Dohc 4k?

[Gavclassic]

Best you learn how to drive first before making the car go faster. Join a car club, do a kahanacross or supersprint learn to drive first then work on going faster!

[WinKE55]

id say its not worth it,

 

Just drop a 4AGE in and be done with it

 

 

He can't drop in a 4A-GE into his car and have it legally driveable on the street as he is under the new L and P laws. Even if he gets a blue plate, we are not allowed ANY blue plate what so ever.

 

 

So what you're proposing isn't a "modified" engine? :(

 

Modified being Turbo, Supercharger, or Engine conversions or making the engine output of more than 200 kW

[anastasios]

huge waste of time mate, and money, and bodgyness, i don't see the point, get a 5k shove a 4k head on it or even a 3k for more comp, just drive the thing

[Felix]

huge waste of time mate, and money, and bodgyness, i don't see the point, get a 5k shove a 4k head on it or even a 3k for more comp, just drive the thing

 

:( You would lower the compression ratio doing this. The vast majority of 5k's have dished pistons.

[styler]

i say go the 4ag head on the 4k, no ones done it before and it would be sweet.

 

no lol just kidding, dummy it up and you will realise nothing lines up.

 

best modification would go from a

 

mild 4k

worked 4k

4ag NA / 2tg

4ag supercharged / ca18det / 12a / 13b

4ag turbo / 1ggte / 1ggze / sr20det / 12a or 13b turbo

2jz / v8 / v8 super or turbocharged (drag only)

 

roughly anyway... some ideas for you.

 

not sure on your driving situation but seems these restricted modifications are quite

tight and don't leave much of an option for you younger guys.

[Kid-Ae]

Mate, if you want to have some more power from the 4k, i wouldnt head down the DOHC path.

 

Stick with a 4k. Your father being a mechanic will surely know a few tricks to improve performance.

 

Have a tinker and see how far you can push a 4k. Worst comes to worst, if/when she blows up, go grab another one, bolt it in and have another crack.

 

:(

[dfunkt]

i honestly cannot believe this thread has stayed on track.....i guess i should try and rectify this.

 

they kinda made a DOHC head for a K engine, if you ask the right questions to the right people, i'm sure you could get ALL the technical data outta them and then just build your own moulds so that you can mass produce them and sell them for MEGA $$$$$$ (it might help to learn some Japanese tho)

 

alternatively, you can pull your current head off, make a template and carry it around a wreckers looking for another DOHC head that matches closely enough, and just fudge the bits that don't line up properly so that you can bolt it on and go do some sick skids.

 

you could always design your own DOHC K head and have it built out of Billet or Alloy, with access to a CNC machine (4 axis maybe)

 

no conclusions....

 

dF

 

 

PS taz_rx knows best here is your answer

Edited June 25, 2008 by dfunkt

[st.nick]

Pointless, pointless, pointless!!

 

 

Can you imagine HOW you'd even begin to align all the water-jackets?? Not to mention all the issues with the cylinderhead aligning with the 4k cylinders.

And how much would it cost?? $10k?? $20k???

 

f@$k that!!

 

Build a super tough 4k!! Won't need a mod plate, won't have teething problems surrounding a stupid hand-built hybrid, and it'll f@$king fly!!

 

 

 

Thats where my money would be... Screw the twin-cam 4k pipedream!!

[Doogs]

Pointless, pointless, pointless!!

 

 

Can you imagine HOW you'd even begin to align all the water-jackets?? Not to mention all the issues with the cylinderhead aligning with the 4k cylinders.

And how much would it cost?? $10k?? $20k???

 

f@$k that!!

 

Build a super tough 4k!! Won't need a mod plate, won't have teething problems surrounding a stupid hand-built hybrid, and it'll f@$king fly!!

 

 

 

Thats where my money would be... Screw the twin-cam 4k pipedream!!

 

Exactly.

 

Start with a 3k/4k/5k, cheap easy mods and cops wont realise the difference (as long as your not to wild).

 

For the head swap to actually work a number of things need to line up, as has been said.

(valves, water jackets, studs etc)

 

Just have a look at the faq etc and start with something easyer.

[philbey]

Cheaper and easier to learn some patternmaking skills, design your own twincam head and pattern it and cast them.

 

Seriously.

[snot35]

I remember hearing years ago about people putting twin cam heads from something like a BMW motor cycle on an old single cam block. I think maybe it was for a mini motor?

 

I know the theory was good, but I'm not sure that they ever got it working properly, if at all. If you wanted to do it, you'd have to trawl through many many engine specs, find a head with the same cylinder spacing, and then start worrying about cam drive train, head stud spacing etc etc etc.

 

It doesn't sound like much, but to build something that doesn't blow up in 10k's is a monumental effort.

 

If you have access to a mechanic and a workshop, just work with what you've got. Learn to port properly, maybe stroke the motor. Learn about performance induction, build your own exhaust etc etc. This will be plenty to keep you busy, and should go OK if you do it properly.

 

You'll also get a heap more speed by learning to properly tune suspension etc, and by lightening your car. All this can be done without attracting unwanted attention.

 

To make a well balanced modified modified car will take you quite some time. Half the fun in modifying is getting the most bang for your buck.

 

Trying to hack on a DOHC isn't going to be the most...

[tas_ae71]

Cheaper and easier to learn some patternmaking skills, design your own twincam head and pattern it and cast them.

 

Seriously.

 

design a one off cnc'd head if your that passionate about it.

 

once you have the car sorted as far as handling goes, a few "simple" bolt on mods will probaly keep you happy for a while while you have something screwing together on a engine stand..

 

the biggest issus with most single cam heads is the fact that they tend to be non cross flow. look at t-series motors for example, 2tg (1600cc twin cam) and 3tc (1800cc pushrod) both have near identical ports and are both cross flow. there isnt that much performance difference between them because of the head.

 

it is common to put a 2tg head onto a 3tc bottom end as the head bolts on and the water/oil galleries line up.

 

putting a 4ag head onto a 4k block is like going to maccus and trying to drink your coke with a chip. with a lot of careful work you maybe able to hollow out the chip to that you can suck the coke threw it but why do that when there is a straw that came with the coke?

 

point being is that its a wakk idea. if you want twin cam go into the 1600cc class, its not exactly a huge step up and what are you going to be competing with? also what car is this going into? the lighter the better obviously. do you have a power figure in mind that you want to achive?

[Taz_Rx]

:P @ straw/chip comparison.

 

Nice work Az!

[Doogs]

putting a 4ag head onto a 4k block is like going to maccus and trying to drink your coke with a chip. with a lot of careful work you maybe able to hollow out the chip to that you can suck the coke threw it but why do that when there is a straw that came with the coke?

 

Nice :P

 

As people have said, start simple and probably stick with a k motor.

[maxyboy55]

if you want twin cam go into the 1600cc class, its not exactly a huge step up and what are you going to be competing with?

 

you would be surprised,

one of the guys i know there owns a honda CRX, 11.5:1(ish) compression ratio, 156hp @ the wheels, very fast

i reackon i'll just stick with my good old 1300...