That's great info... Thanks for that. Makes me more confident about my decision.

 

x2 on the comments with that being excessive oil. Not sure the source, but the drip of oil visible on the cyl#4 valve makes me want to think something related to leaking valve seals as an initial source.

As much as I'm sure it sucks to deal with financially, I do think your turbo BP route will be better suited to your end goals. The NVH on a BP is superior to the K24 no matter how you slice it.

 

Good point about the drip coming from the valve. It might be as simple as valve stem seals, which is a good thing for you even if you are parting out the K stuff. It could be a pretty easy fix if it's just valve stem seals dumping into the cylinders and not something more major in the bottom end like oil control rings.

 

Operation "I Screwed Up" has begun. Pulled the Kswap out of the car including the subframe. I have a buyer coming this weekend to pick it up. Will provide enough cash to buy a used Mazdaspeed block and 6 Speed and some of the build parts so I can start with the machining and rebuilding.

Engine Out






Used OEM subframe purchased and powder coated

 

sucks to see such a clean swap being re-done, but you'll be much happier in the end! look forward to seeing progress!

 

Ok.. on to round 2! New lump showed up today. Engine has around 60K miles on it. Should be a very good candidate to build. This build will be done in 2 phases.
Phase 1, overbuild the motor, update the turbo (bnr), get it on the car and working. Only compromising on the "bolt-on" components.
Phase 2, update all the turbo setup, and bolt on components to complete the build.

Here's the engine and transmission:

 

First bit of internals coming in. Haven't ordered rods yet, b/c I wasn't sure which ones I wanted. Really wanted Carrillo Pro-H's but then figured if I'm not going to go with a billet crank, no reason to go with 1000HP rods. So I'll likely just stick with the Manleys. Looked at Maruha H beams and would have gotten those, except they support a 22mm wrist pin. So they only work with their pistons. I still might go with Carrillo... but obviously not the intelligent choice.

So now the goal is a build to support 500'ish HP, even though I'll likely only a little more than 1/2 of that.

 

Great choice on the engine/trans, I’d skip the upgraded turbo though. You’re still over spinning it to reach higher HP figures, might as well keep the stock one, keep it at 200 or less, until you’re ready to upgrade turbo/mani.

 

Those wrinkle red/burgundy valve covers always make me feel tingly inside. Glad to see more progress made.

Didn't see you post it yet, do you have a full parts list on the engine build aside from the undecided rods? Those look like +1mm FM/Wiseco pistons, then you've got oversized and/or inconel valves there as well?

With the upgraded mains, you basically have to make over 500whp for us now

 

I know you're right.. but i couldn't live with myself doing that. The BNR upgrade puts a bigger compressor wheel mated to the smaller turbine, so it'll lag a bit more but at the same RPM will be more efficient and push out more CFM. So there is an upside to it, and I should be able to get the car "comfortably" to 250. I will also be doing a small port and cleanup of the manifold so it doesn't look like trash. My hope is I can sell all of this when the time comes and make most of the money back. But like I said.. I'm aware not all of the choices are the "smartest" ones .

 

So the intended parts list is:
FM Wiseco 9:1 pistons
Supertech +1 inconel valves
Supertech dual spring valve springs (85lb seat pressure)
Carrillo or Manley Pro-H rods (my heart still says Carrillo, we'll see)
ARP main / head studs
FM MSM rebuild kit , which will include new acl bearings, thrust bearings, cometic head gasket, seals, etc...
OEM Valve Seals
Fluidampr Pulley
Boundary Stage 2 Oil Pump
Napp Cast Impeller Water Pump

Then quite a few things on the outside of course, like a crossflow radiator, coolant reroute, etc.. Will cerakote the block and the head (outside only)

So that's the gist of the ideas in my head... just assembling the parts I need for the machine shop for now. Hoping to get it disassembled this weekend, maybe to the machine shop in a week or so.

 

Engine tore down (head will be later this week). All in all, i'm really happy with this engine. Very little staining on the valve train, which suggests regular oil changes. Cylinder walls look to be pretty great. The bearings show the tiniest bit of wear, but after 60-70K miles, I think they look really good. Definitely shows signs of running rich (intake has all kinds of staining and pistons as well). But no pitting on the pistons etc.... So all in all... should be smooth running at the machine shop!

Here's the head:









Parts from the block











These are pistons / cylinders 3 and 4. Pistons definitely show running a bit rich. Which is expected for a turbo engine.

 

Damn, no varnish at all in that head. Definitely better than can be said of some others we've seen on here! That amount of carbon on the pistons could be a rich condition, but the last two N/A Ford motors I pulled apart had about the same amount of carbon on the piston crowns as well, with ~60k and ~80k miles respectively. I suspect some of that buildup might just be the previous owner not givin' 'er the ol' Italian tune up very often

Excited to see more progress. I wanna see a drag race between the Miata and M2 in the background when you're done.

 

Agreed, that engine looks like a peach! Psyched to see the built motor come together here.

And +1 on the m2 drag race.

 

So a wonderfully genius move on my part. In removing the freeze plugs, I got in a bit of a rhythm and didn't think about the "rear" freeze plug. That plug doesn't have the depth of space behind it the others do, and I think I likely ended up grinding into the cylinder wall a little. Not sure if the wall will be salvageable, if not, I'll go ahead and sleeve the cylinders.






What are your thoughts on this head. It looks like casting flaws. See cylinder 3 has odd pitting and what looks like just bad casting. Decking should clean it up, but wondering if you all feel this is a casting flaw or caused by something in the engine?




Last update... this tool is AWESOME (lol). Made getting the keepers out a breeze. It's not fast, but it is easy. I'm sure putting them back will be a bit more tedious, but still very thankful for it!

 

Cyl 3, that's not bad casting. that's something got eaten in the past.

 

I'm with Iron on this one. That looks like something got into the cylinder and pounded into the head by the piston. Based on the photos of the pistons from the previous post it looks like you can see some pitting on one of them. Almost looks like detonation to me, but I'd be interested to see what it looked like after the piston was cleaned up.

On second thought it almost looks like detonation on the head and the piston.

 

You might be right about the detonation... one of the edges of that head looks almost melted.. not beat up. I checked the piston, and I do think I see what you suggested. I'm going to clean it up later today and see if I can't get a better idea.
I am going to reach out to the shop and see the cost to fix this. I think it's fixable, with a bit of weld and machining, since I'm already getting the head decked..

We'll see.

 

I'll be interested to see what route you take. I'm sure there's a plethora of used OEM pistons that people would basically give away. Not much of a use for the OEM pistons when you go forged outside of making cupholders or metal art. Not sure if a used OEM would be better than just throwing that one back in. I'd think the head could be cleaned up pretty easily.

I wire wheeled my pistons at one point to see what they looked like. One of mine was pretty pitted but the engine still ran pretty well aside from consuming some oil.

 

So it's been a bit since I've posted. This thing definitely tries the patience. Long story short for this bit. Last update showed the state of the engine after the tear down. I took the head and block to a local machine shop with good reviews. When the parts got back, everything looked really good, until I started to measure. I had to order undersized King bearings to get it even close to spec, and then when I went to check ring gap, there was very little gap at all. Essentially the machine shop didn't check anything, but on the plus side, at least they messed up on the small size.

Here are pics from that time about 6 months ago.

Rods and Pistons ready to go In




Block back from the shop and cerakoted







Freeze Plugs In


Arp Main Studs and Oil Squirters blocked off




Crank with Billet Mains Installed





Head Cerakoted, Inconel Valves Installed (before tipping using cheap SuperTech seals.. OEM Seals going in after tipping)
Notice on cylinder 3 the machine shop did a 1/2 decent job of filling the pits with weld and then machining. Unfortunately, as you can see, the combustion chamber edge is still a mess.






And a pic of the SuperTech Dual Valve Springs


Valve Cover back from Powder Coat with AN bungs for catch can