Felix Posted October 9, 2010 Report Share Posted October 9, 2010 Ask Redwarf, he had a very healthy 3k motor with 4k crank in it. Quote Link to comment Share on other sites More sharing options...
towe001 Posted October 10, 2010 Report Share Posted October 10, 2010 Pretty possible, all it'll need is either different rods or pistons. 3k-h block, rods and pistons fitted to a 4k crank. 4k rod at the top 3k-h at the bottom Back of the block Counter weight hits the piston towards BDC. As can be seen the rods cap can't be fitted Past that point the cap can be screwed down. But around the half mark number one rod jams up on something. I'm not sure what it is can't see anything hitting Piston sits about 3mm proud 1 Quote Link to comment Share on other sites More sharing options...
GJM85 Posted October 10, 2010 Report Share Posted October 10, 2010 Using a 4k crank and 3k rods it could be as simple as having the crank lobes machined down a few millimetres and use shortened pistons. You could call it a 3k stroker kit. Quote Link to comment Share on other sites More sharing options...
towe001 Posted October 10, 2010 Report Share Posted October 10, 2010 Could but i'd think it'd defeat the idea of running the 4k crank but. Unless your talking about the counterweights. But i'd sooner just do the pistons. Should be able to find some 75mm bike pistons Quote Link to comment Share on other sites More sharing options...
Clapped out Posted October 10, 2010 Report Share Posted October 10, 2010 charade.................. 1 Quote Link to comment Share on other sites More sharing options...
GJM85 Posted October 10, 2010 Report Share Posted October 10, 2010 Could but i'd think it'd defeat the idea of running the 4k crank but. Unless your talking about the counterweights. But i'd sooner just do the pistons. Should be able to find some 75mm bike pistons yeah i mean the counterweights... they contact the piston sleaves and a shorter piston may not rectify that issue. Quote Link to comment Share on other sites More sharing options...
Felix Posted October 10, 2010 Report Share Posted October 10, 2010 (edited) With a 3k running 4k crank and rods. CB Charade pistons look like they'd come close. Level with the block at TDC and are 14.5mm shorter than 3/4k pistons. Come in 76mm plus 20 and 40 thou oversize. Only issue I see is the area for the little end is 25mm compared to the 3/4k of 28.6. Run the 40 thou pistons and you'd have a 1360cc 3k. :) You'd need to do some block clearancing. Edited October 10, 2010 by Felix 1 Quote Link to comment Share on other sites More sharing options...
ninja-philbo Posted October 11, 2010 Report Share Posted October 11, 2010 i blame the massive hp of k motors lol Quote Link to comment Share on other sites More sharing options...
towe001 Posted October 11, 2010 Report Share Posted October 11, 2010 CB Charade pistons look like they'd come close. <snipe>Only issue I see is the area for the little end is 25mm compared to the 3/4k of 28.6. Should be able to get the holes bored out - on-centre, off-centre. Quote Link to comment Share on other sites More sharing options...
7FOUR7 Posted October 11, 2010 Report Share Posted October 11, 2010 So if I understand correctly I should be able to run 4k crank and rods with some 40thou charade pistons, does anyone make forgies for them? Quote Link to comment Share on other sites More sharing options...
Felix Posted October 11, 2010 Report Share Posted October 11, 2010 (edited) So if I understand correctly I should be able to run 4k crank and rods with some 40thou charade pistons Quite possibly, I'd be doing some more maths and measuring to be sure. Download the ACL piston catalog and compare specs. Standard 3k's have 75mm bore, the Charades 76mm. So with the 40thou charades would effectively be a 2mm overbore taking you to 77mm. You would have to check skirt to crank clearance, but the charades were 14.5mm shorter. Plus as I said grind the block in places for crank/rod clearance. I do have a feeling though that these are the pistons used in Redwarfs old grunter 3k. Should be able to get the holes bored out - on-centre, off-centre. The piston pin diameters are the same. It is the width of the little end which may be the biggest issue. Edited October 11, 2010 by Felix Quote Link to comment Share on other sites More sharing options...
coonaPWR Posted July 19, 2011 Report Share Posted July 19, 2011 is putting a 3kc head onto a 4kc as easy as unbolt them and bolt it on?? or does any of the gear out the 4k head have to be swapped into the 3k head? thanks in advance. oh and what head gasket to use? Quote Link to comment Share on other sites More sharing options...
towe001 Posted July 20, 2011 Report Share Posted July 20, 2011 Yep, just as easy as that. Don't really have to swap valve train stuff over. But in saying that, there is a few different 3k heads, but in simple terms there's the early heads and the late heads. The late version head is the one to go for, cause of alloy pedestals (instead of cast iron), better valve stems and oil seals. For the head gasket i'd just go 4k, the 3k is the same anyways. If your planning on fixing the 3k head it'd be ideal to work out what vehicle the head came from before getting a valve regrind kit. cause the valve stems and seals are different. But if your going to get the head machined firstly, get them to also replace the stems with ones for a ke70 4k head, their the better ones. Quote Link to comment Share on other sites More sharing options...
coonaPWR Posted July 20, 2011 Report Share Posted July 20, 2011 ah sweet! thanks heaps matey. good info! Quote Link to comment Share on other sites More sharing options...
GJM85 Posted July 20, 2011 Report Share Posted July 20, 2011 This is a good thread. I wonder why it died in the arse... maybe more people should post up their 'K' motor builds! :yes: Quote Link to comment Share on other sites More sharing options...
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