"Honey Badger" Miata: Turbo Track Build (new brakes installed)

[CleanNeon98]

The hardest part I can imagine is maybe aligning the hole for the ABS sensor. Otherwise simple

[CleanNeon98]

So after about 1000 miles of break-in I have a ticking noise. Seems to happen over 2800rpm and is a very fast paced sound, not like a bearing, rod, piston slap, etc. We've narrowed it down to the head, and popped off the cover, and used a feeler to record the following clearances.



The looser numbers seem to be tied to the cylinders that failed before. Tuner tells me the .012 are the tickers, and with a dowell, the noise seems to be more pronounced in that area. However, the tighter ones are the ones that are out of spec according to Service Manual tolerances. Cams are going to come out and we'll check that the lobes are the same all the way through.

noise is fast paced and starts around 2800rpm. Does not have the tap rate of a rod, or piston skirt, much faster. Almost sounds like someone knocking on a desk with their knuckles. If we listen around the engine bay, it sounds up higher, in the head. More pronounced when warm, only thing you hear on cold start are the forged pistons clacking around 1-2 minutes before they expand. Here are some fullsize images of the lobes, see if you see something unusual.



Exhaust front 2


Exhaust rear 2


Intake front 2


Intake rear 2


Tuner said "check rods and mains, oil pressure vs spec, maybe a weak spring in valvetrain, over-revved (only had it at 7000rpm so far), clearance between valve tip and underside of bucket, they also make an engine ear setup that clamps microphones to the engine and you listen to the channels with the headphones". Comprehensive plan of attack. One thing for sure, if head comes of, it's my second chance to do coolant reroute and a cam and I'm gonna take it.

The idea to measure lobes was to make sure they were the same size throughout, check for wear on the shaft itself. One of the lobes had a sand-grain size pit in the lobe, but on the smaller side, not the compression side. Look at Exhaust Front 2 image, far left lobe, you'll see the pit.


Shop 1 mistakes - installed cylinder 4 tube seal gasket upside down, according to tuner used wrong kind of sealant around valve cover (in addition to gasket), and greased my pipes, PCV grommet, etc. to make them easier to slide on/in, which was utterly retarded because all those things never sealed. and had to be taken apart and redone.

Shop 2 mistakes - not setting valve lash

[CleanNeon98]

Got some goodies in

Manifold


Super smooth collector


Smoothed inlets






There is also much more clearance than I imagined

[OutToWinPAHC]

shop one, forgot to replace my valvesprings

[CleanNeon98]

BMS had my head apart so that was their job, not my guys. I brought them a fully assembled head to inspect and rebuild. Also their bearing mixing may have cost me a crank. I'll know soon enough.

[CleanNeon98]

Sad update. The ticking we heard was not a valve, or valve lash, or anything in the head at all. Turns out it was my #1 bearing, and here it is! Like an episode of gold rush







The weird thing is that the oil pickup is in the middle of the pan, and it goes through cylinder 1 first, so it's down to contamination from something from the last rebuild, or improper clearancing on the bearings, or my crank was slightly not perfect, or a combo of the above.

With the bearing completely missing (just about) there is about 2mm of play where I can push the piston down, then push on the rod end and it goes back up. This caused the piston to also touch the head slighly, though nothing there looks damaged.

Lots of rechecking to do, and all I should need are bearings, a crank, a new oil cooler (goes between block and filter), lots of cleaning, and maybe a set of rods. Head build is an option at this point too, and I will change to a different cooling setup with a big radiator and a reroute to bring the coolant from back to front of engine, making cylinders 3 and 4 run much cooler. All of my exhast studs and nuts on the back were loose from the usual excess heat.

Manifold is also in mail to be White Lightninged. Meanwhile I've been busy

New sway bar, adjustable endlinks, and brakes


Sway bracket reinforcement pins the bar to the frame rails vs a <1/16" sheetmetal stock


New vs old bar

[DPancoast]

Wow man, I'm sorry to hear of your troubles. I too have run into a probably spun rod bearing and am waiting to take her apart and see the damage.

Best of luck.

[CleanNeon98]

****ty. All things considered, this is not a normal issue, but on custom engines, I feel there is just more probability for failure than with standard ones Mazda or Honda or whoever churn out thousands of at a time that have all the research behind them.

Heading to the shop this morning to remove rods pistons and crank and inspect

[Vr-4-Life]

pooor miata...

[CleanNeon98]

Needs a crank, two new sets of bearings, piston rings, a light hone, and one connecting rod. Not too too bad, though crappy regardless.

[Vr-4-Life]

Is the shot paying?

[CleanNeon98]

No, because nothing can be traced back to being their fault. If the tolerances were too tight, it would have broken much sooner. Probably what happened is an old piece of metal came and wrecked the bearing, since cylinder 1 gets fed first. There's a sandwich plate between the block and oil filter which I should have replaced, but it's not the definite cause either.

It's all pretty cheap parts however.

[11secdsm]

Damn dude, this sucks. Sorry to hear you're having more issues. Hopefully you get it fixed and everything works out. Good luck!

[CleanNeon98]

Did some valve work today, going to assemble head tomorrow and thursday. The porting was done by a shop, I just did the valve lapping









Wonder how leakdown will be after this. Also my tuner suggested possibly enlarging the overall head bowl, i.e. laying down headgasket, marker, and make the entire chamber in the head more round vs having the flat walls. We're going to port-match the intake manifold. Hopefully the exhaust one is a good match, but it's at Swaintech so I can't check. The shop used the gasket when porting so hope not to have to mess with the runners in the manifold.

[OutToWinPAHC]

who did that port

[CleanNeon98]

BMS. It's smoother than it looks, but I hope they didn't take too much out of the intake runners.

[CleanNeon98]

Heres the overlay on the manifold, cylinders 1-4. Manifold ports are 50mm x 30.5mm









Here's the overlay on the head, cylinder 1-4 same order. Manifold ports are 51mm x 31mm










I'm trying to decide whether to port the manifold out a little or if it's not important since it will be stepping from smaller into a larger area, not hitting a barrier as it would if it was going from large to small. Also debating whether I want to de-shroud the chamber around the valves, there are gains to be had but I feel I won't be able to do an even job with it.

Manifold ships back from Swaintech next week. Main bearings for re-assembly are back-ordered until at least mid August

[Elbeau]

I've always wanted a miata

[disturbedfan121]

hey alex, i just picked up a NB shell, have anything lying around you don't need?

[EatmyDust83]

Mazda makes some pretty cool rides.. Good luck man!