You can purchase the MMD / Maruha solid lifters individually which is handy if ever you damage a couple like I did due to valve float.

My engine is back up and running now with the 5.6mm shim caps. I have a whole stack of 5.6mm shims spare around the 1.5 - 2mm sizing if anyone needs a few for sizing.

My head is still at the machine shop. I'd like to get it back this week so I can order shims and have it back together by the weekend after.

The supertech shims are super short, i'm amazed that they could interfere with valve retainers. Maybe non stock valves or something. The "hangover" is super small.

It only took me 4 days to get the head rebuilt. I ordered 4 x 3mm shims from Precision overnight, built the head the next night and measured tolerances. Ordered the required shims the following day and received them all by lunch the next. Excellent service!

The Precision shims have a long base which is good for me due to the thickness of the shims I need which run up to around 4mm. I'm not sure I'd like that sizing sitting on a small amount of the stem, but I suppose they can't really go anywhere. The old shims that sat on the valves were very short.

here is a video of the engine idling, with a few quick revs testing the 949racing twin. It's running even more lumpy now with the lightened flywheel.

Vroom, lump, lump, lump, lump

Sounds serious.

Just to reconfirm - I have the MMD SUBs and I ordered the supertech 5.5mm caps. **They absolutely did not fit.** I had to trim down the stem diameter on the SUBs to get the lash caps to fit and it was a massive pain. I didn't give one enough clearance and the cap actually shattered when I was checking lash.

I spoke with Bill at Miataroadster and the guys at MMD and no-one seemed to be aware of the issue. :cry:

This all happened last year. Wish I'd seen this thread earlier so I could have given you the heads up. At least you only ordered one shim.

All the mazda subs I messed with got 5.5mm caps they are a tight fit but usually a punch and a strike of the hammer gets them on and a second to be absolutely sure they are seated.

Good info guys. Seeing soot shatter a cap. Makes me not want to do the Twibs method.

Maybe I'll call supertech and see what they can do about 5.6mm shims. But I doubt anything reasonably priced.

Either way, 6mm shims are known to work on the valves if needed.

How did he shatter a cap?

also iv has issues where there isn't enough stem height and the 6mm cap touches the keepers. i was in a bind once and ran the 6mm upside down on the posts of the lifters and that worked out for some time without issue. i wouldn't recommend it, but sometimes you gotta make it happen.

I tried this - I actually pushed the cap onto the stem with just some of my weight behind it and it shattered. No hammer needed, and I'm a slim (170/6'1") guy. Trying to fit a 5.56mm slightly tapered post - yes, I measured and some were that large :vash: - into a 5.54mm cap gets you bad things. The caps are extremely hard, brittle steel, so there's no give, just break.

edit - I might even still have a SUB with half of a shattered lash cap stuck on it. I'll try and grab a photo later today.

Wishing I had seen this before buying MS subs a few months ago. Should have bought from 949. Guess I'll be buying shims from Australia since I am not using OEM valves. Thanks for the great info!

SUBs CAN come out
 

Sorry, but yes they can. I ingested a screw or something, it got caught by the closing valve, the (Precision) shim floated out as the valve stopped and the bucket kept going. 180 degrees later the lobe comes around, jams the shim by the edge that is supposed to sit over the stem, and presto, I have a valve that won't close, held open by an amount roughly equal to the depth of the recess for the head of the stem.

The biggest mystery is where did the nut/screw/whatever come from? All the usual suspects checked out ok, the engine has never run without an air cleaner ...

The up side was that the valves got reseated, and no damage occurred. Given the big overlap in my engine, I was lucky to escape without piston or valve damage.

That would occur with any shim though. It's not ideal if you ingest anything into an engine let alone something metallic. I think you were very lucky to just drop a shim.

So about half the shims supertech sent me measure out to 6.42mm in diameter instead of 6mm. They are sitting on the valve. Should I be worried about them coming off somehow?

My gut tells me the answer is no, you would need an ingestion of something to prevent the valve closing to cause that (as happened to me). That is not a scientific opinion. I would email Supertech, or even Skype them if they have a freecall number (1800 here).

Supertech says not to run it. No idea what happened. But something got screwed up somewhere.

Did you buy your shims directly from supertech? I'll be getting some very soon as well to use with the MMD lifters I have. I'll be putting it on the top of the valve stem which people are reporting it measures 6mm.

They were drop shipped to me from supertech. The sealed parts bag has LC-60 on it. Which means 6mm shim. But they aren't 6mm shims.

Someone fucked up somewhere.

They are probably ok as some of my older shims were fairly loose, although probably less than 0.5mm gap. It would be hard to loose them off the valve stem unless something else jammed it up first.

I'd be concerned with them chattering or moving on the valve stem and damaging either the valve stem or the shim itself. I'm not sure if that can happen or not but if you have ever seen extreme slow motion video of a high reving valve train its a bit disturbing how everything moves like jelly and bounces all over the place.

Although they appear to have struggled to package shims correctly, I probably trust them when it comes to valve train things. And if they say not to run them I'm not going to.