alan57 Posted May 31, 2016 Report Share Posted May 31, 2016 Does anyone have, or know of, a Triumph 2500S cylinder head, casting number 219016, for sale? Must be good condition, and completely unmolested/unmodified. Quote Link to post Share on other sites
Keith Warren Posted June 7, 2016 Report Share Posted June 7, 2016 Alan I fitted one of those 2.5S head, changed it from the standard CP Head and got 7 less BHP on the rolling road, so if I had known I would have left alone. Keith Quote Link to post Share on other sites
Mark69 Posted June 7, 2016 Report Share Posted June 7, 2016 Alan Chris witor ,one on his web site. Mark Quote Link to post Share on other sites
ray gill Posted June 9, 2016 Report Share Posted June 9, 2016 Nice to meet you alan. Please that Raymond could help you. Helen Quote Link to post Share on other sites
ncoll Posted June 13, 2016 Report Share Posted June 13, 2016 Alan I fitted one of those 2.5S head, changed it from the standard CP Head and got 7 less BHP on the rolling road, so if I had known I would have left alone. Keith I don't know too much about these engines, but didn't the 2.5S engine have domed pistons and the CP engine had flat top pistons running a few thou down the bore. If you didn't machine any off the face of the 2.5S head you will have a low compression ratio, this could be the reason you are a few brake horse power down. ncoll Quote Link to post Share on other sites
Stevecross Posted June 14, 2016 Report Share Posted June 14, 2016 I have Mk 2 2000 head tucked away. Steve Quote Link to post Share on other sites
alan57 Posted June 14, 2016 Author Report Share Posted June 14, 2016 Alan I fitted one of those 2.5S head, changed it from the standard CP Head and got 7 less BHP on the rolling road, so if I had known I would have left alone. Keith Fret ye not! It won't be staying standard for long!!!!! Quote Link to post Share on other sites
littleone Posted June 15, 2016 Report Share Posted June 15, 2016 Are these 2.5s heads with that casting number particularly good for tuning or do you have a specific purpose ? Paul. Quote Link to post Share on other sites
harrytr5 Posted June 15, 2016 Report Share Posted June 15, 2016 According to Chris Witor these are the best flowing heads. If I remember correctly you have to machine 70 thou off the head to suit a TR5/6 engine. Regards Harry Quote Link to post Share on other sites
Nick Jones Posted June 16, 2016 Report Share Posted June 16, 2016 That part number head has a different profile in the valve throat immediately behind the valve from any other and according to some gives the best flow of any standard Triumph 6 cylinder head. It also has a smaller exhaust valve (as do a couple of other numbers) and a deeper combustion chamber giving a lower compression ratio. Just bolting one straight on will likely give lower power due to the lower CR. A skimmed one might produce a bit more than a typical TR5/6 one though the exhaust valve size won't help. I'd think that some basic port tidying on the original head along with some 3 angle valve seats would give better results. http://sideways-technologies.co.uk/forums/index.php/topic/690-diy-heads/ http://sideways-technologies.co.uk/forums/index.php/topic/6080-nicks-diy-head/ Nick Quote Link to post Share on other sites
Dave McDonald Posted June 16, 2016 Report Share Posted June 16, 2016 Alan Good recent result at Silverstone. You have a PM. Dave McD Quote Link to post Share on other sites
Keith Warren Posted June 17, 2016 Report Share Posted June 17, 2016 Yes I had the head machined down to what it should be I got the head from Chris Witor modified with Valves and guides, may put it back on the CP head at some point but having Emerald ECU will need setting up again. Keith Quote Link to post Share on other sites
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