1983 Toyota Starlet - H27A V6 Swap

Built some custom spark plug boots out of acetal (Delrin) and added them to Ford EDIS wires using new crimp terminals.

Here's a section view of the spark plug boots since the pics aren't very descriptive. Wire slides all the way through before crimping the terminal, then the second step in the boot bore retains the terminal.

Sorry for the lack of updates, everything has been small incremental changes or repairs leading up to the full 24 at HPR for the 24 Hours of Lemons High Plains Drifter. We've had the car out at the track for testing twice in preparation, and had small tuning, fiddling, and repairs to make, but the car seemed ready. 

Long story short, the car was a rocketship, had great power throughout the rev range at anywhere from half to full throttle, and we still had plenty of brake and tire to do 2:20 second laps here at HPR with no sweat.

#2 piston did not like it's new life and exited the opposite side of the block. 35 total laps this race. But we live to fight again some other day.

Vented block...Booo!

Fighting another day...Yay!

Love the Starlet.

Ouch sorry guys

Man, that sucks!  Any idea what caused that?

In reply to pres589 (djronnebaum) :

The current leading theory is that we had a headgasket slowly failing all weekend, it got super hot during testing on Friday morning and we had recurring overheating constantly after that. Thinking it finally got a big slug of water into #2 cylinder and hydrolocked violently.

Gotcha.  Really unfortunate.  Do you have a plan going forward?

In reply to pres589 (djronnebaum) :

Need to tear it down and sort out the chicken vs. egg scenario in regards to what failed first to cause the final rapid disassembly.

Not sure if our cooling system was flawed or inadequate, or if it was a fluke racing engine failure, or if there's some fatal design flaw with this engine family.

Ideally, if we can locate the failure point(s) and solve them for next time, then we'll stick with the Suzuki engine. Might pick up both a 2.7 and 2.5 from the junkyard and build a 2.7l bottom end with 2.5 top end/cams for better RPM potential.

Seems like #1 and #2 got in an argument; but no signs yet of the expected blown head gasket or other coolant ingress. No apparent oil starvation either? Further investigation needed.

Still tearing into the shortblock, still lacking any sort of obvious smoking gun. May just have to chalk it up to way too much nuclear-meltdown level overheating that weekend. Thinking a coolant reroute and custom thermostat is going to help as well as non-ebay electric fans. And coolant temp sensing that we can believe instead of ignoring due to inconsistent readings.

Anyway, how about some non-carnage related race weekend pics? Action pics are courtesy of the Lawsons with #3 - Flat Face Racing. 

Suppose I've never explained our logo in this thread - The firechicken-esque Screaming Moose is a vestigal remnant of the very first theme on our first Lemons car Volvo 940.

"BRAAAAAP"

Had to mutilate my irreplaceable stock Starlet hood in the name of engine cooling. These may or may not be in the right place for this car, they were modeled from work we did on the Volvo based on actual airflow testing of another racer's 740 street car.

An awesome note - we weren't the only Starlet at this race. We've been emailing Noah with team #2 Skid-do and actually gave him most of our stock drivetrain and spares over the last couple years. They had a blast with their mostly stock slow Starlet, just like we did our first weekend out, and they ran the whole time unlike us. 

As someone working on a "mostly stock slow starlet" how'd they do? 

Y'know, I'd rock a Screaming Moose shirt.

I love that track.  We won back to back races there like a decade ago in a mostly stock 12a carbed rx7.

Sooo much fun!

I see some of the same cars are still racing lemons out there!

Get that thing sorted!

P.s. fans usually block airflow above about 40 mph more than they help.  Proper ducting is where it's at!

That's not the first Suzuki 2.5/2.7 I've seen that ventilated the block. I bought a Tracker ZR2 for parts that had a rod saw thru the block, lower main girdle and the oil pan.

Kreb (Forum Supporter) said:

As someone working on a "mostly stock slow starlet" how'd they do? 

They placed 29th out of 69 entries in the September full 24hr at HPR, best lap time 2:43, 363 laps total (201 laps down from P1). Quite comparable to our results back when we ran our Starlet with stock drivetrain.

wvumtnbkr said:

P.s. fans usually block airflow above about 40 mph more than they help.  Proper ducting is where it's at!

Ducting is definitely in order. We're also going to modify the engine cooling plumbing and thermostat, we're not impressed with the location and type of thermostat for a performance application.

Fans will also work much better once we switch to some real Spal fans or similar, the crappy ebay units that came with the radiator claim far more flow and wattage than they are actually providing. They were definitely a restriction simply due to the fact they were vastly underperforming their claimed spec.

untchabl said:

That's not the first Suzuki 2.5/2.7 I've seen that ventilated the block. I bought a Tracker ZR2 for parts that had a rod saw thru the block, lower main girdle and the oil pan.

That's not what we want to hear, but also something we knew could be the case considering we're blazing a new trail in budget endurance racing with an engine that has no endurance racing provenance. We have two more specimens to sacrifice (one going in and one backup); if they can't make another race without carnage we'll be selecting a new engine platform.

looks like you had a rod bolt failure, the rod cap is bent the wrong way (inward) after the bolt broke and freed the end to seek it's own travel route it pounded the gap closed.

I did the same thing to a SBC aluminum rod at 9000 rpm, by the time it coasted to a stop, the only part left over that was useful on the next motor was the water pump.

invest in some ARP fasteners in the future.

love the car, more good racing fun, keep at it.

DC

Got a nice mention from Jay and Nick at 24 Hours of Lemons! I do feel a little attacked by their all-too-accurate analysis of our team mindset haha

In reply to newrider3 :

Haha, just watched it and came here! 

Well, I've fallen behind on mechanical updates on this post in the recent pre-race scramble, but here's the short version race recap of our 2022 BFE GP experience with 24 Hours of Lemons.

Loaded up and headed out Thursday evening, probably 4 hours late and with a not totally complete EWHAUL.

We took both the Starlet and the Volvo this time, and added two guest drivers. The Volvo suffered overheating front brakes all weekend but still squeaked into the top half at 33rd out of 71. 

The Starlet was running GREAT. Multiple drivers got laps in the 2:20-2:23 range, top speed around 102mph on the back straight.

Then, the H27a spit out a #1 piston, same as the last one.

Wrenched Saturday night, well into the early morning Sunday and then some more after sleep/breakfast. Got the crusty backup H25a running and back on track long enough to take the checkered flag and bring it home at 55th place. Earned us the Heroic Fix trophy.

Then, to really round out the weekend, EWHAUL puked a trans seal somewhere in the front pump area 30min out from the track and got an expensive tow home. The 460 was overheating when I pulled over too for reasons unknown.

Here's a little bit of catch-up from pre-race. 

Freshened up the last junkyard victim H27a, opened up the top ring gaps in the hopes of saving pistons (which didn't end up being the problem since we broke a piston anyway :p). It's always fun seeing the space magic timing chains.

While it was apart we threw in the cams from our backup H25a; they were noticably bigger in duration than the H27a versions while the heads and valves etc. were identical. We could definitely tell a major difference in the peppiness of the 2.7 at the track.

Also did a bunch of work to the cooling system to help with the massive overheating we had last fall. Switched to nice Spal fans, moved the radiator in front of the core support, and did a bunch of 'coolant reroute' work to ditch some of the factory plumbing and get the thermostat on the 'correct' end of the cooling system. I built a custom thermostat housing to allow us to use a regular small block thermostat, but ended up taking it out anyway because the system wasn't burping all the air out. We saw 85 deg C coolant temps max all weekend with outside temps between 85 and 90 deg F so it definitely worked out well.

These -16AN fittings were for the back of the cylinder heads, but I ended up needing to change them to a 90deg NPT elbow and JIC hydraulic fitting to fit between the heads and the firewall.

Made the thermostat housing out of Suzuki intake manifold parts that just happened to be the right size.

You can probably also see in that picture that we installed an EFI intake. I have always felt our fabricated short runner carb intake and Weber DGAS were restrictive and/or not runner-length-tuned very well. I wanted to install either a pair of side draft Weber DCOE or three downdraft Weber IDFs, but the cost for even chinese eBay copies was just too much compared to the intake/injectors and random Megasquirts we already had lying around.

The stock H27a intake manifold used a pair of crossovers, one for balance and one to mount a single throttle body. This stuff wouldn't fit under the hood and between the engine and firewall, so I sourced a pair of the smallest throttle bodies I could find (early 90's Corolla) and did a dual throttle setup. I made a pattern for the adapters in Solidworks and cut out a 16ga steel test piece, then made the real versions by hand out of 1/2" aluminum. Once again abusing woodworking tools on 6061 to great success.

Drill press makes a good tapping jig, if a little inconvenient when you have a freestanding drill press rather than a small benchtop unit :p

Used some socket universals and made a cam drive to link the throttle bodies together so that they can both return to idle redundantly using their own springs. 

did i miss it, or did you guys figure out why the second motor let go?

In reply to metty :

Broken #1 piston, again. It seems like they split in half right at the oil ring groove/drain holes. Pics of the debris a couple posts up.

In reply to newrider3 :

Yes, i saw that, i just didnt know if you had determined what caused 2x of them to break. seems like an odd failure if it didnt have valve to piston contact or some detonation 

Just read through this thread and love everything about it, albeit the junky failures. Please keep at it! 

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