I have no idea what caused that bearing failure.

I said ask Leafy because he knows more about oils than I do. I don't know much about oils, I've said that now 3 times in this thread. I don't know much about oils- now 4 times.

I just did a brief search and couldn't find the link I've seen. There is a published list of something like 50 motor oils that were all tested by 1 person (not an oil company), and he measured the shear strength of each oil at the same temperature. Oil manufactures also publish their own data on their oil too.

I have nothing to prove. You said you want to know if Castrol is better, look into it yourself. That's all I did and I found Castrol has high shear strength which is important for bearing wear. I was having bearing wear so I switched oils, and it went away.

Here's a link I found that shows measured shear for a few different oils using the test standard ASTM D-4683 It's a high temp/high shear test.

http://www.upmpg.com/motor_oil/motor...4683_700px.gif

Link to article: Motor Oil Testing Methods

That doesn't include any data for Rotella, but it does for several other oils including Castrol. If you want to know more about it, look into that test number for the oils you're curious about. There is another similar test where they publish a number in PSI that is actually the FORCE in PSI required to shear the oil between two pieces of metal. This test Castrol was something like 100,000 PSI (a guess/estimate) vs Rotella being around 70,000 PSI (another guess/estimate). The last two numbers are guesses/estimates incase that was missed, I don't have the link to point you to or I would, but Castrol was way higher than Rotella which shocked me but did suggest it was causing the bearing wear at high RPMs.

Wasnt' low oil, I kept the oil full on my engines. I check it often. They don't use anyways and usually don't leak it.

Low pressure, dunno. I don't have a real gauge to measure it. I did use the same oil pump on 5 different motors because everyone says the oil pumps break gears, so I kept using the same one so if it were going to break eventually it would. Never happened, guess I was lucky.

You said there are so many reasons, what else? What you posted is about all I could think of.

Last 2 motors had the exact same failure, a cracked piston. Everything else appeared fine/motor ran fine up until the failure. I don't know what else you are looking for to be honest?

What do you mean by "we don't REALLY know if it was fine or not. Etc." Do you mean you don't believe my words? Or I didn't test/measure enough things to know? Or something else? I don't get this part at all.

My guess/opinion/whatever is that the motor was working well and then I broke a piston. I have them both sitting on my bench.

Like it or not, I do draw conclusions based on my experience. Some are right, some are wrong. It happens. After I broke my first piston I thought it was a tuning issue, and built another motor with stock pistons and then broke it in half too. I thought stock pistons would take it and I was wrong. Got to build/break 2 motors over that. That's me being wrong. It happens. In fact my car is apart getting repairs right now for things I f'd up and am having to redo. I do not know everything. But I'm not making shit up to mislead anyone either.

On this particular point, the castrol motor did have a VVT motor/VVT pump and VVT pumps are a touch bigger than the non-vvt pump. So in theory it could be oil pressure related since the VVT motor had a slightly bigger pump. I don't know if the oil pressure on VVT motors is higher than a non-vvt motor though.

Good point.

Aluminum flywheel + 949 damper = RPMs drop like a brick. I really need to work on my idle PID settings so I don't look like a complete choach every time I come to a stoplight.

I drove it to work this morning and got a tiny bit of what I believe is piston noise at startup, but it went away as soon as there was some heat in the motor. My cold starts are actually MUCH better now, but then I also lost a full point of compression so that probably counts for something ;)

Also, fully warmed up I was seeing 60+psi at 3000RPM cruise. Unknown temp because my oil temp gauge decided it didn't want to go over 130°F this morning (thanks VEI!) but it should have been around 170°F~ish based on previous experience. I had 18-22 psi @ 850rpm idle right before I parked and walked into the office. The pressure seems to move around a lot, but that might just be the gauge, and I'm not sure I trust it at this point.

Was it a tap or did it sound like a diesel engine idling?


If the numbers you posted are accurate, then that's great!

GL on the gauge, I posted yesterday in another thread about those gauges, I posted a couple wiring things to check/change to possibly fix the erratic behavior. If it works for him then maybe it will work for you!

Kinda like a diesel I guess? Its a different noise, one I'm not used to. Ove the years I've had cars with rod knock, piston slap, valve train noise etc but this is my first motor with forged slugs. I guess we'll find out :)

I've got an email in to Reverant to find out if the serial OUT on the Innovate MTX-D oil pressure and temperature gauge can be chained in to the serial connection with my MTX-L wideband and into the MS3-B via the MSLabs Wideband CAN Interface. That means conceivably I can log oil temp and pressure in realtime without additional sensors/wiring. That feature alone makes it no longer worth while to screw with the VEI stuff.

If it can be made to work, I'm gonna get me some D

Then probably piston slap. What pistons are they?

The ones you love to hate.

Braineack makes pistons?

:likecat:

Thupertechs, 84mm 8.whatever:1 CR

I'm assuming Supertech pistons...

Well that's odd then, those shouldn't slap when clearance correctly. I'd be curious what the piston to wall clearances are if those are slapping.

Good news is it's mostly harmless. If the noise doesn't bother then I wouldn't worry about it.

Ordered replacement senders for the VEI stuff. Let's see what happens.

Still waiting on the reply about the serial output on the MTX-D, but then it was 1AM in Greece when I sent the email. ;)

<p></p><p>Often that does not matter. I'm convined that Greek Goddeses do not sleep.</p>

I think he said somewhere that he tweaked his back again? I'm not in a mad panic rush for a reply, I'm sure he'll get back to me eventually.

The way I understand that the system works, it should be able to do it, I just don't know how to set it up and such. Honestly, I feel like that would be a major selling point for the CAN Module in and of itself. Like I say, we'll see.

I did some actual work on my tune this morning. Rather than idling at 11.2:1 @ 1000rpm its back to 14.7 @ 850. Yay! I autotuned on the way in and it only pulled a small amount from the load and cruise cells, so I'm feeling somewhat confident in my decisions.

Slightly confused as to why it went so stupid rich at idle after the head, intake and compression change because honestly I would have expected it to be leaner. Idle vac is slightly lower, but I guess that is to be expected? /boggle

I really need to bone up on tuning idle, its still having a hard time catching at stoplights and I still get a little bit of RPM oscillation. It's not terribad, but its also not as good as I'd like it to be.

bump up the delay per that one thread by DNmakinson. it will probably hang, but will never dip

I shall look post haste, thanks! :bigtu: Hanging for a sec is better than dying.

Also, congrats on 28k :giggle:

https://www.miataturbo.net/attachmen...ine=1438277267

If you want, email me your tune and I'll go through it. Will need to know firmware/ecu type, and your basic hardware (inj size, coils, idle valve?, things like that).

Yes, but then the illusion will be dispelled and you'll see exactly how bad I am at this stuff ;)