1992 Miata, LS1, then LS3 swapped

[mazpower]

The rear end is done!

Front diff mount bracket






Adapter piece to go from 3 bolt flange to 4 bolt


New beefy driveshaft, good for 500 hp




New axles...thicker and heavier than stock. Good for 400 hp


Gotta do something with that fuel line...its not touching the driveshaft but its too close.




I drove the car last night for the first time since November. I'll get video later!

[mazpower]

Well I finally got the car on the road! Had the exhaust finished Saturday, drove it home in the afternoon and started tuning the Haltech. I drove it to the street legal drags at Fontana yesterday, just to watch, and on the way home disaster struck. The engine developed a rod knock but made it home without throwing a rod. I discovered quickly that there were some slight engine issues, like a bit of blue smoke on acceleration that was worse when the engine wasn't all the way up to operating temps. So I figured I was gonna have to build the engine sooner than later...but not this quick.

So the engine comes back out this Friday and I'm tearing it down Saturday. Then its off to the machine shop Monday. If the crank is good, I'm going with Eagle H-beam rods, Mahle pistons, LS6 heads and a LS6 cam. If the crank is shot then I'm going the 383 stroker route with an Eagle crank and rods and Mahle pistons and the LS6 bits.

And holy shit was the car fast even with this junk engine... :shock:

[mazpower]

The teardown.









Damaged journals on 5 & 6.




Shot of 1 & 2. 1 was the worst, all the crank's journals were fucked. Definately gonna need a new crank. Stroker? :shock:






At this point its looking like the culprit was the ARP rod bolts I installed as a precautionary measure when I had the oil pan off, before the engine went in the car. I was told by my machinist that because of the LS1's cracked cap design, changing the bolts would be fine...others on LS1Tech have done the same thing with no issues. Looks like my luck just ran out there. Oh well, live and learn. The new setup will be nice.

[mazpower]

Started the engine build last weekend!

Ended up going with a 402 stroker kit with the LS1 block. That's 6.6 liters. Went with a Scat 4.000" crankshaft, Scat I-beam rods and Mahle forged pistons. The cam is a Texas Speed and Performance 228R, also have Comp Cams valve springs and moly pushrods. Heads are the stock LS1s ported out, freshened up with a valve job and brand new exhaust valves. Milled .040" off each head to bring the compression ratio to 11:1. Picked up a roller timing set and TSP ported LS6 oil pump.

On to the pictures!

Nice shiny bores!


Mic'ing the Scat 4.000" crankshaft...rod journals came out as 2.100", mains were 3.559". I ran the dial bore gauge on the rod & main bearings and everything was well within spec.


ARP main studs installed...


Pistons in!

[mazpower]

I think this whole build is cursed.

Ever since my machinist decided to go with the 402 instead of the 383 - and bored my stock block to 4" - I've been worried cause the general wisdom is a LS1 can't be bored to a size larger than 3.908". My machinist is a good dude and knows what he's doing but he hasn't done a lot of LSx engines. So we both start investigating. He says Scat told him that you can go to 4" on the LS1 and that's why he went with the 402 kit. Then he calls them back and they say "oh we meant with a LS2". So my machinist is getting me another LS1 block and I'm going with the 383. He's taking care of everything, the only penalty to me is time. I took him the short block last week and I should have the "new" short block back in a couple weeks. Maybe then I can finally get this build over with.

[mazpower]

Got the shortblock back from my machinist Saturday afternoon. By 4 am this morning, I'm an hour and a half away from starting her up. Only got about 3 hours of sleep before going to work this morning but it was all worth it.

All that's left is to hook up the PCV hoses, add coolant and oil, verify oil in the pushrods during cranking and starting her up. Just hoping that oil pressure is good...I got a gauge this time.

On to the pictures!

Saturday's progress.


Sunday, heads are on!


Greddy oil pressure sending unit - gonna make sure pressure is good this time


Coolant temp sending unit


Starting to look like an engine!


Haven't I been down this road before? After a long long day we're almost there!

[mazpower]

Update!

Drove the Miata up to Nipomo yesterday to get some more miles on the engine. It was about 600 miles round-trip.

I really need wider tires and LSD. Managed to get wheelspin in 4th earlier today, right before my friend took video...



This car is a hoot...

[mazpower]

Got protection for my head and a new tire. All set for a track day this Saturday.

[mazpower]

The Miata survived the track day! The engine ran awesome, the chassis still needs some work though. Here's some video if anyone wants to see.

In-car, with me driving...


Me filming while my friend tries to destroy my tires.

[mazpower]

300 lb-ft of torque at 2400 rpms is nice. 350+ lb-ft of torque from 2800 to 6000 is even nicer.



Definately not bad, but could be much better. I'll probably throw in a slightly larger cam when I put the ported 243s on there, see where that gets me.

I picked up 35 lb-ft of torque and 20ish hp by bringing up the timing to 26 at WOT, with the AFRs as close to a steady 12.7 as I could get it. There was a rich spot from 6k to 6500 that I couldn't clean up, I ran out of time. I'll fix that later with a street run. 3rd and 4th are even more of a blur now.

[mazpower]

Oh and here's the first run, compared to the best run. The bulk of the power increase was from bringing the WOT ignition timing from 21.5 to 26.

[mazpower]

Its been a little while since I updated this. I've got a LSD now, along with Tein Flex coilovers, oil cooler, and NT-01s in 225 on the rear. No more wheelspin in 2nd!

Anyways got more goodies for the Miata. Now I can stop, thanks to my friend Miguel at Wilwood!

Wilwood 4-piston "big brake" kit for the Miata. Using the "E" pads and standard rotors.

These definately are not enough for a V8 Miata.


MUCH larger.


Caliper mounted up.


Back shot of caliper to show mounting. Yeah my balljoints are kinda sad, balljoints & bushings are next on my list.

You have to shim the calipers to get them centered on the rotor for equal pad wear. I only had to use one of the shims per bolt, where the caliper bolts to the supplied bracket.


The only real issue I ran into was that the Rotas I run wouldn't clear the caliper. So I used a set of 5mm spacers on the front, problem solved.


The car stops AWESOME now. It doesn't take much to lock up the front with the little 615k's, with the NT-01s it should be perfect.

[mazpower]

Took it to Chuckwalla Raceway in Desert Center, CA. Managed to outrun a ZR1 on the straights. That's the Vette that I pass and he tries to keep up. Ran flawless other than some oil smoke as the temps came up, might be the rocker bolts not sealing correctly.

Both videos are the same timeframe, one is front view, one is back.

[mazpower]

I haven't updated this thread in a while, all sorts of new stuff for the Miata.

I got a hardtop for cheap. Painted it satin black and called it good.


Then I had a mini catastrophe. I let a good friend drive the car, who had driven it several times in the past, and during a hard 2nd to 3rd shift the passenger side diff mount stud ripped right out of the subframe.













I had the diff repaired and picked up another subframe and reinforced it.









Then I finally got to get started on the set of Z06 243 heads I'd been sitting on for a while. I cleaned up the ports a bit and had them flowed on a bench. At .550 lift, the ported heads flowed 286 cfm on the intake side, stock is 275 cfm. Exhaust was in the low 200s. In comparison, the 853 heads that were on the car before flowed 247 cfm. That's an increase of 39 cfm on the intake side and the mid lift flow is much higher in comparison as well. With the increased port volume - 210 cc versus 200 cc on the old heads - these heads are definately an improvement.





I had a full valve job done on the heads and took .015" off to maintain compression near 11.4:1 static. Since the heads were coming off, I decided to go with LS7 lifters. This helped tremendously with the "sewing machine" noise this engine has had since the beginning. Lifter preload was in the .040"s before, now its at .090".

Bores are still in great shape, pistons look new after 12k miles of HARD driving.



But then disaster struck. Trying to bolt down the new heads I pulled head bolt threads on both banks.



I picked up a Time-sert kit to repair the holes and get the engine back together with ARP head bolts.



With the new heads I have definately picked up horsepower but the bottom end torque is a little weaker now. As I haven't taken it to a dyno yet, the only measurement I could make was a freeway run with my friend's supercharged C5 Z06 making 636 rear wheel HP. We ran 50 - 150 and before the heads I would hang for about 3 seconds and he would pull by about 5 cars. Now with these heads I pull on him until I get into 5th, and he barely starts pulling away, to about 2 cars at 150.

[mazpower]

Updates! Lots has happened since I've been here last. Some good, some bad.

First let me give a HUGE thanks to my friend Brian at Indio Motor and Machine for helping me out with my latest build!

Last engine went boom at a local track day. 5th lap into the run, on a brief straight in between turns, loud boom at 6k RPM in 3rd gear, WOT, engine shuts down followed by an insane vibration until I press the clutch in. I pull off the track and check the car out once the tow truck comes out...no leaks, nothing looks broken. Once I'm in the pits, I find that one of the Haltech fuses are blown and the ECU isn't coming on. I fix that, crank the engine and see that the Haltech isn't reading RPMs...there's something wrong with the crank position sensor. This, along with the bad vibration, leads me to think something bad happened in the engine.

I get it back to my shop, pull the oil pan, and find this.



That's the big end of #7, still on the crank. It spun freely so it wasn't an oiling issue that broke it. I pulled the engine and stripped it down.



Fresh marks on the piston are from it hitting the head as the rod snapped.









Crank journals on #7 and #8 were in excellent condition.



The block and camshaft were trash. What ended up happening on the track was once the rod let go, schrapnel from the break hit the crankshaft position sensor and destroyed it, which blew the fuse for the Haltech and shut the engine down. This saved me more catastrophic damage like a hole in the block which most certainly would have led to an engine bay fire.



After consulting with my machinist and Scat - the manufacturer of the I-Beam rods and 4340 crank I'm running - it was determined that quench (the distance between the piston and head at TDC) was too tight and that an overrevving condition allowed piston to head contact, which in turn fatigued the rods until they broke. There were almost a dozen times where I mechanically overrevved the engine, trying to shift from 3rd to 4th and ended up in 2nd...thanks T56 shit shifter...anyways the datalogs in the ECU showed that I never went over 8500 but revving up there was obviously too much for the rods. The next engine needed to be better.

With the engine trashed, I needed a new setup. All that was salvagable was the crank, heads, and main studs. So I opted for a brand new LS3 block from GM using my Scat 4" crank, which gave a displacement of 415 cubic inches, or 6.8 liters, with 4.065" Mahle pistons, K1 H-Beam stroker rods, and a Texas Speed & Performance "Magic Stick 3" cam. MS3 is 237/242 duration int/exh at .050", .604/.609 int/exh lift, and 111 LSA. I needed new valves for the head as the #7 piston had hit the valves but not bent them, we didn't want to take any chances. LS6 valves are no longer available so I ended up with Ferrea SS valves. The heads were reworked for more flow at .300 to .550, picking up 20 cfm at .300 and .400 and flowing 295 cfm at .550. Another 15 FPS of flow were picked up across the board. We ended up with 11.7:1 compression when everything was said and done. A little high but nothing a tune can't adjust for.

Mahle pistons


Assembling the short block








Keyed SLP harmonic balancer with a ARP balancer bolt. This way I don't have to stress out setting trigger angle in the Haltech, as stock LS stuff doesn't have timing marks.


Shiny combustion chambers


A whole bunch of aluminum


And back in the car. Took 2 1/2 days of work to get running.


Finally with the car running again, I could install the AIM MXL Strada dash I had been sitting on since shortly after the engine died in February. First I needed to get the Haltech reading the vehicle speed sensor on the T56. I thought this was going to be an easy task, but no, nothing with this car is.

The VSS on the T56 is a reluctor. This means that it works like the trigger sensor on a RX-7, where you have a metal ring with teeth and a reluctor sensor...as the teeth pass the reluctor, the reluctor generates a sine wave which can be interpreted by the ECU as a trigger event. The Haltech only accepts a 5 volt square wave signal for speed...same goes for the speed input on the AIM MXL. They won't work with a sine wave. So I searched for a solution. There are converter boxes which transform the signal and even massage it to compensate for changes in tire diameter. They are $150 and above. Then there are reluctor adapters sold by Haltech and other companies that take a reluctor signal and convert it to a square wave. They are $200 and above. Lastly I could go the "fancy" route and have a trigger wheel machined to sit on one of my wheel hubs and use a hall-effect sensor, which natively creates a 5v square wave, to read speed. That would be $200-$300 and would be a lot of work.

For a while I've had a theory that a GM HEI ignition module could be used as a cheap reluctor adapter, but I never had an opportunity to try it until now. The HEI ignition module sits in the distributor of the car it came from, and processes the reluctor signal into a square wave for the ECU...it also controls timing and fires a coil but I wouldn't need all that. I went down to Auto Zone and bought a 7-pin ignition module for a whopping $27...it was for a '84 Chevy Camaro with the High Performance 305. I wired up the reluctor wires from the VSS to the inputs on the sensor, taking care to match polarity, and ran the tach output to a Timed Input wire for the Haltech, and hooked up power to the sensor. Grounding is done via the mounting holes for the sensor.

Basic wiring layout


I then got a usable signal in the Haltech and got an accurate speed reading, after messing around with the pulses per km value in the Haltech. I made an aluminum backing plate for the ignition module and put the thermal paste on it (the sensors tend to burn up if you're not careful, in a "stock" setting...I'm not running a coil off of it so it should run cooler but better safe then sorry) and bolted the whole thing down near the Haltech. Then I discovered a nagging issue with the E11v2 where it would read 400 km/h until you moved for the first time. This would really screw with my trip and main odometers, which was the reason for the MXL in the first place, so I ended up wiring the module to the MXL directly and everything works perfectly.

And damn do I love the MXL...one of the best investments for the car so far. It connects to the Haltech via the CAN bus and shows all of the sensors that the Haltech sees. You can configure 6 sensors to view in the MXL, 2 of which are displayed all the time while the other 4 are paired up and can quickly be toggled by pressing a button on the unit. It also has 6 warning lights that can be assigned to any sensor, customizable shift lights, current gear, rpm, and speed.

I gutted the stock gauges, leaving only the fuel gauge, and used a piece of aluminum to mount the MXL to. I screwed up on the hole for the fuel gauge and had to drill two so the whole gauge was visible. Version 2 of the cluster will be done in painted lexan with the "hole" over the fuel gauge left unpainted, along with a plastic ring placed between the gauge and lexan for a "stock" appearance. I'll also set up turn signal, high beam and warning lights.