kickn5k Posted November 24, 2011 Report Share Posted November 24, 2011 I think, realistically, the only way you'll pull this off is with CAD and CNC. Its not as expensive as you might think, but still way too much money to spend on a K motor. It would need at a minimum a 4 axis machine. Cut time would be around a day. We have a 4 axis lathe at work that would do it all. Boss said he COULD do it, but really wasn't interested in doing it. What you have to realize is these machines cost atleast 500k+ and they need to earn there money. What about getting one cast up? A pattern and core box would be around the $600-1000 mark too. That's before casting, heat treating and final journal finishing. It's by no means new tech. F5000 cars had them in the 70's. Stu. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted November 24, 2011 Report Share Posted November 24, 2011 Nah- such pessimists! I mean, how reliable is a 4K crank? How often do they break? Almost never! They are over-engineered and bulletproof, so there is a lot of redundancy built in there. Even if it ran for a year maxed at 6,000rpm its a great proof of concept. Cost might be something else, there are engineers in Orange that do those sorts of jobs on mining machinery, but I imagine they aren't cheap. Quote Link to comment Share on other sites More sharing options...
orangeLJ Posted November 24, 2011 Report Share Posted November 24, 2011 Spool do custom cranks, BAZDA was looking at having custom cranks made to stroke 4As. At one stage there was talk of all alloy holden 6 blocks for around 5-7k a piece. The expense is generally in the cad work and the amount of hours it takes to measure and design each individual aspect of the finished product. Actually cutting it is the easy part. As for welding cranks, Ford 221 cranks have the snout cut off and replaced (welded on) with a 186 version (holden) to build a 234ci stroked Holden 6... And they last :) That said the snout position sees little un suported load, I'm not overly familiar with what you are proposing, but if the area was heated and welded appropriately, and wouldnt see any excessive loading (like the crank snout example) there is no reason it couldnt work Quote Link to comment Share on other sites More sharing options...
irokin Posted November 24, 2011 Report Share Posted November 24, 2011 I mean, how reliable is a 4K crank? How often do they break? Almost never! They are over-engineered and bulletproof, so there is a lot of redundancy built in there. Even if it ran for a year maxed at 6,000rpm its a great proof of concept. How many of them are cut through the main journals and welded back together though? Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted November 24, 2011 Report Share Posted November 24, 2011 How many of them are cut through the main journals and welded back together though? Well, funny you should mention that Boss.... I think its the best place to weld them, you would machine both sides to a cone and build them up again to be ground off. That would at least have the bearing spread the load across the join. I'm no welder, so it really depends on what they're made of and what a welding shop reckons. The exhaust company working on the rally Stanza we had managed to break the input shaft of the Nissan factory CR gearbox we were using. ("just driving it up on the ramps..." Yeah right) We had that welded and it lasted until we went over a yump flat-out in 5th one night, when it snapped beside the weld. The second time it was welded was more successful, I don't think we ever had trouble with it again, so that could take a 160bhp hammering. Quote Link to comment Share on other sites More sharing options...
KO 10 Posted November 26, 2011 Author Report Share Posted November 26, 2011 ke70dave I'm not sure how you think the benefits will be restricted to high reving engines the idea is to get more traction through the more spaced out firing so it dos'nt matter if the engine is reving to 12000 or 6000 it'll still achive the same result Having said that the R1 is a modern style four stroke have a look at almost all modern dirt bikes ie big bore short stroke shallow pistons = less drag ,less weight ,bigger surface area everything I'm looking for aswell why can't the bore be taken out to suit this new style of piston? why can't the block be milled down (not 20mm but to suit)? I'm sure there are rods out there that can be made to fit i've seen a lot done to xs650's they were built in the 60's and i know they stay together i've even seen a pre-85 xr 250 be retro fited with a KTM piston and a short rod so the capacity was still the same to keep it in the classic classes and yes the barrel was machined down about 3/8 of an ince it's still together and winning its class up against CR250's of the same age Getting one cast sounds like the go but i am going to cut and weld one from two using an old block butchered into a jigg and the process i said earlier this might only achive something for the caster to work off in building one properly Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted November 26, 2011 Report Share Posted November 26, 2011 Ah- Which block do you reckon?? Are you going to aim for an 80mm bore and 5K pistons on the shortest stroke you can find? When you start to look around there have been some strange pistons in 4K blocks- a guy used 80mm VW Golf pistons in one. Quote Link to comment Share on other sites More sharing options...
Mitch-12 Posted November 26, 2011 Report Share Posted November 26, 2011 ke70dave I'm not sure how you think the benefits will be restricted to high reving engines the idea is to get more traction through the more spaced out firing so it dos'nt matter if the engine is reving to 12000 or 6000 it'll still achive the same result..... urmm they don't loose traction anyway? Quote Link to comment Share on other sites More sharing options...
19914afc Posted November 26, 2011 Report Share Posted November 26, 2011 Sounds very interesting, why a K motor may I ask? Quote Link to comment Share on other sites More sharing options...
KO 10 Posted November 27, 2011 Author Report Share Posted November 27, 2011 Well my reasoning behind the k motor is ther's so many of them and almost every thing has been done to them also there is a lot of info on hotted up k's plus they are a simple engine to work on plus i've got access to a fair few so trial and error dos'nt cost much but there is no reason this could'nt be done with a 4a engine and i would love to see that but- VVTI, injection and twin cam all add new problems to the mix . the brain is streched working this out on a k as it is lol Quote Link to comment Share on other sites More sharing options...
---Pimp-My-Rolla--- Posted November 27, 2011 Report Share Posted November 27, 2011 LOL Braaap.Braaaap.......Braaaap.Braaaap.......Braaaap.Braaaap how is that piece of sh#T passing me!!! I say f&ck your brain and doo IT! Braaap.Braaap....Scrunch BANG Beer :drinks: Quote Link to comment Share on other sites More sharing options...
19914afc Posted November 27, 2011 Report Share Posted November 27, 2011 fair enough, sounds very interesting. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted November 28, 2011 Report Share Posted November 28, 2011 Going to get the crank lightened & knife-edged first?? Then again, maybe afterwards... in case it doesn't work! Quote Link to comment Share on other sites More sharing options...
ke70dave Posted November 28, 2011 Report Share Posted November 28, 2011 (edited) agreed that this setup would probably have gains over the whole rev range, but i believe it will have the most effect at peak power, which is at high RPM..... if the basis for the decision is to get "more traction through even spaced firing", i doubt you will notice this at lower RPMs.... good luck having traction issues at anything other than high RPM's in a high powered 'race spec' ~1300CC engine i belive they have done it to road bikes becuase they have 1 rear tyre, with the contact patch the width of around.....stuff all, when compared to the rear tyres on a car...which don't have to lean over around corners. a 150kg bike going flat out on a track....with 1 rear tyre on its side attempting to harness ~240HP.....yeah i can belive the traction issue here. along with the fact that it is the rider that really keeps the bike off the pavement (probably -40% of the total weight of the bike/driver), so the smoother the engine is on the limit, the less the rider has to do to keep it off the road, and i guess the harder and more confident they can drive it.... i am highly skeptical that you could feel any difference in traction in a ~1000kg car with 2 rear tyres that sit relatively flat.. and where the driver is merely a passenger to his own inputs, as opposed to moving his weight to drive it. Edited November 28, 2011 by ke70dave Quote Link to comment Share on other sites More sharing options...
KO 10 Posted November 28, 2011 Author Report Share Posted November 28, 2011 Going to get the crank lightened & knife-edged first?? Then again, maybe afterwards... in case it doesn't work! That is one sexxy crank yes,yes and ah good point,glad you asked about what block bore stroke plus pistons cause i wanted to know what the strongest block is and the shortest stroke of all I'm asuming the 1k would be the shortest stroke so i'll do some serching and get all the specs i can put them on paper gather collect scrounge and borrow as many parts as possible then source the pistons rods so if the crank part wont work at least i can put them to good use and still hava kick arse k motor The firing order is UNeven so there is a greater breake in power, dirt track use this to there advantage when the wheel starts spinning they loose speed and no body wants that. The breake gives the rider or driver greater control over when he wants it to let go there is a fine line and you may not be able to notice but the clock dos'nt lie only time and experimentation will tell and high reving race spec 1300+cc is exactly what i want who would'nt ,I'm thinking late motor X pistons, short light rods, high lift cam, twin 38 makunies, ported,extractors,valve stems ground,bigger valves (if needed they might do fine),bigger v-springs (also only if they need to be) lihtened fly,balanced lightened cross plane crank,shaved head,block machined,elec dizzy,every thing that goes near or through oil rounded what do ya think ??? now can i try to build it Quote Link to comment Share on other sites More sharing options...
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