What is considered as a minimum safe final wall thickness after boring? I'm guessing that would also vary between major and minor thrust sides.

I’ve refrained from using ceramic coatings on the street engines simply due to the hours or cycle times in which the coatings are good for. If those coatings start to peel or lose their adhesion properties after an extended period of time, then that debris will damage the cylinder walls and rings.

Lorena, Texas (South of Waco)

Sleeves properly installed should pose no problem but as mentioned, the cost is prohibitive when attempting to do all eight cylinders. Not all machine shops are capable of properly installing sleeves so be cautious when getting that operation performed. Using used pistons is fine as long as they are in ‘like new’ condition but unless they are low mileage, that will likely not be the case. The money that is spent to sleeve eight cylinders in a block to use a set of old pistons is much better spent on a set of custom pistons that are sized to fit the next oversize of bore or ring sizing availability. And with custom pistons comes the ability to use a more modern piston ring design which helps with both the power and efficiency of the engine.

Lorena, Texas (South of Waco)

The accepted minimum cylinder wall thickness is 0.100”. Boosted or high horsepower applications will typically require more than this.

Lorena, Texas (South of Waco)

Others will probably know more about this than me.

I recall reading an article on the internet quite some time ago about trying to get max cubes out of Yblock for a dyno shoot out. The engine was sleeved on all eight cylinders and I think they had problems with water getting into the oil. After tearing the engine down it was discovered that the block had twisted through lack of rigidity after being sleeved on all eight.

Would that only be an issue when trying to produce maximum power?

Ian, i think that was the 4" engine ? TED ? In normal sleeve installation and fitted correctly as Ted points out, that would be unlikely. its when reaching for the stars that you push the boundaries.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

Ted: the reason for my original query was not to suggest re-fitting used pistons. In as much as the alloy cylinder block project seems to be still born, what is possible to achieve with 8 high quality sleeves in a factory 272 or 292 block? Combined with a small diameter, offset ground crankshaft, can a reliable "big inch motor" be built for the street and occasional quarter mile laps?

Exactly what I was thinking, that was the question on my mind as well.

Ian YES !, i think that was the 4" engine ? TED ? In normal sleeve installation and fitted correctly as Ted points out, that would be unlikely. its when reaching for the stars that you push the boundaries.                            In normal sleeving situaton there is still original block walls to support sleeevs, but critical thing is when trying to bore block out for largest diameter bore/sleeve size, then the deck isnt attached to the walls strongly, thus big load as you mention causes leaks at sleeve and deck area, this is in the case of more than normal boresizes wanted. I think TED and TIM have tried it, i havent fired mine up yet. My memories fadeing but i know TED is full book on it.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

As Bill brings up, simply boring the block for big bore sleeves destroys the built in support between the decks and the main webbing. To simply sleeve the block for the sake of sleeving gains you nothing in cylinder wall wear or block integrity. In the grand scheme of things, any installed sleeve in an iron block actually weakens the block integrity to some degree as the original cylinder wall thickness is compromised.

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Sleeves for the Ford Y-Block engines are reserved simply for those cylinders that need repairing due to some kind of damage. If the original cylinder wall is severely damaged to the point where the ring wearing surface is exposed to coolant (cracks, holes, etc), then even a sleeve may not be an adequate repair due to the head gasket design on the Y engines. Most engines have a round sealing ring on the head gasket that can catch the top of a sleeve for sealing purposes but the unique design of the Y combustion chamber requires the use of a head gasket that does not fully seat on the edge of the bore. If there’s a chance for coolant seepage between the sleeve and the original cylinder wall, it typically happens because the head gasket is sealing on the deck and not the edge of the bore.

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It was my 4” bore engine that was sleeved in such a manner that the original cylinder walls were removed to accommodate the thick wall sleeve installation. While the engine made a tremendous amount of power, the block did take a twist early on which allowed coolant seepage between the decks and the installed sleeves. Furnace brazing the block may have helped with this but that operation is not available in my part of the country.

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On a lesser horsepower engine, this problem would have still occurred but simply would have taken longer for it to take place. An example I have is a 347” Y here that was fully sleeved and it did manage to run for awhile before coolant seepage came to the forefront. In examining the water jackets on that engine, some of the sleeves did break through the original cylinder walls which reduces the block strength and also gives the coolant a path to the top of the deck when conditions are right. That engine will be put together again as a smaller bore engine without sleeves.

Lorena, Texas (South of Waco)