Imported From Japan: Z20 Soarer Rebuild In Kentucky, Part 1
- August 18, 2014
- Posted by Bird
- Comments Off on Imported From Japan: Z20 Soarer Rebuild In Kentucky, Part 1
I can’t say I’m happy about the circumstances, but I recently spent a week working on our Soarer Aerocabin with my dad and grandfather. I’ve always lived several hundred to several thousand miles away, so it’s not something that I’ve had the chance to do very often. It made for a very memorable end to a stressful road trip.
Since our car wasn’t performing at it’s peak, we ended up needing some help along the way. From family and friends to total strangers, there’s no way we would have made it to our destination without them.
Notable mentions include our friends in Arizona, my dad and cousin for driving 5 hours through the night to pick us up from the final breakdown, my sister and her boyfriend for helping get the car unloaded at my grandparents, a guy in a W124 Mercedes who gave us some coolant somewhere in Oklahoma, and the friendly people at the Days Inn in West Memphis that gave us a great price on a room, and let us check in at 8am to sleep it off after we drove through the night to make it through Arkansas without overheating.
Before I get too far into the teardown story, I want to talk a little bit about the garage I’m working in. As a kid, my parents shipped me off to my grandparents for most of the summer. This is the garage where I oiled the chain on my bike or cleaned sparkplugs after I fouled them trying to cold start my three wheeler.
It’s pretty basic, just a pole barn really. It hasn’t changed much since I was a little kid. Dirt floor, metal siding, and posts made from trees felled on the property. Supposedly, the metal siding was leftover material from the Corvette factory.
I can’t say for sure if the siding really was from the Corvette factory, but the garage fridge was made by GM.
It has one really nice feature though, a steel beam that runs over the middle bay. Hanging from the beam is the differential hoist we’re using. It’s older than me…and there’s a good chance it’s older than my father too. It’s been used to pull a lot of motors…and skin at least one goat. That was a shock to see when I transferred their old 8mm films (why that was film worthy, I have no idea…) Although, I’m sure people have seen more disturbing things when they transferred their parents or grandparents old movies to dvd…
If you read our last post, you’ll know we have a blown head gasket. It’s a fairly common problem for the 7M motors. They tend to go around 75k miles and that’s right about where we are. They go out slowly, and ours was likely blown since we got the car. It made it all the way from LA to West Memphis only showing the faintest signs of a problem. A lot of people blame the factory head bolts for it, but I’m not so sure. The factory torqued them to 56ft-lbs, and later revised it in the service manual to be higher. While they may contribute, I think the real issue is the head gasket itself.
Stock it uses a composite design, and we’ll be switching to a full metal design to better cope with the cylinder pressures of a turbo engine. That and ARP head studs should solve the problem for good. Using a metal head gasket requires a different surface finish to the head and block to seal correctly, so that means full rebuild time. We already had Driftmotion rebuild our turbo, and I’ve replaced every wear item I can get my hands on…ball joints, bushings, shocks, brakes, etc. After this it’ll be completely mechanically restored.
Here you can see the extent of the damage on cylinder #6. The gasket’s metal ring deformed around the top of the cylinder, and eventually broke. Over time the gasket eroded to the point where exhaust gasses could make their way into the water jackets on the right. Initially it’s only a very slow leak of exhaust gas into the water jacket. This slowly puts ‘air’ in your cooling system diminishing it’s ability to cool. In our case, so slowly that you had to drive it a couple hours across the desert in July to have any real issues. When it gets worse, you’ll end up with coolant flowing into the cylinder when you turn the car off. Hence the water damage to the piston, and the unseen damage to the cylinder wall. Having coolant in the cylinder when the engine starts causes the oil film in the bore to be steam cleaned, and the piston rings eventually gouge the cylinder wall.
We actually had two leaks. This is cylinder #1. It’s not as bad as 6, but still blown out. We drove over 3000km’s with a tiny leak. We didn’t so much as stumble all the way from LA. It wasn’t until we reached Memphis that it started to show signs of low compression.
While we’ve got the car apart we decided to go ahead and rebuild the transmission and the rear differential. We noticed the input bearing was whining just a little on the highway, and the LSD I swapped in has a little more play than I would like. Every time I take a car apart I get a case of the ‘might as wells’…might as well do it now while it’s apart…
We took all the parts to the machine shop, placed another big order with Driftmotion, and then I left the car under the watchful eye of my grandparents German Shepherd, ‘Betty’. That was a couple weeks ago, and we’re back in Kentucky now to put it back together. It’s going to be a busy couple of weeks. As well as working on the Aerocabin, we have to finalize our dealership setup. We need to rent a building/lot, file a bunch of paperwork, and apply for our dealer’s license.
I’ll leave you with the timelapse of our tear down. If you want to see even more photos check out the gallery on BirdHasACamera.com. I hope everyone’s enjoying reading about our saga. It’s a lot of fun sharing it, and we can’t wait to be able to write about it as a licensed car dealer in the state of Kentucky.
This post originally appeared on Oppositelock.