Felix Posted October 24, 2005 Report Share Posted October 24, 2005 but isn't the 4k block about 3/4" taller to make up for the stroke? yes. think it is 10.5mm taller. there is the extra stroke, plus the 4k rods are also a little longer. Cookie, you are probably thinking of Stewart Fords article on his website. 3k heads are overated. really it isn't that hard to get extra compression using your existing head, just get it skimmed. Quote Link to comment Share on other sites More sharing options...
rjenman Posted October 24, 2005 Author Report Share Posted October 24, 2005 Ok. So you are saying that stroke made up the 100cc difference between the 3k and 4k. So, if i fit a 4k crank into my 3k block, I will then have a 1300?If so, if I fit a 5k crank into a 3k block, will I get the same result (1500cc)? So there was no changes in bore sizes, only stroke and compression? Sorry to move in on your topic rjenman read the rollaclub wiki mate K series engines : blocks Quote Link to comment Share on other sites More sharing options...
Redwarf Posted October 24, 2005 Report Share Posted October 24, 2005 FYI, You can't bolt a 4K crank directly into a 3K. Some clearance work is required due to the larger stroke. Quote Link to comment Share on other sites More sharing options...
Dan Posted October 25, 2005 Report Share Posted October 25, 2005 read the rollaclub wiki mate Ha... good point. Should really get round to doing that... FYI, You can't bolt a 4K crank directly into a 3K. Some clearance work is required due to the larger stroke. Ah, ok. I was just going to do it as a sort of backhand manouvere to get some extra capacity out of my engine, as we are only allowed to run 1200cc engines. I now know that the crank has 4k on it now as well, so there is definitely no chance of me getting away with it (Has to be engine sealed by a CAMS official, yes I do know ways around it, no I'm not going to.). Oh well, that'll teach me to think about cheating.... Cheers for the help. Sorry for stealing a thread :D Quote Link to comment Share on other sites More sharing options...
Redwarf Posted October 25, 2005 Report Share Posted October 25, 2005 I never said it can't be done :D, it just requires a bit of work. It's one of the reasons I have a 1360cc 3K :(. Quote Link to comment Share on other sites More sharing options...
st.nick Posted October 25, 2005 Report Share Posted October 25, 2005 Redwarf... LOVE the sig!! So true, my friend. So true!! I think my old car was the basis for this saying!! :D Quote Link to comment Share on other sites More sharing options...
Redwarf Posted October 25, 2005 Report Share Posted October 25, 2005 Hmmm, a Mazda Gearbox-Eater... :D Quote Link to comment Share on other sites More sharing options...
st.nick Posted October 25, 2005 Report Share Posted October 25, 2005 Uh huh!!!! :D Especially with a 250BHP group A engine!! :( Tho seeing video of 4wd tyre-smoke at a tarmac hillclimb is pretty awesome!! Quote Link to comment Share on other sites More sharing options...
cookie Posted October 25, 2005 Report Share Posted October 25, 2005 Cookie, you are probably thinking of Stewart Fords article on his website. 3k heads are overated. really it isn't that hard to get extra compression using your existing head, just get it skimmed. yes yes that is the person :D Quote Link to comment Share on other sites More sharing options...
cookie Posted October 25, 2005 Report Share Posted October 25, 2005 Uh huh!!!! :( Especially with a 250BHP group A engine!! ;) Tho seeing video of 4wd tyre-smoke at a tarmac hillclimb is pretty awesome!! bring it on want to watch :D Quote Link to comment Share on other sites More sharing options...
Dan Posted October 26, 2005 Report Share Posted October 26, 2005 Yeah but I couldn't do it without the authorities noticing... Quote Link to comment Share on other sites More sharing options...
rjenman Posted October 26, 2005 Author Report Share Posted October 26, 2005 you don't need to READ the whole wiki, look for a table in the K series block section, its got some useful stats on all the engines :D Quote Link to comment Share on other sites More sharing options...
TRD ke70 Posted October 26, 2005 Report Share Posted October 26, 2005 all engines (k/3k/4k) have the same bore size (75mm) apart from a 5k and 7k(both 80.5mm), which have dished pistons. if you bolt a k/3k/4k head on a 5k (7k has extra headbolts and isn't interchangable) you will lose compression. there is 5K engines with flat top(very small dish) pistons out there, how you tell them is under number 1 spark plug hole there's no alloy lump sticking out, that's the best way of knowing what piston you have without pulling the head off it. if you put a 4k head on to one of these engines you'll end up with a healthy compression ratio. i think the 5k engine i gave nick had flat tops in it. Quote Link to comment Share on other sites More sharing options...
rjenman Posted October 26, 2005 Author Report Share Posted October 26, 2005 5K block, flat top pistons and 4K head is my current plan :D Quote Link to comment Share on other sites More sharing options...
TRD ke70 Posted October 26, 2005 Report Share Posted October 26, 2005 5K block, flat top pistons and 4K head is my current plan :D good plan, i had the same in my starlet in NZ with twin carbs, lightened flywheel, exhaust, and cam and it use to shit on rotaries. new flat top pistons can be brought in Aus for around $150 a set with sizes up to 1mm oversize. if you do bore it to 1mm oversize make sure you have a good cooling system as there is a increase in temp. the 4k head is a good idea as you can shape the chamber better. good luck with the engine. Quote Link to comment Share on other sites More sharing options...
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