Thanks so much for the offer! I will definitely take you up on that. This will be the second time you came through for my team and I. Can we chat on the phone? I believe I still have your number from the last time we talked 1.6 dyno sessions on DynaPak. At least 3 years ago.
To clearly summarize my issue after calling Mazda:
Mazda sells 3 different valve springs
- OEM Production Intake Valve Spring: BJ01-12-125
- OEM Production Exhaust Valve Spring: B61P-12-125
- This part number above does not fit with any spring retainers I have from my existing engine. It also does not fit the corresponding new spring retainers that I ordered for the exhaust side. This problem was probably the reason why the general aftermarket spring kit was used on the crate engines years ago. See next point.
- Aftermarket General Valve Spring used on 1.6 crate engines years ago: B6BF-12-125
- This valve spring was used on intake and exhaust side of the 1.6 crate engines sold by Mazda for Spec Miata. Somebody with more SM history than I can detail what years these crate engines were sold. The spring kit used in these engines used the exact same valve springs for intake and exhaust. This valve spring set is the most desirable by 1.6 SM engine builders. I'm guessing that the exhaust spring is a little lighter and makes a bit more power. Maybe Steve can clarify why.
- Also, these aren't listed on the "Valve System" page on MazdaMotorsport online store, I had to call and specifically ask for these by name. James was the one who I talked to.
- James from MM tells me that there is nothing that notes that a special retainer is needed for these springs, and either OEM retainer will work. Good thing because Mazda has discontinued all valve spring retainers.
Mazda also sells different Valve Spring Retainers (aka Seat, Valve Upper) for Intake and Exhaust side.
- OEM Exhaust Retainer -
B660-12-113 (Now Superseded by B6BF-12-113) Both DISCONTINUED
- OEM Intake Retainer - BJ01-12-113 DISCONTINUED
From what I can gather, I am likely dealing with a cylinder head off of a 1.6 Crate Engine sold by Mazda years ago for SM. I can tell this because both intake and exhaust valve springs are identical dimensions. And my other spare engine out of a low mileage daily driver has different springs from exhaust to intake. EUREKA!
My problem has rooted from the fact that I am trying to Valve Spring #2 with Retainers #1 that are from a Mazda Crate Engine cylinder head.
This still does not explain why by Brand New OEM exhaust valve spring B61P-12-125 does not fit the Brand New OEM Valve Spring Retainer B6BF-12-113 (I was able to source the very last 2 pieces from Mazda in October, lucky me and they don't fit). But chances are they will indeed fit the general crate engine spring #3. Especially considering the identical PN Prefix for the Crate Engine Spring and Retainer "B6BF"
So what I need to do is exchange my exhaust valve springs #2 for the Mazda Aftermarket springs sold in the 1.6 SM crate engines #3. And use my existing retainers. That should fix it.
But I definitely cannot use my brand new Exhaust Valve Spring #2 for this engine since I do not have any valve spring retainers which fit. I do have another production engine which might have retainers that will fit this spring.
In summary: If you want to replace valve springs, make sure you order the springs out of the crate engines B6BF-12-125, and re-use your existing retainers. Both Intake and Exhaust retainers will work with this spring. However if you order production springs, B61P-12-125 you will need to make sure your cylinder head originally came with those springs (can be identified by looking at the wire used to create the coil spring. The coils will be slightly squarish when looking at the cross section, and the free length and spring rate should match the FSM). Finally, make sure you re-use or hold on to those spring retainers, as they are discontinued.
Thanks, and I hope this helps people from making the same mistake I did.
By the way, check your spring specs according to FSM, you may not even need new valve springs. And springs, being made of steel, will have an endurance knee and may never need to be replaced if they are used correctly. (not overheated often or damaged from engine failure)