K engine info

K engine tune up
Setting the timing to 10 degrees rather than 8 degrees is often much better. As usual, advance the timing till it pings then back it off a bit. The result will depend on the fuel and compression ratio.
I have an electronic ignition modual, which is the first thing to upgrade to on any old points operated engine. Imported engines such as the 4K-E and 2T-GEU (any many newer engines) come with a electronic distributor, which has the magnetic style pickup. I have had one of these distributors, and normal points, running my homemade ignition box (igniter) made from a DickSmith / Jaycar kit. There are a few circuits to choose from in the kit so you can use points if you want, or hall effect sensor. The kit is $50 in Australia. On a second thought, just buy a Toyota igniter (ignition moduel), and get the hi-energy coil at the same time from the wreckers, but you need the Toyota magnetic distributor.

Everything in the 4K motor is small, but the carby is a good place to start. If you can't replace it, you can rejet it. I increased the primary jet from about 1.21mm to about 1.3mm, and the secondary to about 1.5mm. It goes better now. I also removed the choke and extra butterfly in the secondary barrel, which improves throtle responce and flow. The small exhaust manifold (and everything else) are still holding it back, as well as the inablility to rev hard due to the pushrod design with weak springs. The carby stud pattern is the same as used on other Jap engines of that time, such as Datsun 200B's and maybe Coronas. A poor mans option may be to fit a larger carby off a 200B that is jetted to suit (if you can't afford a webber or something), and you may even get wheelspin as I did! For a bit of rpm you really need to get some fresh or stiffer valve springs.

It's a long time ago now that I had a 4K engine. Mine was not very good because I spent all my time building the 2T-G. For handling the 4K is better because it is lighter than a 2T-G. The 2T-G makes my car a bit heavy overall, and front heavy also.