Well, it finally happened. Things went too smoothly for too long.

I raised the front end of the car off the ground via a shop lift yesterday to bleed the cooling system. I had time during work and ran the engine with the front end lifted and a funnel filled with distilled water in the radiator cap opening 3 times throughout the day for probably 10-15 minutes each. Given that I had a lift at my disposal, I raised the front end of the car pretty high. How high? I don't know, maybe a foot and a half off the ground? Anyways, I think I might have partially starved the engine of oil from the incline it was at. I drove the car home about 10 miles, gave it a good 2nd to 5th gear pull about a mile from my house and then the motor started knocking at anywhere above 3,000rpm. I pulled into my driveway and drained the oil to find what I believe is bearing material in it. I ran a magnet through it with no effect. Pics to come later.

At any rate, the motor's coming out again this Saturday. Hopefully I can have it torn down and any necessary machine work done within the next couple/few weeks. Anyone have insight to what else could have gone wrong aside from possibly lifting the front end too much while the engine was running? Main bearing clearances were checked to be .015-.020" before assembly. I can't remember what the rod bearing clearances were except that I plastigage'd them and found them to be within spec.

Did I mention I received my BX1175 brake duct kit from Supermiata yesterday and started installing that earlier as well? Yeah, I guess that project will be on hold for a bit.

This is what I came here for. This is fun. I'm paying money for this. I'm having fun.

Edit: Yeah, I know I didn't supply enough information for a proper internet diagnosis on my engine internals to be done. I'll post more details and pics once I get the motor pulled and opened.

My opinion is that would not do it. Rear sump car tipped towards the back, wouldn't all the oil be in the sump? I do the same thing outside, but I can't get it as high as a lift can.

Do you have something like a race dash recording oil pressure?

I thought the same thing but was surmising that maybe the baffle plate was blocking oil from entering at the angle it was sitting at. The more I think about it though, that's not a likely cause.

I have an oil pressure gauge but nothing as far as recording instruments. Oil pressure didn't seem to drop after the knock started. Oil that was drained doesn't smell like blowby gases. I put new oil in it last night and I'm trailering the car to my work tonight. I was thinking about getting a stethoscope to listen in the morning but I don't want to risk running any contaminated oil through the motor and causing further damage. It's gotta come apart either way so I'll start pulling it tomorrow.

Pic of sparkly oil. Engine removal begins tomorrow.

https://cimg9.ibsrv.net/gimg/www.mia...5069ea0ac.jpeg

Also I started the engine to get the car onto the trailer today. Oil pressure shot up off the chart (gauge goes to 150psi) then dropped to about 40psi at cold idle (way lower than normal for 80*f) Yay.

Got much more done than expected today. Went in early to work, worked through my lunch break, and stayed late to work on the car. Pulled the motor from the car and got the head off just as the shop closed. Hoping to get the oil pan off tomorrow and see what’s going on with the crank and bearings. Only had time to take a couple brief pictures of the cylinder walls and cam lobes.

More to come tomorrow and I’ll probably make a separate thread to ask about what can/should be retained or discarded.

https://cimg0.ibsrv.net/gimg/www.mia...d71ead5a4.jpeg
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That is a total bummer... But you are working fast.

Wonder what the bearings look like

What the actual hell? A bunch of the coolant passages in my head gasket weren't drilled out.

https://cimg4.ibsrv.net/gimg/www.mia...3f30b47a61.jpg
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Sorry for the crap pics, currently at work but Jesus I should've caught that. Guess that solves my cooling issue during boost...

What HG did you use?

https://www.miataturbo.net/race-prep...8/#post1156275

Used a 94-00 Cometic 84mm .030" HG. Had no idea those holes needed to be drilled out. Live and learn...

I don't know that you should drill them, I don't know how the flow goes.
Here is an analysis of HG comparison 94-00 vs later.

https://www.miataturbo.net/engine-pe...3/#post1431638

I need to slow down, sorry guys. Just briefly read over that post and how that dude punched out four extra holes in the HG. Thanks for the insight.

From the looks of things maybe more holes on ex side is good. Let us know what you decide to do.
I've been having good luck with the FEL-PRO 9717 gaskets.

Good luck with the what? Lol

#2 Rod bearing spun. Other bearings are smoked as well. Gonna drop off the block at the machine shop tonight to see if I can get away with just honing the cylinders. I'm gonna toss the crankshaft and get a new one coming. I'll make another thread to ask for advice on what else should/shouldn't be discarded.

https://cimg4.ibsrv.net/gimg/www.mia...8263deb9e3.jpg
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There are different HGs, that differ in the cooling holes, a fellow competitor lost an engine that way, just off the truck from the workshop and cooked it straight away. Workshop acknowledged it was their problem and rebuilt engine.

Not my issue so only have the basics, can't help further but matching HG to head/block cooling passages has been in my routine since, and making sure I get an MX5-specific HG, not a generic BP one. Search on here I am sure someone will have the right HG p/n.

I have never heard of drilling out a HG for cooling holes, seem to me you have to do that you have the wrong HG.

My quip on the head gasket was a false alarm. I compared mine to the oem Mazda 94-00 head gasket hole pattern and the patterns on others' HGs on here and found them all to be the same. I guess I just wasn't expecting so many of the cooling passages to be blocked.

Dropped the block off at the shop yesterday and have a crankshaft coming in the mail from MiataMecca. Cleaned out the oil pump in the parts cleaner and just finished packing it with pre-lube. Hoping to hear back from the machine shop next week that all the cylinder walls need is a hone and new rings.

Hone and rering is the boss. Loose is fast :rofl:

You'll be back in no time!

My engine performance instructor back in trade school was an an old hot rod/dragster guy. I remember him always drilling into us “Loose engines don’t blow up!” :rofl:

Went into work yesterday to get some more stuff done on the car and my van. Cleaned all the silicone off the oil pan, pump, coolant inlet, etc and finished installing the brake ducts.

Bonus pic of all the bearing bits leftover in the oil pan :loser:


https://cimg6.ibsrv.net/gimg/www.mia...4a106372b.jpeg
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More peripheral stuff while the motor's out. Drilled and tapped the breather ports for 10AN fittings (and enlarged the internal passage).

https://cimg7.ibsrv.net/gimg/www.mia...bbe42bbe46.jpg
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More holes, more vents, more more more!

https://cimg1.ibsrv.net/gimg/www.mia...427c9b0601.jpg
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I dropped the head off as well last week to get the cams and cam caps polished. The machinist called me yesterday saying upon preliminary inspection, we should be good to go with just a cylinder hone. I'll hopefully know for sure today or tomorrow. As long as that goes smoothly, I've already obtained new Wiseco XX rings (thanks 949Racing), a used crankshaft which I had a .010"/.010" ground done on, and corresponding new main and rod bearings. I have an OEM head gasket, new Boundary oil pump gears, all the necessary gaskets and a replacement rod on order. Single K1 rods have a 2 month lead time so I ordered a whole extra set of them as well to get here sooner. I'm fine with that as I'll have them ready to go in another motor once they arrive.

I'm going to build a backup VVT engine after this is done. I found out I'm not willing to toss my original engine back in and have to deal with rewiring the CAS and having to clean up all the oil that thing drips on the subframe and my garage floor. It's minor stuff and I could easily splice in a 4-pin connector to swap back and forth between CAS and CMP/CKP harnesses... but I'd just rather have a straight drop in that I don't have to change tunes, wiring, etc for.

More on that later. Hopefully I can start reassembling the block this weekend and get the motor back in the car next week/weekend. A bunch of my buddies are racing NASA Buttonwillow the weekend of 10/7 and I'd like to see how this thing does in TT3!

Jeeze dude, sorry to see about the motor trouble. You'll get it sorted though, it looks like you work quick! The BP is surprisingly a workhorse and I'm sure will hold up to track duty. Mines been going on 20k now hard boosted, some badly tuned, and lots of track miles. Though the first few oil changes I feared the glitter, that fear eventually goes away.