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Piston Fitting Guide for Mechanics

1. When removing pistons from an engine, mark the installation direction and position of parts. Remove carbon from the cylinder and pistons to avoid damage. Loosen connections in the manufacturer's specified order and remove the piston and connecting rod. 2. Before fitting used parts, check each part's dimensions and test for damage. Inspect ring grooves, connecting rods, cylinders, cooling nozzles, and pins. Verify piston and cylinder diameters allow for the specified clearance. 3. When fitting pistons, note installation markings. Clean and lubricate parts thoroughly. Use new circlips and install piston rings as specified. Insert pistons into cylinders using a clamping band and push them in carefully to avoid damaging

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110 views1 page

Piston Fitting Guide for Mechanics

1. When removing pistons from an engine, mark the installation direction and position of parts. Remove carbon from the cylinder and pistons to avoid damage. Loosen connections in the manufacturer's specified order and remove the piston and connecting rod. 2. Before fitting used parts, check each part's dimensions and test for damage. Inspect ring grooves, connecting rods, cylinders, cooling nozzles, and pins. Verify piston and cylinder diameters allow for the specified clearance. 3. When fitting pistons, note installation markings. Clean and lubricate parts thoroughly. Use new circlips and install piston rings as specified. Insert pistons into cylinders using a clamping band and push them in carefully to avoid damaging

Uploaded by

lossonfire
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as PDF, TXT or read online on Scribd
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PISTON FITTING

1. REMOVAL
Mark the installation direction and position of the pistons, conrod caps, etc.
✔
✔
Remove cooling oil nozzles, if present, to avoid damaging them when fit-
✔
Ctingarefully
or removing the pistons.
remove oil carbon from the cylinder to avoid damaging the piston

✔
during disassembly.
Loosen the screw connections in the order indicated in the manufacturer
specifications.
✔
✔
RRemove the piston and conrod from the cylinder.
emove the piston pin and disconnect the conrod from the piston—see
the “CONROD FITTING” poster for details.

2. TESTING
✔
Before used parts are fitted, the dimensional accuracy of each individual
part must be checked.
✔
CCarefully remove oil carbon and other residue from the ring grooves.
✔
Check the conrod for damage and distortion.
✔
Check the cylinder surfaces for damage and wear.
✔
Forhecknewthepistons,
cooling oil nozzles for damage and proper flow.
✔
Before fitting, verifytheand
pin should also always be replaced.
✔
✔
The diameter of the cylinder compare the diameter of the new piston.
is equal to the diameter indicated on the
piston crown plus the fitting clearance. Example:
piston diameter (76.475 mm) + fitting clearance (0.035 mm) = cylinder

diameter (76.510 mm)
✔ Caution: for pistons with a coated piston skirt, the measured piston diame-
ter is 0.04 mm larger. This amount must be subtracted from the calculation.

3. FITTING
Note the installation markings prior to assembly.
✔
Thoroughly clean all parts and lubricate generously.
✔
Use only new circlips—see details on the “CONROD FITTING” poster.
✔
✔
Fit the piston rings as specified—see details on the “PISTON RING
FITTING” poster.
✔
✔
UCarefully
se a clamping band to insert the piston into the cylinder.
push the oiled pistons into the cylinder—the piston rings must
slide into the bore without resistance. Take care not to damage them in the

process.

✔ Fit the cooling oil nozzles.
✔ Tighten the connecting rod bolts in the order indicated in the manufacturer


specification.

✔ Anti-fatigue bolts must always be replaced.


✔ On diesel engines, also check the piston protrusion.
✔ When using hard-anodised (elox) pistons, ensure that the piston crown
does not break off under any circumstances. These pistons can be identi-
fied by the black coating on the crown.

www.mahle-aftermarket.com

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