4 replies to this topic

[jonb_5]

Hi,

Im completely some training at work and as a side project I am going to be machining a cylinder head for my mini, with ported and polished head etc.

Its is going to be done on a CNC machine so i need to model the head and write the program.

I was wondering if anyone has any experience of this, I am starting to model the head in Mastercam X, but as i dont have a head i was wondering if anyone might have any component drawings etc to give me a start.

Cheers

Jon

[THE ANORAK]

to be honest, i think you need to get a cylinder head first, unless your planning to machine the whole head from a solid block ????

unless i'm very much mistaken, just about all heads are machined castings.

anyway, good luck and i look forward to hearing how it comes out.


PS: you should try writing the program free hand, using a PC is cheating

[998dave]

Doing the outside shape wouldn't be that hard, I'd be more worried about how your going to get the water jacket in there, this is why they're normally cast! unless you're going to drill the jacket and have core plugs everywhere?

[jonb_5]

The idea is not to machine the head, what we are going to be machining is the modifications, i.e opening up the inlet/oulet holes etc, skimming the head. Normally this is all done by hand but its a little project work have come up with to help me learn all aspects.

Firstly I need to model the head, and then i can modify it with enlarging the the valve holes etc and then write a program to do this on the cnc machine.

Its something i think would be quite a good idea as most of it that i know of is done by hand, once we had the program it wouldnt be very hard to machine many heads on the cnc machine and they would all be exactly the same. Going to go for a full race spec because of the greater accuracy i can achieve from not doing it by hand.

Thanks

Jon

[998dave]

Aaah, now that is interesting.

You wouldn't need the full shape of the head then, just a locating jig, probably using the head stud holes, and treate the outside of the head as an oblong. Then using a reference machine valve seats and combustion chambers.

If you got it just right you would know how much you've removed, and how much to skim to get the comperession ratio you want.

I've not got the time to model a head but I'd measure it's maximum length, width and height, and then model it as a solid block, based around the mating surfaces. Then use good references, (I'm sure there's already some that BL used), and make the mods.

Edit: What you should do is get Vizards Book and start with the machining work he suggests, should get good results very quickly.


Dave

Edited by 998dave, 29 October 2008 - 03:50 PM.