Targa Miata
October 8, 2013 - And out it comes.
The L33-based 5.3 has done excellent work in this car, but it's done. A 6.2 LS3 with a big cam is going to be in charge now. There's nothing wrong with the 5.3, it just doesn't have the low-end grunt of the big motor. I'm going to take this down time to sort out a bunch of other little things on the car. You know, while I'm in there...
entry 1099 - tags: engine, 6.2
October 17, 2013 - Did you know the LS engines have really nice valve covers underneath all those coils?
I was thinking of relocating the coils to where they wouldn't see so much heat and vibration, and the look of these is only reinforcing that.
The old engine has been stripped of all (or most) of the parts that I need, and the new LS3 is partially torn down in preparation to receive them. I'll be doing a cam swap in this next week, which is why the coils are off.
entry 1101 - tags: engine, 6.2
October 24, 2013 - Cam swap time!
Working on this engine is almost like unwrapping a Christmas present - I'm discovering all sorts of new things. It's fun seeing how all the parts work together. You can look at diagrams and read about how the valvetrain works, but it's something else to actually peer down the cam bore and see the lifters tucked away. After so many years of Miata, Miata, Miata, seeing different solutions is interesting. It's also been a long time since I personally built an engine, I miss it.
The new "ASA" cam is now in place, with the timing chain back on and the front of the motor all buttoned up. All that remains is to flip the fuel rail over so the inlet is on the Miata-friendly side, change out the valve springs and install the new oil pan. Then I can start looking at putting everything back in the car.
By the way, the two dowels were supposed to help hold the lifters in place. I can't see how, I think that was a poor tech tip I found online. But they didn't do any harm.
entry 1102 - tags: engine, 6.2, cam
October 28, 2013 - Time to upgrade the valve springs.
As you may recall, I'm converting an LS376/480 crate engine into an LS376/525. According to GM Performance, the differences are the ASA cam and "higher rate" valve springs. So I called GMPP and got the part number for the new springs: 12586484.
Looking for these springs, I've found they've been superseded by spring 12625033. Fair enough, JEGS even sells the cam and springs as a kit so I picked one up. This handy little Comp Cams tool lets me swap out the springs easily without pulling the heads off.
entry 1103 - tags: engine, 6.2, cam
October 28, 2013 - Curious.
The new valve springs look exactly like the old ones. I checked further, and the 12625033 is the standard spring on an LS3. So I was swapping these out for nothing.
The older 12586484 part number was an LS6 spring, and they were typically yellow. Interestingly, they also have the exact same spring rates as the current LS3 spring, with the only difference being a max lift of 0.570" instead of 0.550".
Just for fun, I peeked under the valve covers of a true LS367/525 engine and what did I see? Blue springs.
Busted! GM doesn't actually change the springs on these engines anymore. Even if they did, the rates aren't any different. The max lift isn't an issue, as the 0.525" max lift is the same as that found on the 480 hp "hot cam".
So I wasted some time and money, but I learned something. Isn't that how it always goes?
entry 1104 - tags: engine, 6.2, cam, valve springs
November 6, 2013 - More preparation of the new engine.
The water pump has a couple of fittings for the heater. That's not needed here. When I installed the previous engine, I'd just installed rubber caps. These had a tendency to degrade over time, unfortunately. I never had one fail, but it was only a matter of time.
This time, I pulled off the fittings, tapped the holes and installed steel plugs. No failures here! If I ever decide to retrofit a heater, I can just screw in some brass nipples.
entry 1105 - tags: engine, 6.2
November 6, 2013 - More preventative maintenance.
These motor mounts see a lot of abuse, both from a rambunctious engine and heat. Mine were in pretty good shape, but I figured it was much easier to change them now than later. I'm taking other steps to help them last longer - you'll see more of that later.
entry 1106 - tags: engine, 6.2
November 6, 2013 - After a bunch of little individual jobs, adventures and solved problems, the engine is almost ready to install.
There's a new LS7 clutch and flywheel inside the transmission bellhousing. The oil pan came off again to check some clearances for another installation, then went back on. The new motor mounts are in, plus of course the cam and valve springs. I found a little squeak from where the rear cover had been just barely touching the crankshaft, and that's been sorted. The intake manifold insulation has been removed for hood clearance, and the fuel rail is flipped around to put the inlet where I want it. My dual oil pressure sensors are in place. A little bit of interference between the steering rack and the oil pan has been clearanced. We're almost there.
The only thing left is to reinstall the balancer, and for that I needed a special tool. The LS engines have been made by the millions over the last 16 years, but it's still a new and exotic engine according to most parts stores and tool manufacturers. It's almost impossible to find a balancer installation tool that is compatible. I had to build my own out of materials from McMaster Carr!
entry 1108 - tags: engine, 6.2
November 11, 2013 - This should take care of the heat problems I've been experiencing.
The headers and the first part of the exhaust system have been given a Swain "White Lightning" ceramic coating. It's a big step up from the locally applied "ceramic" I had done years ago. That particular coat lasted about as well as my high-temp paint job did. This is much thicker and stronger.
entry 1109 - tags: engine, 6.2, ceramic, exhaust
November 11, 2013 - Future failure avoidance.
Prior to installing the engine, I spent a fair bit of time going over the wiring harness and ensuring it was well restrained but accessible. In a couple of spots, I was unable to avoid wires making contact with the block. In those places, I made sure the wires were protected. They're not quite in contact, but with all the vibration to come they need something.
entry 1110 - tags: engine, 6.2, wiring
November 13, 2013 - And the engine is in!
This makes it sound a lot quicker than it really was, but after a bunch of fiddling about and checking I have it installed. And now comes the fun part - the wiring.
entry 1111 - tags: engine, 6.2
November 13, 2013 - Because the Targa Miata has a stripped out interior and no HVAC system, I've got some space that's not usually available on the street cars.
I've decided to mount the engine computer to the interior side of the firewall so it'll stay a bit cooler than being underhood. This means I have to pass some significant cables and connectors through the firewall. I don't have any wire grommets that size.
This panel is the answer. It has a clip on the backside to lock the bottom into place and the top is bolted down - it's upside down here. The wires are all centered in the grommet before the second half is riveted in place.
entry 1112 - tags: engine, 6.2, wiring
November 13, 2013 - Wiring fun!
This poor car has been through a lot. I stripped out the harness when I built it, and modified it for my purposes. When the original V8 conversion was done, the engine wiring came from a 2002 Firebird - but had already been installed in another Miata. Then I kept modifying and tweaking things, changing the harness around further. Wires for electric windows, cameras, dataloggers, extra sensors, goofy rear wings and the like. It's a bit of a mess.
With the new engine, I'm installing a standalone engine computer and wiring harness. I'm taking this opportunity to revisit all the wiring in the car, removing the leftover bits from the four cylinder build and that junkyard GM stuff. This under-dash harness will be greatly simplified, and the whole thing should be much more robust when I'm done.
It sure looks horrific when it's unwrapped and spread out! The junkyard GM parts are still wired in, and the new GM wires are also looped around like snakes in this shot. Fun stuff.
entry 1113 - tags: engine, 6.2, wiring
November 25, 2013 - Progress!
After hours of tracing wires, the harness is getting slimmer and more robust. It's pretty entertaining seeing the convoluted path taken by some of these. I've removed several big connectors and just streamlined the harness overall. The Coralba rally computer and Peltor intercom wiring is better now. It'll be a lot easier to maintain this setup. It still looks a bit frightening because the harness is unwrapped, but it will be all tied up and secured before the dash cover goes back on.
entry 1114 - tags: engine, 6.2, wiring
November 25, 2013 - Here's the real progress.
That's the Miata fusebox in stripped-down mode. What's missing? The main relay! Yes, the relay that failed and cost us the win at Targa Newfoundland. It gives me much glee to pull this little sucker out.
It's been replaced by the new GM Performance Parts wiring harness, with wiring that's built to run a big hefty V8 with eight hungry high-energy coils. The Miata relay was designed to handle a quarter of that.
As you can see, a number of other fuses and relays are also missing from the stock fuse box as they're simply not needed any more.
entry 1115 - tags: engine, 6.2, wiring
February 5, 2014 - Drive time!
Between snow storms, I took the car out for a quick spin down the road to see how the new engine feels and to make sure everything was healthy. The result? It feels very healthy indeed. The engine is a gem, it's got a wickedly sharp throttle response that just begs to be played with. It's reminiscent of the old high compression 2.0, but it's got some serious power and torque behind it. The car has the potential to be very hard on your neck. I didn't drive far, but it was a real promise of what to expect on future drives. The new 6.2 is a lot more potent than the old 5.3 was.
As for the keychain, it was a present from my friend Adam at Revlimiter.net. He does custom gauges and just started doing keychains, so he sent me a Martini one for the racer. I like it a lot. Thanks!
entry 1119 - tags: engine, 6.2, test, martini
March 27, 2014 - Dyno time!
Was all that engine swap work worthwhile? Short version: yes. The car spun the rollers at 466 hp and 432 lb-ft. Even better, it was making 300 ft-lb at 1700 rpm and more than 400 from 2900 to 6100. That's one healthy little car.
Here's the dyno run - the whine is from the tires on the rollers.

In other words, yes. It was well worth the work. The old 5.3 made decent power, but didn't have that massive amount of torque. On the road, it's just ridiculously eager, ready to rip forward at any moment. The 6.2 with the ASA cam has the same light feel as the old high compression 2.0 that I used to run, but with approximately three times as much power.
Wow, that puts it in perspective. Nearly three times as much power as the 2008 Targa Newfoundland spec.
entry 1120 - tags: dyno, ls3, 6.2