Felix Posted July 27, 2004 Report Share Posted July 27, 2004 ben, a 5k has the same stroke as a 4k. both 73mm. a 5k crank actually has 4k cast on it. 4k's have a 75mm bore. 5k's have a 80.5mm bore, and reinforced block. i think the 5k flywheels are heavier to help dampen the extra mass of heavier pistons and beefier conrods. i have a 5k on the engine stand out back i am giving a freshen up. not sure what to do with it yet, whether to put it in becs ke16, or replace my 4k in my ke15. becs car is mod plated for a 5k so is legal. maybe i should put it in mine and get it plated?? it is going to get a 4k-e head which have larger ports to start with.. it has a high lift 3k-b spec grind cam, so will have mega grunt. playing with dyno 2003 it should have more torque at 2 grand than my current 4k has at 5500, and the same peak HP but at 6500 rather than 7500. should really go in a lightweight ke1x shell. xany, what are the specs of your engine? Quote Link to comment Share on other sites More sharing options...
demuire Posted July 28, 2004 Report Share Posted July 28, 2004 I wonder if you can get done for having a 4K in a car that's been plated for a 5K? Wouldn't make any sense, but then there's a lot of things that don't make sense either... Quote Link to comment Share on other sites More sharing options...
Xany Posted July 28, 2004 Report Share Posted July 28, 2004 you can read about my engine build up....here Engine Build Up lets just say that the 5k has lots of torque......and as you can see with those pictures.....a 3K bigport head, ported out more. parts that are unique i have listed in my signature below.... Quote Link to comment Share on other sites More sharing options...
Felix Posted July 28, 2004 Report Share Posted July 28, 2004 so what pistons and compression ratio? are the pistons dished? a 3k bigport head combustion chamber is normally around twice the volume of a dished 4/5k head. did you use holden/chev solid lifters or lock the existing hydraulic ones? i'm more building for maximum grunt, and the widest powerband possible, staying within the constraints of the hydraulic lifters. my 4k goes to 8 grand. the 5k will only need 7 grand. the 5k was previously in becs ke16 before we got it. it used to smoke 3rd gear when it had a 4.4 and 12 inch tyres. it will have even more go after i'm finished with it. fook normally you can only go to a 4k legally in a ke1x. doesn't matter if you bolt in a smaller engine once mod plated for a 5k. anyone got any standard bore 5k pistons laying around? i have another 5k turbo bottom end i need a spare piston for. one is cracked. Quote Link to comment Share on other sites More sharing options...
pro_ke Posted July 28, 2004 Report Share Posted July 28, 2004 in sa you can bolt a 5k into a ke1x so long as you put the later discs on the front, no inspection/cert required. its just an engine number change here. Quote Link to comment Share on other sites More sharing options...
Felix Posted July 28, 2004 Report Share Posted July 28, 2004 i thought it was A12 pushrods Quote Link to comment Share on other sites More sharing options...
Xany Posted July 28, 2004 Report Share Posted July 28, 2004 ok sorry....havent been near my computer in the last 2 hours....been under the engine bay of my car..... dastun a12 pushrods. chev solid lifters. same as holden six and 253 v8 holdens, and yes the pistons are dished. i couldnt find any flat top ones, i havent had any problems with comp ratio either. max power on my 411 lift cam is around 7500rpm, i can truthfully tell you that my engine revs to 8 grand easily. i still havent had it valve bounce. Quote Link to comment Share on other sites More sharing options...
Felix Posted July 28, 2004 Report Share Posted July 28, 2004 thanks xany. would certainly liven up the performance in the top end with the proper solids. rereading your engine build post, you are running dished pistons? you must have had to grind alot of metal off the face of your bigport head to get a decent compression ratio out of it. do you know the final CR? your oversized valves, what were they from. how much did they cost to get cut down, regrooved and the seats opened up? i have looked through many valve catalogs and there is nothing i've found yet that is a direct drop in. alex unfortunately up here they expect you to run boosted brakes with an upgrade. supposedly need to run the equivalent setup from what the chosen engine you are going to run came with. boosted brakes are just wrong on a ke1x. becs are way to touchy with subaru m/cyl booster and ke20 discs. legal though. i prefer my ke30 discs with standard m/cyl. pull up real good and go twice as far before they start to fade. much safer, with a much more progressive pedal feel. Quote Link to comment Share on other sites More sharing options...
irokin Posted July 28, 2004 Report Share Posted July 28, 2004 I'm of the opinion that on new springs you wont hit valve bounce...the engine wont be able to gulp enough air quickly enough to hit that kind of RPM Quote Link to comment Share on other sites More sharing options...
irokin Posted July 28, 2004 Report Share Posted July 28, 2004 i prefer my ke30 discs with standard m/cyl. pull up real good and go twice as far before they start to fade. much safer, with a much more progressive pedal feel. My KE70 discs and calipers fade just as quickly as the only KE20 discs...I have a feeling its to do with the brake pads...VN commo Bendix ultimates on the way ;) Quote Link to comment Share on other sites More sharing options...
Xany Posted July 28, 2004 Report Share Posted July 28, 2004 4k's have a 75mm bore. 5k's have a 80.5mm bore, and reinforced block or 81.5mm fully bored out. < the size mine is. felix: i didnt change the valves at all....they are the ones that came out and went straight back in. i don't know the final cr or how much metal was ground off.....it was done at a very cheap price (mates rates) and i don't think i ever got a card with the head to say what had been done. Quote Link to comment Share on other sites More sharing options...
irokin Posted July 28, 2004 Report Share Posted July 28, 2004 If it was done by ANY respectable engineering workshop there will be a number stamped on the head somewhere. Take it down ring them up and they will have a data sheet on it ;) ahh the things you pick up hanging around an engineering workshop. Quote Link to comment Share on other sites More sharing options...
Felix Posted July 28, 2004 Report Share Posted July 28, 2004 ok, i'd be expecting a rather low CR. probably perfect for forced induction. so you are just running standard sized valves. 3k bigport heads run the same valve size as on any other 3k/4k/5k. the only engines to run different sized valves were the original k and k-b heads which were smaller. normally the 5k hydraulic lifters weigh about 4 times what k/3k/4k solids do. brings on valvefloat quicker as the springs have a hard time controlling the extra weight of the lifters. i'd say the chev solids would have to weigh less than half of the 5k hyds. they'd be a bit heavier than the k/3k/4k solids due to the larger diameter. a big improvement though. wonder if you could sleeve down the lifter bores in a 5k block to use the earlier smaller diameter k/3k/4k solids? might have to look into that. you can shim valve springs. normally good for at least an extra 500 rpm. just make sure to avoid coil bind or you will rip out the rocker pedestal studs/bolts and/or bend pushrods.. Quote Link to comment Share on other sites More sharing options...
pro_ke Posted July 28, 2004 Report Share Posted July 28, 2004 alex unfortunately up here they expect you to run boosted brakes with an upgrade. supposedly need to run the equivalent setup from what the chosen engine you are going to run came with. boosted brakes are just wrong on a ke1x. becs are way to touchy with subaru m/cyl booster and ke20 discs. legal though. that would feel horrible! boosted brakes on old, small cars are utterly revolting... but a mans gotta do what a mans gotta do right? ;) Quote Link to comment Share on other sites More sharing options...
Xany Posted July 28, 2004 Report Share Posted July 28, 2004 the cr is realitively high i think.....with the timing advanced on the engine my old starter motor had a hard time cranking the bitch over. the head is actually a 3K tosco spec head.......i was told by the previous owner never to let it out of my sight......so i been told they are fairly rare. the chev lifters didnt really feel that much lighter to the hydro ones....but i can't exactly remember how much lighter. Quote Link to comment Share on other sites More sharing options...
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