mk1-forum.net

Hello,

The last generation of Weslake 8-port heads was assembled together with an extra pipe to have a better cooling. Are there any detailed pictures about this pipe or is it still available anywhere?

Thank you very much.

The MK4 is the rarest of the Weslake heads. There are 1 or 2 about, but I have no detailed images.

Taken from the main site;

There were 4 versions of this Weslake head, these changes broke down as follows,

MK1 - As it came, ported etc

MK2 - As MK1, but with dry deck water outlet. Link pipe from block to head.

MK3 - As MK2, but with dry deck water outlet utilising Auxiliary radiator on OS inner wing.

MK4 - As MK3, but with extra piping to the head. Special tubing used, tapping in 3 places. (as per OBL 45F - Tour de France). - Over-heating problems finally sorted.

Only found two pictures from, I probably may not reproduce here, one from a circuit car with a Tecalemit-Jackson and the other one a 1275GT Works-Rally car with DCOEs. Both have this small tube.

The 1970 rallye clubman GT YMO 886J uses the MK IV layout as well. There was an article about that car in the october 2011 issue of Mini World but the picture of the engine bay doesn't show that many details of the MK IV layout.

Are there any difference in terms of the head itself between MK II and III?

Were the MK IV heads just tapped between the four inlet ports using this additional tube and some hoses? Or were there some internal changes as well?
What about the thermostat on a MK IV head?

By the way: there have been two spark plug thread sizes been used on Weslake heads - standard and something smaller. Does anybody know the reason?

Thanks
Regards Philipp

Here are the pictures of YMO 886J I took at Beaulieu in 2009, hope these help.

@ surfblue63, thank you very much ! In the meantime I spoke with Dean Daniel. He claimed that only the recast he intended, does have standard valve lengths, standard sparkplugs and different water ways to the early heads. He does not have any drawings from the MK4 specification but will send pictures. I may get the possibility to help an old head to run French hills. Therefore a reproduction of the MK4 specifications will help. But first we will do Chamrousse next week with our old Arden. The battle about the last place with a Porsche 911 2.0l, a Lotus Elan, an Alpine 1300 and an Alfa gtj demonstrates where all this is moving to. Maybe within three weeks we will see another mini in Turckheim. The only French one still running championship hillclimbs from time to time .

@surfblue63: thanks a lot for those pictures. That's helpfull.