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Cylinder Sleeve
INTRODUCTION
Machining a cylinder block to accept a repair sleeve is an excellent way
to salvage an otherwise junk block. Most cylinder damage is in the form
of a crack, vertical scratches or dents and can be restored to normal
service by installing a sleeve.
PROCEDURE
Measure the sleeve top-middle-bottom, rotate the sleeve 90 degrees, and
measure again top-middle-bottom. The average measurement is the size of
the sleeve. This measurement is what is used to calculate press or interference
fit. Some minor sleeve distortion may have occurred during shipment, however
the sleeve will conform to the shape it is pressed into. A little trick
to aid in pressing in a sleeve is to refrigerate or freeze the sleeve
to shrink it slightly. So stick the sleeve into the freezer AFTER you
measure it.
Determine the amount of press needed for the application.
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Cylinder
Bore
|
Maximum
Press
|
| |
|
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2.00"
to 5-1/8"
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.003" |
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5-1/8"
to 6-1/2"
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.004" |
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6-1/2
to 8-1/2"
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.005 |
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The above figures
are for perfect to normal conditions, not for use in all applications. Please
keep in mind that the machinist's past experiences should also be considered.
There are numerous factors that will effect the amount of press that should
be used.
Some of these factors include but are not limited to:
- The location of the damage: crack or hole.
- A long crack or a large chunk missing will reduce press because the
damage will open under stress. Increase or decrease the amount of press
according to what will seal the damage. Pressure testing recommended.
- The material and strength integrity of the block (an air cooled aluminum
jug vs. a high nickel block and a lightweight design vs. a rigid type
block casting).
- If the remaining cylinders are going to be bored or not. (Remember,
the more press - the greater the distortion to the surrounding cylinders.
This distortion may not become round with just finish honing.
- Not using a step at the bottom of the cylinder means more press should
be used to help keep the sleeve from dropping.
Stop the boring tool 1/8" to 1/2" (depending on type of block,
piston travel, oil ring location, length of crack, etc.) from the bottom
of the cylinder to leave a step (ledge) for the sleeve to sit on. The cylinder
head will hold the sleeve from the top. When the block has been bored to
size to accept the sleeve, change the boring machine cutter to a pointed
tool. In order to square the step/ledge, set the tool about .010" (per
side) less than the block has been bored to. Lightly cut away some of the
chamfer until the cutter reaches the flat, or the top of the step/ledge.
This allows the sleeve to sit fully on the step/edge, not partially on the
chamfered edges.
Apply a sleeve retainer compound of your choice (optional if not repairing
a cracked block) to the outside diameter of the sleeve, then either press
or carefully drive the sleeve into the block. Make sure the sleeve is all
the way down and bottomed on the step/ledge. Trim the excess sleeve material
from the top of the block (with the bottom flat of the boring tool if there
is substantial material). Bore the sleeve to required inside diameter size.
With a long sharp file, remove any sleeve protrusion that would cause head
gasket problems, or deck the block with a mill. If you don't want to mill
the block you might try stoning the top deck of the block as a finishing
touch. I like to use a hard griddle stone or a soft knife sharpening stone.
Finally, chamfer the top inside diameter of the sleeve.
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