October 25, 200520 yr comment_78942 Right, I know this has be covered 43,462 times, but... 3k head (bigport or otherwise) onto 4k block: Will it work?? I read Rollered posts on this topic and got nothing useful... Advice?? Experience?? Report
October 25, 200520 yr Author comment_78947 Ok. So no changing of rocker-gear (as rollered seemed to believe)?? Is it likely to ping its tits off?? And if i buy extractors, they'll have to be KE20 ones, not KE30, correct?? Anything else I should know?? Report
October 25, 200520 yr comment_78955 ? KE30 had a 3k didn't it... did last time I checked, and so did KE20?!? Don't mean to act like a know-it-all, cos I want to know this as much as the other bloke, but wouldn't that mean that the 30 extractors fit? Anyone? :D Report
October 25, 200520 yr Author comment_78960 Wouldn't the 'bigport' head have different sized (bigger??) exhaust ports?? If so, then a 'regular' set of 3k extractors wouldn't be the same size as the 'bigport' ports... I'm totally lost, I've only ever dealt with the factory cast manifolds, and only found out last month that there was sucha thing as a'bigport' head!! :D Report
October 25, 200520 yr comment_78966 Wouldn't the 'bigport' head have different sized (bigger??) exhaust ports??I'm totally lost, I've only ever dealt with the factory cast manifolds, and only found out last month that there was sucha thing as a'bigport' head!! :D Wouldn't the 'bigport' head have different sized (bigger??) exhaust ports?? No, the main difference is in the inlet ports. You buy the extractors for your make of Coroola, for the simple reason KE20 pipes won't fit on a 30 and vice versa. You would either need to match port your inlet manifold, or find a big port one. Report
October 25, 200520 yr Author comment_78970 Ah, Sweet!! Thats what I needed to know... Cool. That helps alot. :D Heads and engines will be swapped for "P:36" this week, I'll keep y'all posted :( Report
October 25, 200520 yr comment_78986 Just popped down stairs with the measuring stick and can confirm there is negligable difference between the two. :D Edited October 25, 200520 yr by Redwarf Report
October 25, 200520 yr Author comment_78998 Nice one!! thanks 4 dat... I think Rjenman & I were thinking the same ideas at nearly the same time. Hence 2 threads with the same meanings!! :D Report
October 27, 200520 yr comment_79342 all i can say is that if you put a 3k head on the 4k block it will turn over once then either put a hole in the top of your piston or bend the hell out of the valves. this is from experience. we then threw the internalls away. Report
October 27, 200520 yr comment_79346 ummm, no... i ran my 3k bigport on my 4k for a while, burned a valve, had it totally rebuilt, but they shaved WAYYYYYYY too much off of it it ran fine before it was shaved, hauled ass after, but i had to run super and retard the timing 12* Report
October 27, 200520 yr comment_79357 all i can say is that if you put a 3k head on the 4k block it will turn over once then either put a hole in the top of your piston or bend the hell out of the valves. this is from experience. we then threw the internalls away. you probably put a dished piston head (with long reach spark plugs) onto a flat top block. much like the guy who put a flattop 3k head onto a dished piston 4k bottom end then wondered why his car ran like a lawnmower. :( pay attention to what you're doing, think about it, and if in doubt measure! a syringe costs you 4 bucks at the chemist, it's accurate enough for backyard stuff like this rocker posts ARE different, in that early 3k rockers have alloy posts, later 4k rockers have cast iron posts, but they both place the shaft in the same position, so the difference doesn't really matter. you could theoretically mix and match alloy/iron posts if you wanted to. the iron posts are the better to use, as they don't expand as much as the alloy ones under heat (hence making valve clearances unreliable) extractors are dependant on vehicle, not engine/head. ke10/20 extractors won't fit a ke30/55 as the floorpan is different. likewise for ke70 extractors, which have a different floorpan again ALL THIS ASIDE, 3k valve gear is shit and prone to leaking oil down the stems, and the older the head, the more likely it is to either have internal corrosion in the water jackets, or crack when placed under extreme running conditions (such as the extra heat of high compression). i would much rather just take your existing 4k head into an engine builder and get them to skim it for 50 or 60 bucks then bolt it back on Report
October 27, 200520 yr comment_79453 Awww, not $4!!! My coupe sounds like a lawnmower on steroids... :shrugs: Report
October 28, 200520 yr comment_79783 Nice one!! thanks 4 dat...I think Rjenman & I were thinking the same ideas at nearly the same time. Hence 2 threads with the same meanings!! :( hehe yeah sort of.... both being confused about head swaps between K motors and what could possibly go wrong... :) Report
October 29, 200520 yr comment_79896 Just for anyone thats interested... heres a comparison between bigport and small port intake manifolds. Report
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