Welcome to Hankey's guide to the Toyota K-Series, from rebuilds to modding.
First thing you probably noticed when you drove it away was how low it was on power, correct? Here is where you're given two options.
You can either;
A: Ditch the K-engine and upgrade to a 3T, or 4AGE, or SR, KA, CA, or whatever engine you want.
or
B: Keep the little K series in there and have some fun with it!
If you're still reading this, you probably are going with B, for now atleast.
Types of "K" engines.
When you say "K", most KE30/KE70/KP60 guys will think of either the 3K, or the 4K, but believe it or not there are quite a few of these, I'll go over the most important.
"K" Engine
This was the 1.1 liter "proto" engine, the first version of the K-series, found in the KP30 Publica, and the KE10 Corolla, this engine if very plain and not much can be done with it, if you have it, it's probably best to just drive it and leave it alone, not much is known about the capabilities of this engine because it's pretty rare.
2K
This is the 1.0 liter engine found in the KP30/KP40/KP60s Publica/Starlet. It only made 50 HP, it's advised this engine not be modded due to a common casting defect in the pistons made any and all pinging a potentially dangerous to the engine.
3K
This is probably the most common of the K-series engines, it is a 1.2L. It came equipped in the Corolla, Starlet, Publica, Kijang, liteace, it has a 75MM bore and 66MM stroke.
This is the most popular to mod because the large bore makes for a very rev happy engine, and lets be honest, who DOESN'T smile at a 1.2L turning 9000 RPM?
3K-B
This derivative came equipped with a highcompression big port head and twin carburetors, when most people try to build a high-performance "K" series, they start with a 3K-B, or find a 3K-B head.
3K-R
Good luck finding one, these are as rare as rocking horseshit to find, but they were the most high-output K series designed, Originally built by TOM's for the KP40 Starlet racecars, this 3K was bored out to 1.3liters, it came equipped with a DOHC 16v head, uprighted cross-flow, this puppy made a whopping 180HP at over 9700 RPM.
4K
This is my favorite K engine because it has a near square bore and stroke, this engine is essentially a stroked 3K, with a 75MM bore and 73MM stroke.
4K-E
This is a fuel-injected version of the 4K, I believe it was only released in the US to meed EPA standards, but I might be wrong, someone double check! If you're planning on running a turbo on your engine, it would probably be a good idea to find the EFI parts, as it would be easier to tune this than to pressurize a carburetor.
5K
This is basically a 4K, but bored out to 1.5L, with an 80.5MM bore, I don't know too much about these, but to my knowledge they make good power due to the significantly larger displacement.
7K
This is a 5K, but stroked to 1.8, it has a 80.5MM bore, but an 87.5 MM stroke, it makes much more power than the other K series engines, but it's all in the low revs due to the large stroke.
The 7K had a bellhousing that would mate the K series engines to the W58 transmission, and would be essential to anyone building a super-high performance K-series.
MAKING POWER IN YOUR K-ENGINE
The K engine is actually a fairly easy to upgrade engine, now of course, it's only a 1.0-1.5 (plus the 7K, but I don't like stroker engines, so I won't talk about that one) so you won't quite get break-neck power like you would from tuning an SR20, or a 3SGE, or anything along those lines, so if you're building a DRIFT KE70, you should probably pick another engine, but if you really want to run a K, go for the 7K due to the large stroke and good torque.
Now I'm trying to find the best way to tell you all the mods you can do to every engine, but I'm just going to copy what Billzilla did with the 4AGE tuning guide and go by increments of horsepower.
3K/4K Single carb.
60 HP
This is your basic K engine, a freshly built engine with good oil will easily make this right out of the box.
60-65 HP
Getting up to 60-65 HP is really easy, this is just a matter removing your cat, giving yourself a full 2" header-back exhaust, and scrapping the stock oil-bath intake for something else a little cooler and easier flowing.
65-70 HP
Here is when you need to start opening the engine a little bit, not much, but cams will help you get more power here. some good 260 duration cams (I buy from Auckland Cams) will easily bring you to high-60s.
This is also about the end of what the stock carburetor can do, BUT a stock Weber 32/36 carburetor will be a basic bolt-on and will support your power output just fine.
70-80 HP
Just a matter of bigger cams at this point, 284 duration cams should bring you to high 70's and maybe even low 80s if you time them right.
80-95 HP
Now you're starting to make some good power, at this point you're going to need 295 duration cams, but to get the most out of these cams, the compression ratio needs to go up some, if you're just shooting for about 100HP, you could probably just take the head off and mill it down to about a 10.0:1 compression ratio and it will be just fine, but my preferance is to find a 3K-B head which has a smaller combustion chamber, and try to find the matching dual carb intake, and hold onto that for later if you're shooting for even more power.
While the head is off, you should probably give it a three angle valve job, and match the exhaust ports, but not the intake ports. Deshroud the combustion chambers a little bit, and give it stiffer valves, I managed to score a TRD set, so you'll have to dig around and find some that might work in your head.
95-105 HP
Upgrade the cam to about a 300 duration, not much else has to be done here, you'll be sitting pretty at about 100 with the single carb, twin carbs will yield about 105-110 ish.
105-110 HP
Now the K is becoming a VERY serious engine, say goodbye to the good fuel economy and most streetability.
After around 105, intake, now if you managed to find a 3K-B intake, you can use your old Weber 32/36 and just buy another one to match. Or it's time to run two side draft carbs, I prefer Mikuni 44's, but those are discontinued, so Weber 40 DCOE's are probably your best bet in this case.
You're also nearing the end of what the stock bottom end is capable of, the crank is fine up to about 160 ish, but the rods and pistons need to be addressed
Now, lots of people use Daihatsu CB23 pistons, I personally have not done these because I got lucky and found TRD 11.5:1 pistons, so I don't know how the pistons affect the compression ratio, but the head can be milled no problem, these came out of the 1.0 Charade BUT the charade only came as a 3CYL, so you'll have to custom order the pistons to get the extra one. They are 76MM, so the block will need to be bored out, but the wrist pin is the same diameter.
The rods have some casting marks, so these needs to be polished off, hitting them with a Dremel would be a good idea at this point, but make sure all pistons weight about the same. With the rods cleaned up, they should be good to 130-ish horsepower.
110-140
If you've made it this far, your car won't be doing much more on the street unless it's a sole weekend warrior.
Assuming you've done all the previous mods, your current restriction is your valve size, actually, it's been restricted since about 90 HP, but we've been running with it.
Now, you HAVE to get bigger valves. Almost any valve size will work as long as it doesn't shroud too much. I heard of guys putting in 22R valves into these things. This is not something I would do at home though, definately take the head to a shop and get it done by a professional. Getting the proper sized valves and getting portsizes are INVALUABLE to getting more power.
140-160 HP
Truthfully, I have NEVER seen a K-series get this powerful, apparently TRD made the Stage 3 3K run up to 160HP, so it might be worth it to find that guide if you care so much. I'm not sure the real restrictions at this point, here, you would have to order custom connecting rods, something light like titanium, new pistons will likely be needed at this point, custom ones will have to be ordered, as I don't think anyone made aftermarket charade pistons. A cam is definately needed, I'm sure that the weber 40's will be able to withstand this power, but I at this point would sell them and make the upgrade to 45's. A bigger cam too, Auckland doesn't make a cam this big, but it's going to have to have high lift and LONG duration, something like 350 duration.
Word limit reached, continue here.http://forums.mightycarmods.com/show...055#post478055
sumber https://forums.mightycarmods.com/forum/technical/tech-talk/28114-hankey-s-guide-to-the-mighty-toyota-k-series-engine-3k-4k-5k-and-7k