Felix

Yep, they share the same head casting as a 5k. The inlet ports are sized between that of the smallport 3/4k heads, and bigport 3k's. I wouldn't say they are a monster, but they definitely go harder than your normal flat top 4k in standard form. Things going for the dished 4k's are: More efficient combustion chamber. Thinner compression rings for less bore friction. Mid-sized inlet ports giving better allround performance. Undercut exhaust valve stems for better exhaust port flow. I say bump up the compression to around 10:1, tidy up the ports, fit a 270 degree cam, add extractors, and 1 7/8" system, a 28/36 DCD weber. Fit it to a ke1x and go have fun wasting v6 commodores, whilst getting 12km/L fuel economy. :y: Wait a minute, thats what I did with my old 4k. :)

Has it got the cap which is smaller in diameter at the top than at the base? If so just replace the button and cap with the more normal wider one.

I agree, I've found that the dished piston 4k's go a lot harder than normal 4k's as well. Probably came into australia through a jap engine importers at some stage.

A 4k head is taller than a dished piston 5k head. I think what Cam was getting at, is you need to run a non-dished head with the chev lifter/a12 pushrod combo. The pushrods are a touch to long to use with a dished 5k head.. Cam, the correct terminology is "quick and dirty lifters". :) The zero dollar solid lifter conversion in my 5k (with dished 5k head) has been going strong for 3 years now with no problems whatsoever. :D

I know that. I just wanted to see Sbox's reasoning for his statement. :lolcry:

Why does the carb need to be in a pressure vessel??

You would be better off with an old holden or ford for a demo derby car. A decent hit from say an old kingswood and your ke70 would be rooted, whereas the kingswood would barely be dinted. Those things are battering rams on wheels. The only way you would have a chance is to play the whole cat and mouse thing and run and hide until the end.

Zany, yep you got the lifters correct. I am running 3k pushrods though as they are a bit shorter, though I think you worked that out by your post where you are chasing some 3k pushrods. My setup has been going strong for about 3 years now with the 5k head. Didn't cost a cent. :P Only hassle I ever had was initially the adjusters just tapping on the underside of the rocker cover which was remedied with a dremel. K pushrods would be the perfect length if you can find some.

Xany, what head is on it? 5k? From what I have seen pretty much every one who has done the chev lifter conversion with a12 pushrods has used a 3k head which is taller than a 5k one. Maybe this is the difference between the setup in your car and the one you are currently playing with...

Yes they do. They do not limit how much body roll you get, BUT they control the rate of body roll in transient conditions. ie. They control how fast the car is allowed to roll. This is one of the most important aspects of suspension setup as it has a vast effect on weight transfer in cornering and under braking and acceleration conditions. Handling is all about controlling and taking advantage of weight transfer to best suit the vehicle you are driving and your driving style for given road or track conditions.

Trev, you could also look at Jaycars latest programmable HEI kit here. The HEI system is programmable via a Hand Controller kit. It can be used with the Ignition Coil driver for a standalone ignition system, also you can add a knock sensor module to it.

I agree. A lot of people tend to get carried away with themselves when it comes to carb selection. The same could be said for too big a cam choice and over the top compression ratios. Ideally you want a well matched overall package suited to your type of driving. Books by A. Graham Bell and David Vizard are the best investment you can make when it comes to tuning a car for performance and economy. :locked:

Actually flat out is correct. A coil spring is basically a torsion bar which has been wound up to conserve space. Take two torsion bars of the same diameter, one a given length and one 20% shorter.... the short one will be stiffer due to less leverage. If you take a coil spring which has say 5 active coils and cut one coil off, you will increase the spring rate by 20%. Obviously cutting isn't ideal if it heats up the spring too much. The main reasons that most cars with chopped coils handle like shit, is because the cheapskate owners do not increase the dampening rate of their shocks to match the increased spring rate they end up with, causing a bouncy choppy ride. Also once you lower a car to much you f@$k up the suspension geometry which alters the roll center of the car, causing increased body roll for a given cornering load.

No it won't work. For one the ke1x struts have a 3 bolt mount on the bottom to the steering arms, whereas the ke20 has a 2 bolt lower mount. You can use ke20 ball joints with the ke20 steering arms, but then you will end up with even more positive camber than with the original ke1x setup and probably more bump steer. Ke20 strut tubes are also an inch longer. Why not just drill and tap your existing ke15 struts to take the larger later backing plate bolts. You can then always enlarge the holes on the ke15 backing plates if you want to bolt the original discs back on at a later date. Just use aftermarket ke2/3/5x strut inserts. They slip straight into the ke15 strut bodies, but you need to use a 1" spacer. Attached pic shows how.

Put a 4 wire O2 sensor in your exhaust and install an A/F meter. Makes carb tuning a breeze, as you can see what is happening in real time as you are driving.

If it has a round welschplug on the back of it, it is a bigport. If it has a plate with 4 bolts it isn't. Bigport heads are overrated, unless you want to drop the compression of a dished piston motor for forced induction.

For best power between 2500-7000 rpm in a 4k I'd look at a cam around 256-260 degrees duration. Keep in mind that a 4k's powerband will be about 1000 rpms higher for a given cam, compared to running the same cam in a 5k. So if someone says my cam will pull hard from 3500-7500 in a 5k, it will more than likely work from 4500-8500 in a 4k.

Sounds to me it is most likely a blocked idle airbleed. Very common in DGV webers.

Just build your motor to make peak HP at 7500 or lower and save your $$$. A stock bottom end is good for 8 grand (or more) :) Biggest weakness in a high revving K motor is piston ring groove wear.

First thing I would try is replacing the needle and seat. $15-$20. If it is worn fuel will continue to leak past it when the engine is switched off, until the residual pressure in the fuel line drops.

My ke15 had a ke30 km/h speedo in it when I bought it. You have to run a later speedo cable as the connection end on the back of the speedo is different to the original setup. Alternatively you could try to maybe print out the following and stick it onto your existing speedo. Pic came from Stewart Ford of oldcorollas.

Go find a mini or MG tuner, preferably with a dyno. They would most likely have a good selection of needles to fine tune your SU's.

I'll retract my earlier statement about the reduction type being larger than the ke1x type. More like similar sized. :P Attached a pic of ke1x starter:

I've got a tighe regrind, and it has served well in two motors over about 6 1/2 years. I've also known a couple of people to have had problems with tighe cams. I'd look at someone more local to you. At least if you have any problems help is closer at hand. Also you would save on freight in both directions.

LOL the ND ke10 starter is shorter than the bosch one you posted Raven. The motor part is just a touch longer than the solenoid. I have no doubt a reduction starter would spin the motor over a lot faster. I just haven't had any issues with the type I run now. If I ever run out of the smaller starters, I may change to the reduction type at a later stage.