have is "normal" and I should just press it in to flush with the deck surface.

I was really just curious because most of my work is from the automotive side, where sleeves are designed to be pressed in until it sits on the lip. If I did this with this engine, the sleeve would sit under the deck surface.
 
(quoted from post at 11:05:52 10/26/22) I'm working on rebuilding a 640 tractor that had some engine damage
and while working with the machine shop we have an interesting problem.
The machine shop found the sleeves (both old and new) do not match the step in the deck.
The sleeves have a 180 thou step on the top, but the block has a 208 thou step. If the sleeve was pressed in, the sleeve would sit under the deck.
.....so [b:2aecc88b9a][i:2aecc88b9a]we're[/i:2aecc88b9a][/b:2aecc88b9a] wondering if this is correct ....
IMHO
You say, "[b:2aecc88b9a][i:2aecc88b9a]we're[/i:2aecc88b9a][/b:2aecc88b9a] wondering" as in both you and the machine shop.
If your machine shop is "wondering" if this is correct, run, don't walk away from that shop.

Having the sleeves' lip, be able to move 0.028 below the top of the deck is a recipe for disaster.

I'm not sure of the spec for your exact engine off the top of my head, but a typical spec is the sleeve needs to be .001 -- .002 or .003 [b:2aecc88b9a][i:2aecc88b9a]above[/b:2aecc88b9a][/i:2aecc88b9a] the deck. In reality it can be even (flush) with the top of the deck as long as it is not below.

Understand the reason for this.
As the pistons move up and down in the cylinder, a thousand or more times a minute, for hours upon hours, it will try to drag the sleeve with it, in either direction. This applies to all sleeves, wet, dry, pressed in, etc. The lip keeps the sleeve from moving downwards. The cylinder head, tightened against the top of the lip, keeps the sleeve from moving upwards. In your case, it seems there would be .028 room for movement. Even pressed in, with that amount of room, the sleeve can begin moving this distance. Maybe right away, maybe not until hours later. Eventually though, the lip can break enough that the sleeve can be dragged down to collide with the base of the connecting rod, or the crankshaft itself. Not pretty.

In some cases, depending on the design of the sleeves' lip, shims are used to bring the position of the lip back into spec.
Another solution is to bore the cylinder with a lip in the bore at the bottom. Then a custom sleeve can be pressed to this lip, and machined even with the deck. For me, this is the only scenario where I would allow a sleeve to not be standing slightly "proud" of the deck.


Oh yea, and get that repair manual!

This post was edited by jimtrs on 10/30/2022 at 09:12 am.
 
thanks for the reply, I appreciate you explaining it to me but I've already quite familiar with the process. I come from the automotive side, where when a engine is sleeved the block is also machine with a step that is slightly shallower than the sleeve's step. The idea is to press the sleeve into the step until it bottoms out, and then the sleeve and block are decked together to get a uniform height.

What is puzzling to me is[b:b1b9ed6964] why the original and new sleeves don't have the step deep enough down to have the sleeve sit on the lip[/b:b1b9ed6964]. Everything i'm reading says to just press the sleeves down to be flush and be done with it.
 
(quoted from post at 13:15:52 10/30/22) What is puzzling to me is why the original and new sleeves don't have the step deep enough down to have the sleeve sit on the lip
I don't know.
What I do know is that anything could have been done to a 60+ year old tractor.


You say:
thanks for the reply, I appreciate you explaining it to me but I've already quite familiar with the process
Then I would reconsider your previous statement:
(quoted from post at 14:40:58 10/28/22) ..... but after some research it seems like the situation I have is "normal" and I should just press it in to flush with the deck surface.
 

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