DutchManDann

Hey everyone,

So I was checking over my somewhat recently installed 2001 Windsor 4.6L just to make sure everything was still connected properly and such. I then noticed that there are numbers written near each cylinder on the engine block, underneath the intake manifold.

The numbers appear to be "-.020". I pondered what these numbers could mean, and the only thing I can think of is bore measurements.

The engine was rebuilt in november of 2002 by Ford, there is a plate on the side of the engine with all of the information. I contacted Ford and they confirmed that it was rebuilt by them but did not have any specifics on the rebuild.

Is it possible that my engine was bored out by Ford as part of the rebuild process?

cliffyk

Intuitively "bored out" would be +.020, however if Ford does not know what they indicate I shall not hazard a guess.

If they are overbore numbers, and in inches, then you can take pleasure in having a 4.65 L engine.

Then again they could be deck height indicators, if the block was milled then -.020" would be a likely number...

DutchManDann

Is there really any way I can check to confirm if the engine is overbored? and would there be any performance advantages/disadvantages to either?

cliffyk

None...

Another 0.0528 L (see below) is not going to any noticeable difference...

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0.020" = 0.02 * 25.4 = 0.508 mm;

the stock bore is 90.2 mm + 0.508 = 90.708 mm;

the area of the "overbored" cylinder is 90.708 ^ 2 * pi * 0.25 = 6462.2 mm²;

the volume of each cylinder = 6462.2 mm² * 90.0 mm (bore) = 581598.9 mm³ = 0.5816 L

0.5816 L * 8 cylinders = 4.6528 L; or some 1.0% larger than stock...

I.e. not enough to matter...
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There is no way to "check it" short of pulling the heads and measuring the bores. 0.020" is roughly the same as the thickness of six sheets of copy paper.

DutchManDann

Alright well in that case it doesn't seem to be worth my time. Thanks for the info. I guess the fact that it might be slightly bored out is pretty cool and will make me feel good about myself, even if it won't be any different than any other 4.6

cliffyk

I suspect they represent the amount milled off the block to level out the deck height. As that is a difficult value to measure (as opposed to cylinder bore), and is one that is important to track in engine rebuilding, it would make sense to record it on the block...

DutchManDann

If that was the case, would there be a possibility of there being different values at each cylinder? because I got a better look on the drivers side and found "-.030". I dont think they would bore out each cylinder a different amount either

cliffyk

If the block was milled it would be possible that the amount removed would differ from bank to bank--if before machining the deck was not perpendicular to the bores the amount removed at each cylinder might be different.

As you said it would be quite unusual for the bores to be different from bank to bank...