After market cylinder head to rocker cover issue

[samuel]

The following was produced having suffered excessive oil losses from my rocker cover gasket having replaced the original cylinder head with an after market cylinder head following an overheat. I hope some of you find this interesting and hopefully proves a cure for a similar problem you have. The club has been made aware of this problem which is beyond their control of course.

IMPORTANT NOTE REGARDING THE LENGTH OF THE ROCKER COVER SECURING SCREW STEEL BUSHES
Please note that original factory fit cylinder heads on 2.5 TD Mazda Bongo's and Ford Freda's were machined with small counterbores on the top of the cylinder head to accept steel bushes which come as part of the rocker cover fastening arrangement, i.e. bolt, cap, rubber bush and steel bush. As such the steel bushes supplied by the club should fit without any issues to original to factory fitted cylinder heads.

However it has now come to our notice that some after market cylinder heads are not machined in the same way as the original heads and as such do not have counterbore's. Instead they are flush. The result of this omission is that the steel bushes will now sit higher from the cylinder head than normal preventing the installer from screwing down tight enough to get a proper seal on the gasket between the rocker cover and cylinder head. This could result in an oil leak from the rocker cover gasket.

It might therefore be necessary to remove 3-4 mm from the length of each steel bush in order to allow for the omitted counterbore.

NB The steel bushes are quite soft and can be reduced in length easily and quickly by the use of a junior hacksaw and vice. Take care not to squash the bushes as the screws (bolts) are a good fit. If you do squash them a pair of pliers are all that is required to form them round again.

I have now overcome the leak by shortening the steel bushes as above and now have a prefectly clean and dry engine. Phew!

[Doone]

'Steel bushes' are also known as 'spacers'.
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