scooterfrog wrote: [...] many well priced Matias are 5 speeds and have been driven hard. [...]
Yes, but in the Miata world, the hard driven cars are often well cared for and maintained properly. I would like to think my car falls into this category 
scooterfrog wrote: [...] many well priced Matias are 5 speeds and have been driven hard. [...]
Yes, but in the Miata world, the hard driven cars are often well cared for and maintained properly. I would like to think my car falls into this category
oldeskewltoy wrote:Keith wrote: The heads seem to hit a wall. The engine was originally designed in the mid-80's. The flip side is that they're built like tanks internally. There are some little barbed comments in the insider development books aimed at the 4AGE being a tad overrated in official power outputs, tooNot sure what you've heard... I've SEEN a 4AGE plant 263 crank hp @ 9800 rpm. I've also seen numerious 7AGEs plant 260+hp and 175#/ft. The 4AGE heads is FAR SUPERIOR
I said OFFICIAL power outputs, and this dates back to when the Miata was introduced. The Mazda development team was of the opinion that a few of the other 1600s on the market didn't quite live up to their ratings, and that the B6-ZE was right there with them.
The E-Production BP engines are in the 250 hp range. I wish I knew exactly what they were doing, but I know it's not something that would be streetable or likely pump gas friendly.
Keith wrote:oldeskewltoy wrote:I said OFFICIAL power outputs, and this dates back to when the Miata was introduced. The Mazda development team was of the opinion that a few of the other 1600s on the market didn't quite live up to their ratings, and that the B6-ZE was right there with them. The E-Production BP engines are in the 250 hp range. I wish I knew exactly what they were doing, but I know it's not something that would be streetable or likely pump gas friendly.Keith wrote: The heads seem to hit a wall. The engine was originally designed in the mid-80's. The flip side is that they're built like tanks internally. There are some little barbed comments in the insider development books aimed at the 4AGE being a tad overrated in official power outputs, tooNot sure what you've heard... I've SEEN a 4AGE plant 263 crank hp @ 9800 rpm. I've also seen numerious 7AGEs plant 260+hp and 175#/ft. The 4AGE heads is FAR SUPERIOR
Fair enough....
The head truly is the problem with the Miata... here is a recent job of mine - 4AGE O/S valve head - exhaust port
Loyning built 7AGE are doing it on pump gas... and with "only" 270 duration camshafts 
Keith - was that high RPM engine using stock rods or aftermarket?
I seem to recall a VW racer tracing rapid rod bearing wear to flexible stock rods. They could handle 9000rpm but the big ends moved around so much under load that it was eating bearings. Good aftermarket units solved that problem.
Carrillo rods and quite light pistons. Stock rods would have grenaded for sure.
Keith, as far as my engine blowing oil smoke during off-throttle/decel......................valve guides? I've seen some stuff that says PCV, but that doesn't seem to make sense. I thought a clogged PCV would cause blue smoke under load?
z31maniac wrote: Keith, as far as my engine blowing oil smoke during off-throttle/decel......................valve guides? I've seen some stuff that says PCV, but that doesn't seem to make sense. I thought a clogged PCV would cause blue smoke under load?
On my MX6 when i thought it'd be fun to not hook the PCV back up, it smoked like crazy under decel due to crankcase pressure.
The PCV opens under vacuum i believe.
See, I was thinking it was the other way around, bleeding off pressure under load due to the natural bit of blow-by in the engine.
I did go ahead and install a new PCV, but the car has been on the jackstands since then, so I won't know until probably next month.
z31maniac wrote: See, I was thinking it was the other way around, bleeding off pressure under load due to the natural bit of blow-by in the engine. I did go ahead and install a new PCV, but the car has been on the jackstands since then, so I won't know until probably next month.
Nope, that's the "vent."
PCV is the one that attaches to the intake manifold, vent goes to intake pipe. 
Well good, hopefully the fresh PCV will have solved the problem!
I drove several 1.6 Miatas, and the one I bought definitely felt the strongest.
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