Cross Flow Head

[anonymous-user]

I am looking to build a spare 1600 cross flow from bits I have around, I will bore the block +20 so cc will be 1619, I have a good head with huge valves but is a 'semi hemi' head with a small combustion chamber with a capacity of 20cc, I can't find a piston to use with this head, if I use a 1300 piston then the chamber in the piston is 36cc so add the 20 and the CR will be 7;1, (1600cc piston has a chamber around 44cc so even lower) I also have some flat top Lotus Twin Cam pistons but if I use them I'll have a CR of 20;1. Does any one have experience of these heads and what pistons they use.

[spitfire4v8]

Back in the day I had a dutton with a 1600 xflow .. it had a semi chambered head. The engine was from Burtons .. so presumably they would know what pistons ?

[DVandrews]

20cc seems like a lot for the diddy shallow chambers on a xflow head, have you buretted it. Have you allowed for the gasket volume?

Dave

[anonymous-user]

Dave, its not an early head, its been machined, I was given it so don't know the source, I've got pictures of the early ford head, and the chambers on my head are different, no I've not allowed for the gasket in my calcs, but the area of the piston is 52sg cm so 4mm gasket would add 20cc, and give a compression ration of around 11 with 16
00cc.
I am looking to try to build this engine 'cheap' so don't want to buy expensive flag top pistons, I was hoping to use the lotus one's I have spare, but they appear to be around 4mm short, I was thinking of decking the block to match. But all I want is a spare engine for my caterham, so if I have to spend money I may as well keep all the bits as is as spares and no try to assemble an engine.

[Sardonicus]

I would deck the block and fit the Lotus pistons personally after CCing and getting your calcs the X Flow really spins up well with the lighter non Heron/heavy pistons fitted however I made good HP back in the day running those heavy 1.3 GT pistons on a 90 over block running severe CR but eventually succumbing to detonation melt down after nearly 30k and a failed dizzy advance stop the rebuild with much lighter decked Lotus TC pistons was a whole new ball game inc my machining costs on the more uprated build

Edited by Sardonicus on Sunday 9th February 21:38