now that i've got the hang of uploading images, here are some pics i've taken (with my mobile phone). click here to view
here's whats been done: # bottom end balanced - crank,clutch,flywheel,rods and pistons. # 84mm flat top pistons (milled to give 11:1 c.r.) # block bored and ground # head ported and skimmed, 3 angle valves and seats (standard size valves) # modified combustion chambers # kent cam and vernier pulley # straight through bored throttle body # intake manifold matched to head, modified and 'tidy up' # have got supersprint exhaust manifold and de-cat # FSE fuel pressure regulator # will be getting remap as soon as its built ! bhp output - hopefully 465 at the wheels (joke!)
rick, yes i'm doing the rebuild but the bearings all seem fine so they are not getting replaced. everything else is new
Who the hell drilled the underside of the piston crowns? Just where I'd want a selection of stress risers, straight under the crown!
NOT a good idea to be drilling under the centre of the crown, especailly as the pistons have been decked already.The crown thickness must be very thin in places. I have to ask, but where did you find those pistons/who machined them??(look like audi items). Reason being is that if they were a matched set, then they would be in balance with each other within about 4 grams to start. If they have been drilled to this extent then either they were not a matched set or who ever decked them has done a very poor job, as if you remove the same material from each piston then they should be pretty good weight wise. I decked mine and kept them within 3 grams when they were measured. Also, you might want to think about piston crown to valve clearances before you turn the engine over. Do a dry run first, turning it by hand. As there is no negative dish in the piston crowns, then there is very little clearance between the valves and the crowns during a small part of the engines cycle. Check it twice and turn it once. Get your timing bang on!
thanks for the concern guys. but these pistons are strong puppies- they're from a turbo'd nissan and are made by sanico. this engine is being done as a whole package and all these issues were taken into account- i'm not some hill billy going to a machine shop without doing any homework! the pistons were skimmed by less than a mm, and the heights were all previously measured one by one in the bores connected to the rods and crank. and the guy who did them has been in racing a long time and built some very fast cars. we have measured this, volumed that, and calculated the next thing. it will be safe. em, i hope! no seriously i've been working on this a long time. can't wait to get it built !
Right, now to jump on the thread. How thick is the piston crown at it's thinest point? I've taken 1.35mm off the top of my valver pistons to achieve +/- 0 deck height using my diesel crank. The crown is now 4.65mm thick at it's thinest(6mm to start)with no drilling underneath and am concerned about it blowing through. Any thoughts?
Why the drilling on the clutch plate housing? Is the flywheel machined as well? Did Alec do that too?
the drilling on the clutch is for balancing, the whole bottom end was done. and the flywheel has been machined to lose some weight! all done by engine services. i've not yet measured the piston crown thickness, but i'm not worried.
