Piston gaps for our forged pistons with article number beginning with the letter "K" (eg K8925-22)
To calculate which piston ring gap is recommended, calculate as the following example.
Standard and slightly tuned engine.
E.g. B20 0.030 "89.67mmØ drilling dimensions. (Mahle 3731-030)
89.67 x 0.0045 = 0.4035 = Approx. 0.40mm ring gap on the top piston ring.
89.67 x 0.0055 = 0.4931 = Approx. 0.50mm ring gap on the second ring.
Oil ring must be at least 0.10 mm larger on standard pistons.
Tuned engine and competition use.
E.g. B20 90mmØ drilling dimensions. (our forged piston K9000-22)
90 x 0.0055 = 0.495 = Approx. 0.50mm ring gap on the top piston ring.
90 x 0.0060 = 0.540 = Approx. 0.55mm ring gap on the second ring.
The oil ring must be at least 0.90 mm on these pistons.
The important thing is that the ring gap should be at least on the top ring, and then become larger on the next ring.
For a standard engine, multiply by 0.0045 on the top piston ring and on the second ring 0.0055.
And when tuning, you use 0.0055 and 0.0060.
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Piston ring gap according to Volvo's tables.
B4B
1st ring 0.25-0.50mm
2nd ring 0.25-0.50mm
Oil ring 0.25-0.50mm
B16
1st ring 0.25-0.50mm
2nd ring 0.25-0.50mm
Oil ring 0.25-0.50mm
B18
1st ring 0.25-0.50mm
2nd ring 0.25-0.50mm
Oil ring 0.25-0.50mm
B20
1st ring 0.40-0.55mm
2nd ring 0.35-0.45mm
Oil ring ring 0.25-0.45mm
B30
1st ring 0.40-0.55mm
2nd ring 0.40-0.55mm
Oil ring 0.40-0.55mm
B17 / B19 / B21 / B23
1st ring 0.35-0.65mm
2nd ring 0.35-0.55mm
Oil ring 0.25-0.60mm
B200
1st ring 0.30-0.50mm
2nd ring 0.30-0.55mm
Oil ring 0.25-0.50mm
B230
1st ring 0.30-0.55mm
2nd ring 0.30-0.55mm
Oil ring 0.30-0.60mm
B27 / B28
1st ring 0.40-0.58mm
2nd ring 0.40-0.58mm
Oil ring 0.38-1.43mm
To calculate which piston ring gap is recommended, calculate as the following example.
Standard and slightly tuned engine.
E.g. B20 0.030 "89.67mmØ drilling dimensions. (Mahle 3731-030)
89.67 x 0.0045 = 0.4035 = Approx. 0.40mm ring gap on the top piston ring.
89.67 x 0.0055 = 0.4931 = Approx. 0.50mm ring gap on the second ring.
Oil ring must be at least 0.10 mm larger on standard pistons.
Tuned engine and competition use.
E.g. B20 90mmØ drilling dimensions. (our forged piston K9000-22)
90 x 0.0055 = 0.495 = Approx. 0.50mm ring gap on the top piston ring.
90 x 0.0060 = 0.540 = Approx. 0.55mm ring gap on the second ring.
The oil ring must be at least 0.90 mm on these pistons.
The important thing is that the ring gap should be at least on the top ring, and then become larger on the next ring.
For a standard engine, multiply by 0.0045 on the top piston ring and on the second ring 0.0055.
And when tuning, you use 0.0055 and 0.0060.
------------------------------------------------------------------------------------------------------------------------------------------
Piston ring gap according to Volvo's tables.
B4B
1st ring 0.25-0.50mm
2nd ring 0.25-0.50mm
Oil ring 0.25-0.50mm
B16
1st ring 0.25-0.50mm
2nd ring 0.25-0.50mm
Oil ring 0.25-0.50mm
B18
1st ring 0.25-0.50mm
2nd ring 0.25-0.50mm
Oil ring 0.25-0.50mm
B20
1st ring 0.40-0.55mm
2nd ring 0.35-0.45mm
Oil ring ring 0.25-0.45mm
B30
1st ring 0.40-0.55mm
2nd ring 0.40-0.55mm
Oil ring 0.40-0.55mm
B17 / B19 / B21 / B23
1st ring 0.35-0.65mm
2nd ring 0.35-0.55mm
Oil ring 0.25-0.60mm
B200
1st ring 0.30-0.50mm
2nd ring 0.30-0.55mm
Oil ring 0.25-0.50mm
B230
1st ring 0.30-0.55mm
2nd ring 0.30-0.55mm
Oil ring 0.30-0.60mm
B27 / B28
1st ring 0.40-0.58mm
2nd ring 0.40-0.58mm
Oil ring 0.38-1.43mm