Joined: Apr 2018 Posts: 507 Threads: 129
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Location: Staffordshire
Car type: Ruby mk 2
Hello
My friend who regularly run his mk1 ruby is considering a head “upgrade “ from the standard one fitted.
He has heard of machining the face NON PARALLEL to set the head at an angle to the block.
This sounds strange to me.
Comments please
Regards
Tim
Joined: Aug 2017 Posts: 2,400 Threads: 33
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Location: Deepest Frogland 30960
Car type: 1933 RP Standard Saloon
"Wedging" the earlier low compression head by surface grinding is/was a way of increasing the compression ratio without resorting to the late 37 head or similar such as Alta , Ricardo and others. The holes for the head studs require easing to allow for the angle. In some respects the wedging of an earlier head is better than the late 37 design as the plug location remains central to the bore. Metal is removed from the side of the head furthest away from the valves until close to the plug hole, maintaining a flat surface across the head. Hope that makes sense.
Joined: Jan 2019 Posts: 1,565 Threads: 20
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Location: Bala North Wales
Car type: 1933 RP Standard Saloon
Robert Foreman (of this forum) carries out such head modifications.
Joined: Aug 2017 Posts: 919 Threads: 18
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Location: North Yorkshire
The best thing to do would be to get a Ricardo aluminium head from Dave Dye. It will fit straight on, will not strain the head studs and has an integral water outlet, so less joints in the plumbing system. I have used planed low compression heads but they all tend to be different and the shape of the combustion chamber varies accordingly, some are thin castings and can break through during the machining. I don't know about you but I would rather not have the grief!
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Whatever choice he makes, I'm a firm believer in Bill Williams' advice to limit compression ratio for a road car to 6.5 or so. Unless of course you have a bottom end uprated to suit...
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I would also suggest that if you are proposing to 'pep up' an unknown standard engine, with a low comp head, keep to 18mm plugs. Many are the people who have fitted a late Ruby head to an unknown engine only to find that it runs as rough as a badgers bottom due to the 14mm plugs oiling up. Another reason to go with the Ricardo head, you can order it with the 18mm plugs and Dave will do it to a sensible compression ratio.
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I have machined many heads by wedging them. The stud holes do not need easing and the head will drop straight on. For me it is far easier to turn them in the lathe.
It is certainly less expensive to wedge a head than buying a new one.
Joined: Apr 2018 Posts: 507 Threads: 129
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Location: Staffordshire
Car type: Ruby mk 2
Many thanks Gents for all the information.
Regards
Tim
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