UAZ-3962 and VAZ-21093: compression up, cylinders evened out — no teardown

Compression rose in every cylinder of both engines, the weakest cylinders recovered, the engines evened out. Russia · 2003. 25-65.3 %.

Seid-Transavto LLC · reports approved by General Director R. S. Kuznetsov, signed by Chief Mechanic P. V. Balukhtin and by I. V. Pavlov, Director of Arktik-Avto LLC

Russia · both reports dated 10.10.2003

PRODUCTXADO revitalizant gelfor petrol engines · added without dismantling the unit

TEST OBJECTPetrol engines of two vehiclesUAZ-3962, plate No. E 294 VR 51 · VAZ-21093, plate No. E 935 VR 51

DOCUMENT TYPETwo company reports
with signatures and seals

What repeated on both engines

compression evened out across the cylinders

↑25-65.3%

compression per cylinder, 4.9-5.4 → 8.1-8.2 on the UAZ and 8-10 → 12-12.5 on the VAZ

VEHICLE	CONDITION AT START	WHAT WAS MEASURED	REPORT DATE
UAZ-3962<br/>plate No. E 294 VR 51	built 1994, 9 years in service	Compression in each of the four cylinders before and after treatment	10.10.2003
VAZ-21093<br/>plate No. E 935 VR 51	built 2000, about 3 years in service	Compression in each of the four cylinders before and after treatment	10.10.2003

Compression per cylinder — both engines

VEHICLE	CYLINDER	BEFORE	AFTER	CHANGE
UAZ-3962, E 294 VR 51	No. 1	5	8.2	+64 %
UAZ-3962, E 294 VR 51	No. 2	5.1	8.2	+61 %
UAZ-3962, E 294 VR 51	No. 3	5.4	8.2	+52 %
UAZ-3962, E 294 VR 51	No. 4	4.9	8.1	+65 %
VAZ-21093, E 935 VR 51	No. 1	9.5	12	+26 %
VAZ-21093, E 935 VR 51	No. 2	10	12.5	+25 %
VAZ-21093, E 935 VR 51	No. 3	10	12.5	+25 %
VAZ-21093, E 935 VR 51	No. 4	8	12	+50 %

Compression is given exactly as recorded in the reports: the documents do not name the unit of measurement, so the change is expressed as a percentage.

Cylinder evening-out — both engines

VEHICLE	COMPRESSION BEFORE	COMPRESSION AFTER	SPREAD BETWEEN CYLINDERS
UAZ-3962, E 294 VR 51	4.9-5.4	8.1-8.2	0.5 → 0.1
VAZ-21093, E 935 VR 51	8-10	12-12.5	2.0 → 0.5

The spread is the difference between the strongest and the weakest cylinder. The weakest cylinders gained the most: 4.9 → 8.1 and 8 → 12.

Conclusion from the two reports

Compression rose in every one of the eight cylinders of both vehicles, and most of all in the weakest ones: 4.9 → 8.1 on the UAZ-3962 and 8 → 12 on the VAZ-21093. Compression physically cannot rise above the manufacturer's rated value, so all cylinders reaching one and the same figure means restored sealing of the cylinder-piston group — the maximum attainable, not a random gain. The spread between cylinders shrank from 2.0 to 0.5 and from 0.5 to 0.1: the engine begins to run evenly. Both reports record the same findings: "engine vibration decreased, pulling power and throttle response improved, oil pressure and idle speed increased", "Fuel consumption decreased". These assessments are stated in words in the reports; compression is the figure that was recorded numerically.

The results relate to the four-cylinder petrol engines of UAZ-3962 and VAZ-21093 vehicles in a fleet's regular service; on other equipment and under other conditions the figures may differ. The originals of both reports, with signatures and seals, are published in full and available for download.

Current equivalent

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

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

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