Glenn Posted June 11, 2006 Share Posted June 11, 2006 I've just helped my friend remove the engine from a scrap 2500S. He wants to rebuild it to fast road spec.Someone told him the "S" head was his best starting point. However I always thought the PI head gave better performance because of the higher compression ratio and bigger exhaust valves.I'd really appreciate any advice on his behalf. Cheers, Glenn. Link to comment Share on other sites More sharing options...
jonathan binnington Posted June 11, 2006 Share Posted June 11, 2006 glenn, suggest you arm yourselves with the run down of all the piston types, different valve sizes and combustion chamber volumes and make your decisions.bear in mind that all the 2.5 engines use the same basic castingj Link to comment Share on other sites More sharing options...
Deleted User Posted June 11, 2006 Share Posted June 11, 2006 2500 S head is best... need a 0.075" skim to give PI compression but inlet ports are far superior to a PI headSmall exhaust are better (seats less prone to cracking and room for a bigger inlet where all the power is to be made.Head number stamped above ports 1 and 2 should be 219016see here http://www.tr6.org/cylheads/index.html Link to comment Share on other sites More sharing options...
jonathan binnington Posted June 12, 2006 Share Posted June 12, 2006 ooh, that's interesting... Link to comment Share on other sites More sharing options...
Glenn Posted June 12, 2006 Author Share Posted June 12, 2006 Thanks Andy - that's superb information. I've printed the article for my friend. I'm now very jealous of his cylinder head!I've got a 2000 TC with a rumbling bottom end. The head is the 218225. I think this one was in the 125bhp PI. Any ideas how it flows? It's the 3.4" height.I've got the chance of a decent 2500 block. It would be very handy if I could use this head.Thanks again,Glenn Link to comment Share on other sites More sharing options...
Deleted User Posted June 13, 2006 Share Posted June 13, 2006 218225 is the so called "big valve PI head also fitted to 2000's with domed pistons.It is OK but prone to exhaust valve issues compared to the later heads... it will fit any 2.5 Link to comment Share on other sites More sharing options...
Glenn Posted June 14, 2006 Author Share Posted June 14, 2006 Cheers Andy. Once again that's really helpful.I think in the short term I'm going to go for a quick, easy and cheap fix to get my TC running sweetly again. Rather than get the crank ground on the 2000 engine (it's in a bad way) I'll fit the good PI block I've got lined up along with the existing 218225 TC head. With the HS6 carbs I'd be hoping for 120ish bhp perhaps?In the longer term for my "good" car I'll look out for a nice 219016 head to mate with its early PI block, have this skimmed down to 3.4", and perhaps indulge in a little cleaning up of the ports. Oh and save up for a 6 into 3 into 1.Incidentally the PI head I have is a 516816. I'm assuming it's pretty much the same as the 218225.All the best,Glenn Link to comment Share on other sites More sharing options...
Greeks Posted June 14, 2006 Share Posted June 14, 2006 According to http://www.triumphclub.co.nz/technical.html it's just the EGR hump and water slot that are different ... Link to comment Share on other sites More sharing options...
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