These damn f*cking valve springs....

[markmdz89hatch]

Jean --> yep yep. Thanks for those p/n's too. I already have a handful of the 86-87 intake springs and retainers, but I need extra keepers too.

LX-incredible --> Those comparison pics are perfect. ...but are you sure that retainer pic has an exhaust retainer on the upper right, and not an 86-87 intake? Either way, what I think is awesome is that in an earlier post, you said 'who cares anyway' and at the end of the day, it was you that really went hunting in the boneyard to find out. My hat goes off to you my friend. Do you have a caliper? If so, can you measure the o/d and i/d of the bisi's, along with the wire diameter? I can get a coil count from your pics. ...I just want to try and get a rough estimate of the spring rate of each spring, and the coil-bind for the bisi's as compared to the stockers.

Dennis --> Where in the flying fUk did you get those retainers? Are those JG too?

Tdurr --> I'm with rjudgey. Be careful with the intake keepers on the exhaust valve. Not saying it's not going to work, but the intake keepers are much smaller diameter, and sit far lower into the retainer than the stock exhaust keepers do. I have a bunch in my basement too, so I'll tinker in the next few days as well. Honestly, I would just hit up the yard again and snag a full set of retainers and keepers from the 86-87 intakes, and as you had suggested, snag 8 exhaust seats. That will make those Bisi's feel perfectly perfect.

[LX-incredible]

Positive it's an exhaust.

Aint no thing, I'll admit when I'm wrong.

86 intake retainers (and I say 86 so someone doesn't grab the smaller ones from a later 87), and exhaust seats is the way to go for the intakes. 86 intake seats should also work, as the bisi springs don't have much of a gap between the inner and outer coils. The exhausts are a better choice IMO.

I'll post some measurements later today.

[markmdz89hatch]

nah, you weren't wrong at all. ...in fact, everything you've posted (especially the last few) have been hugely important to figuring this puzzle out.

[guaynabo89]

LOL

The retainers were custom made out of the strongest grade aluminum. The strongest alum is not as strong as titanium and thats why they are a little thick to compensate. They are still lighter than titanium as is and a hell of alot lighter than the stock steel ones.

My cylinder head is an 87 and uses the larger diameter intake springs with the dual seat retainers. My alum retainers were made this way as well and Im thinking getting some of the Bisimoto springs and turbo cam.

[markmdz89hatch]

No, you can't do it. I won't allow it. haha, j/k man.

Sweet setup there. Me likes.

[Tdurr]

meh, well i guess im going to the jy wed... lol
so 86 retainers, and any intake keepers?

[markmdz89hatch]

dunno about the 'any keepers' thing as I have yet to figure out the angle of the center hole or the diameter. I'll break out the caliper tonight and measure the center holes to see if they're the same. If so, then yes. If not, then no.

[Tdurr]

wanna just look up part #'s for the keepers and see if they are the same? lol

[Tdurr]

48124 is the keeper #'s for 86 lxi and 88 lxi. so should be good, worse case scenario ill just grab those when i get the retainers.

[markmdz89hatch]

48124 is the keeper #'s for 86 lxi and 88 lxi. so should be good, worse case scenario ill just grab those when i get the retainers.

so there you go. that answers that. You're good to go.

[Tdurr]

so there you go. that answers that. You're good to go.

[guaynabo89]

lol

Is that you?

[stat1K]

rofl.

['A20A3']

that's interesting...the top end of my motor was tampered with before it ever even left japan...

[Tdurr]

lol

Is that you?

lol no. google my friend.
and harvey, u have a jdm motor right?

also, anyone have a good tool that i can use to pull the springs off so i can put the new retainers on w/o having to remove the head? lol

[LX-incredible]

Inner bisi spring:
OD: 0.904"
ID: 0.678"
UC Length: 1.871"
Wire diameter: 0.113"

Outer bisi spring:
OD: 1.221"
ID: 0.897"
UC Length: 1.981"
Wire diameter: 0.162"

['A20A3']

and harvey, u have a jdm motor right?

it was from a Export Editon Coupe. one that was built here and then shipped to Japan. i know it sounds weird. it's true though. it runs perfectly, no fouling plugs, no oil consumption(running Amsoil 5w30), no strange noises, excellent compression, etc.

it says A20A3 on the block though, that why i dont understand why it has 86-87 valvetrain on it. cause i didn't swap that stuff out. hmmmm...

[Tdurr]

^^ hmmm well at least u kno u got the god stuff... lol

and lx-incredible is on point!

[markmdz89hatch]

^^ hmmm well at least u kno u got the god stuff... lol

and lx-incredible is on point!

....oh and yes, I have the rolls royce of valve spring / valve retainer tools. Give me a few days and I'll have worked out some details and hopefully get a tid-bit of a discount on the retail, which I'll obviously share the savings with you guys.

lx-incredible --> Who da man? ....U da man! Thanks for posting up those specs. Dammit, if only I didn't work 13 hrs a day, and have to take care of the kids when I get home, I would have a little more time to work on this. Thanks for really stepping up there.

[markmdz89hatch]

Ok, so here's what I started to come up with. I'll get the measurements and calculations on the 88-89's tomorrow (shit, it's real late/early, so make that 'tonight') and plug those into the spreadsheet.

*Note: The Bisi spring rates are listed individually, which is misleading. I'll clear that up when I get to work and can clean up the spreadsheet a little more. I'm tired, so I'm going to get my usual 4 hrs of shut-eye before groundhog day starts again. I also still have to add a row for coil-bind (which can be VERY important when selecting lift specs on a cam).

LX-incredible --> Can you measure up the Bisi Exhaust springs for me too? (If it's not too much more trouble.)

[Tdurr]

the bisi springs are the same all the way around. intake and exhaust are the same

and omg i dont even know how to read all that info lol....

[markmdz89hatch]

the bisi springs are the same all the way around. intake and exhaust are the same

and omg i dont even know how to read all that info lol....

hold onto your hat because here's the updated version of that sheet...

Now the graph below has spring rates just from a calculation of the spring measurements, which is not as accurate as just putting the spring itself on a spring compression tester and getting the individual specs that way, but given that I don't have $1500.00 to drop on a professional tester right now, and don't have the time to make my own just yet, this will have to do. ...but I did find some plans for a home-made tester that looks as though it'd work well enough for me, so I'll get to that one day.





Calc used:



Where
G: modulus of rigidity (shear modulus)
d: diameter of spring wires
D: diameter of spring coil
n: number of active coils (see below)

[Tdurr]

hmm. ur #'s show a huge difference from what i saw with my own eyes at the shop. I might toss the stock 88 springs in the car and go to another place and see if i can get the springs tested for rates.

[markmdz89hatch]

...ok, so basically if you take a look at that table, you'll see that much of this is in vain (kinda) because this desire to find the best inexpensive upgrade to the stock valve springs has proven more difficult than originally thought.

As you can see, although the 86-87 and 88-89 springs are VERY different in appearance, the calcs prove that there's less than a 5% difference in their spring rates. Now what's a real kick in the pants is that the exhaust springs are actually WEAKER despite the dual spring, and the more intimidating look to them. (based on the measurements and calcs [which i'm going to verify soon], and assuming the same spring wire material is used across the board).

Now also bare in mind that these specs are derived from an uncompressed spring measurement. All (or at least most) of the springs are progressively wound as opposed to linear, so their spring rates should really be line graphed to see what rates are attained at certain height intervals all the way to coil bind. You'll also want to consider that coil bind spec very carefully when determining if the lift on your cam is going to work without resulting in a coil bound spring.

[markmdz89hatch]

hmm. ur #'s show a huge difference from what i saw with my own eyes at the shop. I might toss the stock 88 springs in the car and go to another place and see if i can get the springs tested for rates.

But note the * on the table which states that the modulus of rigidity number that was used was for that of carbon steel. While it may not be the material used on our springs, all the final spring rates % of change between each should be accurate.

If the machine shop, or Bisi, has any more insight on the actual material used for the springs, if I need to make any corrections, iI can certainly do just that.

Either way, one note that can be made is that the bisi intake springs should only be used with 86-87 oem retainers. Keepers (thanks to you) we now know can be used from any oem 3G intake springs.