13th Jul 09 at 20:52

red tops are heavy, and boring

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Originally posted by mobby

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You dont speak much of yours, id like more info please

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i do when asked
the main problem with the 1800 is piston selection, there arent any off the shelf omegas like there are for the 1600, so you have to look at other options if you want high comp
i ended up buying some pistons from steve at SBD which were originally made for his 1700 short stroke c16xe(240 bhp, 148 lb/ft) he had 5 spare and they relly are nice bits of kit, 82mm 2 ring beam type slippers which are the same design as ducatis WSB pistons and pretty similar to current F1 pistons too
these had a workable pin height but would need custom rods with a smaller little end as the pistons run very small pins to save weight, this is a an expensive option but allowed me to set my own compression height while still having plenty of valve clearance
i spoke to martin bowyer who has built two or three of these for rallycross and other stuff so knows the engine well, he supplied the rods i needed which were 3mm longer than stock, which was handy as it reduced the rod angle to help with the revs
he also supplied some solid lifters, 288 cams with huge lift as large ports engines tend to get on with less duration but more lift, and you can get away with the ramp angles with solid lifters
i did the head work myself, but as stock its actually a very good casting, with a 5mm valve train
this does cause some more expense though as you need to get custom valves with a more suitable collet arrangement to cope with the revs, as the stock valves tend to crack on the collet grooves and destroy the whole engine
i used my old simpson race exhaust manifold as it has perfect primary and secondary size/length for the engine, and only needed a small mod to the flange to fit
other than that, dry sump with custom installation on the back of the engine rather than the front, 45mm tbs, peco yellow band injectors and a good mapper gets you 230 and 157, with peak torque at 6500
its really tractable too, and will pull hard from 2k all the way to the 8600 limiter, with the power trace not even hinting at dropping, so there would be more power there if i got a steel crank and revved it harder, but everything else then starts to wear a lot more quickly so for me its not worth it
bet you wished you never asked now

[Edited on 13-07-2009 by lee303]

[Edited on 13-07-2009 by lee303]