There's spring rate calculators online if you Google. Measuring will get you close.

Just got off the phone with Jegs and apparently TONIGHT they're getting a shipment of 50-100 springs. I'm 6th on the waiting list so if its 100 there would be JUST enough for my order .. if not I have to wait until the next shipment.

So apparently these are available .. just order yours 3-6 months in advance of when you think you will need them ?

I got the diameter of the oem spring coils on a 01-05 VVT head

Intake: 3.78mm

Exhaust: 3.60mm

Looks like you were one of the lucky ones. I just got an email this morning from Jegs saying I have a "new estimated ship date" of the 23rd. I ordered mine back in early March.

I now have the same updated "next shipment expected on the 23rd" date as well. You might actually be ahead of me in the queue :vash: I ordered mine 3/13.

Sorry for the delay.

The spring suggested to me from BC is the BC1600. I was told that it would have approx. 65 lbs on the seat or if you want more pressure you can shim the spring to 1.450 “ for 73 LBS or a 1.400” 85 lbs. This was going off of the measurements that I had taken of the stock VVT head with a caliper along with a little basic math.


What do you guys think about this possible solution?

BrianCrower.com | RunBC.com // Subaru / EJ257

https://store.briancrower.com/produc...13489426169921

So does that mean just use the factory seat and retainers with the BC1600 spring?

That sounds really promising

That is what my researching is based off of - Stock head, Stock Valves, Stock Retainers, Stock Keepers, but Aftermarket Beefed Up Valve Springs. I am not sure the metallurgical tollerances here etc haha, but based on the data I took from the VVT head I have (Japanese Domestic Market version w/ flat top, not US) this was the closest to the stock intake spring which looked to be the bigger spring of the two based on it's larger coil diameter. My numbers are all in this thread only a few posts above so please double check on yours to be certain.

OD/ID on this BC1600 spring is 1.050"/.755". Stock is 1.032"/.725". Is this within tolerance? Seems damn close. Also, you think the 65lbs is enough and I can stop my search for shims? GT28R power coming is all, nothing crazy.

The only thing I'm having a tough time with is finding shims. I don't know if I'm being too picky with the size differences or not, as in, how off is too off vs it can be this much off and be fine. :likecat:

P.S. Would be awesome if this works out and between us all we can vet out numbers and agree on something. BC has been supporting import engine builders for a while now, would be nice to see a Miata offering of some sort and maybe them have interest in other stuff for the BP.

I definitely think we might have a replacement for the Volvo springs, but like you mentioned, I don't know if the seat pressure will be enough for someone doing something stupid like 350+ wheel.

Thanks for the research and numbers; this is definitely interesting. Link to related (sticky) thread for comparison reasons hereafter:

https://www.miataturbo.net/engine-pe...ng-info-70450/

The BC spring rate is 240lb/in; need to check the OEM VVT rates. Dimension-wise, they seem like they will work just fine.

The VS855 drought continues .. expected ship date now pushed to 05/06.

In stock. just talked to them. actually have an invoice ready.

5.50$ each. = 88$ a set.
8$ shipping.
Valve spring B18/B20/B30E/F

email John@vp-autoparts.com
phone 8437600170
stateside address. 3225 Fortune Drive STE #B North Charleston SC 29418

Order yourself some. and Cat me up.
have a great day.

I ordered a set of these yesterday (their website does not allow you to pay online) and got an email this morning with a phone number to call
my visa number into. The two people I spoke to, both had proper Swedish accents and confirmed this will be going out Monday. My shipping was $10.95, however
if you order the valves in sets of 8 (418737-SET), the costing comes in at $37.50/set.

Thanks JR Master!

Yeah, I ordered some Thursday, but I haven't heard anything back.

Do I just have to call the number in order to pay?

https://cimg9.ibsrv.net/gimg/www.mia...ee9c0275d2.jpg

FYI oreo. you need 2 sets for a miata.

You may want to call to confirm they have your order. I placed my order later than yours, but got a confirmation email right away. And an email with the shipping costs, the next day.

and yes, I ordered 2 sets. :)

This shop is literally 20 minutes from my house. I might stop by today.

Ok my order of springs from VP Volvo parts just came in and I thought I'd give a little update if anyone else was trying to get some springs. Ended up paying like $93 or something shipped to my door. Really nice people there.

The dimensions appear to be perfect and the factory top retainer fits well into the ID of the springs. My head is at the shop so I can't test actual fitment, but I took measurements and everything looks good.
https://cimg2.ibsrv.net/gimg/www.mia...389a99a87b.jpg
Volvo Miata valve spring dimensions

awesome. soo happy it works.