SUB's for a BP4W
 

As always, I'm late to the party when it comes to mods. When I (re-)built my engine (again, after bending a stock rod) three years ago I was looking around for the right size shims to set the valve lash properly. I was finding that the "normal" suppliers were drying up and even finding Toyota shims were proving to be difficult. I lusted after a SUB setup, but I didn't have the coins to make that happen so I ,ade do with the shims that I had laying around. That got me close, but not perfect.

Now, it seems that trying to find new SOB shims is next to impossible (unless I'm looking in the wrong places). So, I thought; "You've got the cash to go for SUB's, so let's do this!" Unfortunately, all I'm finding out there are two options; Supertech, or Maruha - again, I could be looking in all the wrong places.

So. I'm reaching out to the gurus on MT to ask;

• Are SUB's realistic/worthwhile for a street-driven, HPDE-prepped, turbo-Miata sporting about 300WHP and occasionally sees 7200RPM?
• If not SUB's then where can I find "stock" shims in various sizes to reduce the tappity-tap-tap that I'm currently experiencing?
• If SUB's are the answer, then are there other options available and - more importantly - where can I source a range of shims for them?

I'm not in a terrible rush, but an over-winter project would be nice.

SUBs are mainly for high-revving aggressively-cammed engines, the lobes sometimes scoop a SOB shim out of the bucket. If you have been running your SOBs for three years the answer to the 'need' question is probably not. Unless you plan on running more often, running more revs, and/or going to more aggressive cams.

If you do decide on SUBs: One option (which I have used) is to gut the hydraulic lifter from a B6, and sit the SUB on the post. I believe these are a bit heavier than the bespoke ones, but in my case they were on hand and costless. I get my shims from Precision Shims in Melbourne (overnight for me), they are very good, and while it seems like a stretch if you have supply problems there it would be worth a question to them, particularly as to whether they currently supply into USA. Contacts Us (precisionshims.com.au) Do you have access to a shim grinder? In your situation I'd get a few extra, I find that it is not unusual to need to get an extra one or two because I have made a mistake, or the measurement was wrong for one reason or another - I can get them tomorrow, but for you with that logistics chain I'd order a few extra sized across the larger sizes so I could grind them down to size as/if needed.

I also think you don’t need SUBs. Standard redline even if 300hp is fine with SOBs, even more so if it’s only occasionally 7200.
fwiw, I ran my NB8a track car with larger cams to 7500 every gear change every lap so probably 200 times a day for five years with std SOBs and never had an issue,
If you were revving to or beyond 8000 then I’d think about it, otherwise don’t waste your time/money..

can’t help with finding shims, as (same as GM above) I get mine from precision shims. Order by lunchtime and they are in my letterbox the next morning.
one of the few times sourcing miata bits seems easier for those of us down under!

I agree that you probably do not need shim-under-buckets. They may be sexy and cool, but they're even more of a PITA to install. I ran 350+ rwhp turbo at stock redline for years and never had a problem with the stock shim system.

I have always just bought shims from Mazda via the racer discount web site. Do they not have them any more?

--Ian

So, the consensus (so far) is that SUBs are probably overkill for my application. And I was leaning towards that conclusion, so thanks.

@Gee Emm ; I don't have access to a shim grinder so I'll have to get off the shelf shims and size the as best as I can. But I did reach out to Precision Shims and got a positive response regarding shipment to the US.
@codrus ; The last time I bought shims my go to was Rosenthal but they don't seem to be in the parts business any more. I wasn't aware of the Mazda racer discount website, so I'll give that a look-see.

At least now I may have options.

You should create a Mazda racers account and purchase the Mazdaspeed SUBs. They’re quite affordable last time I looked.

I respectfully disagree. Adding SUBs when they arent needed is just a waste of time/money and a lot of hassle for almost zero benefit in OPs case..

I would not be so respectful. It is bad advice (in the OP's circumstances).

Second this, OP's need is fixing his valve clearances, and installing SUBs is not the simplest or cheapest way of doing that.

The real cost of SUBs is not their purchase price which is trivial, but the installation process - BTDT. Unless there is a good reason for them, remember the KISS principle.

Simply pointing out there is another option beyond ST and Maruha.

They've changed the name a few times, but the core of it is that if you race a Mazda they will sell you OEM parts at something close to dealer cost on a special web site (online order only). You have to submit results periodically to prove that you are still running that car, and you are only supposed to buy parts for that car, not for any street Mazdas you might own or for other peoples' cars.

The term "race" is used fairly liberally here. It's open to road racers, autocrossers, and (as of a few years ago) track day people too. Submitting "results" for a track day is a bit odd, in the past I've sent them online registration lists and links to photo sites that show my car at the event and they've never denied a submission.

It's not perfect, I get the impression that this is a fairly low-budget program on Mazda's part so the web site is clunky, the parts database has a few holes in it, there's not a lot of tech support or documentation, and the shipping costs are kind of all over the place. I've seen $7 to ship a front undertray and $20 to ship a couple of shims :). IME, it's best used for ordering lots of parts together because the incremental shipping cost to add one more item is usually much lower than shipping it separately.

That said, it's hugely valuable because you get OEM parts for half what a local dealer wants, and it often ships to my house faster than it would take the dealer to get it (my local dealers never have anything in stock).

https://www.mazdamotorsports.com/get...am-membership/

--Ian

Thanks for the info Ian. I've signed up and am awaiting "blessings" from Mazda to enter hallowed grounds. We'll see how this all works out.

And, just to clear up any confusion I've generated with this. My only rationale for even broaching the subject of SUBs was because I wasn't finding any state-side sources for the normal stock shims. I couldn't even find anyone that stocked the Toyota-alternatives and that had me worried. Now that I've discovered some new sources, the question of SUBs as a reasonable alternative is off the table.