Cam Grind For 4k

[mighty_4k]

Hey guys I will soon be getting twin Dellorto sidedrafts and headwork done on my 4k. While the heads out I'm going to get my cam reground. I have decided that I'm going to go with 1 of the 2 following grinds.

 

Grind 1 234@ .050" 291 cam lift

 

Grind 2 238 degrees of duration at .050" and .296" cam lift and 108 lobe separation

 

The guy thats going to be doing my headwork thinks I should go with grind 1 since its milder but I'm seriously considering grind 2 I'm thinking if I'm get my cam ground might as well go all out and do it properly first time. Appertaley if I go with grind 2 I'm gonna lose a bit of driveability down low anyone how how bad this will be especially is traffic? My ke70 will mostly be a weekend car but due to the fact I live in a city I will get stuck in (sometimes heavy) traffic from time to time. Also can anyone well me what the powerbands of both grinds would be? I would like my powerband to be in a pretty streetable range which is another concern of mine with grind 2 will it start making power too high in the rev range? No point in making all my power at like 6000rpms+ in a street car.

 

Also before anyone starts flaming me I have used search but I didn't find anything similar to the grinds mentioned above, thanks in advance for your responses guys.

[Evan G]

go for a cam with good low or low - mid range. i can't see myself getting a cam witch you have to rev between 6 and 8 grand!

 

isnt really practical street cam at alllll

[snot35]

Do you have the advertised duration at all? There is really bugger all difference between those two cams. Both will probably be annoying to drive. What sort of car is it in?

[mighty_4k]

Going onto a ke70 mate and no don't have advertised duration unfortunately.

[altezzaclub]

Those figures don't make sense to me- Look at Tighes Toyota cams (http://www.tighecams.com.au/cars.htm) and the 50thou durations of about 240deg are described as fast road/ rally. However you will have lift of over 0.4".

 

Anyway, either one will do it seems, but if you don't get the carbs and everything matched it will still be a dog to drive in traffic.

 

It will probably bog down and stall when you try to get it moving in the queue, and the idle will randomly die and stall just when you don't want it to...

 

A lightened flywheel will make it worse.

 

So you'll end up blipping the throttle all the time at the lights, and revving it up with slipping the clutch to move it two car places further forward towards the red traffic light!

 

I've just got the car running with the equivalent of their 113 grind & SUs, and it does make a good difference from about 1500rpm up. (& even that cam is grumpy at idle)

[snot35]

It's probably lobe lift rather than valve lift. It needs to be multiplied by 1.5

[mighty_4k]

I have looked at the tighe website and yeah the figures are certainly different I live in New Zealand so maybe their measured differently like snot said?

[RainWarriorDregs]

i've been recommended the Tighe 104 cam grind for my 4k. just your normal mods

 

32/36, 4-1 extractors, exhaust, port matched manifolds, complete rebuild (new fuel pump, water pump, bearings etc)

 

i've been told its a good cam for these mods, but also that its a good cam for low to midrange power. maybe that'll help you out

[pink_gemmy]

Those figures don't make sense to me- Look at Tighes Toyota cams (http://www.tighecams.com.au/cars.htm) and the 50thou durations of about 240deg are described as fast road/ rally. However you will have lift of over 0.4".

 

Anyway, either one will do it seems, but if you don't get the carbs and everything matched it will still be a dog to drive in traffic.

 

It will probably bog down and stall when you try to get it moving in the queue, and the idle will randomly die and stall just when you don't want it to...

 

A lightened flywheel will make it worse.

 

So you'll end up blipping the throttle all the time at the lights, and revving it up with slipping the clutch to move it two car places further forward towards the red traffic light!

 

I've just got the car running with the equivalent of their 113 grind & SUs, and it does make a good difference from about 1500rpm up. (& even that cam is grumpy at idle)

 

I have nothing to say about the cam, but seriously... If this is how your car behaves in traffic just because of a cam there is something wrong! I have driven plently of cammed car's, from 2 litre gemini's with larger than the largest cam available with a power band of 4000 - 7000, with said sidedraught's in traffic and no stallage! Just bring the rev's up a bit and she will be fine, i have also driven 308 burnout car's that seriosuly have like half a second of lope inbetween each idle pickup and still no stallage... If you think it will be that much of pig to drive, have you ever seen a bridge/ j port rotor? NO power at all until at least 3500 rpm and a complete DOG before that, were talking splutters, chokes, fart arseing about and the stench of unburnt fuel but still if you know how to drive your own car there will be NO stallage.

 

If you do go big cam it will be a bitch, but soooo much better!

 

You can't half tell i'd rather drive an absolute PIG of a car and fight with it at a daily just because i enjoy that sort of thing, rather than just drive something mildy done up because Oh well when there's some traffic i like it be "comfortable"

 

Just my 2c..

[Suziefox73]

USE A SPLIT DURATION CAM!!!!!!!!!!!!! Use a well known cam grinder, give him the best condition stock cam you can and ask him for a split duration cam thats lumpy, ie: intake 25/65 exhaust 30/70+! A cam like that will work well on a non crossflow setup where the airflow though the head changes direction, as it allows the compression chamber to be free of burnt mixture! Which has the effect of allowing more fresh mixture to be drawn in through the inlet tract allowing you to run leaner mixtures with your jetting and keeping chamber temps down! In short terms, more torque, top end power, less fuel and a lumpy idle but no overheating or fowled plugs! Just make sure to get your tune right and do reg services and no probs KO!

[altezzaclub]

If this is how your car behaves in traffic just because of a cam there is something wrong!

 

Pink jemmy, read this line-

 

but if you don't get the carbs and everything matched it will still be a dog to drive in traffic.

 

Having driven rally cars for years I can appreciate the difference between a well-setup car and a poorly setup car, both using the same cam. No, my car's not a dog to drive in traffic, but having driven ones that are I can tell you there is very little pleasure in having a daily driver that only works above 3500rpm.

 

Here is the usual list of mid-range cams-

Edited June 1, 2010 by altezzaclub

[Suziefox73]

Yeah, i reckon the Tighe 154 grind hey, but it's a personal choice! I,ve owned cars between 1.3-1.6 with Tighe, Camshaft engineering and Waggot cams! Found all to be of top quality, Tighe cams are hardcore street weekend racetrack options, Waggot are more mainstream with big torque and camshaft engineering are damn good! I built one engine for a 1300 Mazda i owned many years ago in which i used a camshaft engineering cam and the damn thing rev'd out clean to 8500rpm and made a sound like a cross between a die grinder and a 10A and used $20 a week in fuel!!!!

[B.L.Z.BUB]

Is there a straight answer for daily, 2" zorst, extractors, gemi carb? If I missed it in all the tech talk, sorry I'm learning! And enjoying every freakin minute.

[altezzaclub]

Nope!

 

Too many options- At least a dozen cams would do more or less what you want, and some more would be useless for you.

 

Unfortunately the only real way to find out is to try one!

 

Try something around the 270deg mark.

[mighty_4k]

Well time for a bit of an update finally took the head and cam out today gonna be sending my cam away in the next day or two. I think I'm gonna go with grind 2 especially after reading pink_gemmy's comment lol. My 4k will be getting extensive headwork done and twin rebuilt and jetted Dellorto DHLA's put on. With that setup do you think I could get away with a cam that big or would it still be too much? Will I be making all my power too high is the rev range? I want something that could make power from say 2500-3000rpms to 7000-7500rpms which I should be realistically should be able to rev out to without any problems given my other mods, not that i plan to rev that high too often.