Buying a cylinder head - what to check.

Technical questions and answers about the Mazda Bongo

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Buying a cylinder head - what to check.

Post by Doone » Tue Mar 27, 2012 4:23 pm

When a new cylinder head is supplied as 'fully dressed' or 'ready to fit', do not assume that it is ready to fit.
It is advisable to check it first.
The following suggestions are intended as general guidance only, to alert you to some of the checks that may be needed.

Once unpacked, check for hidden packaging debris.
Check the head face for scratches, nicks or damage.
The head face should be clean and free from grease.
It is likely that valves and collets will already be fitted. But you should check to ensure the collets have been fitted correctly.
New studs should be used.
Check cam caps are tight.
Check all fitted items are correctly torqued, including the rocker cups.
Check valve/tappet clearances.
Check the camshaft oil seal is in place.
Fit injector heat shields.
Ensure the oil gallery plug is tight.
Ensure the dowel pin is perfectly aligned and fitted correctly.
If the head is supplied with a seal kit, you may not need all the seals - check with the supplier.

Some parts are often transferred from the old head.
But it is recommended that a new fan switch is fitted. This is especially important if the previous head has overheated, as this can damage the switch.
A 3 branch water pipe should be fitted. If a new one is needed, the Mazda part number is: WL02-10-2EO, see below:
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Remember, unless you are doing the job yourself, it is safer, if not cheaper, to get the workshop to supply and fit the parts. If anything should go wrong afterwards, you only have one place to seek recompense or repair.

The torque settings and sequences are in the Mazda manual, available from Ian on THIS LINK.

For more information on cylinder heads, please see the members area ON THIS LINK.
My Trading Standards Approved garage: http://www.allansvehicleservices.co.uk