mark ogram Posted July 10, 2004 Share Posted July 10, 2004 I recently bought a big valve, semi chambered head (e-bay £10) I did not know whether I would use it, but having just cleaned it up, I am amazed at the quality of the porting/polishing work that has been done - this head has cost someone a lot of money to have worked, hence, I now want to use it to upgrade my current 1600 (AX bock) engine. Thoughts, past experience, would be very welcome - Roger King, are you out there ?. Many thanks Mark. Link to comment Share on other sites More sharing options...
mark ogram Posted July 11, 2004 Author Share Posted July 11, 2004 Link to comment Share on other sites More sharing options...
greg Posted July 11, 2004 Share Posted July 11, 2004 You probably already have a flat head an pistons to suit - going to a chambered head would probably mean new pistons to keep the Compression ration up (as the chambered head has a larger "hole" than the non chambered head. What head does your car currently have? Link to comment Share on other sites More sharing options...
mark ogram Posted July 11, 2004 Author Share Posted July 11, 2004 Currently have flat head, I know I will have to change the pistons - I have a set of Cosworth forged pistons for Lotus twin cam (8 valve) - have been told that I would be able to use these. Link to comment Share on other sites More sharing options...
greg Posted July 11, 2004 Share Posted July 11, 2004 ok. You will probably need to measure the Chamber to work out a decent Compression ratio. Also are you going to change the Cam and springs? Link to comment Share on other sites More sharing options...
mark ogram Posted July 11, 2004 Author Share Posted July 11, 2004 Yes, the camshaft and valve springs will be changed - the target is to try and achieve around 140 HP, do not know whether this is achievable with a chambered head though. Link to comment Share on other sites More sharing options...
Area Representative Paul Richards Posted July 11, 2004 Area Representative Share Posted July 11, 2004 Yes 140 bhp + is possible with a chambered head. This method used to be the favoured route for tuning F2 stockcars in the old days when crossflows were used. I seem to recall flat top pistons were lighter and allowed higher rpm. There was talk of engines producing 140 + bhp and they were limited to 1300cc!! Paul Richards Joint AO - L.A.D.S. (Lancashire and District Sevens) Growing old is compulsory - Growing up is optional Link to comment Share on other sites More sharing options...
mark ogram Posted July 11, 2004 Author Share Posted July 11, 2004 Thanks guys, I work at Cosworth, so can get advise on chamber volumes/comp ratios etc - the pists I have are 85mm, I am led to belive that will give me 1760cc. Link to comment Share on other sites More sharing options...
Peter T Posted July 11, 2004 Share Posted July 11, 2004 Assuming that your rods are 5.23 ", and your stroke is 77.62mm yes. Support the 7 Society...... Ehhh? Link to comment Share on other sites More sharing options...
mark ogram Posted July 11, 2004 Author Share Posted July 11, 2004 Rods will be Cosworth 5.23 inch - at this point I do not know the stroke of the crank fitted in my 1600 sprint engine, any ideas ?. Link to comment Share on other sites More sharing options...
Peter T Posted July 11, 2004 Share Posted July 11, 2004 If it is standard it will be 77.62. Support the 7 Society...... Ehhh? Link to comment Share on other sites More sharing options...
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