Ford 268 piston height issue!

dannyidp · Jul 13, 2023

purchased a Ford backhoe with a spun rod bearing I've got the engine out the piston is sticking out of the block 12 thousands I've got it down at the Machine Shop the where on the cylinders is 3 thousands they will not bore this block due to pin holes so the only other option is sleeves and then they will have to Deck the block. Piston protrusion is already Max according to the book. Do you guys know what my options are now?

buickanddeere · Jul 13, 2023

How thick is the head gasket ?
Max limit on the protrusion on the pistons and valves will improve cold weather starting .

RBnSC · Jul 13, 2023

You can mill the top of the piston if you need to.

caterpillar guy · Jul 13, 2023

The holes will need to be bored and sleeves fitted to your sleeves or the block will have to have sleeves fit in for the pistons to run in. Then for the height I would get them set and see what the actual piston protrusion is with the new bearings and sleeves in then if they don't hit the valves and are even height leave them go and run it. You would want a few thousandths clearance like probably at least .020 or so Using clay you could see what the clearance is between them with the valves open under the head ontop of the piston.

sander · Jul 13, 2023

Your right where I am, just got block back from machine shop, sleeved all 4 cylinders. Crank, block, bearings &
pistons had no sign of wear. Haven't tried pistons yet. Don't look like he had to deck block much so maybe I'll be
lucky. My problem is getting main & thrust bearing, the big Ford go to place in Pa (I'm in Calif.) cant get them, he
contacted Ford, they're NLA, couldn't find another source. Talked to FelPro, they said FB-5122-M, order thru
NAPA. NAPA said NLA- it's the thrust thats a problem getting. You've probably got the same Ford Service Manual I
do, I can;t find anything on deck protrusion.

showcrop · Jul 14, 2023

I was in this situation although not Ford. The machine shop ordered everything for me including pistons. They insured that everything would go together, and saved me money over the usual parts outlets. They are doing this stuff everyday.

Welding man · Jul 14, 2023

Been There, Done that. We check piston protrusion on every engine we rebuild. If a block has been decked a couple of times, it is not
unusual for this to happen. Reconditioning rods will also change the protrusion somewhat. We have had to machine more than one set of
pistons to take care of the problem. Not a big issue.

Destroked 450 · Jul 14, 2023

(quoted from post at 22:47:41 07/13/23)
You've probably got the same Ford Service Manual I
do, I can;t find anything on deck protrusion.

It s listed in my manual in the Specifications section on pistons
Ford calls it (Piston Crown to Block Face)
4.4 bore non turbo .011 - .023 above
4.4 bore turbo .000 - .012 above

Ford 268 piston height issue!

dannyidp

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buickanddeere

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RBnSC

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caterpillar guy

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sander

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showcrop

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Welding man

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Destroked 450

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