Toymods Car Club Inc: Tech & Conversions => 3K Rally Motor Performance Rebuild to 1400cc

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Super Jamie
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On Probation

Location:
North East NSW
Registered:
December 2002

Re: How far can I bore a 3K out to?	Tue, 17 December 2002 12:54

yeah me again not at work now so i can type lots i have a 3k with no head and a bare 4k block in my garage, between the bores is a 1/2" (12.5mm) at the thinnest point. the gap to the surrounding water jackets is 6/16" (9.5mm) and about 9.0mm (hard to tell, cheap shitty plastic measuring calipers) to the water passage between the pushrods and the bores i'm going 60 thou over on my own 4k project, bigger valves and tosco-spec head, balanced and bulletproof everything. but this will be a street motor for my daily driver ke35. if i ever get a cams license and feel like driving to brisbane every month i might compete at some level but i doubt it, i just like learning and building if you go to stewart ford's webpage - http://drive.to/oldcorollas - there is a copy of the TOSCO manual for 3k motors which tells you in great detail how to build a 1293cc (4mm overbore) racing motor using twin dellorto dhla40s (TOSCO were the predecessors to TRD. TOSCO stands for TOyota Sports COrner) if you download the pdf (he has it in html as well) there are very specific head porting diagrams, as well as several camshaft grinds (see table 13). its a fair bet this is the best way to port the head. i'm not sure if it uses a bigport head or not (probably does), there's about 3mm difference between smallport and bigport, bigports are somewhat rare but not impossible to find. they come off 3K-B motors from Sprinters, usually they accompany twincarbs due to the water jackets in the twincarb manifold. smalls have a plate on the back of the head (sometimes a hose, sometimes blocked off) whereas bigs have a welsch plug myself and some of the other members of oldcorollas have compiled a list of many cam grinds for K motors, you can find them in this folder in the oldcorollas yahoo group files - http://autos.groups.yahoo.com/group/oldcorollas/fi les/dyno/ - which i think should be accessible without a group login. if not, chuck me an email (jamie@superjamie.net) and i'll send them all over to you the most powerful cam tested under dyno2000 was the wade 169. this made 180-odd bhp in the tosco 3k, and 141bhp in a stock 3k. these are somewhat optimistic figures (maybe it expects perfect air-fuel mixture and 100% volumetric efficiency) but give you a good indication of whats better than what else. none of the waggot or tighe cams have been put thru that software (i'm trying to get a copy to do it myself. i have a waggot 212 in my garage and i want to know if its any good for my 4k project) stewart overported his first head and ruptured an exhaust port wall, so he cut the head up to see the wall thicknesses to prevent us all making the same mistake again. the photos are in the Engine section of his webpage. just click Engine and scroll way down in the right hand frame, very very useful stuff at the moment stewart's got a 4k with 3k bigport head and jaycar hei in a ke15, its making 42.7kw at the wheels (his dyno sheet is in the yahoo group files as well, somewhere) which means roughly 100bhp. he's away in america at the moment, and is coming back with $333 worth of megasquirt gear (google it, its a diy efi kit) and will rig up something with camira pump, rails, sensors, etc when he gets back he's using a weber idf 34/34 downdraft at the moment, main jets are 150/155. i'm using a 32/36 dfv, aka holley 5200, on my stock 3k - main jets 125/150, airs 165/150, needs to be 180/165 to stop mid-throttle stumble and backfire. the stock aisan carb has shitty shitty mixture qualities, make it the first thing you replace another mate around here has ke30 with a balanced and blueprinted 60-thou 4k with smallport head and a single dellorto dhla40 running 5k electronic ignition (internal ignitor) and thermo fan, i dunno how much power its making (hes never dyno'd or run a quarter) but it could pull away from my old 105bhp bmw fairly fast if you like, join the oldcorollas yahoo group, several of the guys there run hillclimb/autocross/motorkhana cars and lots of the people have been generally playing with K motors for years, its a nice friendly group with lots of good info and skill levels from beginner to expert. as one could guess from my signature, i compile the faq need to stop typing and sleep now [Report message to a moderator]

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