Bono12s Posted August 7, 2012 Report Share Posted August 7, 2012 After reading so much different information on this, i'm not quite sure what to go with. I have a 4k bottom end where i'm putting in a cam with .396" in lift and .399" ex lift. I have been told that the retainers on the 3kbp head will limit the lift that i want. i have a 4k head aswell. Is it best just to swap the valves and rocker assembly over or is there anything aftermarket that would be more appropriate???? Also, i originally wanted a 5k but had no luck. So i would like to bore the 4k block a little. I think that 2.5mm brings me out to around the 1405cc. I know i can't really go much bigger so what would be a good piston to go off around that size? Any help would be appreciated. Cheers Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted August 7, 2012 Report Share Posted August 7, 2012 With 4K the usual story is that 0.4" is the limit before the valve springs bind, but some of the top people on here have run cams with more lift without problems. I don't know if the 3K retainers are any different to the 4K, but can you mock it up with no head gasket and see?. Have the 4K block sonic tested to find the wall thickness and bore it out to take 5K flat-top pistons. That's been done on here too with good results. The sonic testng will tell the engineers where to set the bores to equalise the wall thickness. I assume you're not going to turbo the motor or race the car. Quote Link to comment Share on other sites More sharing options...
Bono12s Posted August 8, 2012 Author Report Share Posted August 8, 2012 Nah mate, definately wont be racing or turboing the motor. I think a little less compression would be the go. The retainers are completely different as with the springs. Springs off the 3kbp are larger in diameter and one would think, hold more pressure. The retainers to suit are also larger. Good idea with the block but i have heard that boring it out to that much is taking it a step too far. Well maybe just for me, hence looking for a piston around the 350cc area. None cross my mind. I might be looking for power in the wrong areas and if so some guidence would be great. I have looked into the "making a tough K motor" and various others. Impressed, but they touch lightly on some subjects. Not really looking to create something different (i'm quite sure plenty of people have done it) but something pretty close to original just to keep the personality of the ke20. Anymore insight would be great, Cheers. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted August 8, 2012 Report Share Posted August 8, 2012 I haven't heard of any intermediate sized pistons that people have used- I gathered these along the way as I investigated it- ""my flat mate had a 4k bored out to 1486cc using 1600 mazda turbo pistons,5k head gasket, valve grind, and f13 cam. went prity good in a road car. not to sure what was dun to the head in regards to compression ratio but i no its about 9.8;1 "" http://www.club-k.co...d.php?tid=14162 ""previous owner took the 4K engine out of his Starlet, bored it out to 5K, put in new pistons, and used it for about 10K, then he ditched it for a 4AGE. "" http://www.club-k.co...d.php?tid=15972 ------------------------------------------------- ""my bro bored a 4k out to 5k (80.5) so it can be done. BUT you need the right block its a commercial block with siameze bores""""i had a 4k that was bored out to a 5k, completlely balanced, shot peened rods, 11.5:1 compression, lightened flywheel, ported head, 304 deg cam and a 32/36 webber as well as 2 1/2inc exhaust and extractors. it made 56 rwkw's and it revved to 8 (as far i felt safe to rev it)"" joeschmo_57 http://www.rollaclub...4k/page__st__30 Engine specs: Twin solex carbs double valve springs ported head extractors Bored out to fit 5k pistons Deburred block knife edged crank electronic ignition http://www.ae86drivi...rens-KE70-wagon ----------------------------------------------------------------------- ""na didnt have any block problems at all just had to use a 5k headgasket with it. thats all a 5k is, a bored out 4k really.... no problems and u really notice the extra torque. compared to a stock 4k it putts along quite nicely and my mate refered to mine as " it goes like a 4age "" --------------------------------- The 9000rpm 4AGE head 4K- ""Block Sonic tested Bores repositioned and overbored by 6mm"" ----------------------------------- Couple of Club-K have worked http://www.club-k.co...d.php?tid=22491 The 4AGE/4K blend is filfredericks on here.. 9000rpm on a 4K bored out to 5K pistons and a 4AGE head!! http://www.rollaclub.com/board/topic/51097-4k-twin-cam/ If you want to bore it less then spend an hour at your local parts store going through piston catalogues and see what you can find. More grunt definately comes from more cc. Other than that, its carbs, cam, compression and exhaust as usual. I did the basics, but its not meant to be a racer.. http://www.rollaclub.com/board/topic/42407-the-girls-ke70/ Quote Link to comment Share on other sites More sharing options...
Bono12s Posted August 8, 2012 Author Report Share Posted August 8, 2012 (edited) Done very well there. Cheers heaps, Ive already got the 32/36 weber. Obviously getting the cam and lifters done. Looking to take the head and block to my nearest engine reconditioner hopefully this week if not next. Just have to spend a few late nights researching a little more information, and with a bit of luck. Pick up some extractors along the way. Well done with inlet aswell. I'm a sheety by trade and that pretty well thought of. Edited August 8, 2012 by Bono12s Quote Link to comment Share on other sites More sharing options...
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