7000rpm

Yes I am sure there are many low boost setups on stock bottom ends. Thing is you get use to low boost, then want more.....get use to that....then want more :) All part of the fun. My advice was to build a tough engine from the get go to set up for future boost increases

If I were in your shoes, id be fitting forged pistons, spool rods, good head gasket and head studs. For the effort of trying to tune a carby on a boosted setup, id get a k series efi manifold and and aftermarket computer. (Full EFI conversion)

Comes with experience. This is my 5th project car

Sounds like a well thought out design from what i know so far. That cam still maintains a decent amount of lift. Perhaps ask the guys at weber performance in vic as to which workshops they sell to the most?

Auckland cam 873 grind (noted on their website ) The critical thing is getting the right timing curve set and right air fuel ratios. Whilst there are general guides, the tuner needs to find what each engine likes on a case by case scenario.

I run over 11:1 comp on 98 octane and detonation hasn't been an issues. Running twin webers and dyno graphed timing was set though. Datsun A series are 1mm over. They have longer stems though, so speak to your machinist about work arounds.

Interesting what compression ratio do you end up with? what octane fuel do you use?

You can use flat top pistons and 3k head. If you use flat top pistons with your head, which is a twin squish head, the compression will be too high. You can just deck the 4k head you have and use the original style pistons to increase the compression ratio

It comes down to how much you want to spend, how much power over standard you seek and how much time off the road modifying. If you want to reach about 55-60 horsepower at the wheels, you can manage this with a well behaved street 4k and not spend big dollars or time. Either way, as all k series and 4ages are old now, best to freshen up with an engine rebuild. Ive managed to get 107bhp out of the 4k I just built, and just took the head off to address some things I missed. Engine is built for track racing but still road drivable as I don't have trailer transport. On an everyday road Corolla, a 5k or if you are prepared to upgrade the driveline a 7k are much better for torque. As above 4ages end up being a nice street engine if done properly, but costs and time add up and possible engineering requirements (depending on your state regs)

Does your cylinder head have two lugs, under number 1 and 4 spark plug?

Hook the resistor back up

A multimetre is a great investment for diagnosis

Some mild cam grinds are suited to help torque and run tight duration. As you know, these little battlers need all the available torque possible lol!

As in that the connection is tightly fitted, not wobbly. ive never tested one, but imagine if you unscrewed it and connected the signal wire up with key turned to reds, you might be able to see the light turn off/on by pushing on the switch valve with something sharp?

I would contact Henry at auckland cams in new zealand. He has over 200 grinds for k series in his computer, so might have some spares sitting around

Silly question, but have you thoroughly checked the electrical connection on the oil pressure switch?

I personally wouldn't introduced a new igniton system till you have got the original diagnosed. what is the battery voltage, static and cranking? I am thinking the alternator wiring plug may have a poor connection after fitting headers

Sounds like a nice build Glad there are a few k series builds happening out there

Haven't seen any back to back results to compare. Out of interest, what other mods have been done to your engine?

Most people do the datsun A15 valve upgrade which are 37mm intake, and 30 mm exhaust. So 1mm oversize on both sides. They are different stem length to the k series, but I am told if you have adjustable rocker gear and a reground cam, it all works out. You can alse get L series datsun valves. There is a 38mm which seemed to be a much better matching stem height when I looked into it. http://www.swmotorsport.com.au/index.php?cPath=9_20

Yes the 5ks are much better for that. Even still though, I know a couple of guys overseas that have developed the 5k engine to extremes for circuit racing, and still use 421s on their race cars. At the end of the day, a small capacity engine is a small capacity engine. If you really want torque, should go for a 7k

All extractors are designed to scavenge. The 421 system helps with low and midrange torque. All out larger capacity, high rpm race cars prefer 4 into 1s cause its all about removing restrictions and flow dynamics There is a company in finland ive learned about this week that seem to cost about $700 aud delviered. https://www.mcnsport.com/collections/kp60-exhaust/products/martelius-kp60-exhaust-manifold might require modifications as made for lhd cars

Thanks John. Its a shame that most of these header supplier make uneven length 4 into 1 units for the k series. Due to the small capacity, I'm after 421 headers, same size primaries as the port. Looks like I am going to need to get a custom set made

Welcome Mike this has to be the best car forum on the Internet. Mature members that help out and post up the facts, without the bs. Is your car a ke10? Got any photos?

Hey Josh is that advertised duration or at .050?