Dual Valve Springs Question

[tioklou]

hello again... i want to put in my 4k head dual valve springs....i have found some sets out of different brands of cars....but in every case the inner spring hits on the valve stem seal..do you have any solution? did you use some different stem seals? thanks a lot.....

[Taz_Rx]

Apparently SR20 springs fit K's and are a stronger rated single spring.

[altezzaclub]

...and another single spring for cam lift over 0.4" is the Holden 202 red motor, part # 4823 I have been told.

 

I'm also interested in knowing of an inner spring that would fit. Anyone run twins??

 

The Datsun 1600 ran twins, but I think the little side-cam 1200 only used singles. Maybe 1300cc motors just don't need them.

[Evan G]

Apparently SR20 springs fit K's and are a stronger rated single spring.

 

o0oo0o0o0o ill have to look into that thanks taz_rx :dance:

[coln72]

5k springs are stronger so I have been told.

 

You need to ask the question "Do you really need twin springs????" The more spring pressure you have, means the more power it takes to compress them, so the less power you have to play with.

 

5k springs will handle 8000 rpm no problems.

[camerondownunder88]

Where to start.

 

there are 2 types of stock spring for a K motor. Springs for solid springs for hydro lifters.

 

Solid lifter springs

load of: 31.8 KG or 70.1 Lbs.

free length of: 46.5mm or 1.831 inches

Installed length of: 38.4mm (all K motors)

 

Hydro springs:

Load of: 35.0 KG or 77.2lbs

Free length: 48.0mm or 1.890 inches

Installed length: 38.4mm

 

Brand new valve springs when i last got a hydro set for a 5K were $90. So if your not hitting 8 grand a day jsut get soem hydro lifter springs better but not to much power will be sucked out.

 

I used to have a set of dual springs for a K motor sold tem on here a while back bolt in fit didnt touch seal. I belive they were for a K motor not another one made to fit.

 

But when talking to a few engine builders abotu dual springs they all seem to say they test there length so there ALL the same height, load all the same load, and calculate the best "frequency" they work at (more ona race engien last one). So they can match the spring to optimum rev range that will be seen. So have to factor a lot in.

 

But the TRD springs for a K motor the outer one is a lot larger in diameter and the inner one is liek the size of a stock spring nearly. Inner spring is more for dampening at high RPM. Also on the valve springs like the suspension springs TRD colour coded tehm for different loads they had there are blue yellow and red springs you can get for your head.

 

Part number for the TRD springs have a heap wont list them all BUT....In the stage 3K/4K TRD engine the valves springs are part number:

90501-RA401 (outer)

90502-RA401 (inner)

 

These 2 part numbers are the same as the TRD 18R-G motor. So try seeing if stock 18R-G parts for a K series head.

 

Also the inner TRD valve spring number for the stage 2 head is:

90502-KE051

 

This is also the same part number as the inner spring used on the 2T-G engine so again try using a 2T-G inner with possibly a holden 202 outer as there quite round so lots of mixing and matching can be done but again is it worth it a good single can do the job. But if you will be at high RPM for ages id get dual so the inner one dampens it all out.

 

Cheers

Cameron

[altezzaclub]

Yes the inner spring is not to help shut the valve, it is there to stop the outer spring getting valve bounce due to its natural harmonics.

[rob83ke70]

I have dual springs fitted to the worked 4k, they were supplied by crow cams, I can't remember the specifics it was so long ago :dance:

 

Robert.

[tioklou]

that means that TRD springs need modification on the head....i believe that the SR20det is an easy solution...thanks Taz....

[camerondownunder88]

Yes to fit TRD springs you do need to mod the head need a larger base under spring machined to hold both adn different retianers on the top.

 

Ill get back to you on a part number of the 2T and 18R outer springs.

 

But later ill post a pic of my TRD springs on a head so you can all see how they go together.

 

Cameron

[tioklou]

o thanks Cameron.... i am waiting a picture of your trd springs.....