Adding Lumpyer Cam To A 4k

[Gareth]

Hi, i have a pretty stock standard 4k in my ke30 and i was going to do something to the engine to give it just alittle more power :dance: my friend said that the cheapest option would to go for a lumpyer cam. is it worth going for a mild race grind (from kelford) and drop it straight in or get a more agressive grind and do some more modification. i am only using it on the road. ( also off topic but will the straight mild grind give me that nice lumpy idle haha )

cheers

[altezzaclub]

First thing is, what revs do you want to drive it at?

 

You'll find the manufacturers give a rev range for each grind, and to make it work properly you'll need better carbs, exhaust and higher compression.

 

I'm getting a Crow 606 for use under 5000rpm, & Rob runs a Tighe 104 I think it is, hot enough to get a grumpy idle on SUs and a set of extractors.

 

These are specs on the lower rev range cams cut in Aussie. There is stacks to learn about!

[philbey]

Don't believe the hype, get the biggest on you can and ride that pony in the 6500+ range.

[corollaart]

Cam ,carb, compression,exhaust .LET MORE IN GET MORE OUT :dance:

 

phew thats a 100

rob

[snot35]

For that lumpy idle, definitely bigger is better. Don't tune the carbs or change the exhaust either, it will sound nasty.

 

Forget about it being drive able though :D

[altezzaclub]

I have a feeling that "lumpy idle" starts with cams around 270deg.

 

Anyone got opinions/experience on that?

 

For the list above I just took all the cams I was interested in for low-down power, there are just as many 270deg and above to pick from.

[Redwarf]

Lumpy idle is not all that it's cracked up to be. I had a big cam (.435 lift) in my 3/4 K and I had idle set at about 1300 rpm and it sound about normal at that!

[philbey]

yeh mine lopes at 900 revs but the idle's been set to 1200 so it's manageable.

 

thats my mystery cam though, whatever it is, it's fairly agressive.

[Old fella]

Hi, i have a pretty stock standard 4k in my ke30 and i was going to do something to the engine to give it just alittle more power :D my friend said that the cheapest option would to go for a lumpyer cam. is it worth going for a mild race grind (from kelford) and drop it straight in or get a more agressive grind and do some more modification. i am only using it on the road. ( also off topic but will the straight mild grind give me that nice lumpy idle haha )

cheers

 

 

G`day mate, I just finished my 4k and have done mild head work, extractors and exhaust, modded carb so both throats open together, balanced, std flywheel and a Tighe 140 grind cam. Its as lumpy as shit and has nothing until 3 grand but is still making grunt at 8000. Its a pain in the arse in traffic but a load of fun in the mountains around Toowoomba.

For a stocky with a lumpy idle, go for a good old 26/65 like a Tighe 113 and work from there. Just keep in mind that a cam ain`t gonna do much without other mods, but its somewhere to start.

 

For info:-

Profile

Number Advertised Timings DURATION VALVE LIFT TAPPET

CLEARANCE REMARKS

Ex Op.

B.B.D.C. Ex Cl

A.T.D.C In Op.

B.T.D.C. In Cl

A.B.D.C Advertised @ 0.050" Gross. @ T.D.C. Ex. In.

 

112 60 20 20 60 260 260 211 211 0.423" 0.423" 0.026" 0.030" 0.014" 0.012" Bottom end

113 65 25 25 65 270 270 207 207 0.400" 0.400" 0.027" 0.033" 0.014" 0.012" 2000 - 5000 RPM

104 65 25 25 65 270 270 215 215 0.423" 0.423" 0.038" 0.048" 0.014" 0.012" Strong Midrange

240 70 30 30 70 280 280 218 218 0.423" 0.423" 0.040" 0.053" 0.014" 0.014" Mild

154 71 25 31 70 276 281 216 227 0.398" 0.398" 0.033" 0.054" 0.014" 0.012" Midrange

424 71 25 31 70 276 281 226 235 0.450" 0.450" 0.043" 0.062" 0.014" 0.012" Rally (PRC)

140 70 37 37 71 287 288 240 240 0.488" 0.488" 0.072" 0.091" 0.014" 0.014" Nice twin carbs / Fast road

150A 71 40 40 71 291 291 240 240 0.474" 0.474" 0.065" 0.095" 0.014" 0.014" Fast road 2750 - 6500 RPM

474 83 31 43 72 294 298 234 244 0.415" 0.426" 0.012" 0.012" Fast road 3000 - 8000 RPM

439C 84 48 50 82 312 312 252 252 0.442" 0.442" 0.014" 0.012" Speedway

413 85 41 45 81 306 306 259 259 0.435" 0.435" 0.014" 0.012" 4000 - 9500 RPM

 

Notes -

[cush]

Do you want lumpy idle or do you want maximum power?

 

I you want lumpy idle, all you need to do is adjust your mixtures or stick a tennis ball in one of the bores.

[Old fella]

Do you want lumpy idle or do you want maximum power?

 

I you want lumpy idle, all you need to do is adjust your mixtures or stick a tennis ball in one of the bores.

Jeez, never thought of that. The tennis ball would help the piston to spring back down the bore faster too. New project here I come.

[RedKE30]

Recipe for lumpy idle:

 

1.Remove spark plug no. 1.

2. Proceed to smash the electrode of spark plug no. 1 on bench.

3. Refit spark plug no 1.

4. Enjoy.

Edited January 20, 2010 by RedKE30

[Old fella]

Recipe for lumpy idle:

 

1.Remove spark plug no. 1.

2. Proceed to smash the electrode of spark plug no. 1 on bench.

3. Refit spark plug no 1.

4. Enjoy.

 

 

Just thought of an alternative to turbo charging for the cash strapped too.

1 Remove cylinder head.

2 Screw or araldite any old valve srpings to the tops of the pistons. (note...do not clean carbon from pistons or combustion chambers, it helps keep the compression ratio up)

3 Replace the cylinder head. No need for new gasket. No increase in compression.

 

The added thrust from the springs being compressed swill help those little suckers really fly down the cylinders in double quick time. No extra fuel consumption problems either so the driver and the envioronment are both winners.

 

I might actually take out a patent on this idea, so get in quick before you have to pay me for my expertise.