Checking the valve guides (Mazda Familia BG)

When repairing a cylinder head with leaky valves, it is not enough to just treat the valves and seat chamfers. It is extremely important to check the valve guides for wear. This check is especially important on engines with high mileage. Worn guides do not ensure the valves are in a central position and lead to high oil consumption. If the wear is too great, the valve guides must be replaced.

1. Remove the valve.

2. Clean the valve guide with a cylindrical brush or cleaner.



3. Measure the inner diameter of the valve guide in 6 places.



4. Measure the valve stem diameter in 6 places with a micrometer.

5. To determine the average value, add the results of six measurements and divide by 6.

[Original version of the article on the website: MazBook.ru]

Engine designation	average size in mm
	Valve stem		valve guide
	inlet	outlet
F	8,985¹	7,975¹	9,185/8,1752
VZ, V6, VRE	5,970 — 5,985	5,965 — 5,980	6,01 — 6,03
VZE, B5, B6E	6,970 — 6,985	6,965 — 6,980	7,01 — 7,03
PN	6,970 — 6,985	6,950 — 6,965	7,017 — 7,037

1 - minimum size.
2 - the highest value for inlet/outlet.

6. Subtract the average diameter of the valve stem from the average diameter of the valve guide. This determines the maximum radial clearance. Maximum radial clearance: 0.20 mm (diesel 0.10 mm).

7. If the values are exceeded, the valve guides should be replaced (is done in the workshop) or valves.