Which Valve Springs Do I Have...Ideas?

[5NDIME]

So I posted this over on that other forum and haven't received any replies...figure I'd try it here:

 

Okay, so I bought an L20B with a W53 closed chamber head on it. I have been able to verify that the cam is an Isky comp cam of the Z-196 grind variety. I also was easily able to tell that the retainers are the NISMO aluminum because of the color (duh, too easy). The guy I got it from had dreams of building something, but he bought the head like it sat; so he had no specs he could remember from the guy he bought it from. I'm just trying to sort it out.

 

Now for the springs, I took them in the machine shop I use and had them do a quick check on them. The stats they came up with @ 1.84" were all right around 80# and @ 1.36" all about 210. Bind averages about 0.96"-ish. So what I am curious about is if anyone can tell from these stats if these are Isky, NISMO, or someone else's. Just would like to have an idea. For the static specs, the height sits at 2.25" on the bench for the outside spring. OD is ~1.34" / ID is ~1". On the inners, they are 1.925" tall on the bench, with OD @ ~1" / ID is ~0.755". I know OE inners are often used with Isky or the like as the outsides. Any indication if this is a full set of one brand or a mix and match?

 

Thanks in advance for any info!

[banzai510(hainz)]

Compitition nissan springs are OD 1.34 coil bind at .970 assembled height 1.72 seat pressure of 120

this is from the compitition book.

 

 

if ca is over say .480 ther inner stock spring will almost BIND.

 

I have used stock inners or outers combind with a compititon spring vise versa but my cam have been 475 or 460 lift

[5NDIME]

So if installed height is 1.72" and bind is at 0.963" in the top end, we have a delta of 0.757". So if this is max spring travel and a rough tollerance of around 0.07" difference between travel and lift, theoretically a cam with lift of up to 0.687" should be possible without danger of spring bind. My math right on this? Which I would guess is why the Z-196 cam was selected with a lift of 530 given the other components. It should all be able to run with this cam. Or am I missing something? Then again it is all theoretical until metal slams into metal and you figure out this doesn't work I guess.

[banzai510(hainz)]

you really want a .530 lift cam?????? if yes then the Compitition springs Both inner outer are a must.

 

a basic math proplem is take the cam lobe measure the lobe at the long part and hen measure 90degs from that. Taht will give base lobe lift. like a .267 then multiply by 1.48 or 1.50 for rocker arm ratio. this will be advertised max lift. but really you got to subtract out the valve lash also of say .010in .012 exhaust.

 

I would look at the Isky site at the 475 or the 480 or maybe webcamshafts.com thry have a 488/252 duration cam might be more streetable

[5NDIME]

Well I already have an Isky comp with 530 lift; it was in the head when I got it with all the other stuff. Just wondering if what was assembled was a dream the PO had or maybe actually ran. I got the engine in pieces, but it looks like it may have been run lightly at some point.

[Sealik]

Assemble the head and check for coil bind.....a minumum of .020" ??? needed between coils

Then...do a wipe pattern

Check every rocker because valve stems could be of various heights...etc...etc

 

Also...FWIW......you'll notice some spring coils lean the opposite way as seen here. Not sure what you have.

Stock application...<...inner coil leans one way, outer leans the opposite.

You can lean them both the same way....but...it's more prudent if they were opposite to each other. Less of a tendency for the inner getting hung-up on the outer.

.......................As seen with the Motorsport springs above.....third from left