speedy sie Posted April 21, 2012 Report Share Posted April 21, 2012 read a bit ...and can it be done and can you lighten valves?? if its a good idea a full pic on the zx7r will follow need to flat face the valves?? Link to comment Share on other sites More sharing options...
2moto Posted April 21, 2012 Report Share Posted April 21, 2012 The best way to drill the stem hollow. HTH Link to comment Share on other sites More sharing options...
kja.busa Posted April 21, 2012 Report Share Posted April 21, 2012 read a bit ...and can it be done and can you lighten valves?? if its a good idea a full pic on the zx7r will follow need to flat face the valves?? Surely you increase the weight of the valves which at speed could potentially cause the valve train to fail, surely a lighter valve train(and trhe ability to rev) is better than a gnats testicles equivalent of compression ratio?? Link to comment Share on other sites More sharing options...
speedy sie Posted April 21, 2012 Author Report Share Posted April 21, 2012 the race kit zx7rr valves are flat faced just want to get to this spec?? Link to comment Share on other sites More sharing options...
Gregorious77 Posted April 21, 2012 Report Share Posted April 21, 2012 what are you gonna weld? Link to comment Share on other sites More sharing options...
V6Jon Posted April 21, 2012 Report Share Posted April 21, 2012 I am guessing (as know fack all) he is talking about filling the recess on the valve face with weld then grinding it flat again. Maybe . . . Link to comment Share on other sites More sharing options...
speedy sie Posted April 21, 2012 Author Report Share Posted April 21, 2012 spot on there Jon Link to comment Share on other sites More sharing options...
Superdunc Posted April 21, 2012 Report Share Posted April 21, 2012 Link to comment Share on other sites More sharing options...
V6Jon Posted April 21, 2012 Report Share Posted April 21, 2012 ?? Link to comment Share on other sites More sharing options...
BudgetBoy Posted April 21, 2012 Report Share Posted April 21, 2012 Think the HTH is meant for Sie V6jon And am i missing something here?? Sie you said LIGHTEN the valve but you want to weld the dip in on the valve face, so hows that lighter? Link to comment Share on other sites More sharing options...
V6Jon Posted April 21, 2012 Report Share Posted April 21, 2012 I did not read Sie's OP that way, and whilst It's not lighter, it would increase the compression ratio. Link to comment Share on other sites More sharing options...
speedy sie Posted April 22, 2012 Author Report Share Posted April 22, 2012 sorry chaps a bit of a paradox..yes i want to get the compressible up as weld the dimples up,but after this can you make them lighter??as in remove material from the rear of the valve? Link to comment Share on other sites More sharing options...
fontyyy Posted April 22, 2012 Report Share Posted April 22, 2012 This is a joke, right? Have you any idea how small the increase in compression will be? And 50p says a stock ZX7r valve the a blob of weld in it weighs a tad more and will fail slightly earlier than a race kit valve. You've got to buy new valves (please, don't tell me you're putting together a motor to kit spec with old valves) just buy flat faced ones. Link to comment Share on other sites More sharing options...
speedy sie Posted April 22, 2012 Author Report Share Posted April 22, 2012 no im building a test engine to dyno for engine results then the race engine will be built to the same spec,just want to try the parts out first before i hunt out more kit parts,. Link to comment Share on other sites More sharing options...
speedy sie Posted April 22, 2012 Author Report Share Posted April 22, 2012 yes in going this way spoke to top engine tuner about this and he said it could be done,with plasma welding but it was only a thought to get an engine to test spec,rather blow up a test engine than the one that has all the kit parts in ti,have taken a set of casings and another head to kit sped,have two works cylinders so will have a good test engine to work with just wanted to see of all the head and squish worked,then copy this to the race engine. Link to comment Share on other sites More sharing options...
BudgetBoy Posted April 22, 2012 Report Share Posted April 22, 2012 Well i for one would not be cutting the backs of a valve. I do not see you getting any real gain Sie..All i can see if you do this (even on a test engine) is a big explosion.. Buy the proper valves that have been machined that way..IMO the old valves you want to "Chop shop" will have been through years of abuse and will be weakened or possible fractured in places within the metal. Get the proper ones,if they dont work sell them. Link to comment Share on other sites More sharing options...
speedy sie Posted April 22, 2012 Author Report Share Posted April 22, 2012 have a set on new stock valves to work with ,but i guise ill just have to go and get the stainless flat face ones for the race engine...was only an idea chaps,and thank form the interest. Link to comment Share on other sites More sharing options...
spannerman Posted April 22, 2012 Report Share Posted April 22, 2012 you could in theory waist the stem before the head of the valve this will improve gas flow but will weaken it as well ie. it will fall of and destroy the head barrel and piston, sie you need to if you havn't done it yet grind a small 1.5mm relife 45degrees on the top of the barrel where the cutout for the valve is in the piston. hard to explain but if you look at a gsxr 750 barrel you will see what i mean (only a small gain but a gain non the less) Link to comment Share on other sites More sharing options...
speedy sie Posted April 22, 2012 Author Report Share Posted April 22, 2012 like the idea there,may just weld the piston top up and machine to the valve?? Link to comment Share on other sites More sharing options...
Superdunc Posted April 22, 2012 Report Share Posted April 22, 2012 Sie, I know we all have ideas about making things better, an curiousity is a marvelous thing. But if you've got all these kit parts lieing around, bolt them together as the factory intended, do you seriously think you can improve on them in a shed, over what Kawasaki spent milions of dollars developing. I suggest you start thinking a bit more logically about this. If you are going to race you have a responsibilty to build somthing that is not going to shit it's self and drop it's guts all over the track, potential resulting the injury of other people. The Volume in the hollow on the standard valves is worth fuck all in terms of compression, and is only there to save weight. Race valves are shaped differently on the back of the head to inprove flow and have less material here, the trade off is that they have a shorter service life. If you want to save a little weight and improve flow, just get a 3 angle valve job, this will see far bigger gains than anything else, you propose. If you have new kit pistons i suspect they will need finish machining around the edge of the crown to set the squish, and material of the top peak to set the C.R. to the desired level. Leave welding engine components to the drag racers and stock car boys. Link to comment Share on other sites More sharing options...
porter_jamie Posted April 22, 2012 Report Share Posted April 22, 2012 please, make it stop. or at least, listen to Duncan! Link to comment Share on other sites More sharing options...
Mark/Foggy Posted April 23, 2012 Report Share Posted April 23, 2012 I've got some old Sodium filled Manx valves (loooong story) lying around somewhere that you could practice on if you like Si. You like an exciting life don't you?!? Link to comment Share on other sites More sharing options...
speedy sie Posted April 23, 2012 Author Report Share Posted April 23, 2012 yep sound good. Link to comment Share on other sites More sharing options...
Mark/Foggy Posted April 24, 2012 Report Share Posted April 24, 2012 Good old British Leyland, couldn't help building an engine with inbuilt grenades. My old man bought one new, gave it back to them after 1 month, crock o shite. Link to comment Share on other sites More sharing options...
zx6rrob Posted April 24, 2012 Report Share Posted April 24, 2012 Volvo used to use them extensively in there turbo`d motors, used to have to drill bent ones and drop them in a bucket of water before we could scrap them. Guess what little old trainee me did a lot of at the volvo dealer I worked at. Link to comment Share on other sites More sharing options...
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