ridethecliche

iTrader: (2)

Ahh, that's going to be the issue then. That thing is pretty tiny. I guess I'll make do with my friends for now.

sixshooter

iTrader: (12)

This would be sufficient.
http://www.google.com/shopping/produ...iABEgKJb_D_BwE

miataman04

iTrader: (1)

There's a boost joke in that somewhere.

ridethecliche

iTrader: (2)

Not sure why, but it took me ******* forever to fix the timing belt. I think the tensioner had come loose and was all sorts of unhappy, so I fixed that and retimed the motor. It was definitely off a bit and the timing belt was loose in a few spots, so this could explain some of the power loss.

I'm going to button things up tomorrow and finally do the leakdown. Is there a good walkthrough for how to go about doing one? I watched the miataking video but he puts mystery oil in for the compression test, which seems a bit odd.
Anything else I should do? Car in neutral or in gear with e-brake up? In gear right?

I'm hoping I can take things out for a test ride tomorrow night.

SpartanSV

Don't add anything to the cylinders for your initial tests. Totally skews the results as the oil can't be compressed.

I've always done leakdown in neutral. If you get it at exactly TDC the engine won't turn. Also make sure you're at TDC on the compression stroke not the exhaust stroke.

ridethecliche

iTrader: (2)

Not sure if I can count this a win, but I guess I got lucky...

One of the spark plugs was cracked and wouldn't come out because the ceramic insulation was caught between the chamber and the nut and wouldn't let a socket in. It forced me to look in where I saw shards everywhere. If that ****** had come out without a fight, I feel like I'd be having a very different conversation right now.

So I guess I need to find a pick that'll get it out if the compressor blasts didn't help, which they didn't yesterday. The other shards came out... this one is just stubborn as fahk. Hopefully I'll be able to do the damn leakdown today!

psyber_0ptix

iTrader: (4)

full send

sixshooter

iTrader: (12)

Everybody should have one of those flexible grabbing tools for drops Nuts and Bolts

psyber_0ptix

iTrader: (4)

all of a sudden I have an image of Arnold Schwarzenegger pulling a tracking device out of his nose from the original Total Recall

ridethecliche

iTrader: (2)

Friend that I borrowed the compressor from let me borrow the 'air gun'. Managed to shoot out the piece. It was the perfect shape to wedge itself into the spark plug nut and make it inaccessible.

Leakdown test done.

Cylinder 1 and 4 were at about 4-6%.
Cylinder 2 and 3 were at about 12-15%.

I had the valve cover off when doing this, so I couldn't listen through the oil cap, but it seemed like air was coming out through the head so to speak. I couldn't hear anything at the intake or exhaust valves. I redid the middle 2 cylinders twice and got the same results each time.

Cylinder 3 had good compression, so I'm not really sure what's going on. What could cause the middle 2 cylinders to have an issue? I have no symptoms of a HG issue that I can ascertain.

Does this seem to implicate the rings? I can redo the test over the weekend with the valve cover on and listen through the oil cap, but I don't think it's going to change anything.

SpartanSV

My leakdown numbers were worse and I seem to be making roughly expected power. Since you messed with cam timing let's see a fresh VD and log.

My Leakdown:
#1-13%
#2-22%
#3-9%
#4-9%

psyber_0ptix

iTrader: (4)

Those leakdown numbers aren't ultra terrible. People have run on worse.

ridethecliche

iTrader: (2)

I mean, lower leakdown on cylinder 2 makes sense because it was low compression. Unsure why 3 is off as well though. I even double checked a few times and trying to turn the crank at all was met with resistance. If it budged at all, it would shoot things over so it was definitely at TDC.

psyber_0ptix

iTrader: (4)

If you have a bent rod, compression can be low in a cylinder, but the leakdown could still be perfect. Not saying that's the case, but just because compression is low doesn't automatically mean leakdown suffers.

ridethecliche

iTrader: (2)

I don't know. I would be super impressed if I bent a forged rod at 170 hp. I should have more updates this weekend. Hopefully I'll be able to get a log then as well.

What I was saying was that, well... seeing these numbers posted would have made me think something was up BETWEEN cylinder 2 and 3. Perhaps HG or something, but it doesn't quite make sense here. I'll do another leakdown with the valve cover on and feel for air passing from the tb or the vband past the turbo.

psyber_0ptix

iTrader: (4)

That was a thought experiment. Not saying you bent a rod, but just letting you know it's not always a correlation.

Also plug up your PCV/Breather ports and check out the dipstick

ryansmoneypit

iTrader: (6)

When I had almost 40% leak, the car still made crazy power. just smoked.

ridethecliche

iTrader: (2)

I have none of that!

Honestly, part of the reason I want to figure this out is so I can call the engine builder and tell him what's going on if it's the bottom end. If it's the head, then that's on me and it's an excuse to do **** to it over the winter.

ridethecliche

iTrader: (2)

Looks like Spartan was right on the money re:timing being off. I had base timing set up correctly, but that's not really good for all that much if the intake cam is a tooth or two off...

Here's a log with the same tune and just about everything else other than fueling with just the timing belt fixed.



So I'm pretty much where I'd expect to be with this turbo at this boost level, especially because I'm hitting 7 psi at 3300-3500 rpm (when starting from 2k) and then slowly creeping up to 10-11 psi by about 6500. I think getting ebc working will fix that and I'm guessing that better fuel tuning should be good for a bit as well. In any event, car feels like a turbo miata again!

I'm going to redo leakdown and compression now that all this is confirmed. Psyber recommended removing a few things during the leakdown to get a better sense of things.

I can't wait to get this puppy running with EBC!

Should I even bother with the adjustable wastegate? I guess I can try some of the adjustable springs to dial in what I want, but I believe. that things will work far better with EBC with regard to spool and such.

codrus

There's something odd going on between 5700 and 6300. Stock Miata cams (you have stock cams, right?) make peak torque at 4800 RPM. To make a bump like that at the top you either need a boost spike, a weirdo timing map, or an error in the dyno reading (wheelspin on a virtual dyno, maybe).

--Ian