Icedawg

I need some information about 1.6 L engine history. To my surprise, I have a 1.6 L engine with solid lifters.
I acquired a Japanese domestic market (JDM) Miata 1.6 L with a transmission attached, to put into my ice racer, and mate it with the old 323 GT turbo system (also the Mercury Capri turbo).
I assumed it was a 1990-93 engine, and since it has a big crank bolt, a later model 92-93 engine.
But the attached transmission case is an exact match to the 99 5 speed transmission.

And having taken the head off to refresh the valves, I find it has SOLID LIFTERS!
I searched the web, and found Wikipedia says that the 1.6 L continued to be sold in Europe in the Miata, after the 1.8 L was introduced, but that it was a "detuned" engine, about 10 hp lower. Not so clear about in Japan.
Another search found a statement on a Mazda forum site that the NB came with a 1.6 L in Japan and Europe. No comment on if it was also "detuned".

It seems likely this engine I have is for a JDM 99, as that 1.8 L also has solid lifters. But I can't find definitive information.

Does anyone know when and how the solid lifters appeared in a 1.6 L? And do you know if this engine would have been "detuned"?

hks_kansei

The solid lifter 1.6 was about the same time as the solid lifters in the 1.8, so the NB

The NB6 was available in both Japan and Europe, where there are some weird tax laws that mean smaller capacity engines are cheaper.


essentially it's just a B6 with BP4W sensors etc on it. (so no rear of head CAS, should have the hall sensor at front like the NB, plus a crank sensor)


From memory the only "detuned" engines were the B6 fitted with an auto gearbox, since from memory they had slightly different camshafts to give a little more torque down low to help deal with the ancient Jatco boxes they had fitted.

Icedawg

Great info, thanks

HarryB

Exactly. All 99-05 1.6L have solid lifters (same ones as in the 1.8 BP4W). They also have a higher compression rate than the pre-99 ones, different intake manifold, same TB as the 1.8, all BP4W sensors.

x_25

To build off the "detuned" ones, I know the USDM Auto NA6s were, lower lift intake cam, same lift but lower overlap exhaust cam, and lower compression pistons. I have not been able to confirm anything later or from other countries.

Icedawg

So now I have a new set of questions, since as far as I know these engines were not sold in Canada or the US.
What do I do for parts?
I assume the bottom end parts are the same for the 99 1.6 L as for the 92-93 Miata 1.6 L.
Head parts must be somewhat different, in both cams and lifters, if nothing else.

Any ideas on the part differences?
Anyone know where to go for JDM parts lists (in English) on line?

HarryB

Europe would be your best bet, as we got these engines here. I can help you out with part numbers (and maybe parts as well); if you already have a list in mind, please post it here.

hks_kansei

Pretty sure they were available in Europe as well.

England/UK will be the best bet for English speaking catalogues etc.

as far as lifters, they should be the same as the 1.8 solids.


unless the cams are damaged you wont need to change them (and if you're wanting bigger cams just get them reground to whatever specs you need)

Icedawg

Thanks for the offer!
I read somewhere on here or Miata.net that the cams and lifters might be different between the 1.6 and 1.8 solid lifter setups, and that the clearance on the lash might be different. Obviously the cams are, since they must be longer. Anyone know?

I need part numbers for the intake and exhaust gaskets. They seem to be different than on the short nose crank 1.6 L from the earliest Miata's. And specs for the clearance on the intake and exhaust lifters.

HarryB

Lifters are the same as in NB/NB2 1.8 engines.

Intake (B61P13111) and exhaust (B69513460A) manifolds-to-head gaskets are the same between 89-05 1.6 engines. Intake manifold to TB and TB to IACV are the same as 99-05 1.8 engines (as the throttle body and IACV are identical to the 1.8 items)

Need to look up valve lash specs, but from memory they were the same as in the BP4W.

Skamba

This is what my Haynes manual says about valve lash:

Icedawg

Great, thanks to both HarryB and Skampa for the info. It is what I needed. I can order 92 Miata intake and exhaust gaskets.and not stress the parts guy out with Euro spec or Jpn spec requirements.
I had read on some forum the lash was not the same for the 1.6 vs the 1.8, but the manual shows the difference is inconsequential. No measuring tool I have in my garage would judge a 10 micrometer difference, at lest not in my hands. My feeler gauges are only good to a thou difference. And on a used engine I would call a thou good anyhow.

hks_kansei

Plus, lash is set with the shims, not the lifters.

you'll be buying new shims anyway if you're using new lifters.


It's worth buying a micrometer anyway if you're doing shims, since it means you can measure the shim thickness accurately and work out what sizes you need to buy.

ie:
measure every shim you have.
assemble valvetrain, noting shim locations.
measure clearances.
Note down difference between measured clearance, and ideal clearance.
add that to shim thickness, and buy shims that thick.

if you're lucky you'll have a few shims that work out close to ideal, and can just move them to the lifter where they're the right thickness.

HarryB

What he said ^

BTW Greg (carpassionchannel) had a nice vid on the topic, if you are more of a visual guy.

Icedawg

LOL. Yeah, I was lapping some of the valves in this engine. It is a JDM unit and has been sitting in a barn in southern Alberta for years. Three cyclinders had 2 % leakdown, but one had 80 %.
I watched a few videos on how to lap, and cleaned up the bad cylinder valves, and got back 2 % leakdown in that one too. The lash is OK.

I watched Greg's video on how to reassemble the valve train with the head on the engine; "takes me 5 minutes to hours" to put the valve keepers in place. But then it took 6 days for one of them, when the keeper blasted off into the nether regions of the garage and he needed another. That was a bit amusing. I certainly felt his pain.

It took me about 6 hours to learn how to do it with my spring compressor, and I managed to get it to the 5 to ten minute range using the method Greg was using. There has to be a special tool for the job, Pro's would not accept that long on such a small step.

I was hoping to assemble it today, but checked the rod bearings and decided I should replace the bearings. I can't help thinking I shouldn't have looked, since they are probably really not that bad.