Ikarus 280 and LiAZ 677: compression increased on both engines

Compression rose on both engines, the weakest cylinders caught up with the strongest, buses stayed in service. Russia · 2001. 8.3-40 %, 8.3-40 %.

Khabarovsk Municipal Passenger Motor Transport Enterprise No. 3 · measurements taken in the presence of the enterprise process engineer and diagnostic mechanic

Khabarovsk, Russia · treatment 9 Nov 2001 · repeat measurements 26 Nov and 6 Dec 2001

PRODUCTXADO technologyrestorative engine repair while the vehicle stays in service

UNITS IN THE SERIESTwo city busesIkarus 280, fleet No. 532 · LiAZ 677, fleet No. 609

DOCUMENT TYPEEnterprise technical reports
signed and stamped

Key results

↑8.3-40%

compression by cylinder, Ikarus 280, 25-27 → 28-30 kgf/cm²; gain in 13 of 14 measurements; the rest unchanged

↑8.3-40%

compression by cylinder, LiAZ 677, 5.0-6.0 → 6.0-7.0 kgf/cm²; gain in 13 of 14 measurements; the rest unchanged

VEHICLE	ENGINE	TREATMENT → REPEAT MEASUREMENT	WHAT WAS MEASURED
Ikarus 280 bus, fleet No. 532	Diesel, 6 cylinders, No. 101490218	9 Nov 2001 → 6 Dec 2001, mileage 2063 km	Compression in all cylinders
LiAZ 677 bus, fleet No. 609	8 cylinders	9 Nov 2001 → 26 Nov 2001, mileage 2987 km	Compression in all cylinders

Result for each vehicle

VEHICLE	ENGINE	COMPRESSION BEFORE, kgf/cm²	AFTER, kgf/cm²	GAIN BY CYLINDER
Ikarus 280, fleet No. 532	Diesel, 6 cylinders	25-27	28-30	+11-16 %
LiAZ 677, fleet No. 609	8 cylinders	5.0-6.0	6.0-7.0	+8-40 %

The absolute levels of the two engines are not comparable with each other: the gain in each cylinder is what should be compared.

Compression by cylinder — both engines

VEHICLE	CYLINDER	BEFORE, kgf/cm²	AFTER, kgf/cm²	CHANGE
Ikarus 280, fleet No. 532	1	26	29	+11.5 %
Ikarus 280, fleet No. 532	2	27	30	+11.1 %
Ikarus 280, fleet No. 532	3	25	29	+16.0 %
Ikarus 280, fleet No. 532	4	26	29	+11.5 %
Ikarus 280, fleet No. 532	5	25	28	+12.0 %
Ikarus 280, fleet No. 532	6	25	28	+12.0 %
LiAZ 677, fleet No. 609	1	6.0	6.5	+8.3 %
LiAZ 677, fleet No. 609	2	5.5	7.0	+27.3 %
LiAZ 677, fleet No. 609	3	5.0	7.0	+40.0 %
LiAZ 677, fleet No. 609	4	6.0	6.5	+8.3 %
LiAZ 677, fleet No. 609	5	5.0	7.0	+40.0 %
LiAZ 677, fleet No. 609	6	6.0	6.0	0 %
LiAZ 677, fleet No. 609	7	6.0	7.0	+16.7 %
LiAZ 677, fleet No. 609	8	6.0	7.0	+16.7 %

The more worn the cylinder, the larger the gain: in the LiAZ cylinders that started at 5.0 kgf/cm², compression rose by 40 %.

Conclusion for the series

Two buses of different classes were treated on the same day, 9 November 2001, and came back for measurement after ordinary service runs — 2063 and 2987 km. On the Ikarus 280 diesel, compression rose in all six cylinders: 25-27 → 28-30 kgf/cm². On the eight-cylinder LiAZ 677 engine the whole range moved up, 5.0-6.0 → 6.0-7.0 kgf/cm²: the weakest cylinder reached the level that had been the engine's best before treatment. The gain followed the wear — where compression was lower, the gain was larger: the revitalizant builds up the coating where metal is missing. Compression cannot rise above the factory nominal, so bringing the lagging cylinders up to the common level is the maximum achievable. The result repeated on two different engines, without taking the vehicles out of service.

The results apply to the Ikarus 280 and LiAZ 677 bus engines in city service at KhMPATP No. 3, Khabarovsk; on other equipment and under other duty cycles the figures may differ. The originals of both technical reports, signed and stamped, are published in full and available for download.

Current equivalent

Revitalizant gel for diesel enginesDiesel engines
Revitalizant gel for petrol enginesPetrol engines
Revitalizant gel for cylinder restorationEngine cylinders, deep wear

How such units are treated: Diesel engine Petrol engine Cylinder-piston group

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