Oil leak between cyl hd and block

[samuel]

Good point Kirsty.

Will drop Ian a line.

Fantastic that the problem wasn't more serious though. Faith has been restored.

Keep well.

Cheers

Tim

[missfixit70]

I bet you were well chuffed it was a relatively simple fix, there's always that lingering paranoia when you've done any major work

[samuel]

Oh Yes

[aitch]

Well done on the fix Tim and thanks for the info..

[samuel]

Thanks Aitch. Your tip was very useful

[missfixit70]

I wonder if this explains why most bongos seem to have a slight rocker cover leak? Keep us informed on how clean (or not) yours stays Tim.

[samuel]

Will do. Off for a good run tomorrow. Will check gasket on return and report back to base. Its an interesting scenario ...

[missfixit70]

Will do. Off for a good run tomorrow. Will check gasket on return and report back to base. Its an interesting scenario ...

Your evening must be as exciting as mine

[samuel]

Following on from yesterday. Have inspected the old cylinder head and noted that it has counterbores on the cylinder head for accepting the steel bushes which come with the rocker cover securing screws. The new aftermarket cylinder head doesn't have these counterbores which means my steel bushes were too long, hence my problem. I have therefore produced the following which might be of help to members:


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.

[Ian]

Excellent. Will add to the Head Gasket fact sheet, and also will supply when we send out bolt sets.

Well done Captain!

[samuel]

Thanks Ian. What a quick reply too!!!

[missfixit70]

Excellent bit of follow up detective work Tim

[dandywarhol]

Ditto the detective work - whats concerning me is what other shortcuts have been made on these copy heads

Having seen first hand the shoddy workmanship on Chinese copies, I'd be very wary of what I'd buy to replace the original head.....................

Are there any engine builders on the forum who could advise on good and bad?

[mikeonb4c]

Cor, this is the kind of stuff I like to read on here. Well done Tim (and Ian for following up on it)

[samuel]

Just to confirm my theory. Have just come back from an 80 mile round trip and the joint is as dry as a bone. What a relief. Can now start cleaning the oil spills on our drive!!

Hopefully other will now benefit from this particular finding.