K Heads

[Pongwow!]

Link:

 

http://www.rollaclub.com/board/index.php?showtopic=41899

 

Read my long post that is all.

 

Cameron

I read it and didnt find out where the bigport heads with bigger valves came out?

[camerondownunder88]

Ok Early K motor heads had large ports small valves. Same as the 2K motor.

 

Toyota then installed larger valves around the time of the 3K in the KE1X. So early to late 1970ish.

 

When we say bigger valves we mean same size valve any KE7X,KE55,KE30 has.

 

When you see a K or 2K valve their small Toyota went to larger valves in all later heads adn that is what you see in any K motor head.

 

So if you looking for large corolla valves just go get a 4K head off a KE70.

 

The only way factory which they get larger is with a TRD valves. RARE AS ROCKING HORSE POO.

 

But why do you want larger valves?

 

If you bore a 4K out think it was 60 thou pop the exhaust valve in the inlet and a Gemini vavle will fit exhaust and is larger. MUST bore motor to do this or gemini valve will hit. This is what my engine builder has done and was going to do for me but I changed plans. Did involve a lot of machining so wasnt going to be cheap either.

 

Cameron

[Pongwow!]

so 4k of ke70 has larger valves?? cheers man,, umm because when we were at the dyno the bloke told us a few things we could do and he recond that having bigger valves are better then bigger ports and do u do racing?

[Redwarf]

What head do you currently have? My Screamer 3/4 K had later (i.e: not small big port) valves. I believe Gemini valves fit, or do you have to stay Toyota?

[Pongwow!]

Umm I'm not 100% sure if we can use other valves we can run other Valve springs thoo ill try find out :D , We run the bigport head at the moment but on new motor were trying the 3k head as the wa2 runs one and it pisses so now were tryingg it, we running next weekend at narrigon with a bigport head the compression ratio at 12:7 instead of 10:7 so also trying thatt

[camerondownunder88]

If it is an early big port head you have smaller valves.

 

If your other head is a 3K head then it should have the later larger valve.

 

I take it you can't bore your block bigger?

 

If your not aloud to then you can't use gemini valves they will hit the cyclinder walls.

 

Cameron

[flamingheads]

Sorry I was thinking of this. I knew it was something about heads with big something on here somewhere. Next time I'll check first.

 

People go on and on about how good 3K bigport heads are. Whatever. A bigport is also well over 30 years old, and probably has a fair bit of corrosion around the water jackets, it might even have developed a crack, will strip at least one manifold or rocker thread, and probably has a few helicoils in it. They also have crappy valve retainers and stem seals, which you need to change to later 4K gear when you make power.

 

With the amount of money you'll spend having an old late 1960s 3K head reconditioned to a working state, you could have taken a 20 yearold 4K-C head which works perfectly fine, is less prone to cracking, and had a port job done on it which is better than a bigport casting. Don't waste your time searching high and low for the elusive mystical 3K bigport, I have two of them and take it from me, they're not that bloody good.

[Pongwow!]

If it is an early big port head you have smaller valves.

 

If your other head is a 3K head then it should have the later larger valve.

 

I take it you can't bore your block bigger?

 

If your not aloud to then you can't use gemini valves they will hit the cyclinder walls.

 

Cameron

 

We have 2 bigport heads, ones of the car so can't see the valves but we have another one of the car that has the same size as the 3k valves so it must be a later one?

And yeah we can bore out block 60thou