Page 2 of 2
Re: 4G93p Porting Progress
Posted: February 12th, 2011, 5:18 pm
by Guy Croft
Looks like the diligent application of some good engineering principles, Iain, well done indeed! A marvellous no-nonsense thread, this one.
Hope the cam does 'the business'.
G
Re: 4G93p Porting Progress
Posted: February 18th, 2011, 7:45 pm
by PersonaGrata
Much appreciated Guy thanks
If you don't mind I've got some more pictures that are worth posting for this job....
Shaved guides on the scrap head. The big plus point of shaved guides for me is that the machining of the ports is much easier and can be performed with the guides in place. Good for low cost development.
- 05122010327 (1).jpg (60.32 KiB) Viewed 3907 times
Combustion Chamber - completely unworked. Smoothing the recess pockets make no difference what so ever to the flow figures and reduce compression ratio. Therefore its completely pointless on this head.
- 30122010380 (1).jpg (110.99 KiB) Viewed 3907 times
Typical inlet port on the head that was actually bolted to the engine. Valve guides re-profiled versus shaved. This is the best in terms of flow for the guide but hard work and manual, and it makes it much harder to machine the ports through the SSR.
- 30122010384.jpg (73.17 KiB) Viewed 3907 times
Re: 4G93p Porting Progress
Posted: February 19th, 2011, 10:11 am
by Guy Croft
Irrespective of valve-in flow and behaviour around the valve during inlet and ex event - don't overlook the influence of cc shape on burn. I take the view that any intrusion (particularly a sharp edge) into the flame front is going to reduce efficiency; I would definitely trade CR in favour of that (that is my exp anyway) and get on and do some nice blending there.
GC