hyd roller spring pressure

[chasmat2316]

How much spring pressure for a .550 lift hyd roller. cam is an old Kenny D 218-224 116 lsa
I'm using k-motion k-750's just looking at what other's use?

 

[bison]

Thats an odd ball for a hyd profile with that much LS. Seems more like a solid grind. What lobe #'s? Id want 165-175lbs on the seat and 450lbs over the top for a hyd. That should have you covered to 6200rpm/30psi unless its some special fast ramp lobe. If it is you will need even more. I dont think the K 750 spring will get enough pressure on the seat and still make it without coil bind. If you are in doubt of the lobe #'s you better give KD a call. There isnt room for error if you plan on making power and having valve train reliability. I ran comp 26120 with a 218/224 grind i had in an engine and they were close to coil bind but worked really good. The lobes werent the most aggressive though.

 

[chasmat2316]

grind #bv69 3313s / 3314s gross lift is .511 - .519 but I'm using a 1.65 T&D rocker

 

[Slow91z]

I have a 218/218 with 1.65 rockers...lift is almost .550...my k-750's work great.

 

[bison]

grind #bv69 3313s / 3314s gross lift is .511 - .519 but I'm using a 1.65 T&D rocker

I ran the same lobes with 110LS installed at 108 cl with 26120 springs and made a lot of power on a 9.3:1 engine with 1.65 rockers. 137+mph@27psi with an old cast 66 compressor. 700+whp. With more turbo it would have have made even more. You need at least a 67 compressor to take advantage of the power band with that cam. It's really strong from 5400-5900@27-30psi. If you want to make power without much drop off over 6000 you will need a 67cea or t70 compressor. 65/66or 68 turbine.

 

[chasmat2316]

Will the 26120's fit my GN-1's with out cutting the spring pocket? looks like installed height is taller also .
Yes T-70 comp. 68 or 69 S-trim turbine Tang housing

 

[bison]

Will the 26120's fit my GN-1's with out cutting the spring pocket? looks like installed height is taller also .
Yes T-70 comp. 68 or 69 S-trim turbine Tang housing

There isn't much room for pocket depth on GN1's. You need to measure everything. If I recall the installed height winds up around 1.900 with a .060 locator and +.050 10* lock and retainer. If you used machined 7* locks/retainers you could get a taller installed height but you should be able to get the heights you need without coil bind with common 10* stuff. I didn't bother with titanium on mine. Those springs work very well and you can run very close to coil bind with no problem. Use I.d.locators under the springs. I wouldn't use anything other than a zero preloaded/lashed 885 lifter with this cam either.

 

[chasmat2316]

Thanx for the info. I thought the K-motions were light on seat pressure from the day I got them from Tom @ Champion
would you have a part # for a spring seat?

 

[bison]

Thanx for the info. I thought the K-motions were light on seat pressure from the day I got them from Tom @ Champion
would you have a part # for a spring seat?

I'll look when I get home

 

[Scott Atk]

K750's work OK but they go away fast. Plan on changing them every year.

 

[chasmat2316]

I'll look when I get home

By any chance did you have a part # for the spring cup for the 26120's to fit GN1's ?

 

[bison]

I dont have it. It was an i.d. locator. Just go to summit or jegs and use the spring dimensions for 26120 to find the correct one. You need to know the guide o.d. also. i think mine were .570 guides but measuring is best. Ive seen two different guide diameters on Champion heads. On the same head so measure an intake and an exhaust guide.

 

[chasmat2316]

There isn't much room for pocket depth on GN1's. You need to measure everything. If I recall the installed height winds up around 1.900 with a .060 locator and +.050 10* lock and retainer. If you used machined 7* locks/retainers you could get a taller installed height but you should be able to get the heights you need without coil bind with common 10* stuff. I didn't bother with titanium on mine. Those springs work very well and you can run very close to coil bind with no problem. Use I.d.locators under the springs. I wouldn't use anything other than a zero preloaded/lashed 885 lifter with this cam either.

I was wondering how you got 1.900 installed height ? with a comp 795 retainer - comp 614, +50 10* lock without any spring cup or shim I only have 1.840 on installed height? This is on GN-1 alum heads so I need a spring cup

 

[bison]

I have have the actual installed height written down somewhere. I wasn't worried about the installled height as much as coil bind. It may very well have been around 1.84". Those springs can go really close to coil bind with no problems. I've been tighter than .050 from theoretical lift with no problem. I probably used a +.050 machined small lock and a .060 I.d. Locator. I run a different set of double springs now.