the GT86 learning journey

[tekno]

Greetings from Italy,

Eversince I first drove a GT86 back in 2015, I wanted one, but they were out of my budget at the time... so I bought a Miata instead , put a lot of miles on it, had great fun, made it a bit faster, had even more fun, put some more miles on it, but I still wanted an 86. So I decided to finally get one.But because I don't usually do things the way normal people do, I found a really cheap one with a damaged engine and since I knew I wanted to turbocharge it from the beginning I thought why should I pay the full market price for a working one when I can get it for half and build the engine a bit more reliable, hopefully...


And yes, I am obsessed with black cars...

[tekno]

And now the nasty bit....


It's pretty obvious that it suffered severely of oil starvation, having all that RTV blocking the pick up tube and oil passages contributed to that, and yes, it did go through the valve spring recall, thank you incompetent mechanics for this opportunity...

[tekno]

The build plan...

First of all, the car's purpose is to be a fun, relatively comfortable and fast Gran Tourer. Due to work I travel a lot through Europe, mostly by car and I always take my wife and dog with me, sometimes I take the van, which is not that fun to drive, sometimes the Miata, which is not the comfiest thing for two persons, a medium sized dog, and luggage. It will also see a track day or two per year, and a lot of spirited mountain driving, I live in a valley between the mountains .
The power goal of the build is nothing special, 350 whp would make me happy, but if I can not safely achieve that on 95 octane I'll probably settle for less, corn juice is not a option because it's not easy to find around here.
So to prevent detonation I ordered a set of 10.5:1 pistons. To keep the rods in the block I went for a set from Eagle. I also have to order a new crank and timing cover, but I'm still searching for the best deals, you guys in the US are lucky everything costs half or less than half there. Quick question, I've read on a thread around here, don't remember the OP, that he used a FA20DIT crank, is that a thing? are there any benefits to that, larger oil holes maybe? Turbocharger will probably be a GT2867 or a G25-550, haven't decided yet, exhaust and headers will be home built and the charge air cooling will be provided by original chinesium... Clutch will be custom built by the same local company that built the clutch for my Miata. For the fueling part I did not make other plans than "get larger capacity pump and injectors" will decide later on those.

The part that I'm most concerned now is gathering the right parts to build the engine, so to address the oiling problems the plan is to fit the typical stuff, oil cooler, baffle plate, killer b oil pick up tube, but I also want to mod the timing cover as @ETM_Shaman did. I'm kinda bummed out @solidsnake11 censored he's posts, I'm sure the info would have been very helpful for my build.

OK I bored you enough with my shopping list...

[soundman98]

lol, for a minute there, i thought you swapped the miata motor into the 86!


good luck on your project!

[tekno]

Originally Posted by soundman98

lol, for a minute there, i thought you swapped the miata motor into the 86!


good luck on your project!

nah, I wouldn't disrespect her like that...

[BrahmaBull1990]

Beautiful car!

[ermax]

If I recall the most significant change solidsnake11 did was add another feed but I can’t remember exactly where the source or destination was. This car’s weak link is #2 and #3 rod journals because they share a single feed from the crank that is just a hair bigger than the other two feeds. So what Solidsnake11 did was bore out the main feed that supplies 2 and 3 and modified the main bearings to match.

He also used a modified 2JZ pickup which has a WAY bigger screen than the FA20 and even the Killer B.

It really is a bummer he wiped his posts. He had some of the most interesting and informative posts on this form.

[soundman98]

Originally Posted by ermax

If I recall the most significant change solidsnake11 did was add another feed but I can’t remember exactly where the source or destination was. This car’s weak link is #2 and #3 rod journals because they share a single feed from the crank that is just a hair bigger than the other two feeds. So what Solidsnake11 did was bore out the main feed that supplies 2 and 3 and modified the main bearings to match.

He also used a modified 2JZ pickup which has a WAY bigger screen than the FA20 and even the Killer B.

It really is a bummer he wiped his posts. He had some of the most interesting and informative posts on this form.

Perhaps contact @ichitaka05 as he should be able to see the edited versions of the posts

[tekno]

Long time no update... a lot has happened, my 86 is now turbo and functional, but still note quite done as I'm on a base map for now...

After disassembling and thoroughly cleaning every bit till it was all silicone free (except the parts that had to be replaced), I started measuring everything up and arrived to the conclusion that the main tunnel journals were showing bore variations and it was also misaligned. Weirdly the #2 main journal, the one that looked like the bearing spun in it, had the smallest bore.
To those rebuilding engines after a failures, I would highly recommend to tear apart the VVT pulleys and clean them carefully, or buy new ones if they're in your budget. In one of the pics you can see a small silicone ball, I pulled that out from one of the oil holes in the center piece.

[tekno]

Next step was to order the needed parts and start looking for a machine shop that could perform a quality line bore and the rest of the machine work. Most of the shops I contacted in Italy (where I was located at the time), didn't want to touch it or quoted ridiculous prices. At the suggestion of a member on a FB group, I contacted a company in Latvia, called HCR (https://hcr.lv/), agreed on what needs to be done, and sent the block halves to them. Meanwhile, parts started showing up and I was eager to start the build process.

[tekno]

Among the rest of the prep work, I also did the timing cover/oil galley mods, as recommended by SolidSnake and others here. Three weeks later (shipping time included), my block came back, line bored, resurfaced, honed and with a straight 12mm main oil galley, all the work was done on CNC machines. I had engines spend more time in local machine shops for less work, so I was very pleased with the work HCR did.