patsmx5

iTrader: (16)

Parts look awesome! The letters and details look really nice, not something most people take the time to do that well (myself included). I appreciate that though.

Sorry about your near-eye injury. As bad as that looks when I saw it, I'm glad it didn't do that to your actual eye! One of my biggest fears is loosing my vision due to an accident. Hope that heals up well and quickly!

sonofthehill

iTrader: (1)

Yes, hope you heal quickly and as comfortably as possible.

Chiburbian

iTrader: (1)

I have a problem I could use a hand with. When I bought this motor I didn't pick up any of the bolts and fasteners and assorted hardware such as oil pick up. I did get the oil pan.

the seller told me that he would run the parts over to a mutual friends house and I told him not to rush as I was not in a hurry.

well, a year later and I realize how much stuff I'm missing, and the stuff the seller had cannot be located anymore.

I checked Mazda and the full parts list of what I'd need will cost me about $500.

does anyone have a windowed block that they can pull the parts off of and do a guy a solid? I promise to pay it forward when my stuff is eventually unearthed.

Chiburbian

iTrader: (1)

I'm going to just say this out loud...

Buying this motor was a mistake.

I had to spend money to have it line bored. The pistons were installed with "Turbo Race Clearance" ring gap so I am going to buy new rings. As mentioned above I am missing all the fasteners now (half my fault). I wanted ACL bearings so I threw out (not literally) the King bearings that were in the block. I'm hopefully installing the crank in the motor tonight when I get home. I am hoping that everything works out with bearing clearances etc... <sigh>

Then next step is to remove piston rings from old pistons and check them to see where they REALLY are. And, if they are gapped too big order new ones. :(

The head looks ******* fantastic though. I need to clean it up just to satisfy my vanity but I am super stoked.

Chiburbian

iTrader: (1)

Today was too f'ing hot so I stayed home. When I go back to the shop next I should be mic'ing the crank and mains/rods and checking my ring clearance.

the previous owner of this (never ran) block had the engine shop do the rings. Supposedly they are set up for "race turbo" specs.

Is that the appropriate gap size for my application? (Ported head, 3" exhaust, eventual 6758?)

My calculations based on the Wiseco specs:
Bore:

3.307086614173228 inches




Street moderate turbo

.0165 top ring

.0182 bottom




Drag/Circle

.0182

.0198




Blown race

.0215

.0231

sonofthehill

iTrader: (1)

Curious to hear the answers here as I plan to run tighter gaps than that.

Chiburbian

iTrader: (1)

Tighter gaps than which? Race Forced Induction?

in my head I would try and split the difference between street turbo and race turbo. At most I plan an HPDE or two and I do t relish the idea of burning tons of oil.

sonofthehill

iTrader: (1)

I mean, I'm not the person to be giving advice here.
I am thinking for my street/strip build

Top .010"
2nd .016"
Oil .019"

But I have no clue, just figured the big end of Mazda specs. Perhaps I would seize a ring and tear off my top ring land with these gaps?
I too, don't wish to burn oil, or leak boost.
​​​​​​
edit;
I will be running stock bore though, so not really a good comparison.

patsmx5

iTrader: (16)

I've built street motors before where I honed a stock block, checked and the new rings were basically the outer limits of stock specs, and then ran 28 PSI boost on them. This for street use and drag strip, worked well and burned no oil, none. My current motor is setup loose, and it does burn a touch of oil, but I told the machine shop to set them loose because I wanted to run lots of boost and not worry about breaking a ring land.

Next motor I build will be higher compression, and probably slightly tighter rings. Mine are setup for turbo race specs from Wiseco right now.

sonofthehill

iTrader: (1)

Thanks Pat, good real world experience information.

Sounds like you will be fine and burn just a touch of oil, not tons.

Chiburbian

iTrader: (1)

SOTH, I recommend you read some of the other threads about piston ring gap. What I am hearing is that you want to follow the piston/ring manufacturers specifications not the original Mazda numbers.

https://www.miataturbo.net/engine-pe...end-gap-43415/

aidandj

iTrader: (5)

Do NOT use mazda specs for rings. Use your piston manufacturer. Different pistons expand differently. I bet you would demolish a weisco piston with a .010" ring gap.

patsmx5

iTrader: (16)

Why would you bet that?

My understanding is piston to cylinder wall clearance is dependent on the alloy of the piston used. Different piston manufacturers spec different piston to cylinder wall clearances due to varying degrees of thermal expansion of the alloy they use.

Ring gap is dependent on HP and application (street, drag, track, etc). You're saying ring gap depends on who made the piston?

cal_len1

Ring gap depends mostly on the temperature of the piston. The top ring absorbs heat from the piston and expands, which makes the gap smaller. If the ring end gaps touch, you will most certainly scuff out your engine. You probably won't demolish a piston, but your blow-by and oil consumption will increase exponentially.

sonofthehill

iTrader: (1)

So it sounds like we will both be fine with our gaps.

Chiburbian

iTrader: (1)

It appears that my engine was assembled with "street turbo/moderate" gaps.

trying to decide if I should open them up a tad.

actual data:

Cyl 1: T0.019 ; B0.019
Cyl 2: T0.017 ; B0.019
Cyl 3: T0.017 ; B0.019
Cyl 4: T0.018 ; B0.019

Re-gapped to:

Cyl 1: T0.019 ; B0.021
Cyl 2: T0.019 ; B0.021
Cyl 3: T0.019 ; B0.021
Cyl 4: T0.019 ; B0.021

Tomorrow I'm going to bring my diamond needle files and check them for burrs and re-check them. If they all check out I'll put them on the pistons.

If my friend brings his measuring instruments I'll start checking crank and piston journal clearances tomorrow.

Chiburbian

iTrader: (1)

I performed two tests involving my "sudden dying when fan kicks on" problem.

First test was to daisy chain another confirmed good battery (from my Fiesta ST) to my Miata. No change.

Second test was to connect negative battery terminal to ECU ground at the front of the intake manifold via direct 14ga wire. No change.

Swapped in brand new main relay. No change.

Disconnected VVT wires. No change.

Any other ideas?

Chiburbian

iTrader: (1)

If I'm inspired enough I'll try swapping alternators tonight. Not optomistic.



Just waiting on spark plug wires now.

Mazduh

I may have missed previous posts about your fans. But what amps are they drawing? Aftermarket or oem? Can you just compensate by increasing idle when they are about to kick on? I had a similar issue when I wired in my SPAL fan back in the day and I don't remember what I changed on the megasquirt but there was a table I adjusted and it helped.

Chiburbian

iTrader: (1)

I did some troubleshooting today on the fans. I am still confused. Here is what I did:

Ran 14ga wire from negative battery terminal to the fan.
Ran a 14ga wire to an in-line fuse holder with a 15a fuse. From there it went to a switch rated for 60a. From there to the positive connection of the fan.

I then (with the motor and ignition off) switched on and off the fan. I had no problems. The fan turned off and no with no problems.

After that, I started the car. I switched on the fan and it came on with no sputter or stalling of the motor. I switched the fan off, and a few moments later switched it back on. The fuse blew.

I swapped the fuse with another 15a fuse and watched the fuse this time. On the first power up of the fan I could see the solder on the fuse melt but not break contact on the first switch-on. However, on the second switch-on the fuse blew again.

Why is my fan blowing a 15a fuse connected directly to the battery when the car is running but not when the engine ignition is off? I will buy another 20a fuse set on my way home tonight and put my meter in-line to see what the max amperage draw is under both conditions.

My plan going forward will be to slowly walk the ground supply and the power supply forward on the chain one link at a time to see at which point it causes the motor to stall.