hustler

iTrader: (6)

My upper two trans bolts fell out...that can't be good, lol.

shuiend

iTrader: (24)

Time to safety wire them in.

Oscar

iTrader: (2)

better yet: get inconel trans bolts and resbond the **** out of them. You know you want to

spoolin2bars

iTrader: (1)

not really, i drove mine daily and to/from track for 3.5yrs.
strange that your valves are bent on a non-interference motor. was there evidence of piston contact? strange that the intake valves were bent but you heard the air escaping from the exhaust side. how does a valve erode? too hot? is there something you missed in tuning? am i asking too many questions? not bustin' your *****, just feel as a pioneer of turbo track miatas in your region, you owe it to those that follow to report problems as they arise in your track beast. the cause and remedy are also essential to helping others. only other way i can imagine you bending a valve is thru severe detonation. the detonantion that would bend a valve, would also leave evidence on the piston tops. basically look like a hammertone finish on top.
lastly, why would you have to retune? did you just do your first tune a few weeks ago? no? i would have to guess that you tuned your car when you first put the absurdflow kit on. most likely pre bent valve stage, so no, you shouldn't pick up any horsepower from when you originally tuned it.

sixshooter

iTrader: (12)

I lol'd and almost spit out my beer.


Yeah, like spoolin says, we are interested in what you learn about the root cause. Well, those of us who diligently subscribe to your thread are.

ZX-Tex

iTrader: (15)

It is still possible to bend valves on a non-interference motor. Not easy, but possible. If the engine spins fast enough then the valve has so much momentum that when the cam lobe pulls away from the lifter, the valve continues to travel towards the piston since the spring does not have enough force to reverse its motion quickly enough. In other words if there is severe valve float then there could be piston contact. Also, the springs could hit resonance and cause a similar problem. If you had a heavily shaved head, or decked block, or pistons with poorly shaped valve pockets, or a lot of carbon buildup, then that could also contribute.

I have no idea if this happens at 9000 or 19,000 RPM with a Miata motor but it is possible.

pusha

iTrader: (5)

drinking beer... you're so cool

Savington

iTrader: (31)

bent intake valve = does not fully contact seat = leaks and burns

Probably could have left the valves and springs stock, replaced them with new parts, and been fine.

18psi

iTrader: (76)

I was always shocked at your spark map and how low you run your boost. Looking at others' as well as researching many professional tuners' tuning methods, many usually like to run more boost and less timing to achieve similar power.

Now this may not be in any way shape or form related to your valve issues, I'm just putting it out there. It would be way easier on your motor that's for sure.

(disclaimer: drunk post so if its retarded please disregard)

hustler

iTrader: (6)

I'll try to hit all of these:
Aparently they can float and the cam/lifter can hit the valve on the "way back up" and bend the valve. I zinged it a handfull of times and twice on the track. Once I missed 6th at MSR-C and another time I shifted to 3rd instead of 5th at TWS (CW). The trans moves way too much in this car, I want a Carbing brace.
I'm guessing that when at TDC on #1, air was leaking out the intake valves from #2, then going through the intake valves on another cylinder, out an open exhaust valve. The machinist said the exhaust valves all held water, all intake valves were a laugh.
Either too much heat, detonation...or bad metalurgy. One exhaust valve was eroded, not both, so the machinist says it's probably a valve from a bad batch. You saw the pics of the pistons and head, there was zero detonation.

See above, the pistons look great. The pistons look new and the quench pads are all smooth.
We'll see what happens with the tune. I'm going to zip-around town a bit the next time it's warm with the det cans and then make the decision.

hustler

iTrader: (6)

It's retarded. I've been 6* advanced further than I am now without detonation.
These were the hottest cylinders:

I don't see how it would be any easier on the engine to run less spark advance. I agree with this logic in general, but consider the low static compression, tubular manifold, big turbine housing, big intercooler, 3" exhaust, no cat, and then the numbers make a bit more sense. Look at those pistons, they've been on the track with the tach hung in 5th gear at 6500 in 100*f heat and they look great.

hustler

iTrader: (6)

I could have, but I got these parts at great prices so I upgrayedded. I also want the stiffer spring to help out with the pressure from the turbo and the turbine sides. I got a set of new valves, seals, springs, retainers, and a hander for under $600. Those springs aren't going to last forever and they already had 70k miles on them before the build.

ZX-Tex

iTrader: (15)

Do you have the stiff mazdaspeed competition engine mounts and the poly diff bushings? Makes a huge difference.

hustler

iTrader: (6)

Yes, I have them.

spoolin2bars

iTrader: (1)

what does a few psi do to the springs? turbo and turbine sides? i've never messed with my miata motor, but coming from honda and dsm world, we've ran up to 30psi on stock springs and never heard of an issue. is it a miata thing? now you got me scared on the springs, i've got over 220k on mine. how much time do i have left?

hustler

iTrader: (6)

Well, X psi reduces spring-rate by X so I don't really know. Again, I don't think this refresh with the springs and valves was really necessary, but more of an attempt to save myself from doing this work again in 3-years. Maybe I can get to 2017 or so on this engine, then refresh it again. I should also note that I broke a spring and dropped a valve in one of my VWs a decade ago, so this scares me more than it probably should.

vehicular

iTrader: (3)

Did you decide on fuel lines?

I will stand by my recommendations from several pages back. Measure your stock feed and return line ODs, call Anthony at Imperial, tell him Chris Spalding recommended him, and that you need to get from X hard line diameter to whatever your fuel rail fitting is, and the other side of the fuel rail to the reg and to Y hard line diameter. Also, be sure to insist on stainless fittings, as he will try to save you a dollar with plated steel or brass fittings by habit. If you can go ahead and measure your lengths he will make up your lines and put some super bad *** Oetiker clamps on them, probably for free.

hustler

iTrader: (6)

I'm doing Earl's 5/16" compression ferrule fittings (Savington's recommendation) and probably ordering $170 of **** from Bat-Inc tomorrow with black nylon braided hose. I went with the most cost-effective, reasonable prices...and great looking stuff.

I also have an order of bullshit from Mazdaspeed and I'm toying with the idea of a Mazdaspeed cam.

Seefo

iTrader: (5)

+1. I am not FI, but it certainly can't hurt. a tad more lift, same duration, so you should get a bit more power across the power band. Some people say they lost a bit of power down low, but I think thats just the stigma with a more aggressive cams. Even if it was the case, doesn't matter much I do what I can not to get under 4k on track and that's where it matters.

hustler

iTrader: (6)

I'm peak HP limited, so I probably won't do the cam. Only one decision left and that's whether I want water.